From 3859a271a003aba01e45b85c9d8b355eb7bf25f9 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 28 Oct 2016 01:22:25 -0700 Subject: randstruct: Mark various structs for randomization This marks many critical kernel structures for randomization. These are structures that have been targeted in the past in security exploits, or contain functions pointers, pointers to function pointer tables, lists, workqueues, ref-counters, credentials, permissions, or are otherwise sensitive. This initial list was extracted from Brad Spengler/PaX Team's code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Left out of this list is task_struct, which requires special handling and will be covered in a subsequent patch. Signed-off-by: Kees Cook --- kernel/futex.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index 357348a6cf6b..5616511abf39 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -212,7 +212,7 @@ struct futex_pi_state { atomic_t refcount; union futex_key key; -}; +} __randomize_layout; /** * struct futex_q - The hashed futex queue entry, one per waiting task @@ -246,7 +246,7 @@ struct futex_q { struct rt_mutex_waiter *rt_waiter; union futex_key *requeue_pi_key; u32 bitset; -}; +} __randomize_layout; static const struct futex_q futex_q_init = { /* list gets initialized in queue_me()*/ -- cgit v1.2.3 From 610467270fb368584b74567edd21c8cc5104490f Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 8 Jul 2017 07:17:02 -0400 Subject: cgroup: don't call migration methods if there are no tasks to migrate Subsystem migration methods shouldn't be called for empty migrations. cgroup_migrate_execute() implements this guarantee by bailing early if there are no source css_sets. This used to be correct before a79a908fd2b0 ("cgroup: introduce cgroup namespaces"), but no longer since the commit because css_sets can stay pinned without tasks in them. This caused cgroup_migrate_execute() call into cpuset migration methods with an empty cgroup_taskset. cpuset migration methods correctly assume that cgroup_taskset_first() never returns NULL; however, due to the bug, it can, leading to the following oops. Unable to handle kernel paging request for data at address 0x00000960 Faulting instruction address: 0xc0000000001d6868 Oops: Kernel access of bad area, sig: 11 [#1] ... CPU: 14 PID: 16947 Comm: kworker/14:0 Tainted: G W 4.12.0-rc4-next-20170609 #2 Workqueue: events cpuset_hotplug_workfn task: c00000000ca60580 task.stack: c00000000c728000 NIP: c0000000001d6868 LR: c0000000001d6858 CTR: c0000000001d6810 REGS: c00000000c72b720 TRAP: 0300 Tainted: GW (4.12.0-rc4-next-20170609) MSR: 8000000000009033 CR: 44722422 XER: 20000000 CFAR: c000000000008710 DAR: 0000000000000960 DSISR: 40000000 SOFTE: 1 GPR00: c0000000001d6858 c00000000c72b9a0 c000000001536e00 0000000000000000 GPR04: c00000000c72b9c0 0000000000000000 c00000000c72bad0 c000000766367678 GPR08: c000000766366d10 c00000000c72b958 c000000001736e00 0000000000000000 GPR12: c0000000001d6810 c00000000e749300 c000000000123ef8 c000000775af4180 GPR16: 0000000000000000 0000000000000000 c00000075480e9c0 c00000075480e9e0 GPR20: c00000075480e8c0 0000000000000001 0000000000000000 c00000000c72ba20 GPR24: c00000000c72baa0 c00000000c72bac0 c000000001407248 c00000000c72ba20 GPR28: c00000000141fc80 c00000000c72bac0 c00000000c6bc790 0000000000000000 NIP [c0000000001d6868] cpuset_can_attach+0x58/0x1b0 LR [c0000000001d6858] cpuset_can_attach+0x48/0x1b0 Call Trace: [c00000000c72b9a0] [c0000000001d6858] cpuset_can_attach+0x48/0x1b0 (unreliable) [c00000000c72ba00] [c0000000001cbe80] cgroup_migrate_execute+0xb0/0x450 [c00000000c72ba80] [c0000000001d3754] cgroup_transfer_tasks+0x1c4/0x360 [c00000000c72bba0] [c0000000001d923c] cpuset_hotplug_workfn+0x86c/0xa20 [c00000000c72bca0] [c00000000011aa44] process_one_work+0x1e4/0x580 [c00000000c72bd30] [c00000000011ae78] worker_thread+0x98/0x5c0 [c00000000c72bdc0] [c000000000124058] kthread+0x168/0x1b0 [c00000000c72be30] [c00000000000b2e8] ret_from_kernel_thread+0x5c/0x74 Instruction dump: f821ffa1 7c7d1b78 60000000 60000000 38810020 7fa3eb78 3f42ffed 4bff4c25 60000000 3b5a0448 3d420020 eb610020 7f43d378 e9290000 f92af200 ---[ end trace dcaaf98fb36d9e64 ]--- This patch fixes the bug by adding an explicit nr_tasks counter to cgroup_taskset and skipping calling the migration methods if the counter is zero. While at it, remove the now spurious check on no source css_sets. Signed-off-by: Tejun Heo Reported-and-tested-by: Abdul Haleem Cc: Roman Gushchin Cc: stable@vger.kernel.org # v4.6+ Fixes: a79a908fd2b0 ("cgroup: introduce cgroup namespaces") Link: http://lkml.kernel.org/r/1497266622.15415.39.camel@abdul.in.ibm.com --- kernel/cgroup/cgroup-internal.h | 3 +++ kernel/cgroup/cgroup.c | 58 ++++++++++++++++++++++------------------- 2 files changed, 34 insertions(+), 27 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h index 793565c05742..8b4c3c2f2509 100644 --- a/kernel/cgroup/cgroup-internal.h +++ b/kernel/cgroup/cgroup-internal.h @@ -33,6 +33,9 @@ struct cgroup_taskset { struct list_head src_csets; struct list_head dst_csets; + /* the number of tasks in the set */ + int nr_tasks; + /* the subsys currently being processed */ int ssid; diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 620794a20a33..cc53111072d8 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -2006,6 +2006,8 @@ static void cgroup_migrate_add_task(struct task_struct *task, if (!cset->mg_src_cgrp) return; + mgctx->tset.nr_tasks++; + list_move_tail(&task->cg_list, &cset->mg_tasks); if (list_empty(&cset->mg_node)) list_add_tail(&cset->mg_node, @@ -2094,21 +2096,19 @@ static int cgroup_migrate_execute(struct cgroup_mgctx *mgctx) struct css_set *cset, *tmp_cset; int ssid, failed_ssid, ret; - /* methods shouldn't be called if no task is actually migrating */ - if (list_empty(&tset->src_csets)) - return 0; - /* check that we can legitimately attach to the cgroup */ - do_each_subsys_mask(ss, ssid, mgctx->ss_mask) { - if (ss->can_attach) { - tset->ssid = ssid; - ret = ss->can_attach(tset); - if (ret) { - failed_ssid = ssid; - goto out_cancel_attach; + if (tset->nr_tasks) { + do_each_subsys_mask(ss, ssid, mgctx->ss_mask) { + if (ss->can_attach) { + tset->ssid = ssid; + ret = ss->can_attach(tset); + if (ret) { + failed_ssid = ssid; + goto out_cancel_attach; + } } - } - } while_each_subsys_mask(); + } while_each_subsys_mask(); + } /* * Now that we're guaranteed success, proceed to move all tasks to @@ -2137,25 +2137,29 @@ static int cgroup_migrate_execute(struct cgroup_mgctx *mgctx) */ tset->csets = &tset->dst_csets; - do_each_subsys_mask(ss, ssid, mgctx->ss_mask) { - if (ss->attach) { - tset->ssid = ssid; - ss->attach(tset); - } - } while_each_subsys_mask(); + if (tset->nr_tasks) { + do_each_subsys_mask(ss, ssid, mgctx->ss_mask) { + if (ss->attach) { + tset->ssid = ssid; + ss->attach(tset); + } + } while_each_subsys_mask(); + } ret = 0; goto out_release_tset; out_cancel_attach: - do_each_subsys_mask(ss, ssid, mgctx->ss_mask) { - if (ssid == failed_ssid) - break; - if (ss->cancel_attach) { - tset->ssid = ssid; - ss->cancel_attach(tset); - } - } while_each_subsys_mask(); + if (tset->nr_tasks) { + do_each_subsys_mask(ss, ssid, mgctx->ss_mask) { + if (ssid == failed_ssid) + break; + if (ss->cancel_attach) { + tset->ssid = ssid; + ss->cancel_attach(tset); + } + } while_each_subsys_mask(); + } out_release_tset: spin_lock_irq(&css_set_lock); list_splice_init(&tset->dst_csets, &tset->src_csets); -- cgit v1.2.3 From 6a8a75f3235724c5941a33e287b2f98966ad14c5 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 11 Jul 2017 10:56:54 +0200 Subject: Revert "perf/core: Drop kernel samples even though :u is specified" This reverts commit cc1582c231ea041fbc68861dfaf957eaf902b829. This commit introduced a regression that broke rr-project, which uses sampling events to receive a signal on overflow (but does not care about the contents of the sample). These signals are critical to the correct operation of rr. There's been some back and forth about how to fix it - but to not keep applications in limbo queue up a revert. Reported-by: Kyle Huey Acked-by: Kyle Huey Acked-by: Peter Zijlstra Cc: Jin Yao Cc: Vince Weaver Cc: Linus Torvalds Cc: Will Deacon Cc: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Stephane Eranian Cc: Namhyung Kim Cc: Jiri Olsa Cc: Link: http://lkml.kernel.org/r/20170628105600.GC5981@leverpostej Signed-off-by: Ingo Molnar --- kernel/events/core.c | 21 --------------------- 1 file changed, 21 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 4d2c32f98482..9747e422ab20 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7308,21 +7308,6 @@ int perf_event_account_interrupt(struct perf_event *event) return __perf_event_account_interrupt(event, 1); } -static bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs) -{ - /* - * Due to interrupt latency (AKA "skid"), we may enter the - * kernel before taking an overflow, even if the PMU is only - * counting user events. - * To avoid leaking information to userspace, we must always - * reject kernel samples when exclude_kernel is set. - */ - if (event->attr.exclude_kernel && !user_mode(regs)) - return false; - - return true; -} - /* * Generic event overflow handling, sampling. */ @@ -7343,12 +7328,6 @@ static int __perf_event_overflow(struct perf_event *event, ret = __perf_event_account_interrupt(event, throttle); - /* - * For security, drop the skid kernel samples if necessary. - */ - if (!sample_is_allowed(event, regs)) - return ret; - /* * XXX event_limit might not quite work as expected on inherited * events -- cgit v1.2.3 From dea1d0f5f1284e3defee4b8484d9fc230686cd42 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 11 Jul 2017 22:06:24 +0200 Subject: smp/hotplug: Replace BUG_ON and react useful The move of the unpark functions to the control thread moved the BUG_ON() there as well. While it made some sense in the idle thread of the upcoming CPU, it's bogus to crash the control thread on the already online CPU, especially as the function has a return value and the callsite is prepared to handle an error return. Replace it with a WARN_ON_ONCE() and return a proper error code. Fixes: 9cd4f1a4e7a8 ("smp/hotplug: Move unparking of percpu threads to the control CPU") Rightfully-ranted-at-by: Linux Torvalds Signed-off-by: Thomas Gleixner --- kernel/cpu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/cpu.c b/kernel/cpu.c index ab860453841d..eee033134262 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -279,7 +279,8 @@ static int bringup_wait_for_ap(unsigned int cpu) /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ wait_for_completion(&st->done); - BUG_ON(!cpu_online(cpu)); + if (WARN_ON_ONCE((!cpu_online(cpu)))) + return -ECANCELED; /* Unpark the stopper thread and the hotplug thread of the target cpu */ stop_machine_unpark(cpu); -- cgit v1.2.3 From 19d39a3810e7032f311ef83effdac40339b9d022 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 11 Jul 2017 23:41:52 +0200 Subject: genirq: Keep chip buslock across irq_request/release_resources() Moving the irq_request/release_resources() callbacks out of the spinlocked, irq disabled and bus locked region, unearthed an interesting abuse of the irq_bus_lock/irq_bus_sync_unlock() callbacks. The OMAP GPIO driver does merily power management inside of them. The irq_request_resources() callback of this GPIO irqchip calls a function which reads a GPIO register. That read aborts now because the clock of the GPIO block is not magically enabled via the irq_bus_lock() callback. Move the callbacks under the bus lock again to prevent this. In the free_irq() path this requires to drop the bus_lock before calling synchronize_irq() and reaquiring it before calling the irq_release_resources() callback. The bus lock can't be held because: 1) The data which has been changed between bus_lock/un_lock is cached in the irq chip driver private data and needs to go out to the irq chip via the slow bus (usually SPI or I2C) before calling synchronize_irq(). That's the reason why this bus_lock/unlock magic exists in the first place, as you cannot do SPI/I2C transactions while holding desc->lock with interrupts disabled. 2) synchronize_irq() will actually deadlock, if there is a handler on flight. These chips use threaded handlers for obvious reasons, as they allow to do SPI/I2C communication. When the threaded handler returns then bus_lock needs to be taken in irq_finalize_oneshot() as we need to talk to the actual irq chip once more. After that the threaded handler is marked done, which makes synchronize_irq() return. So if we hold bus_lock accross the synchronize_irq() call, the handler cannot mark itself done because it blocks on the bus lock. That in turn makes synchronize_irq() wait forever on the threaded handler to complete.... Add the missing unlock of desc->request_mutex in the error path of __free_irq() and add a bunch of comments to explain the locking and protection rules. Fixes: 46e48e257360 ("genirq: Move irq resource handling out of spinlocked region") Reported-and-tested-by: Sebastian Reichel Reported-and-tested-by: Tony Lindgren Reported-by: Pavel Machek Signed-off-by: Thomas Gleixner Not-longer-ranted-at-by: Linus Torvalds Cc: Linus Walleij Cc: Grygorii Strashko Cc: Marc Zyngier --- kernel/irq/manage.c | 63 ++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 53 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 5624b2dd6b58..1d1a5b945ab4 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1090,6 +1090,16 @@ setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary) /* * Internal function to register an irqaction - typically used to * allocate special interrupts that are part of the architecture. + * + * Locking rules: + * + * desc->request_mutex Provides serialization against a concurrent free_irq() + * chip_bus_lock Provides serialization for slow bus operations + * desc->lock Provides serialization against hard interrupts + * + * chip_bus_lock and desc->lock are sufficient for all other management and + * interrupt related functions. desc->request_mutex solely serializes + * request/free_irq(). */ static int __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) @@ -1167,20 +1177,35 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE) new->flags &= ~IRQF_ONESHOT; + /* + * Protects against a concurrent __free_irq() call which might wait + * for synchronize_irq() to complete without holding the optional + * chip bus lock and desc->lock. + */ mutex_lock(&desc->request_mutex); + + /* + * Acquire bus lock as the irq_request_resources() callback below + * might rely on the serialization or the magic power management + * functions which are abusing the irq_bus_lock() callback, + */ + chip_bus_lock(desc); + + /* First installed action requests resources. */ if (!desc->action) { ret = irq_request_resources(desc); if (ret) { pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n", new->name, irq, desc->irq_data.chip->name); - goto out_mutex; + goto out_bus_unlock; } } - chip_bus_lock(desc); - /* * The following block of code has to be executed atomically + * protected against a concurrent interrupt and any of the other + * management calls which are not serialized via + * desc->request_mutex or the optional bus lock. */ raw_spin_lock_irqsave(&desc->lock, flags); old_ptr = &desc->action; @@ -1286,10 +1311,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) ret = __irq_set_trigger(desc, new->flags & IRQF_TRIGGER_MASK); - if (ret) { - irq_release_resources(desc); + if (ret) goto out_unlock; - } } desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \ @@ -1385,12 +1408,10 @@ mismatch: out_unlock: raw_spin_unlock_irqrestore(&desc->lock, flags); - chip_bus_sync_unlock(desc); - if (!desc->action) irq_release_resources(desc); - -out_mutex: +out_bus_unlock: + chip_bus_sync_unlock(desc); mutex_unlock(&desc->request_mutex); out_thread: @@ -1472,6 +1493,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) WARN(1, "Trying to free already-free IRQ %d\n", irq); raw_spin_unlock_irqrestore(&desc->lock, flags); chip_bus_sync_unlock(desc); + mutex_unlock(&desc->request_mutex); return NULL; } @@ -1498,6 +1520,20 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) #endif raw_spin_unlock_irqrestore(&desc->lock, flags); + /* + * Drop bus_lock here so the changes which were done in the chip + * callbacks above are synced out to the irq chips which hang + * behind a slow bus (I2C, SPI) before calling synchronize_irq(). + * + * Aside of that the bus_lock can also be taken from the threaded + * handler in irq_finalize_oneshot() which results in a deadlock + * because synchronize_irq() would wait forever for the thread to + * complete, which is blocked on the bus lock. + * + * The still held desc->request_mutex() protects against a + * concurrent request_irq() of this irq so the release of resources + * and timing data is properly serialized. + */ chip_bus_sync_unlock(desc); unregister_handler_proc(irq, action); @@ -1530,8 +1566,15 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) } } + /* Last action releases resources */ if (!desc->action) { + /* + * Reaquire bus lock as irq_release_resources() might + * require it to deallocate resources over the slow bus. + */ + chip_bus_lock(desc); irq_release_resources(desc); + chip_bus_sync_unlock(desc); irq_remove_timings(desc); } -- cgit v1.2.3 From 69f0d429c413fe96db2c187475cebcc6e3a8c7f5 Mon Sep 17 00:00:00 2001 From: Alex Shi Date: Thu, 13 Jul 2017 14:18:24 +0800 Subject: locking/rtmutex: Remove unnecessary priority adjustment We don't need to adjust priority before adding a new pi_waiter, the priority only needs to be updated after pi_waiter change or task priority change. Steven Rostedt pointed out: "Interesting, I did some git mining and this was added with the original entry of the rtmutex.c (23f78d4a03c5). Looking at even that version, I don't see the purpose of adjusting the task prio here. It is done before anything changes in the task." Signed-off-by: Alex Shi Reviewed-by: Steven Rostedt (VMware) Acked-by: Peter Zijlstra (Intel) Cc: Juri Lelli Cc: Linus Torvalds Cc: Mathieu Poirier Cc: Sebastian Siewior Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1499926704-28841-1-git-send-email-alex.shi@linaro.org [ Enhance the changelog. ] Signed-off-by: Ingo Molnar --- kernel/locking/rtmutex.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel') diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 78069895032a..649dc9d3951a 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -963,7 +963,6 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock, return -EDEADLK; raw_spin_lock(&task->pi_lock); - rt_mutex_adjust_prio(task); waiter->task = task; waiter->lock = lock; waiter->prio = task->prio; -- cgit v1.2.3 From 0e4097c3354e2f5a5ad8affd9dc7f7f7d00bb6b9 Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Sun, 9 Jul 2017 00:40:28 -0700 Subject: sched/cputime: Don't use smp_processor_id() in preemptible context Recent kernels trigger this warning: BUG: using smp_processor_id() in preemptible [00000000] code: 99-trinity/181 caller is debug_smp_processor_id+0x17/0x19 CPU: 0 PID: 181 Comm: 99-trinity Not tainted 4.12.0-01059-g2a42eb9 #1 Call Trace: dump_stack+0x82/0xb8 check_preemption_disabled() debug_smp_processor_id() vtime_delta() task_cputime() thread_group_cputime() thread_group_cputime_adjusted() wait_consider_task() do_wait() SYSC_wait4() do_syscall_64() entry_SYSCALL64_slow_path() As Frederic pointed out: | Although those sched_clock_cpu() things seem to only matter when the | sched_clock() is unstable. And that stability is a condition for nohz_full | to work anyway. So probably sched_clock() alone would be enough. This patch fixes it by replacing sched_clock_cpu() with sched_clock() to avoid calling smp_processor_id() in a preemptible context. Reported-by: Xiaolong Ye Signed-off-by: Wanpeng Li Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Luiz Capitulino Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1499586028-7402-1-git-send-email-wanpeng.li@hotmail.com [ Prettified the changelog. ] Signed-off-by: Ingo Molnar --- kernel/sched/cputime.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index 6e3ea4ac1bda..14d2dbf97c53 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -683,7 +683,7 @@ static u64 vtime_delta(struct vtime *vtime) { unsigned long long clock; - clock = sched_clock_cpu(smp_processor_id()); + clock = sched_clock(); if (clock < vtime->starttime) return 0; @@ -814,7 +814,7 @@ void arch_vtime_task_switch(struct task_struct *prev) write_seqcount_begin(&vtime->seqcount); vtime->state = VTIME_SYS; - vtime->starttime = sched_clock_cpu(smp_processor_id()); + vtime->starttime = sched_clock(); write_seqcount_end(&vtime->seqcount); } @@ -826,7 +826,7 @@ void vtime_init_idle(struct task_struct *t, int cpu) local_irq_save(flags); write_seqcount_begin(&vtime->seqcount); vtime->state = VTIME_SYS; - vtime->starttime = sched_clock_cpu(cpu); + vtime->starttime = sched_clock(); write_seqcount_end(&vtime->seqcount); local_irq_restore(flags); } -- cgit v1.2.3 From 193be41e33168a3a06eb9d356d9e39c69de161d2 Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Wed, 12 Jul 2017 19:24:29 -0700 Subject: sched/deadline: Fix confusing comments about selection of top pi-waiter This comment in the code is incomplete, and I believe it begs a definition of dl_boosted to make sense of the condition that follows. Rewrite the comment and also rearrange the condition that follows to reflect the first condition "we have a top pi-waiter which is a SCHED_DEADLINE task" in that order. Also fix a typo that follows. Signed-off-by: Joel Fernandes Reviewed-by: Daniel Bristot de Oliveira Acked-by: Juri Lelli Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170713022429.10307-1-joelaf@google.com Signed-off-by: Ingo Molnar --- kernel/sched/deadline.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index a84299f44b5d..755bd3f1a1a9 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1392,17 +1392,19 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags) struct sched_dl_entity *pi_se = &p->dl; /* - * Use the scheduling parameters of the top pi-waiter - * task if we have one and its (absolute) deadline is - * smaller than our one... OTW we keep our runtime and - * deadline. + * Use the scheduling parameters of the top pi-waiter task if: + * - we have a top pi-waiter which is a SCHED_DEADLINE task AND + * - our dl_boosted is set (i.e. the pi-waiter's (absolute) deadline is + * smaller than our deadline OR we are a !SCHED_DEADLINE task getting + * boosted due to a SCHED_DEADLINE pi-waiter). + * Otherwise we keep our runtime and deadline. */ - if (pi_task && p->dl.dl_boosted && dl_prio(pi_task->normal_prio)) { + if (pi_task && dl_prio(pi_task->normal_prio) && p->dl.dl_boosted) { pi_se = &pi_task->dl; } else if (!dl_prio(p->normal_prio)) { /* * Special case in which we have a !SCHED_DEADLINE task - * that is going to be deboosted, but exceedes its + * that is going to be deboosted, but exceeds its * runtime while doing so. No point in replenishing * it, as it's going to return back to its original * scheduling class after this. -- cgit v1.2.3 From 44ee454670122a959112caaa7aad86d8cacab1ff Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 9 Jul 2017 10:50:14 -0400 Subject: semtimedop(): move compat to native ... and finally kill the sodding compat_convert_timespec() Signed-off-by: Al Viro --- kernel/compat.c | 23 ----------------------- 1 file changed, 23 deletions(-) (limited to 'kernel') diff --git a/kernel/compat.c b/kernel/compat.c index 6f0a0e723a06..772e038d04d9 100644 --- a/kernel/compat.c +++ b/kernel/compat.c @@ -200,29 +200,6 @@ int compat_put_timespec(const struct timespec *ts, void __user *uts) } EXPORT_SYMBOL_GPL(compat_put_timespec); -int compat_convert_timespec(struct timespec __user **kts, - const void __user *cts) -{ - struct timespec ts; - struct timespec __user *uts; - - if (!cts || COMPAT_USE_64BIT_TIME) { - *kts = (struct timespec __user *)cts; - return 0; - } - - uts = compat_alloc_user_space(sizeof(ts)); - if (!uts) - return -EFAULT; - if (compat_get_timespec(&ts, cts)) - return -EFAULT; - if (copy_to_user(uts, &ts, sizeof(ts))) - return -EFAULT; - - *kts = uts; - return 0; -} - int get_compat_itimerval(struct itimerval *o, const struct compat_itimerval __user *i) { struct compat_itimerval v32; -- cgit v1.2.3 From 88e033e326307831922e34e7de0d694274dcc1c7 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 16 Jul 2017 21:40:30 -0400 Subject: cgroup: remove now unused list_head @pending in cgroup_apply_cftypes() Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 620794a20a33..4f02b5edd82c 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3230,7 +3230,6 @@ restart: static int cgroup_apply_cftypes(struct cftype *cfts, bool is_add) { - LIST_HEAD(pending); struct cgroup_subsys *ss = cfts[0].ss; struct cgroup *root = &ss->root->cgrp; struct cgroup_subsys_state *css; -- cgit v1.2.3 From 788b950c62e06b02278a0fd380e1a0667996ce3c Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 16 Jul 2017 21:43:33 -0400 Subject: cgroup: distinguish local and children populated states cgrp->populated_cnt counts both local (the cgroup's populated css_sets) and subtree proper (populated children) so that it's only zero when the whole subtree, including self, is empty. This patch splits the counter into two so that local and children populated states are tracked separately. It allows finer-grained tests on the state of the hierarchy which will be used to replace css_set walking local populated test. Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 37 +++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 4f02b5edd82c..5fe2644cd0f3 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -587,39 +587,44 @@ static bool css_set_populated(struct css_set *cset) } /** - * cgroup_update_populated - updated populated count of a cgroup + * cgroup_update_populated - update the populated count of a cgroup * @cgrp: the target cgroup * @populated: inc or dec populated count * * One of the css_sets associated with @cgrp is either getting its first - * task or losing the last. Update @cgrp->populated_cnt accordingly. The - * count is propagated towards root so that a given cgroup's populated_cnt - * is zero iff the cgroup and all its descendants don't contain any tasks. + * task or losing the last. Update @cgrp->nr_populated_* accordingly. The + * count is propagated towards root so that a given cgroup's + * nr_populated_children is zero iff none of its descendants contain any + * tasks. * - * @cgrp's interface file "cgroup.populated" is zero if - * @cgrp->populated_cnt is zero and 1 otherwise. When @cgrp->populated_cnt - * changes from or to zero, userland is notified that the content of the - * interface file has changed. This can be used to detect when @cgrp and - * its descendants become populated or empty. + * @cgrp's interface file "cgroup.populated" is zero if both + * @cgrp->nr_populated_csets and @cgrp->nr_populated_children are zero and + * 1 otherwise. When the sum changes from or to zero, userland is notified + * that the content of the interface file has changed. This can be used to + * detect when @cgrp and its descendants become populated or empty. */ static void cgroup_update_populated(struct cgroup *cgrp, bool populated) { + struct cgroup *child = NULL; + int adj = populated ? 1 : -1; + lockdep_assert_held(&css_set_lock); do { - bool trigger; + bool was_populated = cgroup_is_populated(cgrp); - if (populated) - trigger = !cgrp->populated_cnt++; + if (!child) + cgrp->nr_populated_csets += adj; else - trigger = !--cgrp->populated_cnt; + cgrp->nr_populated_children += adj; - if (!trigger) + if (was_populated == cgroup_is_populated(cgrp)) break; cgroup1_check_for_release(cgrp); cgroup_file_notify(&cgrp->events_file); + child = cgrp; cgrp = cgroup_parent(cgrp); } while (cgrp); } @@ -630,7 +635,7 @@ static void cgroup_update_populated(struct cgroup *cgrp, bool populated) * @populated: whether @cset is populated or depopulated * * @cset is either getting the first task or losing the last. Update the - * ->populated_cnt of all associated cgroups accordingly. + * populated counters of all associated cgroups accordingly. */ static void css_set_update_populated(struct css_set *cset, bool populated) { @@ -653,7 +658,7 @@ static void css_set_update_populated(struct css_set *cset, bool populated) * css_set, @from_cset can be NULL. If @task is being disassociated * instead of moved, @to_cset can be NULL. * - * This function automatically handles populated_cnt updates and + * This function automatically handles populated counter updates and * css_task_iter adjustments but the caller is responsible for managing * @from_cset and @to_cset's reference counts. */ -- cgit v1.2.3 From 27f26753f8c063c4cd2f06318e977ae136574b28 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 16 Jul 2017 21:44:18 -0400 Subject: cgroup: replace css_set walking populated test with testing cgrp->nr_populated_csets Implement trivial cgroup_has_tasks() which tests whether cgrp->nr_populated_csets is zero and replace the explicit local populated test in cgroup_subtree_control(). This simplifies the code and cgroup_has_tasks() will be used in more places later. Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 30 ++++++++---------------------- 1 file changed, 8 insertions(+), 22 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 5fe2644cd0f3..d5b62313c753 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -325,6 +325,11 @@ static struct cgroup *cgroup_parent(struct cgroup *cgrp) return NULL; } +static bool cgroup_has_tasks(struct cgroup *cgrp) +{ + return cgrp->nr_populated_csets; +} + /* subsystems visibly enabled on a cgroup */ static u16 cgroup_control(struct cgroup *cgrp) { @@ -2971,28 +2976,9 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, * Except for the root, subtree_control must be zero for a cgroup * with tasks so that child cgroups don't compete against tasks. */ - if (enable && cgroup_parent(cgrp)) { - struct cgrp_cset_link *link; - - /* - * Because namespaces pin csets too, @cgrp->cset_links - * might not be empty even when @cgrp is empty. Walk and - * verify each cset. - */ - spin_lock_irq(&css_set_lock); - - ret = 0; - list_for_each_entry(link, &cgrp->cset_links, cset_link) { - if (css_set_populated(link->cset)) { - ret = -EBUSY; - break; - } - } - - spin_unlock_irq(&css_set_lock); - - if (ret) - goto out_unlock; + if (enable && cgroup_parent(cgrp) && cgroup_has_tasks(cgrp)) { + ret = -EBUSY; + goto out_unlock; } /* save and update control masks and prepare csses */ -- cgit v1.2.3 From 546ac1ffb70d25b56c1126940e5ec639c4dd7413 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 17 Jul 2017 09:28:56 -0700 Subject: bpf: add devmap, a map for storing net device references Device map (devmap) is a BPF map, primarily useful for networking applications, that uses a key to lookup a reference to a netdevice. The map provides a clean way for BPF programs to build virtual port to physical port maps. Additionally, it provides a scoping function for the redirect action itself allowing multiple optimizations. Future patches will leverage the map to provide batching at the XDP layer. Another optimization/feature, that is not yet implemented, would be to support multiple netdevices per key to support efficient multicast and broadcast support. Signed-off-by: John Fastabend Acked-by: Daniel Borkmann Acked-by: Jesper Dangaard Brouer Signed-off-by: David S. Miller --- kernel/bpf/Makefile | 3 + kernel/bpf/devmap.c | 264 ++++++++++++++++++++++++++++++++++++++++++++++++++ kernel/bpf/verifier.c | 8 ++ 3 files changed, 275 insertions(+) create mode 100644 kernel/bpf/devmap.c (limited to 'kernel') diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index e1e5e658f2db..48e92705be59 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -2,6 +2,9 @@ obj-y := core.o obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o +ifeq ($(CONFIG_NET),y) +obj-$(CONFIG_BPF_SYSCALL) += devmap.o +endif ifeq ($(CONFIG_PERF_EVENTS),y) obj-$(CONFIG_BPF_SYSCALL) += stackmap.o endif diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c new file mode 100644 index 000000000000..1a878356bd37 --- /dev/null +++ b/kernel/bpf/devmap.c @@ -0,0 +1,264 @@ +/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ + +/* Devmaps primary use is as a backend map for XDP BPF helper call + * bpf_redirect_map(). Because XDP is mostly concerned with performance we + * spent some effort to ensure the datapath with redirect maps does not use + * any locking. This is a quick note on the details. + * + * We have three possible paths to get into the devmap control plane bpf + * syscalls, bpf programs, and driver side xmit/flush operations. A bpf syscall + * will invoke an update, delete, or lookup operation. To ensure updates and + * deletes appear atomic from the datapath side xchg() is used to modify the + * netdev_map array. Then because the datapath does a lookup into the netdev_map + * array (read-only) from an RCU critical section we use call_rcu() to wait for + * an rcu grace period before free'ing the old data structures. This ensures the + * datapath always has a valid copy. However, the datapath does a "flush" + * operation that pushes any pending packets in the driver outside the RCU + * critical section. Each bpf_dtab_netdev tracks these pending operations using + * an atomic per-cpu bitmap. The bpf_dtab_netdev object will not be destroyed + * until all bits are cleared indicating outstanding flush operations have + * completed. + * + * BPF syscalls may race with BPF program calls on any of the update, delete + * or lookup operations. As noted above the xchg() operation also keep the + * netdev_map consistent in this case. From the devmap side BPF programs + * calling into these operations are the same as multiple user space threads + * making system calls. + */ +#include +#include +#include +#include +#include "percpu_freelist.h" +#include "bpf_lru_list.h" +#include "map_in_map.h" + +struct bpf_dtab_netdev { + struct net_device *dev; + int key; + struct rcu_head rcu; + struct bpf_dtab *dtab; +}; + +struct bpf_dtab { + struct bpf_map map; + struct bpf_dtab_netdev **netdev_map; +}; + +static struct bpf_map *dev_map_alloc(union bpf_attr *attr) +{ + struct bpf_dtab *dtab; + u64 cost; + int err; + + /* check sanity of attributes */ + if (attr->max_entries == 0 || attr->key_size != 4 || + attr->value_size != 4 || attr->map_flags) + return ERR_PTR(-EINVAL); + + /* if value_size is bigger, the user space won't be able to + * access the elements. + */ + if (attr->value_size > KMALLOC_MAX_SIZE) + return ERR_PTR(-E2BIG); + + dtab = kzalloc(sizeof(*dtab), GFP_USER); + if (!dtab) + return ERR_PTR(-ENOMEM); + + /* mandatory map attributes */ + dtab->map.map_type = attr->map_type; + dtab->map.key_size = attr->key_size; + dtab->map.value_size = attr->value_size; + dtab->map.max_entries = attr->max_entries; + dtab->map.map_flags = attr->map_flags; + + err = -ENOMEM; + + /* make sure page count doesn't overflow */ + cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *); + if (cost >= U32_MAX - PAGE_SIZE) + goto free_dtab; + + dtab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; + + /* if map size is larger than memlock limit, reject it early */ + err = bpf_map_precharge_memlock(dtab->map.pages); + if (err) + goto free_dtab; + + dtab->netdev_map = bpf_map_area_alloc(dtab->map.max_entries * + sizeof(struct bpf_dtab_netdev *)); + if (!dtab->netdev_map) + goto free_dtab; + + return &dtab->map; + +free_dtab: + kfree(dtab); + return ERR_PTR(err); +} + +static void dev_map_free(struct bpf_map *map) +{ + struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); + int i; + + /* At this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, + * so the programs (can be more than one that used this map) were + * disconnected from events. Wait for outstanding critical sections in + * these programs to complete. The rcu critical section only guarantees + * no further reads against netdev_map. It does __not__ ensure pending + * flush operations (if any) are complete. + */ + synchronize_rcu(); + + for (i = 0; i < dtab->map.max_entries; i++) { + struct bpf_dtab_netdev *dev; + + dev = dtab->netdev_map[i]; + if (!dev) + continue; + + dev_put(dev->dev); + kfree(dev); + } + + /* At this point bpf program is detached and all pending operations + * _must_ be complete + */ + bpf_map_area_free(dtab->netdev_map); + kfree(dtab); +} + +static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key) +{ + struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); + u32 index = key ? *(u32 *)key : U32_MAX; + u32 *next = (u32 *)next_key; + + if (index >= dtab->map.max_entries) { + *next = 0; + return 0; + } + + if (index == dtab->map.max_entries - 1) + return -ENOENT; + + *next = index + 1; + return 0; +} + +/* rcu_read_lock (from syscall and BPF contexts) ensures that if a delete and/or + * update happens in parallel here a dev_put wont happen until after reading the + * ifindex. + */ +static void *dev_map_lookup_elem(struct bpf_map *map, void *key) +{ + struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); + struct bpf_dtab_netdev *dev; + u32 i = *(u32 *)key; + + if (i >= map->max_entries) + return NULL; + + dev = READ_ONCE(dtab->netdev_map[i]); + return dev ? &dev->dev->ifindex : NULL; +} + +static void __dev_map_entry_free(struct rcu_head *rcu) +{ + struct bpf_dtab_netdev *old_dev; + + old_dev = container_of(rcu, struct bpf_dtab_netdev, rcu); + dev_put(old_dev->dev); + kfree(old_dev); +} + +static int dev_map_delete_elem(struct bpf_map *map, void *key) +{ + struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); + struct bpf_dtab_netdev *old_dev; + int k = *(u32 *)key; + + if (k >= map->max_entries) + return -EINVAL; + + /* Use synchronize_rcu() here to ensure any rcu critical sections + * have completed, but this does not guarantee a flush has happened + * yet. Because driver side rcu_read_lock/unlock only protects the + * running XDP program. However, for pending flush operations the + * dev and ctx are stored in another per cpu map. And additionally, + * the driver tear down ensures all soft irqs are complete before + * removing the net device in the case of dev_put equals zero. + */ + old_dev = xchg(&dtab->netdev_map[k], NULL); + if (old_dev) + call_rcu(&old_dev->rcu, __dev_map_entry_free); + return 0; +} + +static int dev_map_update_elem(struct bpf_map *map, void *key, void *value, + u64 map_flags) +{ + struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); + struct net *net = current->nsproxy->net_ns; + struct bpf_dtab_netdev *dev, *old_dev; + u32 i = *(u32 *)key; + u32 ifindex = *(u32 *)value; + + if (unlikely(map_flags > BPF_EXIST)) + return -EINVAL; + + if (unlikely(i >= dtab->map.max_entries)) + return -E2BIG; + + if (unlikely(map_flags == BPF_NOEXIST)) + return -EEXIST; + + if (!ifindex) { + dev = NULL; + } else { + dev = kmalloc(sizeof(*dev), GFP_ATOMIC | __GFP_NOWARN); + if (!dev) + return -ENOMEM; + + dev->dev = dev_get_by_index(net, ifindex); + if (!dev->dev) { + kfree(dev); + return -EINVAL; + } + + dev->key = i; + dev->dtab = dtab; + } + + /* Use call_rcu() here to ensure rcu critical sections have completed + * Remembering the driver side flush operation will happen before the + * net device is removed. + */ + old_dev = xchg(&dtab->netdev_map[i], dev); + if (old_dev) + call_rcu(&old_dev->rcu, __dev_map_entry_free); + + return 0; +} + +const struct bpf_map_ops dev_map_ops = { + .map_alloc = dev_map_alloc, + .map_free = dev_map_free, + .map_get_next_key = dev_map_get_next_key, + .map_lookup_elem = dev_map_lookup_elem, + .map_update_elem = dev_map_update_elem, + .map_delete_elem = dev_map_delete_elem, +}; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6a86723c5b64..4016774d5cca 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1276,6 +1276,14 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id) func_id != BPF_FUNC_current_task_under_cgroup) goto error; break; + /* devmap returns a pointer to a live net_device ifindex that we cannot + * allow to be modified from bpf side. So do not allow lookup elements + * for now. + */ + case BPF_MAP_TYPE_DEVMAP: + if (func_id == BPF_FUNC_map_lookup_elem) + goto error; + break; case BPF_MAP_TYPE_ARRAY_OF_MAPS: case BPF_MAP_TYPE_HASH_OF_MAPS: if (func_id != BPF_FUNC_map_lookup_elem) -- cgit v1.2.3 From 97f91a7cf04ff605845c20948b8a80e54cbd3376 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 17 Jul 2017 09:29:18 -0700 Subject: bpf: add bpf_redirect_map helper routine BPF programs can use the devmap with a bpf_redirect_map() helper routine to forward packets to netdevice in map. Signed-off-by: John Fastabend Signed-off-by: Jesper Dangaard Brouer Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/devmap.c | 12 ++++++++++++ kernel/bpf/verifier.c | 4 ++++ 2 files changed, 16 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 1a878356bd37..36dc13deb2e1 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -159,6 +159,18 @@ static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key) return 0; } +struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key) +{ + struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); + struct bpf_dtab_netdev *dev; + + if (key >= map->max_entries) + return NULL; + + dev = READ_ONCE(dtab->netdev_map[key]); + return dev ? dev->dev : NULL; +} + /* rcu_read_lock (from syscall and BPF contexts) ensures that if a delete and/or * update happens in parallel here a dev_put wont happen until after reading the * ifindex. diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 4016774d5cca..df05d65f0c87 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1312,6 +1312,10 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id) if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY) goto error; break; + case BPF_FUNC_redirect_map: + if (map->map_type != BPF_MAP_TYPE_DEVMAP) + goto error; + break; default: break; } -- cgit v1.2.3 From 11393cc9b9be2a1f61559e6fb9c27bc8fa20b1ff Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 17 Jul 2017 09:29:40 -0700 Subject: xdp: Add batching support to redirect map For performance reasons we want to avoid updating the tail pointer in the driver tx ring as much as possible. To accomplish this we add batching support to the redirect path in XDP. This adds another ndo op "xdp_flush" that is used to inform the driver that it should bump the tail pointer on the TX ring. Signed-off-by: John Fastabend Signed-off-by: Jesper Dangaard Brouer Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/devmap.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 83 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 36dc13deb2e1..b2ef04a1c86a 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -53,6 +53,7 @@ struct bpf_dtab_netdev { struct bpf_dtab { struct bpf_map map; struct bpf_dtab_netdev **netdev_map; + unsigned long int __percpu *flush_needed; }; static struct bpf_map *dev_map_alloc(union bpf_attr *attr) @@ -87,6 +88,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) /* make sure page count doesn't overflow */ cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *); + cost += BITS_TO_LONGS(attr->max_entries) * sizeof(unsigned long); if (cost >= U32_MAX - PAGE_SIZE) goto free_dtab; @@ -97,6 +99,14 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) if (err) goto free_dtab; + /* A per cpu bitfield with a bit per possible net device */ + dtab->flush_needed = __alloc_percpu( + BITS_TO_LONGS(attr->max_entries) * + sizeof(unsigned long), + __alignof__(unsigned long)); + if (!dtab->flush_needed) + goto free_dtab; + dtab->netdev_map = bpf_map_area_alloc(dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *)); if (!dtab->netdev_map) @@ -105,6 +115,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) return &dtab->map; free_dtab: + free_percpu(dtab->flush_needed); kfree(dtab); return ERR_PTR(err); } @@ -112,7 +123,7 @@ free_dtab: static void dev_map_free(struct bpf_map *map) { struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); - int i; + int i, cpu; /* At this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, * so the programs (can be more than one that used this map) were @@ -123,6 +134,18 @@ static void dev_map_free(struct bpf_map *map) */ synchronize_rcu(); + /* To ensure all pending flush operations have completed wait for flush + * bitmap to indicate all flush_needed bits to be zero on _all_ cpus. + * Because the above synchronize_rcu() ensures the map is disconnected + * from the program we can assume no new bits will be set. + */ + for_each_online_cpu(cpu) { + unsigned long *bitmap = per_cpu_ptr(dtab->flush_needed, cpu); + + while (!bitmap_empty(bitmap, dtab->map.max_entries)) + cpu_relax(); + } + for (i = 0; i < dtab->map.max_entries; i++) { struct bpf_dtab_netdev *dev; @@ -137,6 +160,7 @@ static void dev_map_free(struct bpf_map *map) /* At this point bpf program is detached and all pending operations * _must_ be complete */ + free_percpu(dtab->flush_needed); bpf_map_area_free(dtab->netdev_map); kfree(dtab); } @@ -159,6 +183,14 @@ static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key) return 0; } +void __dev_map_insert_ctx(struct bpf_map *map, u32 key) +{ + struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); + unsigned long *bitmap = this_cpu_ptr(dtab->flush_needed); + + __set_bit(key, bitmap); +} + struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key) { struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); @@ -171,6 +203,39 @@ struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key) return dev ? dev->dev : NULL; } +/* __dev_map_flush is called from xdp_do_flush_map() which _must_ be signaled + * from the driver before returning from its napi->poll() routine. The poll() + * routine is called either from busy_poll context or net_rx_action signaled + * from NET_RX_SOFTIRQ. Either way the poll routine must complete before the + * net device can be torn down. On devmap tear down we ensure the ctx bitmap + * is zeroed before completing to ensure all flush operations have completed. + */ +void __dev_map_flush(struct bpf_map *map) +{ + struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); + unsigned long *bitmap = this_cpu_ptr(dtab->flush_needed); + u32 bit; + + for_each_set_bit(bit, bitmap, map->max_entries) { + struct bpf_dtab_netdev *dev = READ_ONCE(dtab->netdev_map[bit]); + struct net_device *netdev; + + /* This is possible if the dev entry is removed by user space + * between xdp redirect and flush op. + */ + if (unlikely(!dev)) + continue; + + netdev = dev->dev; + + __clear_bit(bit, bitmap); + if (unlikely(!netdev || !netdev->netdev_ops->ndo_xdp_flush)) + continue; + + netdev->netdev_ops->ndo_xdp_flush(netdev); + } +} + /* rcu_read_lock (from syscall and BPF contexts) ensures that if a delete and/or * update happens in parallel here a dev_put wont happen until after reading the * ifindex. @@ -188,11 +253,28 @@ static void *dev_map_lookup_elem(struct bpf_map *map, void *key) return dev ? &dev->dev->ifindex : NULL; } +static void dev_map_flush_old(struct bpf_dtab_netdev *old_dev) +{ + if (old_dev->dev->netdev_ops->ndo_xdp_flush) { + struct net_device *fl = old_dev->dev; + unsigned long *bitmap; + int cpu; + + for_each_online_cpu(cpu) { + bitmap = per_cpu_ptr(old_dev->dtab->flush_needed, cpu); + __clear_bit(old_dev->key, bitmap); + + fl->netdev_ops->ndo_xdp_flush(old_dev->dev); + } + } +} + static void __dev_map_entry_free(struct rcu_head *rcu) { struct bpf_dtab_netdev *old_dev; old_dev = container_of(rcu, struct bpf_dtab_netdev, rcu); + dev_map_flush_old(old_dev); dev_put(old_dev->dev); kfree(old_dev); } -- cgit v1.2.3 From 2ddf71e23cc246e95af72a6deed67b4a50a7b81c Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 17 Jul 2017 09:30:02 -0700 Subject: net: add notifier hooks for devmap bpf map The BPF map devmap holds a refcnt on the net_device structure when it is in the map. We need to do this to ensure on driver unload we don't lose a dev reference. However, its not very convenient to have to manually unload the map when destroying a net device so add notifier handlers to do the cleanup automatically. But this creates a race between update/destroy BPF syscall and programs and the unregister netdev hook. Unfortunately, the best I could come up with is either to live with requiring manual removal of net devices from the map before removing the net device OR to add a mutex in devmap to ensure the map is not modified while we are removing a device. The fallout also requires that BPF programs no longer update/delete the map from the BPF program side because the mutex may sleep and this can not be done from inside an rcu critical section. This is not a real problem though because I have not come up with any use cases where this is actually useful in practice. If/when we come up with a compelling user for this we may need to revisit this. Signed-off-by: John Fastabend Acked-by: Daniel Borkmann Acked-by: Jesper Dangaard Brouer Signed-off-by: David S. Miller --- kernel/bpf/devmap.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++ kernel/bpf/verifier.c | 2 +- 2 files changed, 74 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index b2ef04a1c86a..899364d097f5 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -34,6 +34,17 @@ * netdev_map consistent in this case. From the devmap side BPF programs * calling into these operations are the same as multiple user space threads * making system calls. + * + * Finally, any of the above may race with a netdev_unregister notifier. The + * unregister notifier must search for net devices in the map structure that + * contain a reference to the net device and remove them. This is a two step + * process (a) dereference the bpf_dtab_netdev object in netdev_map and (b) + * check to see if the ifindex is the same as the net_device being removed. + * Unfortunately, the xchg() operations do not protect against this. To avoid + * potentially removing incorrect objects the dev_map_list_mutex protects + * conflicting netdev unregister and BPF syscall operations. Updates and + * deletes from a BPF program (done in rcu critical section) are blocked + * because of this mutex. */ #include #include @@ -54,8 +65,12 @@ struct bpf_dtab { struct bpf_map map; struct bpf_dtab_netdev **netdev_map; unsigned long int __percpu *flush_needed; + struct list_head list; }; +static DEFINE_MUTEX(dev_map_list_mutex); +static LIST_HEAD(dev_map_list); + static struct bpf_map *dev_map_alloc(union bpf_attr *attr) { struct bpf_dtab *dtab; @@ -112,6 +127,9 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) if (!dtab->netdev_map) goto free_dtab; + mutex_lock(&dev_map_list_mutex); + list_add_tail(&dtab->list, &dev_map_list); + mutex_unlock(&dev_map_list_mutex); return &dtab->map; free_dtab: @@ -146,6 +164,11 @@ static void dev_map_free(struct bpf_map *map) cpu_relax(); } + /* Although we should no longer have datapath or bpf syscall operations + * at this point we we can still race with netdev notifier, hence the + * lock. + */ + mutex_lock(&dev_map_list_mutex); for (i = 0; i < dtab->map.max_entries; i++) { struct bpf_dtab_netdev *dev; @@ -160,6 +183,8 @@ static void dev_map_free(struct bpf_map *map) /* At this point bpf program is detached and all pending operations * _must_ be complete */ + list_del(&dtab->list); + mutex_unlock(&dev_map_list_mutex); free_percpu(dtab->flush_needed); bpf_map_area_free(dtab->netdev_map); kfree(dtab); @@ -296,9 +321,11 @@ static int dev_map_delete_elem(struct bpf_map *map, void *key) * the driver tear down ensures all soft irqs are complete before * removing the net device in the case of dev_put equals zero. */ + mutex_lock(&dev_map_list_mutex); old_dev = xchg(&dtab->netdev_map[k], NULL); if (old_dev) call_rcu(&old_dev->rcu, __dev_map_entry_free); + mutex_unlock(&dev_map_list_mutex); return 0; } @@ -341,9 +368,11 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value, * Remembering the driver side flush operation will happen before the * net device is removed. */ + mutex_lock(&dev_map_list_mutex); old_dev = xchg(&dtab->netdev_map[i], dev); if (old_dev) call_rcu(&old_dev->rcu, __dev_map_entry_free); + mutex_unlock(&dev_map_list_mutex); return 0; } @@ -356,3 +385,47 @@ const struct bpf_map_ops dev_map_ops = { .map_update_elem = dev_map_update_elem, .map_delete_elem = dev_map_delete_elem, }; + +static int dev_map_notification(struct notifier_block *notifier, + ulong event, void *ptr) +{ + struct net_device *netdev = netdev_notifier_info_to_dev(ptr); + struct bpf_dtab *dtab; + int i; + + switch (event) { + case NETDEV_UNREGISTER: + mutex_lock(&dev_map_list_mutex); + list_for_each_entry(dtab, &dev_map_list, list) { + for (i = 0; i < dtab->map.max_entries; i++) { + struct bpf_dtab_netdev *dev; + + dev = dtab->netdev_map[i]; + if (!dev || + dev->dev->ifindex != netdev->ifindex) + continue; + dev = xchg(&dtab->netdev_map[i], NULL); + if (dev) + call_rcu(&dev->rcu, + __dev_map_entry_free); + } + } + mutex_unlock(&dev_map_list_mutex); + break; + default: + break; + } + return NOTIFY_OK; +} + +static struct notifier_block dev_map_notifier = { + .notifier_call = dev_map_notification, +}; + +static int __init dev_map_init(void) +{ + register_netdevice_notifier(&dev_map_notifier); + return 0; +} + +subsys_initcall(dev_map_init); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index df05d65f0c87..ebe9b38ff522 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1281,7 +1281,7 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id) * for now. */ case BPF_MAP_TYPE_DEVMAP: - if (func_id == BPF_FUNC_map_lookup_elem) + if (func_id != BPF_FUNC_redirect_map) goto error; break; case BPF_MAP_TYPE_ARRAY_OF_MAPS: -- cgit v1.2.3 From a696712c3dd54eb58d2c5a807b4aaa27782d80d6 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 17 Jul 2017 19:47:02 +0200 Subject: genirq/PM: Properly pretend disabled state when force resuming interrupts Interrupts with the IRQF_FORCE_RESUME flag set have also the IRQF_NO_SUSPEND flag set. They are not disabled in the suspend path, but must be forcefully resumed. That's used by XEN to keep IPIs enabled beyond the suspension of device irqs. Force resume works by pretending that the interrupt was disabled and then calling __irq_enable(). Incrementing the disabled depth counter was enough to do that, but with the recent changes which use state flags to avoid unnecessary hardware access, this is not longer sufficient. If the state flags are not set, then the hardware callbacks are not invoked and the interrupt line stays disabled in "hardware". Set the disabled and masked state when pretending that an interrupt got disabled by suspend. Fixes: bf22ff45bed6 ("genirq: Avoid unnecessary low level irq function calls") Suggested-by: Thomas Gleixner Signed-off-by: Juergen Gross Signed-off-by: Thomas Gleixner Cc: xen-devel@lists.xenproject.org Cc: boris.ostrovsky@oracle.com Link: http://lkml.kernel.org/r/20170717174703.4603-2-jgross@suse.com --- kernel/irq/chip.c | 10 ---------- kernel/irq/internals.h | 10 ++++++++++ kernel/irq/pm.c | 2 ++ 3 files changed, 12 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index d171bc57e1e0..a3cc37c0c85e 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -170,21 +170,11 @@ static void irq_state_clr_disabled(struct irq_desc *desc) irqd_clear(&desc->irq_data, IRQD_IRQ_DISABLED); } -static void irq_state_set_disabled(struct irq_desc *desc) -{ - irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED); -} - static void irq_state_clr_masked(struct irq_desc *desc) { irqd_clear(&desc->irq_data, IRQD_IRQ_MASKED); } -static void irq_state_set_masked(struct irq_desc *desc) -{ - irqd_set(&desc->irq_data, IRQD_IRQ_MASKED); -} - static void irq_state_clr_started(struct irq_desc *desc) { irqd_clear(&desc->irq_data, IRQD_IRQ_STARTED); diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index dbfba9933ed2..a2c48058354c 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -227,6 +227,16 @@ static inline bool irqd_has_set(struct irq_data *d, unsigned int mask) return __irqd_to_state(d) & mask; } +static inline void irq_state_set_disabled(struct irq_desc *desc) +{ + irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED); +} + +static inline void irq_state_set_masked(struct irq_desc *desc) +{ + irqd_set(&desc->irq_data, IRQD_IRQ_MASKED); +} + #undef __irqd_to_state static inline void kstat_incr_irqs_this_cpu(struct irq_desc *desc) diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c index cea1de0161f1..6bd9b58429cc 100644 --- a/kernel/irq/pm.c +++ b/kernel/irq/pm.c @@ -149,6 +149,8 @@ static void resume_irq(struct irq_desc *desc) /* Pretend that it got disabled ! */ desc->depth++; + irq_state_set_disabled(desc); + irq_state_set_masked(desc); resume: desc->istate &= ~IRQS_SUSPENDED; __enable_irq(desc); -- cgit v1.2.3 From 3cf29931453215536916d0c4da953fce1911ced3 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Fri, 14 Jul 2017 19:38:36 +0900 Subject: LSM: Remove security_task_create() hook. Since commit a79be238600d1a03 ("selinux: Use task_alloc hook rather than task_create hook") changed to use task_alloc hook, task_create hook is no longer used. Signed-off-by: Tetsuo Handa Signed-off-by: James Morris --- kernel/fork.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index aa1076c5e4a9..3a13a940a6ea 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1568,10 +1568,6 @@ static __latent_entropy struct task_struct *copy_process( return ERR_PTR(-EINVAL); } - retval = security_task_create(clone_flags); - if (retval) - goto fork_out; - retval = -ENOMEM; p = dup_task_struct(current, node); if (!p) -- cgit v1.2.3 From 8f716c9b5febf6ed0f5fedb7c9407cd0c25b2796 Mon Sep 17 00:00:00 2001 From: Tom Lendacky Date: Mon, 17 Jul 2017 16:10:16 -0500 Subject: x86/mm: Add support to access boot related data in the clear MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Boot data (such as EFI related data) is not encrypted when the system is booted because UEFI/BIOS does not run with SME active. In order to access this data properly it needs to be mapped decrypted. Update early_memremap() to provide an arch specific routine to modify the pagetable protection attributes before they are applied to the new mapping. This is used to remove the encryption mask for boot related data. Update memremap() to provide an arch specific routine to determine if RAM remapping is allowed. RAM remapping will cause an encrypted mapping to be generated. By preventing RAM remapping, ioremap_cache() will be used instead, which will provide a decrypted mapping of the boot related data. Signed-off-by: Tom Lendacky Reviewed-by: Thomas Gleixner Reviewed-by: Matt Fleming Reviewed-by: Borislav Petkov Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brijesh Singh Cc: Dave Young Cc: Dmitry Vyukov Cc: Jonathan Corbet Cc: Konrad Rzeszutek Wilk Cc: Larry Woodman Cc: Linus Torvalds Cc: Michael S. Tsirkin Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Radim Krčmář Cc: Rik van Riel Cc: Toshimitsu Kani Cc: kasan-dev@googlegroups.com Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-efi@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/81fb6b4117a5df6b9f2eda342f81bbef4b23d2e5.1500319216.git.thomas.lendacky@amd.com Signed-off-by: Ingo Molnar --- kernel/memremap.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/memremap.c b/kernel/memremap.c index 124bed776532..9afdc434fb49 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -34,13 +34,24 @@ static void *arch_memremap_wb(resource_size_t offset, unsigned long size) } #endif -static void *try_ram_remap(resource_size_t offset, size_t size) +#ifndef arch_memremap_can_ram_remap +static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size, + unsigned long flags) +{ + return true; +} +#endif + +static void *try_ram_remap(resource_size_t offset, size_t size, + unsigned long flags) { unsigned long pfn = PHYS_PFN(offset); /* In the simple case just return the existing linear address */ - if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn))) + if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) && + arch_memremap_can_ram_remap(offset, size, flags)) return __va(offset); + return NULL; /* fallback to arch_memremap_wb */ } @@ -48,7 +59,8 @@ static void *try_ram_remap(resource_size_t offset, size_t size) * memremap() - remap an iomem_resource as cacheable memory * @offset: iomem resource start address * @size: size of remap - * @flags: any of MEMREMAP_WB, MEMREMAP_WT and MEMREMAP_WC + * @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC, + * MEMREMAP_ENC, MEMREMAP_DEC * * memremap() is "ioremap" for cases where it is known that the resource * being mapped does not have i/o side effects and the __iomem @@ -95,7 +107,7 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags) * the requested range is potentially in System RAM. */ if (is_ram == REGION_INTERSECTS) - addr = try_ram_remap(offset, size); + addr = try_ram_remap(offset, size, flags); if (!addr) addr = arch_memremap_wb(offset, size); } -- cgit v1.2.3 From bba4ed011a52d494aa7ef5e08cf226709bbf3f60 Mon Sep 17 00:00:00 2001 From: Tom Lendacky Date: Mon, 17 Jul 2017 16:10:28 -0500 Subject: x86/mm, kexec: Allow kexec to be used with SME MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Provide support so that kexec can be used to boot a kernel when SME is enabled. Support is needed to allocate pages for kexec without encryption. This is needed in order to be able to reboot in the kernel in the same manner as originally booted. Additionally, when shutting down all of the CPUs we need to be sure to flush the caches and then halt. This is needed when booting from a state where SME was not active into a state where SME is active (or vice-versa). Without these steps, it is possible for cache lines to exist for the same physical location but tagged both with and without the encryption bit. This can cause random memory corruption when caches are flushed depending on which cacheline is written last. Signed-off-by: Tom Lendacky Reviewed-by: Thomas Gleixner Reviewed-by: Borislav Petkov Cc: Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brijesh Singh Cc: Dave Young Cc: Dmitry Vyukov Cc: Jonathan Corbet Cc: Konrad Rzeszutek Wilk Cc: Larry Woodman Cc: Linus Torvalds Cc: Matt Fleming Cc: Michael S. Tsirkin Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Radim Krčmář Cc: Rik van Riel Cc: Toshimitsu Kani Cc: kasan-dev@googlegroups.com Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-efi@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/b95ff075db3e7cd545313f2fb609a49619a09625.1500319216.git.thomas.lendacky@amd.com Signed-off-by: Ingo Molnar --- kernel/kexec_core.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index 1ae7c41c33c1..20fef1a38602 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -301,7 +301,7 @@ static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order) { struct page *pages; - pages = alloc_pages(gfp_mask, order); + pages = alloc_pages(gfp_mask & ~__GFP_ZERO, order); if (pages) { unsigned int count, i; @@ -310,6 +310,13 @@ static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order) count = 1 << order; for (i = 0; i < count; i++) SetPageReserved(pages + i); + + arch_kexec_post_alloc_pages(page_address(pages), count, + gfp_mask); + + if (gfp_mask & __GFP_ZERO) + for (i = 0; i < count; i++) + clear_highpage(pages + i); } return pages; @@ -321,6 +328,9 @@ static void kimage_free_pages(struct page *page) order = page_private(page); count = 1 << order; + + arch_kexec_pre_free_pages(page_address(page), count); + for (i = 0; i < count; i++) ClearPageReserved(page + i); __free_pages(page, order); -- cgit v1.2.3 From 7af608e4f9530372aec6e940552bf76595f2e265 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 18 Jul 2017 17:57:46 -0400 Subject: cgroup: create dfl_root files on subsys registration On subsystem registration, css_populate_dir() is not called on the new root css, so the interface files for the subsystem on cgrp_dfl_root aren't created on registration. This is a residue from the days when cgrp_dfl_root was used only as the parking spot for unused subsystems, which no longer is true as it's used as the root for cgroup2. This is often fine as later operations tend to create them as a part of mount (cgroup1) or subtree_control operations (cgroup2); however, it's not difficult to mount cgroup2 with the controller interface files missing as Waiman found out. Fix it by invoking css_populate_dir() on the root css on subsys registration. Signed-off-by: Tejun Heo Reported-and-tested-by: Waiman Long Cc: stable@vger.kernel.org # v4.5+ Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index cc53111072d8..744975947d01 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4673,6 +4673,10 @@ int __init cgroup_init(void) if (ss->bind) ss->bind(init_css_set.subsys[ssid]); + + mutex_lock(&cgroup_mutex); + css_populate_dir(init_css_set.subsys[ssid]); + mutex_unlock(&cgroup_mutex); } /* init_css_set.subsys[] has been updated, re-hash */ -- cgit v1.2.3 From 848618857d2535176037bdc085f8d012d907071f Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Wed, 12 Jul 2017 19:14:16 -0700 Subject: tracing/ring_buffer: Try harder to allocate ftrace can fail to allocate per-CPU ring buffer on systems with a large number of CPUs coupled while large amounts of cache happening in the page cache. Currently the ring buffer allocation doesn't retry in the VM implementation even if direct-reclaim made some progress but still wasn't able to find a free page. On retrying I see that the allocations almost always succeed. The retry doesn't happen because __GFP_NORETRY is used in the tracer to prevent the case where we might OOM, however if we drop __GFP_NORETRY, we risk destabilizing the system if OOM killer is triggered. To prevent this situation, use the __GFP_RETRY_MAYFAIL flag introduced recently [1]. Tested the following still succeeds without destabilizing a system with 1GB memory. echo 300000 > /sys/kernel/debug/tracing/buffer_size_kb [1] https://marc.info/?l=linux-mm&m=149820805124906&w=2 Link: http://lkml.kernel.org/r/20170713021416.8897-1-joelaf@google.com Cc: Tim Murray Cc: Ingo Molnar Cc: Andrew Morton Acked-by: Vlastimil Babka Acked-by: Johannes Weiner Acked-by: Michal Hocko Signed-off-by: Joel Fernandes Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ring_buffer.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 4ae268e687fe..529cc50d7243 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1136,12 +1136,12 @@ static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu) for (i = 0; i < nr_pages; i++) { struct page *page; /* - * __GFP_NORETRY flag makes sure that the allocation fails - * gracefully without invoking oom-killer and the system is - * not destabilized. + * __GFP_RETRY_MAYFAIL flag makes sure that the allocation fails + * gracefully without invoking oom-killer and the system is not + * destabilized. */ bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()), - GFP_KERNEL | __GFP_NORETRY, + GFP_KERNEL | __GFP_RETRY_MAYFAIL, cpu_to_node(cpu)); if (!bpage) goto free_pages; @@ -1149,7 +1149,7 @@ static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu) list_add(&bpage->list, pages); page = alloc_pages_node(cpu_to_node(cpu), - GFP_KERNEL | __GFP_NORETRY, 0); + GFP_KERNEL | __GFP_RETRY_MAYFAIL, 0); if (!page) goto free_pages; bpage->page = page_address(page); -- cgit v1.2.3 From b0659ae5e30074ede1dc08f2c6d64f0c11d64e0f Mon Sep 17 00:00:00 2001 From: Shu Wang Date: Tue, 18 Jul 2017 14:37:24 +0800 Subject: audit: fix memleak in auditd_send_unicast_skb. Found this issue by kmemleak report, auditd_send_unicast_skb did not free skb if rcu_dereference(auditd_conn) returns null. unreferenced object 0xffff88082568ce00 (size 256): comm "auditd", pid 1119, jiffies 4294708499 backtrace: [] kmemleak_alloc+0x4a/0xa0 [] kmem_cache_alloc_node+0xcc/0x210 [] __alloc_skb+0x5d/0x290 [] audit_make_reply+0x54/0xd0 [] audit_receive_msg+0x967/0xd70 ---------------- (gdb) list *audit_receive_msg+0x967 0xffffffff8113dff7 is in audit_receive_msg (kernel/audit.c:1133). 1132 skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr)); --------------- [] audit_receive+0x52/0xa0 [] netlink_unicast+0x181/0x240 [] netlink_sendmsg+0x2c2/0x3b0 [] sock_sendmsg+0x38/0x50 [] SYSC_sendto+0x102/0x190 [] SyS_sendto+0xe/0x10 [] entry_SYSCALL_64_fastpath+0x1a/0xa5 [] 0xffffffffffffffff Signed-off-by: Shu Wang Signed-off-by: Paul Moore --- kernel/audit.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/audit.c b/kernel/audit.c index 7cad70214b81..07def5e49cc9 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -641,6 +641,7 @@ static int auditd_send_unicast_skb(struct sk_buff *skb) ac = rcu_dereference(auditd_conn); if (!ac) { rcu_read_unlock(); + kfree_skb(skb); rc = -ECONNREFUSED; goto err; } -- cgit v1.2.3 From 5c0338c68706be53b3dc472e4308961c36e4ece1 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 18 Jul 2017 18:41:52 -0400 Subject: workqueue: restore WQ_UNBOUND/max_active==1 to be ordered The combination of WQ_UNBOUND and max_active == 1 used to imply ordered execution. After NUMA affinity 4c16bd327c74 ("workqueue: implement NUMA affinity for unbound workqueues"), this is no longer true due to per-node worker pools. While the right way to create an ordered workqueue is alloc_ordered_workqueue(), the documentation has been misleading for a long time and people do use WQ_UNBOUND and max_active == 1 for ordered workqueues which can lead to subtle bugs which are very difficult to trigger. It's unlikely that we'd see noticeable performance impact by enforcing ordering on WQ_UNBOUND / max_active == 1 workqueues. Let's automatically set __WQ_ORDERED for those workqueues. Signed-off-by: Tejun Heo Reported-by: Christoph Hellwig Reported-by: Alexei Potashnik Fixes: 4c16bd327c74 ("workqueue: implement NUMA affinity for unbound workqueues") Cc: stable@vger.kernel.org # v3.10+ --- kernel/workqueue.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'kernel') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index a86688fabc55..abe4a4971c24 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3929,6 +3929,16 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, struct workqueue_struct *wq; struct pool_workqueue *pwq; + /* + * Unbound && max_active == 1 used to imply ordered, which is no + * longer the case on NUMA machines due to per-node pools. While + * alloc_ordered_workqueue() is the right way to create an ordered + * workqueue, keep the previous behavior to avoid subtle breakages + * on NUMA. + */ + if ((flags & WQ_UNBOUND) && max_active == 1) + flags |= __WQ_ORDERED; + /* see the comment above the definition of WQ_POWER_EFFICIENT */ if ((flags & WQ_POWER_EFFICIENT) && wq_power_efficient) flags |= WQ_UNBOUND; -- cgit v1.2.3 From 3bda69c1c3993a2bddbae01397d12bfef6054011 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Tue, 18 Jul 2017 14:08:34 +0300 Subject: perf/core: Fix scheduling regression of pinned groups Vince Weaver reported: > I was tracking down some regressions in my perf_event_test testsuite. > Some of the tests broke in the 4.11-rc1 timeframe. > > I've bisected one of them, this report is about > tests/overflow/simul_oneshot_group_overflow > This test creates an event group containing two sampling events, set > to overflow to a signal handler (which disables and then refreshes the > event). > > On a good kernel you get the following: > Event perf::instructions with period 1000000 > Event perf::instructions with period 2000000 > fd 3 overflows: 946 (perf::instructions/1000000) > fd 4 overflows: 473 (perf::instructions/2000000) > Ending counts: > Count 0: 946379875 > Count 1: 946365218 > > With the broken kernels you get: > Event perf::instructions with period 1000000 > Event perf::instructions with period 2000000 > fd 3 overflows: 938 (perf::instructions/1000000) > fd 4 overflows: 318 (perf::instructions/2000000) > Ending counts: > Count 0: 946373080 > Count 1: 653373058 The root cause of the bug is that the following commit: 487f05e18a ("perf/core: Optimize event rescheduling on active contexts") erronously assumed that event's 'pinned' setting determines whether the event belongs to a pinned group or not, but in fact, it's the group leader's pinned state that matters. This was discovered by Vince in the test case described above, where two instruction counters are grouped, the group leader is pinned, but the other event is not; in the regressed case the counters were off by 33% (the difference between events' periods), but should be the same within the error margin. Fix the problem by looking at the group leader's pinning. Reported-by: Vince Weaver Tested-by: Vince Weaver Signed-off-by: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: stable@vger.kernel.org Fixes: 487f05e18a ("perf/core: Optimize event rescheduling on active contexts") Link: http://lkml.kernel.org/r/87lgnmvw7h.fsf@ashishki-desk.ger.corp.intel.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 9747e422ab20..c9cdbd396770 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1452,6 +1452,13 @@ static enum event_type_t get_event_type(struct perf_event *event) lockdep_assert_held(&ctx->lock); + /* + * It's 'group type', really, because if our group leader is + * pinned, so are we. + */ + if (event->group_leader != event) + event = event->group_leader; + event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE; if (!ctx->task) event_type |= EVENT_CPU; -- cgit v1.2.3 From a2b426267c56773201f968fdb5eda6ab9ae94e34 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Sat, 29 Apr 2017 14:12:15 -0500 Subject: userns,pidns: Verify the userns for new pid namespaces It is pointless and confusing to allow a pid namespace hierarchy and the user namespace hierarchy to get out of sync. The owner of a child pid namespace should be the owner of the parent pid namespace or a descendant of the owner of the parent pid namespace. Otherwise it is possible to construct scenarios where a process has a capability over a parent pid namespace but does not have the capability over a child pid namespace. Which confusingly makes permission checks non-transitive. It requires use of setns into a pid namespace (but not into a user namespace) to create such a scenario. Add the function in_userns to help in making this determination. v2: Optimized in_userns by using level as suggested by: Kirill Tkhai Ref: 49f4d8b93ccf ("pidns: Capture the user namespace and filter ns_last_pid") Signed-off-by: "Eric W. Biederman" --- kernel/pid_namespace.c | 4 ++++ kernel/user_namespace.c | 20 ++++++++++++-------- 2 files changed, 16 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index 74a5a7255b4d..4918314893bc 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -101,6 +101,10 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns int i; int err; + err = -EINVAL; + if (!in_userns(parent_pid_ns->user_ns, user_ns)) + goto out; + err = -ENOSPC; if (level > MAX_PID_NS_LEVEL) goto out; diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 2f735cbe05e8..c490f1e4313b 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -986,17 +986,21 @@ bool userns_may_setgroups(const struct user_namespace *ns) } /* - * Returns true if @ns is the same namespace as or a descendant of - * @target_ns. + * Returns true if @child is the same namespace or a descendant of + * @ancestor. */ +bool in_userns(const struct user_namespace *ancestor, + const struct user_namespace *child) +{ + const struct user_namespace *ns; + for (ns = child; ns->level > ancestor->level; ns = ns->parent) + ; + return (ns == ancestor); +} + bool current_in_userns(const struct user_namespace *target_ns) { - struct user_namespace *ns; - for (ns = current_user_ns(); ns; ns = ns->parent) { - if (ns == target_ns) - return true; - } - return false; + return in_userns(target_ns, current_user_ns()); } static inline struct user_namespace *to_user_ns(struct ns_common *ns) -- cgit v1.2.3 From 4d28df6152aa3ffd0ad0389bb1d31f5b1c1c2b1f Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Fri, 12 May 2017 17:33:36 +0300 Subject: prctl: Allow local CAP_SYS_ADMIN changing exe_file During checkpointing and restore of userspace tasks we bumped into the situation, that it's not possible to restore the tasks, which user namespace does not have uid 0 or gid 0 mapped. People create user namespace mappings like they want, and there is no a limitation on obligatory uid and gid "must be mapped". So, if there is no uid 0 or gid 0 in the mapping, it's impossible to restore mm->exe_file of the processes belonging to this user namespace. Also, there is no a workaround. It's impossible to create a temporary uid/gid mapping, because only one write to /proc/[pid]/uid_map and gid_map is allowed during a namespace lifetime. If there is an entry, then no more mapings can't be written. If there isn't an entry, we can't write there too, otherwise user task won't be able to do that in the future. The patch changes the check, and looks for CAP_SYS_ADMIN instead of zero uid and gid. This allows to restore a task independently of its user namespace mappings. Signed-off-by: Kirill Tkhai CC: Andrew Morton CC: Serge Hallyn CC: "Eric W. Biederman" CC: Oleg Nesterov CC: Michal Hocko CC: Andrei Vagin CC: Cyrill Gorcunov CC: Stanislav Kinsburskiy CC: Pavel Tikhomirov Reviewed-by: Cyrill Gorcunov Signed-off-by: Eric W. Biederman --- kernel/sys.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/sys.c b/kernel/sys.c index 2855ee73acd0..9aebc2935013 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1896,15 +1896,11 @@ static int validate_prctl_map(struct prctl_mm_map *prctl_map) /* * Finally, make sure the caller has the rights to - * change /proc/pid/exe link: only local root should + * change /proc/pid/exe link: only local sys admin should * be allowed to. */ if (prctl_map->exe_fd != (u32)-1) { - struct user_namespace *ns = current_user_ns(); - const struct cred *cred = current_cred(); - - if (!uid_eq(cred->uid, make_kuid(ns, 0)) || - !gid_eq(cred->gid, make_kgid(ns, 0))) + if (!ns_capable(current_user_ns(), CAP_SYS_ADMIN)) goto out; } -- cgit v1.2.3 From db9108e054700c96322b0f0028546aa4e643cf0b Mon Sep 17 00:00:00 2001 From: Chunyu Hu Date: Thu, 20 Jul 2017 18:36:09 +0800 Subject: tracing: Fix kmemleak in instance_rmdir Hit the kmemleak when executing instance_rmdir, it forgot releasing mem of tracing_cpumask. With this fix, the warn does not appear any more. unreferenced object 0xffff93a8dfaa7c18 (size 8): comm "mkdir", pid 1436, jiffies 4294763622 (age 9134.308s) hex dump (first 8 bytes): ff ff ff ff ff ff ff ff ........ backtrace: [] kmemleak_alloc+0x4a/0xa0 [] __kmalloc_node+0xf1/0x280 [] alloc_cpumask_var_node+0x23/0x30 [] alloc_cpumask_var+0xe/0x10 [] instance_mkdir+0x90/0x240 [] tracefs_syscall_mkdir+0x40/0x70 [] vfs_mkdir+0x109/0x1b0 [] SyS_mkdir+0xd0/0x100 [] do_syscall_64+0x67/0x150 [] return_from_SYSCALL_64+0x0/0x6a [] 0xffffffffffffffff Link: http://lkml.kernel.org/r/1500546969-12594-1-git-send-email-chuhu@redhat.com Cc: stable@vger.kernel.org Fixes: ccfe9e42e451 ("tracing: Make tracing_cpumask available for all instances") Signed-off-by: Chunyu Hu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2d0ffcc49dba..42b9355033d4 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -7774,6 +7774,7 @@ static int instance_rmdir(const char *name) } kfree(tr->topts); + free_cpumask_var(tr->tracing_cpumask); kfree(tr->name); kfree(tr); -- cgit v1.2.3 From f86f418059b94aa01f9342611a272ca60c583e89 Mon Sep 17 00:00:00 2001 From: Chunyan Zhang Date: Wed, 7 Jun 2017 16:12:51 +0800 Subject: trace: fix the errors caused by incompatible type of RCU variables The variables which are processed by RCU functions should be annotated as RCU, otherwise sparse will report the errors like below: "error: incompatible types in comparison expression (different address spaces)" Link: http://lkml.kernel.org/r/1496823171-7758-1-git-send-email-zhang.chunyan@linaro.org Signed-off-by: Chunyan Zhang [ Updated to not be 100% 80 column strict ] Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 41 +++++++++++++++++++++++++++-------------- kernel/trace/trace.h | 6 +++--- 2 files changed, 30 insertions(+), 17 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 53f6b6401cf0..02004ae91860 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -113,7 +113,7 @@ static int ftrace_disabled __read_mostly; static DEFINE_MUTEX(ftrace_lock); -static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end; +static struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end; ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; static struct ftrace_ops global_ops; @@ -169,8 +169,11 @@ int ftrace_nr_registered_ops(void) mutex_lock(&ftrace_lock); - for (ops = ftrace_ops_list; - ops != &ftrace_list_end; ops = ops->next) + for (ops = rcu_dereference_protected(ftrace_ops_list, + lockdep_is_held(&ftrace_lock)); + ops != &ftrace_list_end; + ops = rcu_dereference_protected(ops->next, + lockdep_is_held(&ftrace_lock))) cnt++; mutex_unlock(&ftrace_lock); @@ -275,10 +278,11 @@ static void update_ftrace_function(void) * If there's only one ftrace_ops registered, the ftrace_ops_list * will point to the ops we want. */ - set_function_trace_op = ftrace_ops_list; + set_function_trace_op = rcu_dereference_protected(ftrace_ops_list, + lockdep_is_held(&ftrace_lock)); /* If there's no ftrace_ops registered, just call the stub function */ - if (ftrace_ops_list == &ftrace_list_end) { + if (set_function_trace_op == &ftrace_list_end) { func = ftrace_stub; /* @@ -286,7 +290,8 @@ static void update_ftrace_function(void) * recursion safe and not dynamic and the arch supports passing ops, * then have the mcount trampoline call the function directly. */ - } else if (ftrace_ops_list->next == &ftrace_list_end) { + } else if (rcu_dereference_protected(ftrace_ops_list->next, + lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) { func = ftrace_ops_get_list_func(ftrace_ops_list); } else { @@ -348,9 +353,11 @@ int using_ftrace_ops_list_func(void) return ftrace_trace_function == ftrace_ops_list_func; } -static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) +static void add_ftrace_ops(struct ftrace_ops __rcu **list, + struct ftrace_ops *ops) { - ops->next = *list; + rcu_assign_pointer(ops->next, *list); + /* * We are entering ops into the list but another * CPU might be walking that list. We need to make sure @@ -360,7 +367,8 @@ static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) rcu_assign_pointer(*list, ops); } -static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) +static int remove_ftrace_ops(struct ftrace_ops __rcu **list, + struct ftrace_ops *ops) { struct ftrace_ops **p; @@ -368,7 +376,10 @@ static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) * If we are removing the last function, then simply point * to the ftrace_stub. */ - if (*list == ops && ops->next == &ftrace_list_end) { + if (rcu_dereference_protected(*list, + lockdep_is_held(&ftrace_lock)) == ops && + rcu_dereference_protected(ops->next, + lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) { *list = &ftrace_list_end; return 0; } @@ -1569,8 +1580,8 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) return 0; #endif - hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash); - hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash); + rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash); + rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash); if (hash_contains_ip(ip, &hash)) ret = 1; @@ -2840,7 +2851,8 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) * If there's no more ops registered with ftrace, run a * sanity check to make sure all rec flags are cleared. */ - if (ftrace_ops_list == &ftrace_list_end) { + if (rcu_dereference_protected(ftrace_ops_list, + lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) { struct ftrace_page *pg; struct dyn_ftrace *rec; @@ -6453,7 +6465,8 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, if (ftrace_enabled) { /* we are starting ftrace again */ - if (ftrace_ops_list != &ftrace_list_end) + if (rcu_dereference_protected(ftrace_ops_list, + lockdep_is_held(&ftrace_lock)) != &ftrace_list_end) update_ftrace_function(); ftrace_startup_sysctl(); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 6ade1c55cc3a..490ba229931d 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1210,9 +1210,9 @@ struct ftrace_event_field { struct event_filter { int n_preds; /* Number assigned */ int a_preds; /* allocated */ - struct filter_pred *preds; - struct filter_pred *root; - char *filter_string; + struct filter_pred __rcu *preds; + struct filter_pred __rcu *root; + char *filter_string; }; struct event_subsystem { -- cgit v1.2.3 From 0c96b27305faf06c068b45e07d28336c80dac286 Mon Sep 17 00:00:00 2001 From: Ethan Barnes Date: Wed, 19 Jul 2017 22:36:00 +0000 Subject: smp/hotplug: Handle removal correctly in cpuhp_store_callbacks() If cpuhp_store_callbacks() is called for CPUHP_AP_ONLINE_DYN or CPUHP_BP_PREPARE_DYN, which are the indicators for dynamically allocated states, then cpuhp_store_callbacks() allocates a new dynamic state. The first allocation in each range returns CPUHP_AP_ONLINE_DYN or CPUHP_BP_PREPARE_DYN. If cpuhp_remove_state() is invoked for one of these states, then there is no protection against the allocation mechanism. So the removal, which should clear the callbacks and the name, gets a new state assigned and clears that one. As a consequence the state which should be cleared stays initialized. A consecutive CPU hotplug operation dereferences the state callbacks and accesses either freed or reused memory, resulting in crashes. Add a protection against this by checking the name argument for NULL. If it's NULL it's a removal. If not, it's an allocation. [ tglx: Added a comment and massaged changelog ] Fixes: 5b7aa87e0482 ("cpu/hotplug: Implement setup/removal interface") Signed-off-by: Ethan Barnes Signed-off-by: Thomas Gleixner Cc: Ingo Molnar Cc: "Srivatsa S. Bhat" Cc: Sebastian Siewior Cc: Paul McKenney Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/DM2PR04MB398242FC7776D603D9F99C894A60@DM2PR04MB398.namprd04.prod.outlook.com --- kernel/cpu.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/cpu.c b/kernel/cpu.c index eee033134262..a88c29ab09be 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1252,7 +1252,17 @@ static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, struct cpuhp_step *sp; int ret = 0; - if (state == CPUHP_AP_ONLINE_DYN || state == CPUHP_BP_PREPARE_DYN) { + /* + * If name is NULL, then the state gets removed. + * + * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on + * the first allocation from these dynamic ranges, so the removal + * would trigger a new allocation and clear the wrong (already + * empty) state, leaving the callbacks of the to be cleared state + * dangling, which causes wreckage on the next hotplug operation. + */ + if (name && (state == CPUHP_AP_ONLINE_DYN || + state == CPUHP_BP_PREPARE_DYN)) { ret = cpuhp_reserve_state(state); if (ret < 0) return ret; -- cgit v1.2.3 From 4cabc5b186b5427b9ee5a7495172542af105f02b Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 21 Jul 2017 00:00:21 +0200 Subject: bpf: fix mixed signed/unsigned derived min/max value bounds Edward reported that there's an issue in min/max value bounds tracking when signed and unsigned compares both provide hints on limits when having unknown variables. E.g. a program such as the following should have been rejected: 0: (7a) *(u64 *)(r10 -8) = 0 1: (bf) r2 = r10 2: (07) r2 += -8 3: (18) r1 = 0xffff8a94cda93400 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+7 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R10=fp 7: (7a) *(u64 *)(r10 -16) = -8 8: (79) r1 = *(u64 *)(r10 -16) 9: (b7) r2 = -1 10: (2d) if r1 > r2 goto pc+3 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=0 R2=imm-1,max_value=18446744073709551615,min_align=1 R10=fp 11: (65) if r1 s> 0x1 goto pc+2 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=0,max_value=1 R2=imm-1,max_value=18446744073709551615,min_align=1 R10=fp 12: (0f) r0 += r1 13: (72) *(u8 *)(r0 +0) = 0 R0=map_value_adj(ks=8,vs=8,id=0),min_value=0,max_value=1 R1=inv,min_value=0,max_value=1 R2=imm-1,max_value=18446744073709551615,min_align=1 R10=fp 14: (b7) r0 = 0 15: (95) exit What happens is that in the first part ... 8: (79) r1 = *(u64 *)(r10 -16) 9: (b7) r2 = -1 10: (2d) if r1 > r2 goto pc+3 ... r1 carries an unsigned value, and is compared as unsigned against a register carrying an immediate. Verifier deduces in reg_set_min_max() that since the compare is unsigned and operation is greater than (>), that in the fall-through/false case, r1's minimum bound must be 0 and maximum bound must be r2. Latter is larger than the bound and thus max value is reset back to being 'invalid' aka BPF_REGISTER_MAX_RANGE. Thus, r1 state is now 'R1=inv,min_value=0'. The subsequent test ... 11: (65) if r1 s> 0x1 goto pc+2 ... is a signed compare of r1 with immediate value 1. Here, verifier deduces in reg_set_min_max() that since the compare is signed this time and operation is greater than (>), that in the fall-through/false case, we can deduce that r1's maximum bound must be 1, meaning with prior test, we result in r1 having the following state: R1=inv,min_value=0,max_value=1. Given that the actual value this holds is -8, the bounds are wrongly deduced. When this is being added to r0 which holds the map_value(_adj) type, then subsequent store access in above case will go through check_mem_access() which invokes check_map_access_adj(), that will then probe whether the map memory is in bounds based on the min_value and max_value as well as access size since the actual unknown value is min_value <= x <= max_value; commit fce366a9dd0d ("bpf, verifier: fix alu ops against map_value{, _adj} register types") provides some more explanation on the semantics. It's worth to note in this context that in the current code, min_value and max_value tracking are used for two things, i) dynamic map value access via check_map_access_adj() and since commit 06c1c049721a ("bpf: allow helpers access to variable memory") ii) also enforced at check_helper_mem_access() when passing a memory address (pointer to packet, map value, stack) and length pair to a helper and the length in this case is an unknown value defining an access range through min_value/max_value in that case. The min_value/max_value tracking is /not/ used in the direct packet access case to track ranges. However, the issue also affects case ii), for example, the following crafted program based on the same principle must be rejected as well: 0: (b7) r2 = 0 1: (bf) r3 = r10 2: (07) r3 += -512 3: (7a) *(u64 *)(r10 -16) = -8 4: (79) r4 = *(u64 *)(r10 -16) 5: (b7) r6 = -1 6: (2d) if r4 > r6 goto pc+5 R1=ctx R2=imm0,min_value=0,max_value=0,min_align=2147483648 R3=fp-512 R4=inv,min_value=0 R6=imm-1,max_value=18446744073709551615,min_align=1 R10=fp 7: (65) if r4 s> 0x1 goto pc+4 R1=ctx R2=imm0,min_value=0,max_value=0,min_align=2147483648 R3=fp-512 R4=inv,min_value=0,max_value=1 R6=imm-1,max_value=18446744073709551615,min_align=1 R10=fp 8: (07) r4 += 1 9: (b7) r5 = 0 10: (6a) *(u16 *)(r10 -512) = 0 11: (85) call bpf_skb_load_bytes#26 12: (b7) r0 = 0 13: (95) exit Meaning, while we initialize the max_value stack slot that the verifier thinks we access in the [1,2] range, in reality we pass -7 as length which is interpreted as u32 in the helper. Thus, this issue is relevant also for the case of helper ranges. Resetting both bounds in check_reg_overflow() in case only one of them exceeds limits is also not enough as similar test can be created that uses values which are within range, thus also here learned min value in r1 is incorrect when mixed with later signed test to create a range: 0: (7a) *(u64 *)(r10 -8) = 0 1: (bf) r2 = r10 2: (07) r2 += -8 3: (18) r1 = 0xffff880ad081fa00 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+7 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R10=fp 7: (7a) *(u64 *)(r10 -16) = -8 8: (79) r1 = *(u64 *)(r10 -16) 9: (b7) r2 = 2 10: (3d) if r2 >= r1 goto pc+3 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R10=fp 11: (65) if r1 s> 0x4 goto pc+2 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3,max_value=4 R2=imm2,min_value=2,max_value=2,min_align=2 R10=fp 12: (0f) r0 += r1 13: (72) *(u8 *)(r0 +0) = 0 R0=map_value_adj(ks=8,vs=8,id=0),min_value=3,max_value=4 R1=inv,min_value=3,max_value=4 R2=imm2,min_value=2,max_value=2,min_align=2 R10=fp 14: (b7) r0 = 0 15: (95) exit This leaves us with two options for fixing this: i) to invalidate all prior learned information once we switch signed context, ii) to track min/max signed and unsigned boundaries separately as done in [0]. (Given latter introduces major changes throughout the whole verifier, it's rather net-next material, thus this patch follows option i), meaning we can derive bounds either from only signed tests or only unsigned tests.) There is still the case of adjust_reg_min_max_vals(), where we adjust bounds on ALU operations, meaning programs like the following where boundaries on the reg get mixed in context later on when bounds are merged on the dst reg must get rejected, too: 0: (7a) *(u64 *)(r10 -8) = 0 1: (bf) r2 = r10 2: (07) r2 += -8 3: (18) r1 = 0xffff89b2bf87ce00 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+6 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R10=fp 7: (7a) *(u64 *)(r10 -16) = -8 8: (79) r1 = *(u64 *)(r10 -16) 9: (b7) r2 = 2 10: (3d) if r2 >= r1 goto pc+2 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R10=fp 11: (b7) r7 = 1 12: (65) if r7 s> 0x0 goto pc+2 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R7=imm1,max_value=0 R10=fp 13: (b7) r0 = 0 14: (95) exit from 12 to 15: R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R7=imm1,min_value=1 R10=fp 15: (0f) r7 += r1 16: (65) if r7 s> 0x4 goto pc+2 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R7=inv,min_value=4,max_value=4 R10=fp 17: (0f) r0 += r7 18: (72) *(u8 *)(r0 +0) = 0 R0=map_value_adj(ks=8,vs=8,id=0),min_value=4,max_value=4 R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R7=inv,min_value=4,max_value=4 R10=fp 19: (b7) r0 = 0 20: (95) exit Meaning, in adjust_reg_min_max_vals() we must also reset range values on the dst when src/dst registers have mixed signed/ unsigned derived min/max value bounds with one unbounded value as otherwise they can be added together deducing false boundaries. Once both boundaries are established from either ALU ops or compare operations w/o mixing signed/unsigned insns, then they can safely be added to other regs also having both boundaries established. Adding regs with one unbounded side to a map value where the bounded side has been learned w/o mixing ops is possible, but the resulting map value won't recover from that, meaning such op is considered invalid on the time of actual access. Invalid bounds are set on the dst reg in case i) src reg, or ii) in case dst reg already had them. The only way to recover would be to perform i) ALU ops but only 'add' is allowed on map value types or ii) comparisons, but these are disallowed on pointers in case they span a range. This is fine as only BPF_JEQ and BPF_JNE may be performed on PTR_TO_MAP_VALUE_OR_NULL registers which potentially turn them into PTR_TO_MAP_VALUE type depending on the branch, so only here min/max value cannot be invalidated for them. In terms of state pruning, value_from_signed is considered as well in states_equal() when dealing with adjusted map values. With regards to breaking existing programs, there is a small risk, but use-cases are rather quite narrow where this could occur and mixing compares probably unlikely. Joint work with Josef and Edward. [0] https://lists.iovisor.org/pipermail/iovisor-dev/2017-June/000822.html Fixes: 484611357c19 ("bpf: allow access into map value arrays") Reported-by: Edward Cree Signed-off-by: Daniel Borkmann Signed-off-by: Edward Cree Signed-off-by: Josef Bacik Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 108 +++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 94 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6a86723c5b64..af9e84a4944e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -504,6 +504,7 @@ static void reset_reg_range_values(struct bpf_reg_state *regs, u32 regno) { regs[regno].min_value = BPF_REGISTER_MIN_RANGE; regs[regno].max_value = BPF_REGISTER_MAX_RANGE; + regs[regno].value_from_signed = false; regs[regno].min_align = 0; } @@ -777,12 +778,13 @@ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, return -EACCES; } -static bool is_pointer_value(struct bpf_verifier_env *env, int regno) +static bool __is_pointer_value(bool allow_ptr_leaks, + const struct bpf_reg_state *reg) { - if (env->allow_ptr_leaks) + if (allow_ptr_leaks) return false; - switch (env->cur_state.regs[regno].type) { + switch (reg->type) { case UNKNOWN_VALUE: case CONST_IMM: return false; @@ -791,6 +793,11 @@ static bool is_pointer_value(struct bpf_verifier_env *env, int regno) } } +static bool is_pointer_value(struct bpf_verifier_env *env, int regno) +{ + return __is_pointer_value(env->allow_ptr_leaks, &env->cur_state.regs[regno]); +} + static int check_pkt_ptr_alignment(const struct bpf_reg_state *reg, int off, int size, bool strict) { @@ -1832,10 +1839,24 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, dst_align = dst_reg->min_align; /* We don't know anything about what was done to this register, mark it - * as unknown. + * as unknown. Also, if both derived bounds came from signed/unsigned + * mixed compares and one side is unbounded, we cannot really do anything + * with them as boundaries cannot be trusted. Thus, arithmetic of two + * regs of such kind will get invalidated bounds on the dst side. */ - if (min_val == BPF_REGISTER_MIN_RANGE && - max_val == BPF_REGISTER_MAX_RANGE) { + if ((min_val == BPF_REGISTER_MIN_RANGE && + max_val == BPF_REGISTER_MAX_RANGE) || + (BPF_SRC(insn->code) == BPF_X && + ((min_val != BPF_REGISTER_MIN_RANGE && + max_val == BPF_REGISTER_MAX_RANGE) || + (min_val == BPF_REGISTER_MIN_RANGE && + max_val != BPF_REGISTER_MAX_RANGE) || + (dst_reg->min_value != BPF_REGISTER_MIN_RANGE && + dst_reg->max_value == BPF_REGISTER_MAX_RANGE) || + (dst_reg->min_value == BPF_REGISTER_MIN_RANGE && + dst_reg->max_value != BPF_REGISTER_MAX_RANGE)) && + regs[insn->dst_reg].value_from_signed != + regs[insn->src_reg].value_from_signed)) { reset_reg_range_values(regs, insn->dst_reg); return; } @@ -2023,6 +2044,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) regs[insn->dst_reg].max_value = insn->imm; regs[insn->dst_reg].min_value = insn->imm; regs[insn->dst_reg].min_align = calc_align(insn->imm); + regs[insn->dst_reg].value_from_signed = false; } } else if (opcode > BPF_END) { @@ -2198,40 +2220,63 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, struct bpf_reg_state *false_reg, u64 val, u8 opcode) { + bool value_from_signed = true; + bool is_range = true; + switch (opcode) { case BPF_JEQ: /* If this is false then we know nothing Jon Snow, but if it is * true then we know for sure. */ true_reg->max_value = true_reg->min_value = val; + is_range = false; break; case BPF_JNE: /* If this is true we know nothing Jon Snow, but if it is false * we know the value for sure; */ false_reg->max_value = false_reg->min_value = val; + is_range = false; break; case BPF_JGT: - /* Unsigned comparison, the minimum value is 0. */ - false_reg->min_value = 0; + value_from_signed = false; /* fallthrough */ case BPF_JSGT: + if (true_reg->value_from_signed != value_from_signed) + reset_reg_range_values(true_reg, 0); + if (false_reg->value_from_signed != value_from_signed) + reset_reg_range_values(false_reg, 0); + if (opcode == BPF_JGT) { + /* Unsigned comparison, the minimum value is 0. */ + false_reg->min_value = 0; + } /* If this is false then we know the maximum val is val, * otherwise we know the min val is val+1. */ false_reg->max_value = val; + false_reg->value_from_signed = value_from_signed; true_reg->min_value = val + 1; + true_reg->value_from_signed = value_from_signed; break; case BPF_JGE: - /* Unsigned comparison, the minimum value is 0. */ - false_reg->min_value = 0; + value_from_signed = false; /* fallthrough */ case BPF_JSGE: + if (true_reg->value_from_signed != value_from_signed) + reset_reg_range_values(true_reg, 0); + if (false_reg->value_from_signed != value_from_signed) + reset_reg_range_values(false_reg, 0); + if (opcode == BPF_JGE) { + /* Unsigned comparison, the minimum value is 0. */ + false_reg->min_value = 0; + } /* If this is false then we know the maximum value is val - 1, * otherwise we know the mimimum value is val. */ false_reg->max_value = val - 1; + false_reg->value_from_signed = value_from_signed; true_reg->min_value = val; + true_reg->value_from_signed = value_from_signed; break; default: break; @@ -2239,6 +2284,12 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, check_reg_overflow(false_reg); check_reg_overflow(true_reg); + if (is_range) { + if (__is_pointer_value(false, false_reg)) + reset_reg_range_values(false_reg, 0); + if (__is_pointer_value(false, true_reg)) + reset_reg_range_values(true_reg, 0); + } } /* Same as above, but for the case that dst_reg is a CONST_IMM reg and src_reg @@ -2248,41 +2299,64 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, struct bpf_reg_state *false_reg, u64 val, u8 opcode) { + bool value_from_signed = true; + bool is_range = true; + switch (opcode) { case BPF_JEQ: /* If this is false then we know nothing Jon Snow, but if it is * true then we know for sure. */ true_reg->max_value = true_reg->min_value = val; + is_range = false; break; case BPF_JNE: /* If this is true we know nothing Jon Snow, but if it is false * we know the value for sure; */ false_reg->max_value = false_reg->min_value = val; + is_range = false; break; case BPF_JGT: - /* Unsigned comparison, the minimum value is 0. */ - true_reg->min_value = 0; + value_from_signed = false; /* fallthrough */ case BPF_JSGT: + if (true_reg->value_from_signed != value_from_signed) + reset_reg_range_values(true_reg, 0); + if (false_reg->value_from_signed != value_from_signed) + reset_reg_range_values(false_reg, 0); + if (opcode == BPF_JGT) { + /* Unsigned comparison, the minimum value is 0. */ + true_reg->min_value = 0; + } /* * If this is false, then the val is <= the register, if it is * true the register <= to the val. */ false_reg->min_value = val; + false_reg->value_from_signed = value_from_signed; true_reg->max_value = val - 1; + true_reg->value_from_signed = value_from_signed; break; case BPF_JGE: - /* Unsigned comparison, the minimum value is 0. */ - true_reg->min_value = 0; + value_from_signed = false; /* fallthrough */ case BPF_JSGE: + if (true_reg->value_from_signed != value_from_signed) + reset_reg_range_values(true_reg, 0); + if (false_reg->value_from_signed != value_from_signed) + reset_reg_range_values(false_reg, 0); + if (opcode == BPF_JGE) { + /* Unsigned comparison, the minimum value is 0. */ + true_reg->min_value = 0; + } /* If this is false then constant < register, if it is true then * the register < constant. */ false_reg->min_value = val + 1; + false_reg->value_from_signed = value_from_signed; true_reg->max_value = val; + true_reg->value_from_signed = value_from_signed; break; default: break; @@ -2290,6 +2364,12 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, check_reg_overflow(false_reg); check_reg_overflow(true_reg); + if (is_range) { + if (__is_pointer_value(false, false_reg)) + reset_reg_range_values(false_reg, 0); + if (__is_pointer_value(false, true_reg)) + reset_reg_range_values(true_reg, 0); + } } static void mark_map_reg(struct bpf_reg_state *regs, u32 regno, u32 id, -- cgit v1.2.3 From 2aeb1883547626d82c597cce2c99f0b9c62e2425 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Thu, 20 Jul 2017 16:14:55 +0200 Subject: perf/core: Fix locking for children siblings group read We're missing ctx lock when iterating children siblings within the perf_read path for group reading. Following race and crash can happen: User space doing read syscall on event group leader: T1: perf_read lock event->ctx->mutex perf_read_group lock leader->child_mutex __perf_read_group_add(child) list_for_each_entry(sub, &leader->sibling_list, group_entry) ----> sub might be invalid at this point, because it could get removed via perf_event_exit_task_context in T2 Child exiting and cleaning up its events: T2: perf_event_exit_task_context lock ctx->mutex list_for_each_entry_safe(child_event, next, &child_ctx->event_list,... perf_event_exit_event(child) lock ctx->lock perf_group_detach(child) unlock ctx->lock ----> child is removed from sibling_list without any sync with T1 path above ... free_event(child) Before the child is removed from the leader's child_list, (and thus is omitted from perf_read_group processing), we need to ensure that perf_read_group touches child's siblings under its ctx->lock. Peter further notes: | One additional note; this bug got exposed by commit: | | ba5213ae6b88 ("perf/core: Correct event creation with PERF_FORMAT_GROUP") | | which made it possible to actually trigger this code-path. Tested-by: Andi Kleen Signed-off-by: Jiri Olsa Acked-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: ba5213ae6b88 ("perf/core: Correct event creation with PERF_FORMAT_GROUP") Link: http://lkml.kernel.org/r/20170720141455.2106-1-jolsa@kernel.org Signed-off-by: Ingo Molnar --- kernel/events/core.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index c9cdbd396770..c17c0881fd36 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4372,7 +4372,9 @@ EXPORT_SYMBOL_GPL(perf_event_read_value); static int __perf_read_group_add(struct perf_event *leader, u64 read_format, u64 *values) { + struct perf_event_context *ctx = leader->ctx; struct perf_event *sub; + unsigned long flags; int n = 1; /* skip @nr */ int ret; @@ -4402,12 +4404,15 @@ static int __perf_read_group_add(struct perf_event *leader, if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(leader); + raw_spin_lock_irqsave(&ctx->lock, flags); + list_for_each_entry(sub, &leader->sibling_list, group_entry) { values[n++] += perf_event_count(sub); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(sub); } + raw_spin_unlock_irqrestore(&ctx->lock, flags); return 0; } -- cgit v1.2.3 From 715c809d9a9e38d8fb9476757ddaf64c1a9f767f Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 15 May 2017 09:34:00 -0400 Subject: cgroup: reorganize cgroup.procs / task write path Currently, writes "cgroup.procs" and "cgroup.tasks" files are all handled by __cgroup_procs_write() on both v1 and v2. This patch reoragnizes the write path so that there are common helper functions that different write paths use. While this somewhat increases LOC, the different paths are no longer intertwined and each path has more flexibility to implement different behaviors which will be necessary for the planned v2 thread support. v3: - Restructured so that cgroup_procs_write_permission() takes @src_cgrp and @dst_cgrp. v2: - Rolled in Waiman's task reference count fix. - Updated on top of nsdelegate changes. Signed-off-by: Tejun Heo Cc: Waiman Long --- kernel/cgroup/cgroup-internal.h | 8 +- kernel/cgroup/cgroup-v1.c | 58 ++++++++++-- kernel/cgroup/cgroup.c | 192 ++++++++++++++++++++-------------------- 3 files changed, 152 insertions(+), 106 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h index 793565c05742..0e81c6109e91 100644 --- a/kernel/cgroup/cgroup-internal.h +++ b/kernel/cgroup/cgroup-internal.h @@ -180,10 +180,10 @@ int cgroup_migrate(struct task_struct *leader, bool threadgroup, int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, bool threadgroup); -ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf, - size_t nbytes, loff_t off, bool threadgroup); -ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes, - loff_t off); +struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup) + __acquires(&cgroup_threadgroup_rwsem); +void cgroup_procs_write_finish(struct task_struct *task) + __releases(&cgroup_threadgroup_rwsem); void cgroup_lock_and_drain_offline(struct cgroup *cgrp); diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index 7bf4b1533f34..60f72475863e 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -510,10 +510,58 @@ static int cgroup_pidlist_show(struct seq_file *s, void *v) return 0; } -static ssize_t cgroup_tasks_write(struct kernfs_open_file *of, - char *buf, size_t nbytes, loff_t off) +static ssize_t __cgroup1_procs_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off, + bool threadgroup) { - return __cgroup_procs_write(of, buf, nbytes, off, false); + struct cgroup *cgrp; + struct task_struct *task; + const struct cred *cred, *tcred; + ssize_t ret; + + cgrp = cgroup_kn_lock_live(of->kn, false); + if (!cgrp) + return -ENODEV; + + task = cgroup_procs_write_start(buf, threadgroup); + ret = PTR_ERR_OR_ZERO(task); + if (ret) + goto out_unlock; + + /* + * Even if we're attaching all tasks in the thread group, we only + * need to check permissions on one of them. + */ + cred = current_cred(); + tcred = get_task_cred(task); + if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) && + !uid_eq(cred->euid, tcred->uid) && + !uid_eq(cred->euid, tcred->suid)) + ret = -EACCES; + put_cred(tcred); + if (ret) + goto out_finish; + + ret = cgroup_attach_task(cgrp, task, threadgroup); + +out_finish: + cgroup_procs_write_finish(task); +out_unlock: + cgroup_kn_unlock(of->kn); + + return ret ?: nbytes; +} + +static ssize_t cgroup1_procs_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + return __cgroup1_procs_write(of, buf, nbytes, off, true); +} + +static ssize_t cgroup1_tasks_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + return __cgroup1_procs_write(of, buf, nbytes, off, false); } static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of, @@ -592,7 +640,7 @@ struct cftype cgroup1_base_files[] = { .seq_stop = cgroup_pidlist_stop, .seq_show = cgroup_pidlist_show, .private = CGROUP_FILE_PROCS, - .write = cgroup_procs_write, + .write = cgroup1_procs_write, }, { .name = "cgroup.clone_children", @@ -611,7 +659,7 @@ struct cftype cgroup1_base_files[] = { .seq_stop = cgroup_pidlist_stop, .seq_show = cgroup_pidlist_show, .private = CGROUP_FILE_TASKS, - .write = cgroup_tasks_write, + .write = cgroup1_tasks_write, }, { .name = "notify_on_release", diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index d5b62313c753..e3bda0752501 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -2421,96 +2421,23 @@ int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, return ret; } -static int cgroup_procs_write_permission(struct task_struct *task, - struct cgroup *dst_cgrp, - struct kernfs_open_file *of) -{ - struct super_block *sb = of->file->f_path.dentry->d_sb; - struct cgroup_namespace *ns = current->nsproxy->cgroup_ns; - struct cgroup *root_cgrp = ns->root_cset->dfl_cgrp; - struct cgroup *src_cgrp, *com_cgrp; - struct inode *inode; - int ret; - - if (!cgroup_on_dfl(dst_cgrp)) { - const struct cred *cred = current_cred(); - const struct cred *tcred = get_task_cred(task); - - /* - * even if we're attaching all tasks in the thread group, - * we only need to check permissions on one of them. - */ - if (uid_eq(cred->euid, GLOBAL_ROOT_UID) || - uid_eq(cred->euid, tcred->uid) || - uid_eq(cred->euid, tcred->suid)) - ret = 0; - else - ret = -EACCES; - - put_cred(tcred); - return ret; - } - - /* find the source cgroup */ - spin_lock_irq(&css_set_lock); - src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root); - spin_unlock_irq(&css_set_lock); - - /* and the common ancestor */ - com_cgrp = src_cgrp; - while (!cgroup_is_descendant(dst_cgrp, com_cgrp)) - com_cgrp = cgroup_parent(com_cgrp); - - /* %current should be authorized to migrate to the common ancestor */ - inode = kernfs_get_inode(sb, com_cgrp->procs_file.kn); - if (!inode) - return -ENOMEM; - - ret = inode_permission(inode, MAY_WRITE); - iput(inode); - if (ret) - return ret; - - /* - * If namespaces are delegation boundaries, %current must be able - * to see both source and destination cgroups from its namespace. - */ - if ((cgrp_dfl_root.flags & CGRP_ROOT_NS_DELEGATE) && - (!cgroup_is_descendant(src_cgrp, root_cgrp) || - !cgroup_is_descendant(dst_cgrp, root_cgrp))) - return -ENOENT; - - return 0; -} - -/* - * Find the task_struct of the task to attach by vpid and pass it along to the - * function to attach either it or all tasks in its threadgroup. Will lock - * cgroup_mutex and threadgroup. - */ -ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf, - size_t nbytes, loff_t off, bool threadgroup) +struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup) + __acquires(&cgroup_threadgroup_rwsem) { struct task_struct *tsk; - struct cgroup_subsys *ss; - struct cgroup *cgrp; pid_t pid; - int ssid, ret; if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0) - return -EINVAL; - - cgrp = cgroup_kn_lock_live(of->kn, false); - if (!cgrp) - return -ENODEV; + return ERR_PTR(-EINVAL); percpu_down_write(&cgroup_threadgroup_rwsem); + rcu_read_lock(); if (pid) { tsk = find_task_by_vpid(pid); if (!tsk) { - ret = -ESRCH; - goto out_unlock_rcu; + tsk = ERR_PTR(-ESRCH); + goto out_unlock_threadgroup; } } else { tsk = current; @@ -2526,35 +2453,33 @@ ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf, * cgroup with no rt_runtime allocated. Just say no. */ if (tsk->no_cgroup_migration || (tsk->flags & PF_NO_SETAFFINITY)) { - ret = -EINVAL; - goto out_unlock_rcu; + tsk = ERR_PTR(-EINVAL); + goto out_unlock_threadgroup; } get_task_struct(tsk); + goto out_unlock_rcu; + +out_unlock_threadgroup: + percpu_up_write(&cgroup_threadgroup_rwsem); +out_unlock_rcu: rcu_read_unlock(); + return tsk; +} - ret = cgroup_procs_write_permission(tsk, cgrp, of); - if (!ret) - ret = cgroup_attach_task(cgrp, tsk, threadgroup); +void cgroup_procs_write_finish(struct task_struct *task) + __releases(&cgroup_threadgroup_rwsem) +{ + struct cgroup_subsys *ss; + int ssid; - put_task_struct(tsk); - goto out_unlock_threadgroup; + /* release reference from cgroup_procs_write_start() */ + put_task_struct(task); -out_unlock_rcu: - rcu_read_unlock(); -out_unlock_threadgroup: percpu_up_write(&cgroup_threadgroup_rwsem); for_each_subsys(ss, ssid) if (ss->post_attach) ss->post_attach(); - cgroup_kn_unlock(of->kn); - return ret ?: nbytes; -} - -ssize_t cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes, - loff_t off) -{ - return __cgroup_procs_write(of, buf, nbytes, off, true); } static void cgroup_print_ss_mask(struct seq_file *seq, u16 ss_mask) @@ -3870,6 +3795,79 @@ static int cgroup_procs_show(struct seq_file *s, void *v) return 0; } +static int cgroup_procs_write_permission(struct cgroup *src_cgrp, + struct cgroup *dst_cgrp, + struct super_block *sb) +{ + struct cgroup_namespace *ns = current->nsproxy->cgroup_ns; + struct cgroup *com_cgrp = src_cgrp; + struct inode *inode; + int ret; + + lockdep_assert_held(&cgroup_mutex); + + /* find the common ancestor */ + while (!cgroup_is_descendant(dst_cgrp, com_cgrp)) + com_cgrp = cgroup_parent(com_cgrp); + + /* %current should be authorized to migrate to the common ancestor */ + inode = kernfs_get_inode(sb, com_cgrp->procs_file.kn); + if (!inode) + return -ENOMEM; + + ret = inode_permission(inode, MAY_WRITE); + iput(inode); + if (ret) + return ret; + + /* + * If namespaces are delegation boundaries, %current must be able + * to see both source and destination cgroups from its namespace. + */ + if ((cgrp_dfl_root.flags & CGRP_ROOT_NS_DELEGATE) && + (!cgroup_is_descendant(src_cgrp, ns->root_cset->dfl_cgrp) || + !cgroup_is_descendant(dst_cgrp, ns->root_cset->dfl_cgrp))) + return -ENOENT; + + return 0; +} + +static ssize_t cgroup_procs_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct cgroup *src_cgrp, *dst_cgrp; + struct task_struct *task; + ssize_t ret; + + dst_cgrp = cgroup_kn_lock_live(of->kn, false); + if (!dst_cgrp) + return -ENODEV; + + task = cgroup_procs_write_start(buf, true); + ret = PTR_ERR_OR_ZERO(task); + if (ret) + goto out_unlock; + + /* find the source cgroup */ + spin_lock_irq(&css_set_lock); + src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root); + spin_unlock_irq(&css_set_lock); + + ret = cgroup_procs_write_permission(src_cgrp, dst_cgrp, + of->file->f_path.dentry->d_sb); + if (ret) + goto out_finish; + + ret = cgroup_attach_task(dst_cgrp, task, true); + +out_finish: + cgroup_procs_write_finish(task); +out_unlock: + cgroup_kn_unlock(of->kn); + + return ret ?: nbytes; +} + /* cgroup core interface files for the default hierarchy */ static struct cftype cgroup_base_files[] = { { -- cgit v1.2.3 From bc2fb7ed089ffd16d26e1d95b898a37d2b37d201 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 15 May 2017 09:34:01 -0400 Subject: cgroup: add @flags to css_task_iter_start() and implement CSS_TASK_ITER_PROCS css_task_iter currently always walks all tasks. With the scheduled cgroup v2 thread support, the iterator would need to handle multiple types of iteration. As a preparation, add @flags to css_task_iter_start() and implement CSS_TASK_ITER_PROCS. If the flag is not specified, it walks all tasks as before. When asserted, the iterator only walks the group leaders. For now, the only user of the flag is cgroup v2 "cgroup.procs" file which no longer needs to skip non-leader tasks in cgroup_procs_next(). Note that cgroup v1 "cgroup.procs" can't use the group leader walk as v1 "cgroup.procs" doesn't mean "list all thread group leaders in the cgroup" but "list all thread group id's with any threads in the cgroup". While at it, update cgroup_procs_show() to use task_pid_vnr() instead of task_tgid_vnr(). As the iteration guarantees that the function only sees group leaders, this doesn't change the output and will allow sharing the function for thread iteration. Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup-v1.c | 6 +++--- kernel/cgroup/cgroup.c | 24 ++++++++++++++---------- kernel/cgroup/cpuset.c | 6 +++--- kernel/cgroup/freezer.c | 6 +++--- 4 files changed, 23 insertions(+), 19 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index 60f72475863e..167aaab04bf9 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -121,7 +121,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from) * ->can_attach() fails. */ do { - css_task_iter_start(&from->self, &it); + css_task_iter_start(&from->self, 0, &it); task = css_task_iter_next(&it); if (task) get_task_struct(task); @@ -373,7 +373,7 @@ static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type, if (!array) return -ENOMEM; /* now, populate the array */ - css_task_iter_start(&cgrp->self, &it); + css_task_iter_start(&cgrp->self, 0, &it); while ((tsk = css_task_iter_next(&it))) { if (unlikely(n == length)) break; @@ -749,7 +749,7 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) } rcu_read_unlock(); - css_task_iter_start(&cgrp->self, &it); + css_task_iter_start(&cgrp->self, 0, &it); while ((tsk = css_task_iter_next(&it))) { switch (tsk->state) { case TASK_RUNNING: diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index e3bda0752501..3c5a37a9a892 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3643,6 +3643,7 @@ static void css_task_iter_advance(struct css_task_iter *it) lockdep_assert_held(&css_set_lock); WARN_ON_ONCE(!l); +repeat: /* * Advance iterator to find next entry. cset->tasks is consumed * first and then ->mg_tasks. After ->mg_tasks, we move onto the @@ -3657,11 +3658,18 @@ static void css_task_iter_advance(struct css_task_iter *it) css_task_iter_advance_css_set(it); else it->task_pos = l; + + /* if PROCS, skip over tasks which aren't group leaders */ + if ((it->flags & CSS_TASK_ITER_PROCS) && it->task_pos && + !thread_group_leader(list_entry(it->task_pos, struct task_struct, + cg_list))) + goto repeat; } /** * css_task_iter_start - initiate task iteration * @css: the css to walk tasks of + * @flags: CSS_TASK_ITER_* flags * @it: the task iterator to use * * Initiate iteration through the tasks of @css. The caller can call @@ -3669,7 +3677,7 @@ static void css_task_iter_advance(struct css_task_iter *it) * returns NULL. On completion of iteration, css_task_iter_end() must be * called. */ -void css_task_iter_start(struct cgroup_subsys_state *css, +void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags, struct css_task_iter *it) { /* no one should try to iterate before mounting cgroups */ @@ -3680,6 +3688,7 @@ void css_task_iter_start(struct cgroup_subsys_state *css, spin_lock_irq(&css_set_lock); it->ss = css->ss; + it->flags = flags; if (it->ss) it->cset_pos = &css->cgroup->e_csets[css->ss->id]; @@ -3753,13 +3762,8 @@ static void *cgroup_procs_next(struct seq_file *s, void *v, loff_t *pos) { struct kernfs_open_file *of = s->private; struct css_task_iter *it = of->priv; - struct task_struct *task; - - do { - task = css_task_iter_next(it); - } while (task && !thread_group_leader(task)); - return task; + return css_task_iter_next(it); } static void *cgroup_procs_start(struct seq_file *s, loff_t *pos) @@ -3780,10 +3784,10 @@ static void *cgroup_procs_start(struct seq_file *s, loff_t *pos) if (!it) return ERR_PTR(-ENOMEM); of->priv = it; - css_task_iter_start(&cgrp->self, it); + css_task_iter_start(&cgrp->self, CSS_TASK_ITER_PROCS, it); } else if (!(*pos)++) { css_task_iter_end(it); - css_task_iter_start(&cgrp->self, it); + css_task_iter_start(&cgrp->self, CSS_TASK_ITER_PROCS, it); } return cgroup_procs_next(s, NULL, NULL); @@ -3791,7 +3795,7 @@ static void *cgroup_procs_start(struct seq_file *s, loff_t *pos) static int cgroup_procs_show(struct seq_file *s, void *v) { - seq_printf(s, "%d\n", task_tgid_vnr(v)); + seq_printf(s, "%d\n", task_pid_vnr(v)); return 0; } diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index ca8376e5008c..252d70c9a49b 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -861,7 +861,7 @@ static void update_tasks_cpumask(struct cpuset *cs) struct css_task_iter it; struct task_struct *task; - css_task_iter_start(&cs->css, &it); + css_task_iter_start(&cs->css, 0, &it); while ((task = css_task_iter_next(&it))) set_cpus_allowed_ptr(task, cs->effective_cpus); css_task_iter_end(&it); @@ -1091,7 +1091,7 @@ static void update_tasks_nodemask(struct cpuset *cs) * It's ok if we rebind the same mm twice; mpol_rebind_mm() * is idempotent. Also migrate pages in each mm to new nodes. */ - css_task_iter_start(&cs->css, &it); + css_task_iter_start(&cs->css, 0, &it); while ((task = css_task_iter_next(&it))) { struct mm_struct *mm; bool migrate; @@ -1284,7 +1284,7 @@ static void update_tasks_flags(struct cpuset *cs) struct css_task_iter it; struct task_struct *task; - css_task_iter_start(&cs->css, &it); + css_task_iter_start(&cs->css, 0, &it); while ((task = css_task_iter_next(&it))) cpuset_update_task_spread_flag(cs, task); css_task_iter_end(&it); diff --git a/kernel/cgroup/freezer.c b/kernel/cgroup/freezer.c index 1b72d56edce5..08236798d173 100644 --- a/kernel/cgroup/freezer.c +++ b/kernel/cgroup/freezer.c @@ -268,7 +268,7 @@ static void update_if_frozen(struct cgroup_subsys_state *css) rcu_read_unlock(); /* are all tasks frozen? */ - css_task_iter_start(css, &it); + css_task_iter_start(css, 0, &it); while ((task = css_task_iter_next(&it))) { if (freezing(task)) { @@ -320,7 +320,7 @@ static void freeze_cgroup(struct freezer *freezer) struct css_task_iter it; struct task_struct *task; - css_task_iter_start(&freezer->css, &it); + css_task_iter_start(&freezer->css, 0, &it); while ((task = css_task_iter_next(&it))) freeze_task(task); css_task_iter_end(&it); @@ -331,7 +331,7 @@ static void unfreeze_cgroup(struct freezer *freezer) struct css_task_iter it; struct task_struct *task; - css_task_iter_start(&freezer->css, &it); + css_task_iter_start(&freezer->css, 0, &it); while ((task = css_task_iter_next(&it))) __thaw_task(task); css_task_iter_end(&it); -- cgit v1.2.3 From 454000adaa2a7420df6e56a42f22726d05872a3f Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 15 May 2017 09:34:02 -0400 Subject: cgroup: introduce cgroup->dom_cgrp and threaded css_set handling cgroup v2 is in the process of growing thread granularity support. A threaded subtree is composed of a thread root and threaded cgroups which are proper members of the subtree. The root cgroup of the subtree serves as the domain cgroup to which the processes (as opposed to threads / tasks) of the subtree conceptually belong and domain-level resource consumptions not tied to any specific task are charged. Inside the subtree, threads won't be subject to process granularity or no-internal-task constraint and can be distributed arbitrarily across the subtree. This patch introduces cgroup->dom_cgrp along with threaded css_set handling. * cgroup->dom_cgrp points to self for normal and thread roots. For proper thread subtree members, points to the dom_cgrp (the thread root). * css_set->dom_cset points to self if for normal and thread roots. If threaded, points to the css_set which belongs to the cgrp->dom_cgrp. The dom_cgrp serves as the resource domain and keeps the matching csses available. The dom_cset holds those csses and makes them easily accessible. * All threaded csets are linked on their dom_csets to enable iteration of all threaded tasks. * cgroup->nr_threaded_children keeps track of the number of threaded children. This patch adds the above but doesn't actually use them yet. The following patches will build on top. v4: ->nr_threaded_children added. v3: ->proc_cgrp/cset renamed to ->dom_cgrp/cset. Updated for the new enable-threaded-per-cgroup behavior. v2: Added cgroup_is_threaded() helper. Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 66 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 3c5a37a9a892..c7e1c243b77d 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -330,6 +330,11 @@ static bool cgroup_has_tasks(struct cgroup *cgrp) return cgrp->nr_populated_csets; } +static bool cgroup_is_threaded(struct cgroup *cgrp) +{ + return cgrp->dom_cgrp != cgrp; +} + /* subsystems visibly enabled on a cgroup */ static u16 cgroup_control(struct cgroup *cgrp) { @@ -565,9 +570,11 @@ EXPORT_SYMBOL_GPL(of_css); */ struct css_set init_css_set = { .refcount = REFCOUNT_INIT(1), + .dom_cset = &init_css_set, .tasks = LIST_HEAD_INIT(init_css_set.tasks), .mg_tasks = LIST_HEAD_INIT(init_css_set.mg_tasks), .task_iters = LIST_HEAD_INIT(init_css_set.task_iters), + .threaded_csets = LIST_HEAD_INIT(init_css_set.threaded_csets), .cgrp_links = LIST_HEAD_INIT(init_css_set.cgrp_links), .mg_preload_node = LIST_HEAD_INIT(init_css_set.mg_preload_node), .mg_node = LIST_HEAD_INIT(init_css_set.mg_node), @@ -575,6 +582,11 @@ struct css_set init_css_set = { static int css_set_count = 1; /* 1 for init_css_set */ +static bool css_set_threaded(struct css_set *cset) +{ + return cset->dom_cset != cset; +} + /** * css_set_populated - does a css_set contain any tasks? * @cset: target css_set @@ -618,10 +630,14 @@ static void cgroup_update_populated(struct cgroup *cgrp, bool populated) do { bool was_populated = cgroup_is_populated(cgrp); - if (!child) + if (!child) { cgrp->nr_populated_csets += adj; - else - cgrp->nr_populated_children += adj; + } else { + if (cgroup_is_threaded(child)) + cgrp->nr_populated_threaded_children += adj; + else + cgrp->nr_populated_domain_children += adj; + } if (was_populated == cgroup_is_populated(cgrp)) break; @@ -747,6 +763,8 @@ void put_css_set_locked(struct css_set *cset) if (!refcount_dec_and_test(&cset->refcount)) return; + WARN_ON_ONCE(!list_empty(&cset->threaded_csets)); + /* This css_set is dead. unlink it and release cgroup and css refs */ for_each_subsys(ss, ssid) { list_del(&cset->e_cset_node[ssid]); @@ -763,6 +781,11 @@ void put_css_set_locked(struct css_set *cset) kfree(link); } + if (css_set_threaded(cset)) { + list_del(&cset->threaded_csets_node); + put_css_set_locked(cset->dom_cset); + } + kfree_rcu(cset, rcu_head); } @@ -781,6 +804,7 @@ static bool compare_css_sets(struct css_set *cset, struct cgroup *new_cgrp, struct cgroup_subsys_state *template[]) { + struct cgroup *new_dfl_cgrp; struct list_head *l1, *l2; /* @@ -791,6 +815,16 @@ static bool compare_css_sets(struct css_set *cset, if (memcmp(template, cset->subsys, sizeof(cset->subsys))) return false; + + /* @cset's domain should match the default cgroup's */ + if (cgroup_on_dfl(new_cgrp)) + new_dfl_cgrp = new_cgrp; + else + new_dfl_cgrp = old_cset->dfl_cgrp; + + if (new_dfl_cgrp->dom_cgrp != cset->dom_cset->dfl_cgrp) + return false; + /* * Compare cgroup pointers in order to distinguish between * different cgroups in hierarchies. As different cgroups may @@ -998,9 +1032,11 @@ static struct css_set *find_css_set(struct css_set *old_cset, } refcount_set(&cset->refcount, 1); + cset->dom_cset = cset; INIT_LIST_HEAD(&cset->tasks); INIT_LIST_HEAD(&cset->mg_tasks); INIT_LIST_HEAD(&cset->task_iters); + INIT_LIST_HEAD(&cset->threaded_csets); INIT_HLIST_NODE(&cset->hlist); INIT_LIST_HEAD(&cset->cgrp_links); INIT_LIST_HEAD(&cset->mg_preload_node); @@ -1038,6 +1074,28 @@ static struct css_set *find_css_set(struct css_set *old_cset, spin_unlock_irq(&css_set_lock); + /* + * If @cset should be threaded, look up the matching dom_cset and + * link them up. We first fully initialize @cset then look for the + * dom_cset. It's simpler this way and safe as @cset is guaranteed + * to stay empty until we return. + */ + if (cgroup_is_threaded(cset->dfl_cgrp)) { + struct css_set *dcset; + + dcset = find_css_set(cset, cset->dfl_cgrp->dom_cgrp); + if (!dcset) { + put_css_set(cset); + return NULL; + } + + spin_lock_irq(&css_set_lock); + cset->dom_cset = dcset; + list_add_tail(&cset->threaded_csets_node, + &dcset->threaded_csets); + spin_unlock_irq(&css_set_lock); + } + return cset; } @@ -1680,6 +1738,7 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp) mutex_init(&cgrp->pidlist_mutex); cgrp->self.cgroup = cgrp; cgrp->self.flags |= CSS_ONLINE; + cgrp->dom_cgrp = cgrp; for_each_subsys(ss, ssid) INIT_LIST_HEAD(&cgrp->e_csets[ssid]); @@ -4408,6 +4467,7 @@ static void kill_css(struct cgroup_subsys_state *css) static int cgroup_destroy_locked(struct cgroup *cgrp) __releases(&cgroup_mutex) __acquires(&cgroup_mutex) { + struct cgroup *parent = cgroup_parent(cgrp); struct cgroup_subsys_state *css; struct cgrp_cset_link *link; int ssid; @@ -4452,6 +4512,9 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) */ kernfs_remove(cgrp->kn); + if (parent && cgroup_is_threaded(cgrp)) + parent->nr_threaded_children--; + cgroup1_check_for_release(cgroup_parent(cgrp)); /* put the base reference */ -- cgit v1.2.3 From 450ee0c1feed657894e0b4bdd48f3974af9d394c Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 15 May 2017 09:34:03 -0400 Subject: cgroup: implement CSS_TASK_ITER_THREADED cgroup v2 is in the process of growing thread granularity support. Once thread mode is enabled, the root cgroup of the subtree serves as the dom_cgrp to which the processes of the subtree conceptually belong and domain-level resource consumptions not tied to any specific task are charged. In the subtree, threads won't be subject to process granularity or no-internal-task constraint and can be distributed arbitrarily across the subtree. This patch implements a new task iterator flag CSS_TASK_ITER_THREADED, which, when used on a dom_cgrp, makes the iteration include the tasks on all the associated threaded css_sets. "cgroup.procs" read path is updated to use it so that reading the file on a proc_cgrp lists all processes. This will also be used by controller implementations which need to walk processes or tasks at the resource domain level. Task iteration is implemented nested in css_set iteration. If CSS_TASK_ITER_THREADED is specified, after walking tasks of each !threaded css_set, all the associated threaded css_sets are visited before moving onto the next !threaded css_set. v2: ->cur_pcset renamed to ->cur_dcset. Updated for the new enable-threaded-per-cgroup behavior. Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 77 +++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 60 insertions(+), 17 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index c7e1c243b77d..a1d59af274a9 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3629,6 +3629,58 @@ bool css_has_online_children(struct cgroup_subsys_state *css) return ret; } +static struct css_set *css_task_iter_next_css_set(struct css_task_iter *it) +{ + struct list_head *l; + struct cgrp_cset_link *link; + struct css_set *cset; + + lockdep_assert_held(&css_set_lock); + + /* find the next threaded cset */ + if (it->tcset_pos) { + l = it->tcset_pos->next; + + if (l != it->tcset_head) { + it->tcset_pos = l; + return container_of(l, struct css_set, + threaded_csets_node); + } + + it->tcset_pos = NULL; + } + + /* find the next cset */ + l = it->cset_pos; + l = l->next; + if (l == it->cset_head) { + it->cset_pos = NULL; + return NULL; + } + + if (it->ss) { + cset = container_of(l, struct css_set, e_cset_node[it->ss->id]); + } else { + link = list_entry(l, struct cgrp_cset_link, cset_link); + cset = link->cset; + } + + it->cset_pos = l; + + /* initialize threaded css_set walking */ + if (it->flags & CSS_TASK_ITER_THREADED) { + if (it->cur_dcset) + put_css_set_locked(it->cur_dcset); + it->cur_dcset = cset; + get_css_set(cset); + + it->tcset_head = &cset->threaded_csets; + it->tcset_pos = &cset->threaded_csets; + } + + return cset; +} + /** * css_task_iter_advance_css_set - advance a task itererator to the next css_set * @it: the iterator to advance @@ -3637,32 +3689,19 @@ bool css_has_online_children(struct cgroup_subsys_state *css) */ static void css_task_iter_advance_css_set(struct css_task_iter *it) { - struct list_head *l = it->cset_pos; - struct cgrp_cset_link *link; struct css_set *cset; lockdep_assert_held(&css_set_lock); /* Advance to the next non-empty css_set */ do { - l = l->next; - if (l == it->cset_head) { - it->cset_pos = NULL; + cset = css_task_iter_next_css_set(it); + if (!cset) { it->task_pos = NULL; return; } - - if (it->ss) { - cset = container_of(l, struct css_set, - e_cset_node[it->ss->id]); - } else { - link = list_entry(l, struct cgrp_cset_link, cset_link); - cset = link->cset; - } } while (!css_set_populated(cset)); - it->cset_pos = l; - if (!list_empty(&cset->tasks)) it->task_pos = cset->tasks.next; else @@ -3805,6 +3844,9 @@ void css_task_iter_end(struct css_task_iter *it) spin_unlock_irq(&css_set_lock); } + if (it->cur_dcset) + put_css_set(it->cur_dcset); + if (it->cur_task) put_task_struct(it->cur_task); } @@ -3830,6 +3872,7 @@ static void *cgroup_procs_start(struct seq_file *s, loff_t *pos) struct kernfs_open_file *of = s->private; struct cgroup *cgrp = seq_css(s)->cgroup; struct css_task_iter *it = of->priv; + unsigned iter_flags = CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED; /* * When a seq_file is seeked, it's always traversed sequentially @@ -3843,10 +3886,10 @@ static void *cgroup_procs_start(struct seq_file *s, loff_t *pos) if (!it) return ERR_PTR(-ENOMEM); of->priv = it; - css_task_iter_start(&cgrp->self, CSS_TASK_ITER_PROCS, it); + css_task_iter_start(&cgrp->self, iter_flags, it); } else if (!(*pos)++) { css_task_iter_end(it); - css_task_iter_start(&cgrp->self, CSS_TASK_ITER_PROCS, it); + css_task_iter_start(&cgrp->self, iter_flags, it); } return cgroup_procs_next(s, NULL, NULL); -- cgit v1.2.3 From 8cfd8147df67e741d93b8783a3ea8f3c74f93a0e Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 21 Jul 2017 11:14:51 -0400 Subject: cgroup: implement cgroup v2 thread support This patch implements cgroup v2 thread support. The goal of the thread mode is supporting hierarchical accounting and control at thread granularity while staying inside the resource domain model which allows coordination across different resource controllers and handling of anonymous resource consumptions. A cgroup is always created as a domain and can be made threaded by writing to the "cgroup.type" file. When a cgroup becomes threaded, it becomes a member of a threaded subtree which is anchored at the closest ancestor which isn't threaded. The threads of the processes which are in a threaded subtree can be placed anywhere without being restricted by process granularity or no-internal-process constraint. Note that the threads aren't allowed to escape to a different threaded subtree. To be used inside a threaded subtree, a controller should explicitly support threaded mode and be able to handle internal competition in the way which is appropriate for the resource. The root of a threaded subtree, the nearest ancestor which isn't threaded, is called the threaded domain and serves as the resource domain for the whole subtree. This is the last cgroup where domain controllers are operational and where all the domain-level resource consumptions in the subtree are accounted. This allows threaded controllers to operate at thread granularity when requested while staying inside the scope of system-level resource distribution. As the root cgroup is exempt from the no-internal-process constraint, it can serve as both a threaded domain and a parent to normal cgroups, so, unlike non-root cgroups, the root cgroup can have both domain and threaded children. Internally, in a threaded subtree, each css_set has its ->dom_cset pointing to a matching css_set which belongs to the threaded domain. This ensures that thread root level cgroup_subsys_state for all threaded controllers are readily accessible for domain-level operations. This patch enables threaded mode for the pids and perf_events controllers. Neither has to worry about domain-level resource consumptions and it's enough to simply set the flag. For more details on the interface and behavior of the thread mode, please refer to the section 2-2-2 in Documentation/cgroup-v2.txt added by this patch. v5: - Dropped silly no-op ->dom_cgrp init from cgroup_create(). Spotted by Waiman. - Documentation updated as suggested by Waiman. - cgroup.type content slightly reformatted. - Mark the debug controller threaded. v4: - Updated to the general idea of marking specific cgroups domain/threaded as suggested by PeterZ. v3: - Dropped "join" and always make mixed children join the parent's threaded subtree. v2: - After discussions with Waiman, support for mixed thread mode is added. This should address the issue that Peter pointed out where any nesting should be avoided for thread subtrees while coexisting with other domain cgroups. - Enabling / disabling thread mode now piggy backs on the existing control mask update mechanism. - Bug fixes and cleanup. Signed-off-by: Tejun Heo Cc: Waiman Long Cc: Peter Zijlstra --- kernel/cgroup/cgroup-internal.h | 2 +- kernel/cgroup/cgroup-v1.c | 5 +- kernel/cgroup/cgroup.c | 355 +++++++++++++++++++++++++++++++++++++--- kernel/cgroup/debug.c | 1 + kernel/cgroup/pids.c | 1 + kernel/events/core.c | 1 + 6 files changed, 340 insertions(+), 25 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h index 0e81c6109e91..f10eb19ddf04 100644 --- a/kernel/cgroup/cgroup-internal.h +++ b/kernel/cgroup/cgroup-internal.h @@ -170,7 +170,7 @@ struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, struct cgroup_root *root, unsigned long magic, struct cgroup_namespace *ns); -bool cgroup_may_migrate_to(struct cgroup *dst_cgrp); +int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp); void cgroup_migrate_finish(struct cgroup_mgctx *mgctx); void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp, struct cgroup_mgctx *mgctx); diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index 167aaab04bf9..f0e8601b13cb 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -99,8 +99,9 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from) if (cgroup_on_dfl(to)) return -EINVAL; - if (!cgroup_may_migrate_to(to)) - return -EBUSY; + ret = cgroup_migrate_vet_dst(to); + if (ret) + return ret; mutex_lock(&cgroup_mutex); diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index a1d59af274a9..c396e701c206 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -162,6 +162,9 @@ static u16 cgrp_dfl_inhibit_ss_mask; /* some controllers are implicitly enabled on the default hierarchy */ static u16 cgrp_dfl_implicit_ss_mask; +/* some controllers can be threaded on the default hierarchy */ +static u16 cgrp_dfl_threaded_ss_mask; + /* The list of hierarchy roots */ LIST_HEAD(cgroup_roots); static int cgroup_root_count; @@ -335,14 +338,93 @@ static bool cgroup_is_threaded(struct cgroup *cgrp) return cgrp->dom_cgrp != cgrp; } +/* can @cgrp host both domain and threaded children? */ +static bool cgroup_is_mixable(struct cgroup *cgrp) +{ + /* + * Root isn't under domain level resource control exempting it from + * the no-internal-process constraint, so it can serve as a thread + * root and a parent of resource domains at the same time. + */ + return !cgroup_parent(cgrp); +} + +/* can @cgrp become a thread root? should always be true for a thread root */ +static bool cgroup_can_be_thread_root(struct cgroup *cgrp) +{ + /* mixables don't care */ + if (cgroup_is_mixable(cgrp)) + return true; + + /* domain roots can't be nested under threaded */ + if (cgroup_is_threaded(cgrp)) + return false; + + /* can only have either domain or threaded children */ + if (cgrp->nr_populated_domain_children) + return false; + + /* and no domain controllers can be enabled */ + if (cgrp->subtree_control & ~cgrp_dfl_threaded_ss_mask) + return false; + + return true; +} + +/* is @cgrp root of a threaded subtree? */ +static bool cgroup_is_thread_root(struct cgroup *cgrp) +{ + /* thread root should be a domain */ + if (cgroup_is_threaded(cgrp)) + return false; + + /* a domain w/ threaded children is a thread root */ + if (cgrp->nr_threaded_children) + return true; + + /* + * A domain which has tasks and explicit threaded controllers + * enabled is a thread root. + */ + if (cgroup_has_tasks(cgrp) && + (cgrp->subtree_control & cgrp_dfl_threaded_ss_mask)) + return true; + + return false; +} + +/* a domain which isn't connected to the root w/o brekage can't be used */ +static bool cgroup_is_valid_domain(struct cgroup *cgrp) +{ + /* the cgroup itself can be a thread root */ + if (cgroup_is_threaded(cgrp)) + return false; + + /* but the ancestors can't be unless mixable */ + while ((cgrp = cgroup_parent(cgrp))) { + if (!cgroup_is_mixable(cgrp) && cgroup_is_thread_root(cgrp)) + return false; + if (cgroup_is_threaded(cgrp)) + return false; + } + + return true; +} + /* subsystems visibly enabled on a cgroup */ static u16 cgroup_control(struct cgroup *cgrp) { struct cgroup *parent = cgroup_parent(cgrp); u16 root_ss_mask = cgrp->root->subsys_mask; - if (parent) - return parent->subtree_control; + if (parent) { + u16 ss_mask = parent->subtree_control; + + /* threaded cgroups can only have threaded controllers */ + if (cgroup_is_threaded(cgrp)) + ss_mask &= cgrp_dfl_threaded_ss_mask; + return ss_mask; + } if (cgroup_on_dfl(cgrp)) root_ss_mask &= ~(cgrp_dfl_inhibit_ss_mask | @@ -355,8 +437,14 @@ static u16 cgroup_ss_mask(struct cgroup *cgrp) { struct cgroup *parent = cgroup_parent(cgrp); - if (parent) - return parent->subtree_ss_mask; + if (parent) { + u16 ss_mask = parent->subtree_ss_mask; + + /* threaded cgroups can only have threaded controllers */ + if (cgroup_is_threaded(cgrp)) + ss_mask &= cgrp_dfl_threaded_ss_mask; + return ss_mask; + } return cgrp->root->subsys_mask; } @@ -2237,17 +2325,40 @@ out_release_tset: } /** - * cgroup_may_migrate_to - verify whether a cgroup can be migration destination + * cgroup_migrate_vet_dst - verify whether a cgroup can be migration destination * @dst_cgrp: destination cgroup to test * - * On the default hierarchy, except for the root, subtree_control must be - * zero for migration destination cgroups with tasks so that child cgroups - * don't compete against tasks. + * On the default hierarchy, except for the mixable, (possible) thread root + * and threaded cgroups, subtree_control must be zero for migration + * destination cgroups with tasks so that child cgroups don't compete + * against tasks. */ -bool cgroup_may_migrate_to(struct cgroup *dst_cgrp) +int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp) { - return !cgroup_on_dfl(dst_cgrp) || !cgroup_parent(dst_cgrp) || - !dst_cgrp->subtree_control; + /* v1 doesn't have any restriction */ + if (!cgroup_on_dfl(dst_cgrp)) + return 0; + + /* verify @dst_cgrp can host resources */ + if (!cgroup_is_valid_domain(dst_cgrp->dom_cgrp)) + return -EOPNOTSUPP; + + /* mixables don't care */ + if (cgroup_is_mixable(dst_cgrp)) + return 0; + + /* + * If @dst_cgrp is already or can become a thread root or is + * threaded, it doesn't matter. + */ + if (cgroup_can_be_thread_root(dst_cgrp) || cgroup_is_threaded(dst_cgrp)) + return 0; + + /* apply no-internal-process constraint */ + if (dst_cgrp->subtree_control) + return -EBUSY; + + return 0; } /** @@ -2452,8 +2563,9 @@ int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader, struct task_struct *task; int ret; - if (!cgroup_may_migrate_to(dst_cgrp)) - return -EBUSY; + ret = cgroup_migrate_vet_dst(dst_cgrp); + if (ret) + return ret; /* look up all src csets */ spin_lock_irq(&css_set_lock); @@ -2881,6 +2993,46 @@ static void cgroup_finalize_control(struct cgroup *cgrp, int ret) cgroup_apply_control_disable(cgrp); } +static int cgroup_vet_subtree_control_enable(struct cgroup *cgrp, u16 enable) +{ + u16 domain_enable = enable & ~cgrp_dfl_threaded_ss_mask; + + /* if nothing is getting enabled, nothing to worry about */ + if (!enable) + return 0; + + /* can @cgrp host any resources? */ + if (!cgroup_is_valid_domain(cgrp->dom_cgrp)) + return -EOPNOTSUPP; + + /* mixables don't care */ + if (cgroup_is_mixable(cgrp)) + return 0; + + if (domain_enable) { + /* can't enable domain controllers inside a thread subtree */ + if (cgroup_is_thread_root(cgrp) || cgroup_is_threaded(cgrp)) + return -EOPNOTSUPP; + } else { + /* + * Threaded controllers can handle internal competitions + * and are always allowed inside a (prospective) thread + * subtree. + */ + if (cgroup_can_be_thread_root(cgrp) || cgroup_is_threaded(cgrp)) + return 0; + } + + /* + * Controllers can't be enabled for a cgroup with tasks to avoid + * child cgroups competing against tasks. + */ + if (cgroup_has_tasks(cgrp)) + return -EBUSY; + + return 0; +} + /* change the enabled child controllers for a cgroup in the default hierarchy */ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, char *buf, size_t nbytes, @@ -2956,14 +3108,9 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, goto out_unlock; } - /* - * Except for the root, subtree_control must be zero for a cgroup - * with tasks so that child cgroups don't compete against tasks. - */ - if (enable && cgroup_parent(cgrp) && cgroup_has_tasks(cgrp)) { - ret = -EBUSY; + ret = cgroup_vet_subtree_control_enable(cgrp, enable); + if (ret) goto out_unlock; - } /* save and update control masks and prepare csses */ cgroup_save_control(cgrp); @@ -2982,6 +3129,84 @@ out_unlock: return ret ?: nbytes; } +static int cgroup_enable_threaded(struct cgroup *cgrp) +{ + struct cgroup *parent = cgroup_parent(cgrp); + struct cgroup *dom_cgrp = parent->dom_cgrp; + int ret; + + lockdep_assert_held(&cgroup_mutex); + + /* noop if already threaded */ + if (cgroup_is_threaded(cgrp)) + return 0; + + /* we're joining the parent's domain, ensure its validity */ + if (!cgroup_is_valid_domain(dom_cgrp) || + !cgroup_can_be_thread_root(dom_cgrp)) + return -EOPNOTSUPP; + + /* + * Allow enabling thread mode only on empty cgroups to avoid + * implicit migrations and recursive operations. + */ + if (cgroup_has_tasks(cgrp) || css_has_online_children(&cgrp->self)) + return -EBUSY; + + /* + * The following shouldn't cause actual migrations and should + * always succeed. + */ + cgroup_save_control(cgrp); + + cgrp->dom_cgrp = dom_cgrp; + ret = cgroup_apply_control(cgrp); + if (!ret) + parent->nr_threaded_children++; + else + cgrp->dom_cgrp = cgrp; + + cgroup_finalize_control(cgrp, ret); + return ret; +} + +static int cgroup_type_show(struct seq_file *seq, void *v) +{ + struct cgroup *cgrp = seq_css(seq)->cgroup; + + if (cgroup_is_threaded(cgrp)) + seq_puts(seq, "threaded\n"); + else if (!cgroup_is_valid_domain(cgrp)) + seq_puts(seq, "domain invalid\n"); + else if (cgroup_is_thread_root(cgrp)) + seq_puts(seq, "domain threaded\n"); + else + seq_puts(seq, "domain\n"); + + return 0; +} + +static ssize_t cgroup_type_write(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) +{ + struct cgroup *cgrp; + int ret; + + /* only switching to threaded mode is supported */ + if (strcmp(strstrip(buf), "threaded")) + return -EINVAL; + + cgrp = cgroup_kn_lock_live(of->kn, false); + if (!cgrp) + return -ENOENT; + + /* threaded can only be enabled */ + ret = cgroup_enable_threaded(cgrp); + + cgroup_kn_unlock(of->kn); + return ret ?: nbytes; +} + static int cgroup_events_show(struct seq_file *seq, void *v) { seq_printf(seq, "populated %d\n", @@ -3867,12 +4092,12 @@ static void *cgroup_procs_next(struct seq_file *s, void *v, loff_t *pos) return css_task_iter_next(it); } -static void *cgroup_procs_start(struct seq_file *s, loff_t *pos) +static void *__cgroup_procs_start(struct seq_file *s, loff_t *pos, + unsigned int iter_flags) { struct kernfs_open_file *of = s->private; struct cgroup *cgrp = seq_css(s)->cgroup; struct css_task_iter *it = of->priv; - unsigned iter_flags = CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED; /* * When a seq_file is seeked, it's always traversed sequentially @@ -3895,6 +4120,23 @@ static void *cgroup_procs_start(struct seq_file *s, loff_t *pos) return cgroup_procs_next(s, NULL, NULL); } +static void *cgroup_procs_start(struct seq_file *s, loff_t *pos) +{ + struct cgroup *cgrp = seq_css(s)->cgroup; + + /* + * All processes of a threaded subtree belong to the domain cgroup + * of the subtree. Only threads can be distributed across the + * subtree. Reject reads on cgroup.procs in the subtree proper. + * They're always empty anyway. + */ + if (cgroup_is_threaded(cgrp)) + return ERR_PTR(-EOPNOTSUPP); + + return __cgroup_procs_start(s, pos, CSS_TASK_ITER_PROCS | + CSS_TASK_ITER_THREADED); +} + static int cgroup_procs_show(struct seq_file *s, void *v) { seq_printf(s, "%d\n", task_pid_vnr(v)); @@ -3974,8 +4216,63 @@ out_unlock: return ret ?: nbytes; } +static void *cgroup_threads_start(struct seq_file *s, loff_t *pos) +{ + return __cgroup_procs_start(s, pos, 0); +} + +static ssize_t cgroup_threads_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct cgroup *src_cgrp, *dst_cgrp; + struct task_struct *task; + ssize_t ret; + + buf = strstrip(buf); + + dst_cgrp = cgroup_kn_lock_live(of->kn, false); + if (!dst_cgrp) + return -ENODEV; + + task = cgroup_procs_write_start(buf, false); + ret = PTR_ERR_OR_ZERO(task); + if (ret) + goto out_unlock; + + /* find the source cgroup */ + spin_lock_irq(&css_set_lock); + src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root); + spin_unlock_irq(&css_set_lock); + + /* thread migrations follow the cgroup.procs delegation rule */ + ret = cgroup_procs_write_permission(src_cgrp, dst_cgrp, + of->file->f_path.dentry->d_sb); + if (ret) + goto out_finish; + + /* and must be contained in the same domain */ + ret = -EOPNOTSUPP; + if (src_cgrp->dom_cgrp != dst_cgrp->dom_cgrp) + goto out_finish; + + ret = cgroup_attach_task(dst_cgrp, task, false); + +out_finish: + cgroup_procs_write_finish(task); +out_unlock: + cgroup_kn_unlock(of->kn); + + return ret ?: nbytes; +} + /* cgroup core interface files for the default hierarchy */ static struct cftype cgroup_base_files[] = { + { + .name = "cgroup.type", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = cgroup_type_show, + .write = cgroup_type_write, + }, { .name = "cgroup.procs", .flags = CFTYPE_NS_DELEGATABLE, @@ -3986,6 +4283,14 @@ static struct cftype cgroup_base_files[] = { .seq_show = cgroup_procs_show, .write = cgroup_procs_write, }, + { + .name = "cgroup.threads", + .release = cgroup_procs_release, + .seq_start = cgroup_threads_start, + .seq_next = cgroup_procs_next, + .seq_show = cgroup_procs_show, + .write = cgroup_threads_write, + }, { .name = "cgroup.controllers", .seq_show = cgroup_controllers_show, @@ -4753,11 +5058,17 @@ int __init cgroup_init(void) cgrp_dfl_root.subsys_mask |= 1 << ss->id; + /* implicit controllers must be threaded too */ + WARN_ON(ss->implicit_on_dfl && !ss->threaded); + if (ss->implicit_on_dfl) cgrp_dfl_implicit_ss_mask |= 1 << ss->id; else if (!ss->dfl_cftypes) cgrp_dfl_inhibit_ss_mask |= 1 << ss->id; + if (ss->threaded) + cgrp_dfl_threaded_ss_mask |= 1 << ss->id; + if (ss->dfl_cftypes == ss->legacy_cftypes) { WARN_ON(cgroup_add_cftypes(ss, ss->dfl_cftypes)); } else { diff --git a/kernel/cgroup/debug.c b/kernel/cgroup/debug.c index dac46af22782..787a242fa69d 100644 --- a/kernel/cgroup/debug.c +++ b/kernel/cgroup/debug.c @@ -352,6 +352,7 @@ static int __init enable_cgroup_debug(char *str) { debug_cgrp_subsys.dfl_cftypes = debug_files; debug_cgrp_subsys.implicit_on_dfl = true; + debug_cgrp_subsys.threaded = true; return 1; } __setup("cgroup_debug", enable_cgroup_debug); diff --git a/kernel/cgroup/pids.c b/kernel/cgroup/pids.c index 2237201d66d5..9829c67ebc0a 100644 --- a/kernel/cgroup/pids.c +++ b/kernel/cgroup/pids.c @@ -345,4 +345,5 @@ struct cgroup_subsys pids_cgrp_subsys = { .free = pids_free, .legacy_cftypes = pids_files, .dfl_cftypes = pids_files, + .threaded = true, }; diff --git a/kernel/events/core.c b/kernel/events/core.c index 1538df9b2b65..ec78247da310 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11210,5 +11210,6 @@ struct cgroup_subsys perf_event_cgrp_subsys = { * controller is not mounted on a legacy hierarchy. */ .implicit_on_dfl = true, + .threaded = true, }; #endif /* CONFIG_CGROUP_PERF */ -- cgit v1.2.3 From 7a0cf0e74ab6cfd8e561f5f12860d4ff8844905a Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Fri, 21 Jul 2017 11:14:51 -0400 Subject: cgroup: update debug controller to print out thread mode information Update debug controller so that it prints out debug info about thread mode. 1) The relationship between proc_cset and threaded_csets are displayed. 2) The status of being a thread root or threaded cgroup is displayed. This patch is extracted from Waiman's larger patch. v2: - Removed [thread root] / [threaded] from debug.cgroup_css_links file as the same information is available from cgroup.type. Suggested by Waiman. - Threaded marking is moved to the previous patch. Patch-originally-by: Waiman Long Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup-internal.h | 2 ++ kernel/cgroup/cgroup.c | 4 ++-- kernel/cgroup/debug.c | 52 ++++++++++++++++++++++++++++++----------- 3 files changed, 42 insertions(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h index f10eb19ddf04..c167a40278e6 100644 --- a/kernel/cgroup/cgroup-internal.h +++ b/kernel/cgroup/cgroup-internal.h @@ -153,6 +153,8 @@ static inline void get_css_set(struct css_set *cset) bool cgroup_ssid_enabled(int ssid); bool cgroup_on_dfl(const struct cgroup *cgrp); +bool cgroup_is_thread_root(struct cgroup *cgrp); +bool cgroup_is_threaded(struct cgroup *cgrp); struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root); struct cgroup *task_cgroup_from_root(struct task_struct *task, diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index c396e701c206..e9a377dc5bdb 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -333,7 +333,7 @@ static bool cgroup_has_tasks(struct cgroup *cgrp) return cgrp->nr_populated_csets; } -static bool cgroup_is_threaded(struct cgroup *cgrp) +bool cgroup_is_threaded(struct cgroup *cgrp) { return cgrp->dom_cgrp != cgrp; } @@ -372,7 +372,7 @@ static bool cgroup_can_be_thread_root(struct cgroup *cgrp) } /* is @cgrp root of a threaded subtree? */ -static bool cgroup_is_thread_root(struct cgroup *cgrp) +bool cgroup_is_thread_root(struct cgroup *cgrp) { /* thread root should be a domain */ if (cgroup_is_threaded(cgrp)) diff --git a/kernel/cgroup/debug.c b/kernel/cgroup/debug.c index 787a242fa69d..f661b4cc5efd 100644 --- a/kernel/cgroup/debug.c +++ b/kernel/cgroup/debug.c @@ -114,27 +114,49 @@ static int cgroup_css_links_read(struct seq_file *seq, void *v) { struct cgroup_subsys_state *css = seq_css(seq); struct cgrp_cset_link *link; - int dead_cnt = 0, extra_refs = 0; + int dead_cnt = 0, extra_refs = 0, threaded_csets = 0; spin_lock_irq(&css_set_lock); + list_for_each_entry(link, &css->cgroup->cset_links, cset_link) { struct css_set *cset = link->cset; struct task_struct *task; int count = 0; int refcnt = refcount_read(&cset->refcount); - seq_printf(seq, " %d", refcnt); - if (refcnt - cset->nr_tasks > 0) { - int extra = refcnt - cset->nr_tasks; - - seq_printf(seq, " +%d", extra); - /* - * Take out the one additional reference in - * init_css_set. - */ - if (cset == &init_css_set) - extra--; - extra_refs += extra; + /* + * Print out the proc_cset and threaded_cset relationship + * and highlight difference between refcount and task_count. + */ + seq_printf(seq, "css_set %pK", cset); + if (rcu_dereference_protected(cset->dom_cset, 1) != cset) { + threaded_csets++; + seq_printf(seq, "=>%pK", cset->dom_cset); + } + if (!list_empty(&cset->threaded_csets)) { + struct css_set *tcset; + int idx = 0; + + list_for_each_entry(tcset, &cset->threaded_csets, + threaded_csets_node) { + seq_puts(seq, idx ? "," : "<="); + seq_printf(seq, "%pK", tcset); + idx++; + } + } else { + seq_printf(seq, " %d", refcnt); + if (refcnt - cset->nr_tasks > 0) { + int extra = refcnt - cset->nr_tasks; + + seq_printf(seq, " +%d", extra); + /* + * Take out the one additional reference in + * init_css_set. + */ + if (cset == &init_css_set) + extra--; + extra_refs += extra; + } } seq_puts(seq, "\n"); @@ -163,10 +185,12 @@ static int cgroup_css_links_read(struct seq_file *seq, void *v) } spin_unlock_irq(&css_set_lock); - if (!dead_cnt && !extra_refs) + if (!dead_cnt && !extra_refs && !threaded_csets) return 0; seq_puts(seq, "\n"); + if (threaded_csets) + seq_printf(seq, "threaded css_sets = %d\n", threaded_csets); if (extra_refs) seq_printf(seq, "extra references = %d\n", extra_refs); if (dead_cnt) -- cgit v1.2.3 From db3e50f3234ba1a477413f56a9e5800a73dca786 Mon Sep 17 00:00:00 2001 From: Sakari Ailus Date: Fri, 21 Jul 2017 14:39:31 +0300 Subject: device property: Get rid of struct fwnode_handle type field Instead of relying on the struct fwnode_handle type field, define fwnode_operations structs for all separate types of fwnodes. To find out the type, compare to the ops field to relevant ops structs. This change has two benefits: 1. it avoids adding the type field to each and every instance of struct fwnode_handle, thus saving memory and 2. makes the ops field the single factor that defines both the types of the fwnode as well as defines the implementation of its operations, decreasing the possibility of bugs when developing code dealing with fwnode internals. Suggested-by: Rob Herring Signed-off-by: Sakari Ailus Reviewed-by: Mika Westerberg Signed-off-by: Rafael J. Wysocki --- kernel/irq/irqdomain.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index f1f251479aa6..e064fd1390f1 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -41,6 +41,8 @@ static inline void debugfs_add_domain_dir(struct irq_domain *d) { } static inline void debugfs_remove_domain_dir(struct irq_domain *d) { } #endif +const struct fwnode_operations irqchip_fwnode_ops; + /** * irq_domain_alloc_fwnode - Allocate a fwnode_handle suitable for * identifying an irq domain @@ -86,7 +88,7 @@ struct fwnode_handle *__irq_domain_alloc_fwnode(unsigned int type, int id, fwid->type = type; fwid->name = n; fwid->data = data; - fwid->fwnode.type = FWNODE_IRQCHIP; + fwid->fwnode.ops = &irqchip_fwnode_ops; return &fwid->fwnode; } EXPORT_SYMBOL_GPL(__irq_domain_alloc_fwnode); @@ -193,10 +195,8 @@ struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, int size, } if (!domain->name) { - if (fwnode) { - pr_err("Invalid fwnode type (%d) for irqdomain\n", - fwnode->type); - } + if (fwnode) + pr_err("Invalid fwnode type for irqdomain\n"); domain->name = kasprintf(GFP_KERNEL, "unknown-%d", atomic_inc_return(&unknown_domains)); if (!domain->name) { -- cgit v1.2.3 From aa7519af450d3c62a057aece24877c34562fa25a Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 19 Jul 2017 15:42:42 +0530 Subject: cpufreq: Use transition_delay_us for legacy governors as well The policy->transition_delay_us field is used only by the schedutil governor currently, and this field describes how fast the driver wants the cpufreq governor to change CPUs frequency. It should rather be a common thing across all governors, as it doesn't have any schedutil dependency here. Create a new helper cpufreq_policy_transition_delay_us() to get the transition delay across all governors. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- kernel/sched/cpufreq_schedutil.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 29a397067ffa..89c4dd9777bb 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -528,16 +528,7 @@ static int sugov_init(struct cpufreq_policy *policy) goto stop_kthread; } - if (policy->transition_delay_us) { - tunables->rate_limit_us = policy->transition_delay_us; - } else { - unsigned int lat; - - tunables->rate_limit_us = LATENCY_MULTIPLIER; - lat = policy->cpuinfo.transition_latency / NSEC_PER_USEC; - if (lat) - tunables->rate_limit_us *= lat; - } + tunables->rate_limit_us = cpufreq_policy_transition_delay_us(policy); policy->governor_data = sg_policy; sg_policy->tunables = tunables; -- cgit v1.2.3 From bd8c9ba3b1e2037af5af4e48aea1087212838179 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Mon, 17 Jul 2017 17:19:25 -0700 Subject: PM / suspend: Export pm_suspend_target_state Have the core suspend/resume framework store the system-wide suspend state (suspend_state_t) we are about to enter, and expose it to drivers via pm_suspend_target_state in order to retrieve that. The state is assigned in suspend_devices_and_enter(). This is useful for platform specific drivers that may need to take a slightly different suspend/resume path based on the system's suspend/resume state being entered. Signed-off-by: Florian Fainelli Acked-by: Pavel Machek Signed-off-by: Rafael J. Wysocki --- kernel/power/suspend.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'kernel') diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 3ecf275d7e44..d0c0b96c2383 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -47,6 +47,8 @@ const char *mem_sleep_states[PM_SUSPEND_MAX]; suspend_state_t mem_sleep_current = PM_SUSPEND_FREEZE; static suspend_state_t mem_sleep_default = PM_SUSPEND_MEM; +suspend_state_t pm_suspend_target_state; +EXPORT_SYMBOL_GPL(pm_suspend_target_state); unsigned int pm_suspend_global_flags; EXPORT_SYMBOL_GPL(pm_suspend_global_flags); @@ -456,6 +458,8 @@ int suspend_devices_and_enter(suspend_state_t state) if (!sleep_state_supported(state)) return -ENOSYS; + pm_suspend_target_state = state; + error = platform_suspend_begin(state); if (error) goto Close; @@ -485,6 +489,7 @@ int suspend_devices_and_enter(suspend_state_t state) Close: platform_resume_end(state); + pm_suspend_target_state = PM_SUSPEND_ON; return error; Recover_platform: -- cgit v1.2.3 From 8d8b2441db9647890251538f60b75a4e45fdef8d Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 19 Jul 2017 02:38:44 +0200 Subject: PM / sleep: Do not print debug messages by default Debug messages from the system suspend/hibernation infrastructure can fill up the entire kernel log buffer in some cases and anyway they are only useful for debugging. They depend on CONFIG_PM_DEBUG, but that is set as a rule as some generally useful diagnostic facilities depend on it too. For this reason, avoid printing those messages by default, but make it possible to turn them on as needed with the help of a new sysfs attribute under /sys/power/. Signed-off-by: Rafael J. Wysocki --- kernel/power/hibernate.c | 24 +++++++++++----------- kernel/power/main.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++ kernel/power/suspend.c | 10 +++++----- 3 files changed, 69 insertions(+), 17 deletions(-) (limited to 'kernel') diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index e1914c7b85b1..e19ee179d211 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -651,7 +651,7 @@ static int load_image_and_restore(void) int error; unsigned int flags; - pr_debug("Loading hibernation image.\n"); + pm_pr_dbg("Loading hibernation image.\n"); lock_device_hotplug(); error = create_basic_memory_bitmaps(); @@ -681,7 +681,7 @@ int hibernate(void) bool snapshot_test = false; if (!hibernation_available()) { - pr_debug("Hibernation not available.\n"); + pm_pr_dbg("Hibernation not available.\n"); return -EPERM; } @@ -727,7 +727,7 @@ int hibernate(void) else flags |= SF_CRC32_MODE; - pr_debug("Writing image.\n"); + pm_pr_dbg("Writing image.\n"); error = swsusp_write(flags); swsusp_free(); if (!error) { @@ -739,7 +739,7 @@ int hibernate(void) in_suspend = 0; pm_restore_gfp_mask(); } else { - pr_debug("Image restored successfully.\n"); + pm_pr_dbg("Image restored successfully.\n"); } Free_bitmaps: @@ -747,7 +747,7 @@ int hibernate(void) Thaw: unlock_device_hotplug(); if (snapshot_test) { - pr_debug("Checking hibernation image\n"); + pm_pr_dbg("Checking hibernation image\n"); error = swsusp_check(); if (!error) error = load_image_and_restore(); @@ -811,7 +811,7 @@ static int software_resume(void) goto Unlock; } - pr_debug("Checking hibernation image partition %s\n", resume_file); + pm_pr_dbg("Checking hibernation image partition %s\n", resume_file); if (resume_delay) { pr_info("Waiting %dsec before reading resume device ...\n", @@ -853,10 +853,10 @@ static int software_resume(void) } Check_image: - pr_debug("Hibernation image partition %d:%d present\n", + pm_pr_dbg("Hibernation image partition %d:%d present\n", MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device)); - pr_debug("Looking for hibernation image.\n"); + pm_pr_dbg("Looking for hibernation image.\n"); error = swsusp_check(); if (error) goto Unlock; @@ -875,7 +875,7 @@ static int software_resume(void) goto Close_Finish; } - pr_debug("Preparing processes for restore.\n"); + pm_pr_dbg("Preparing processes for restore.\n"); error = freeze_processes(); if (error) goto Close_Finish; @@ -888,7 +888,7 @@ static int software_resume(void) /* For success case, the suspend path will release the lock */ Unlock: mutex_unlock(&pm_mutex); - pr_debug("Hibernation image not present or could not be loaded.\n"); + pm_pr_dbg("Hibernation image not present or could not be loaded.\n"); return error; Close_Finish: swsusp_close(FMODE_READ); @@ -1012,8 +1012,8 @@ static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr, error = -EINVAL; if (!error) - pr_debug("Hibernation mode set to '%s'\n", - hibernation_modes[mode]); + pm_pr_dbg("Hibernation mode set to '%s'\n", + hibernation_modes[mode]); unlock_system_sleep(); return error ? error : n; } diff --git a/kernel/power/main.c b/kernel/power/main.c index 42bd800a6755..5ce00902c7e3 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -361,6 +361,57 @@ static ssize_t pm_wakeup_irq_show(struct kobject *kobj, power_attr_ro(pm_wakeup_irq); +static bool pm_debug_messages_on __read_mostly; + +static ssize_t pm_debug_messages_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", pm_debug_messages_on); +} + +static ssize_t pm_debug_messages_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t n) +{ + unsigned long val; + + if (kstrtoul(buf, 10, &val)) + return -EINVAL; + + if (val > 1) + return -EINVAL; + + pm_debug_messages_on = !!val; + return n; +} + +power_attr(pm_debug_messages); + +/** + * pm_pr_dbg - Print a suspend debug message to the kernel log. + * @fmt: Message format. + * + * The message will be emitted if enabled through the pm_debug_messages + * sysfs attribute. + */ +void pm_pr_dbg(const char *fmt, ...) +{ + struct va_format vaf; + va_list args; + + if (!pm_debug_messages_on) + return; + + va_start(args, fmt); + + vaf.fmt = fmt; + vaf.va = &args; + + printk(KERN_DEBUG "PM: %pV", &vaf); + + va_end(args); +} + #else /* !CONFIG_PM_SLEEP_DEBUG */ static inline void pm_print_times_init(void) {} #endif /* CONFIG_PM_SLEEP_DEBUG */ @@ -697,6 +748,7 @@ static struct attribute * g[] = { #ifdef CONFIG_PM_SLEEP_DEBUG &pm_print_times_attr.attr, &pm_wakeup_irq_attr.attr, + &pm_debug_messages_attr.attr, #endif #endif #ifdef CONFIG_FREEZER diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index d0c0b96c2383..4f10773322fa 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -106,7 +106,7 @@ static void freeze_enter(void) static void s2idle_loop(void) { - pr_debug("PM: suspend-to-idle\n"); + pm_pr_dbg("suspend-to-idle\n"); do { freeze_enter(); @@ -124,7 +124,7 @@ static void s2idle_loop(void) pm_wakeup_clear(false); } while (!dpm_suspend_noirq(PMSG_SUSPEND)); - pr_debug("PM: resume from suspend-to-idle\n"); + pm_pr_dbg("resume from suspend-to-idle\n"); } void freeze_wake(void) @@ -547,7 +547,7 @@ static int enter_state(suspend_state_t state) trace_suspend_resume(TPS("sync_filesystems"), 0, false); #endif - pr_debug("PM: Preparing system for sleep (%s)\n", pm_states[state]); + pm_pr_dbg("Preparing system for sleep (%s)\n", pm_states[state]); pm_suspend_clear_flags(); error = suspend_prepare(state); if (error) @@ -557,13 +557,13 @@ static int enter_state(suspend_state_t state) goto Finish; trace_suspend_resume(TPS("suspend_enter"), state, false); - pr_debug("PM: Suspending system (%s)\n", pm_states[state]); + pm_pr_dbg("Suspending system (%s)\n", pm_states[state]); pm_restrict_gfp_mask(); error = suspend_devices_and_enter(state); pm_restore_gfp_mask(); Finish: - pr_debug("PM: Finishing wakeup.\n"); + pm_pr_dbg("Finishing wakeup.\n"); suspend_finish(); Unlock: mutex_unlock(&pm_mutex); -- cgit v1.2.3 From 8915aa2042f85ecf86d4a202ef6d04bf06f05cca Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 20 Jul 2017 03:38:07 +0200 Subject: PM / sleep: Mark suspend/hibernation start and finish Regardless of whether or not debug messages from the core system suspend/hibernation code are enabled, it is useful to know when system-wide transitions start and finish (or fail), so print "info" messages at these points. Signed-off-by: Rafael J. Wysocki Acked-by: Mark Salyzyn --- kernel/power/hibernate.c | 5 +++++ kernel/power/suspend.c | 2 ++ 2 files changed, 7 insertions(+) (limited to 'kernel') diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index e19ee179d211..a5c36e9c56a6 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -692,6 +692,7 @@ int hibernate(void) goto Unlock; } + pr_info("hibernation entry\n"); pm_prepare_console(); error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls); if (error) { @@ -762,6 +763,8 @@ int hibernate(void) atomic_inc(&snapshot_device_available); Unlock: unlock_system_sleep(); + pr_info("hibernation exit\n"); + return error; } @@ -868,6 +871,7 @@ static int software_resume(void) goto Unlock; } + pr_info("resume from hibernation\n"); pm_prepare_console(); error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls); if (error) { @@ -884,6 +888,7 @@ static int software_resume(void) Finish: __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL); pm_restore_console(); + pr_info("resume from hibernation failed (%d)\n", error); atomic_inc(&snapshot_device_available); /* For success case, the suspend path will release the lock */ Unlock: diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 4f10773322fa..18cdb1596d27 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -584,6 +584,7 @@ int pm_suspend(suspend_state_t state) if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX) return -EINVAL; + pr_info("PM: suspend entry (%s)\n", pm_states[state]); error = enter_state(state); if (error) { suspend_stats.fail++; @@ -591,6 +592,7 @@ int pm_suspend(suspend_state_t state) } else { suspend_stats.success++; } + pr_info("PM: suspend exit\n"); return error; } EXPORT_SYMBOL(pm_suspend); -- cgit v1.2.3 From cb08e0353c249a27aed10c6f60a13871ae449d33 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 23 Jul 2017 00:03:43 +0200 Subject: PM / timekeeping: Print debug messages when requested The messages printed by tk_debug_account_sleep_time() are basically useful for system sleep debugging, so print them only when the other debug messages from the core suspend/hibernate code are enabled. While at it, make it clear that the messages from tk_debug_account_sleep_time() are about timekeeping suspend duration, because in general timekeeping may be suspeded and resumed for multiple times during one system suspend-resume cycle. Signed-off-by: Rafael J. Wysocki --- kernel/power/main.c | 10 +++++++--- kernel/time/timekeeping_debug.c | 5 +++-- 2 files changed, 10 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/power/main.c b/kernel/power/main.c index 5ce00902c7e3..b7876eaf83f3 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -388,13 +388,14 @@ static ssize_t pm_debug_messages_store(struct kobject *kobj, power_attr(pm_debug_messages); /** - * pm_pr_dbg - Print a suspend debug message to the kernel log. + * __pm_pr_dbg - Print a suspend debug message to the kernel log. + * @defer: Whether or not to use printk_deferred() to print the message. * @fmt: Message format. * * The message will be emitted if enabled through the pm_debug_messages * sysfs attribute. */ -void pm_pr_dbg(const char *fmt, ...) +void __pm_pr_dbg(bool defer, const char *fmt, ...) { struct va_format vaf; va_list args; @@ -407,7 +408,10 @@ void pm_pr_dbg(const char *fmt, ...) vaf.fmt = fmt; vaf.va = &args; - printk(KERN_DEBUG "PM: %pV", &vaf); + if (defer) + printk_deferred(KERN_DEBUG "PM: %pV", &vaf); + else + printk(KERN_DEBUG "PM: %pV", &vaf); va_end(args); } diff --git a/kernel/time/timekeeping_debug.c b/kernel/time/timekeeping_debug.c index 38bc4d2208e8..0754cadfa9e6 100644 --- a/kernel/time/timekeeping_debug.c +++ b/kernel/time/timekeeping_debug.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include "timekeeping_internal.h" @@ -75,7 +76,7 @@ void tk_debug_account_sleep_time(struct timespec64 *t) int bin = min(fls(t->tv_sec), NUM_BINS-1); sleep_time_bin[bin]++; - printk_deferred(KERN_INFO "Suspended for %lld.%03lu seconds\n", - (s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC); + pm_deferred_pr_dbg("Timekeeping suspended for %lld.%03lu seconds\n", + (s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC); } -- cgit v1.2.3 From 3c74541777302eec43a0d1327c4d58b8659a776b Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 23 Jul 2017 08:14:15 -0400 Subject: cgroup: fix error return value from cgroup_subtree_control() While refactoring, f7b2814bb9b6 ("cgroup: factor out cgroup_{apply|finalize}_control() from cgroup_subtree_control_write()") broke error return value from the function. The return value from the last operation is always overridden to zero. Fix it. Signed-off-by: Tejun Heo Cc: stable@vger.kernel.org # v4.6+ Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 744975947d01..df2e0f14a95d 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3001,11 +3001,11 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, cgrp->subtree_control &= ~disable; ret = cgroup_apply_control(cgrp); - cgroup_finalize_control(cgrp, ret); + if (ret) + goto out_unlock; kernfs_activate(cgrp->kn); - ret = 0; out_unlock: cgroup_kn_unlock(of->kn); return ret ?: nbytes; -- cgit v1.2.3 From cc731525f26af85a1c3537da41e0abd1d35e0bdb Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Sun, 16 Jul 2017 22:36:59 -0500 Subject: signal: Remove kernel interal si_code magic struct siginfo is a union and the kernel since 2.4 has been hiding a union tag in the high 16bits of si_code using the values: __SI_KILL __SI_TIMER __SI_POLL __SI_FAULT __SI_CHLD __SI_RT __SI_MESGQ __SI_SYS While this looks plausible on the surface, in practice this situation has not worked well. - Injected positive signals are not copied to user space properly unless they have these magic high bits set. - Injected positive signals are not reported properly by signalfd unless they have these magic high bits set. - These kernel internal values leaked to userspace via ptrace_peek_siginfo - It was possible to inject these kernel internal values and cause the the kernel to misbehave. - Kernel developers got confused and expected these kernel internal values in userspace in kernel self tests. - Kernel developers got confused and set si_code to __SI_FAULT which is SI_USER in userspace which causes userspace to think an ordinary user sent the signal and that it was not kernel generated. - The values make it impossible to reorganize the code to transform siginfo_copy_to_user into a plain copy_to_user. As si_code must be massaged before being passed to userspace. So remove these kernel internal si codes and make the kernel code simpler and more maintainable. To replace these kernel internal magic si_codes introduce the helper function siginfo_layout, that takes a signal number and an si_code and computes which union member of siginfo is being used. Have siginfo_layout return an enumeration so that gcc will have enough information to warn if a switch statement does not handle all of union members. A couple of architectures have a messed up ABI that defines signal specific duplications of SI_USER which causes more special cases in siginfo_layout than I would like. The good news is only problem architectures pay the cost. Update all of the code that used the previous magic __SI_ values to use the new SIL_ values and to call siginfo_layout to get those values. Escept where not all of the cases are handled remove the defaults in the switch statements so that if a new case is missed in the future the lack will show up at compile time. Modify the code that copies siginfo si_code to userspace to just copy the value and not cast si_code to a short first. The high bits are no longer used to hold a magic union member. Fixup the siginfo header files to stop including the __SI_ values in their constants and for the headers that were missing it to properly update the number of si_codes for each signal type. The fixes to copy_siginfo_from_user32 implementations has the interesting property that several of them perviously should never have worked as the __SI_ values they depended up where kernel internal. With that dependency gone those implementations should work much better. The idea of not passing the __SI_ values out to userspace and then not reinserting them has been tested with criu and criu worked without changes. Ref: 2.4.0-test1 Signed-off-by: "Eric W. Biederman" --- kernel/exit.c | 4 ++-- kernel/ptrace.c | 6 ++--- kernel/signal.c | 72 +++++++++++++++++++++++++++++++++++++++++++-------------- 3 files changed, 59 insertions(+), 23 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index c5548faa9f37..c8f23613df5b 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1616,7 +1616,7 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, user_access_begin(); unsafe_put_user(signo, &infop->si_signo, Efault); unsafe_put_user(0, &infop->si_errno, Efault); - unsafe_put_user((short)info.cause, &infop->si_code, Efault); + unsafe_put_user(info.cause, &infop->si_code, Efault); unsafe_put_user(info.pid, &infop->si_pid, Efault); unsafe_put_user(info.uid, &infop->si_uid, Efault); unsafe_put_user(info.status, &infop->si_status, Efault); @@ -1742,7 +1742,7 @@ COMPAT_SYSCALL_DEFINE5(waitid, user_access_begin(); unsafe_put_user(signo, &infop->si_signo, Efault); unsafe_put_user(0, &infop->si_errno, Efault); - unsafe_put_user((short)info.cause, &infop->si_code, Efault); + unsafe_put_user(info.cause, &infop->si_code, Efault); unsafe_put_user(info.pid, &infop->si_pid, Efault); unsafe_put_user(info.uid, &infop->si_uid, Efault); unsafe_put_user(info.status, &infop->si_status, Efault); diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 60f356d91060..84b1367935e4 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -728,8 +728,7 @@ static int ptrace_peek_siginfo(struct task_struct *child, if (unlikely(in_compat_syscall())) { compat_siginfo_t __user *uinfo = compat_ptr(data); - if (copy_siginfo_to_user32(uinfo, &info) || - __put_user(info.si_code, &uinfo->si_code)) { + if (copy_siginfo_to_user32(uinfo, &info)) { ret = -EFAULT; break; } @@ -739,8 +738,7 @@ static int ptrace_peek_siginfo(struct task_struct *child, { siginfo_t __user *uinfo = (siginfo_t __user *) data; - if (copy_siginfo_to_user(uinfo, &info) || - __put_user(info.si_code, &uinfo->si_code)) { + if (copy_siginfo_to_user(uinfo, &info)) { ret = -EFAULT; break; } diff --git a/kernel/signal.c b/kernel/signal.c index caed9133ae52..6bd53c8189f0 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2682,6 +2682,51 @@ COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset, } #endif +enum siginfo_layout siginfo_layout(int sig, int si_code) +{ + enum siginfo_layout layout = SIL_KILL; + if ((si_code > SI_USER) && (si_code < SI_KERNEL)) { + static const struct { + unsigned char limit, layout; + } filter[] = { + [SIGILL] = { NSIGILL, SIL_FAULT }, + [SIGFPE] = { NSIGFPE, SIL_FAULT }, + [SIGSEGV] = { NSIGSEGV, SIL_FAULT }, + [SIGBUS] = { NSIGBUS, SIL_FAULT }, + [SIGTRAP] = { NSIGTRAP, SIL_FAULT }, +#if defined(SIGMET) && defined(NSIGEMT) + [SIGEMT] = { NSIGEMT, SIL_FAULT }, +#endif + [SIGCHLD] = { NSIGCHLD, SIL_CHLD }, + [SIGPOLL] = { NSIGPOLL, SIL_POLL }, +#ifdef __ARCH_SIGSYS + [SIGSYS] = { NSIGSYS, SIL_SYS }, +#endif + }; + if ((sig < ARRAY_SIZE(filter)) && (si_code <= filter[sig].limit)) + layout = filter[sig].layout; + else if (si_code <= NSIGPOLL) + layout = SIL_POLL; + } else { + if (si_code == SI_TIMER) + layout = SIL_TIMER; + else if (si_code == SI_SIGIO) + layout = SIL_POLL; + else if (si_code < 0) + layout = SIL_RT; + /* Tests to support buggy kernel ABIs */ +#ifdef TRAP_FIXME + if ((sig == SIGTRAP) && (si_code == TRAP_FIXME)) + layout = SIL_FAULT; +#endif +#ifdef FPE_FIXME + if ((sig == SIGFPE) && (si_code == FPE_FIXME)) + layout = SIL_FAULT; +#endif + } + return layout; +} + #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from) @@ -2704,22 +2749,20 @@ int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from) */ err = __put_user(from->si_signo, &to->si_signo); err |= __put_user(from->si_errno, &to->si_errno); - err |= __put_user((short)from->si_code, &to->si_code); - switch (from->si_code & __SI_MASK) { - case __SI_KILL: + err |= __put_user(from->si_code, &to->si_code); + switch (siginfo_layout(from->si_signo, from->si_code)) { + case SIL_KILL: err |= __put_user(from->si_pid, &to->si_pid); err |= __put_user(from->si_uid, &to->si_uid); break; - case __SI_TIMER: - err |= __put_user(from->si_tid, &to->si_tid); - err |= __put_user(from->si_overrun, &to->si_overrun); - err |= __put_user(from->si_ptr, &to->si_ptr); + case SIL_TIMER: + /* Unreached SI_TIMER is negative */ break; - case __SI_POLL: + case SIL_POLL: err |= __put_user(from->si_band, &to->si_band); err |= __put_user(from->si_fd, &to->si_fd); break; - case __SI_FAULT: + case SIL_FAULT: err |= __put_user(from->si_addr, &to->si_addr); #ifdef __ARCH_SI_TRAPNO err |= __put_user(from->si_trapno, &to->si_trapno); @@ -2744,30 +2787,25 @@ int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from) err |= __put_user(from->si_pkey, &to->si_pkey); #endif break; - case __SI_CHLD: + case SIL_CHLD: err |= __put_user(from->si_pid, &to->si_pid); err |= __put_user(from->si_uid, &to->si_uid); err |= __put_user(from->si_status, &to->si_status); err |= __put_user(from->si_utime, &to->si_utime); err |= __put_user(from->si_stime, &to->si_stime); break; - case __SI_RT: /* This is not generated by the kernel as of now. */ - case __SI_MESGQ: /* But this is */ + case SIL_RT: err |= __put_user(from->si_pid, &to->si_pid); err |= __put_user(from->si_uid, &to->si_uid); err |= __put_user(from->si_ptr, &to->si_ptr); break; #ifdef __ARCH_SIGSYS - case __SI_SYS: + case SIL_SYS: err |= __put_user(from->si_call_addr, &to->si_call_addr); err |= __put_user(from->si_syscall, &to->si_syscall); err |= __put_user(from->si_arch, &to->si_arch); break; #endif - default: /* this is just in case for now ... */ - err |= __put_user(from->si_pid, &to->si_pid); - err |= __put_user(from->si_uid, &to->si_uid); - break; } return err; } -- cgit v1.2.3 From 9305706c2e808ae59f1eb201867f82f1ddf6d7a6 Mon Sep 17 00:00:00 2001 From: Edward Cree Date: Fri, 21 Jul 2017 14:37:34 +0100 Subject: bpf/verifier: fix min/max handling in BPF_SUB We have to subtract the src max from the dst min, and vice-versa, since (e.g.) the smallest result comes from the largest subtrahend. Fixes: 484611357c19 ("bpf: allow access into map value arrays") Signed-off-by: Edward Cree Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index af9e84a4944e..664d93972373 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1865,10 +1865,12 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, * do our normal operations to the register, we need to set the values * to the min/max since they are undefined. */ - if (min_val == BPF_REGISTER_MIN_RANGE) - dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - if (max_val == BPF_REGISTER_MAX_RANGE) - dst_reg->max_value = BPF_REGISTER_MAX_RANGE; + if (opcode != BPF_SUB) { + if (min_val == BPF_REGISTER_MIN_RANGE) + dst_reg->min_value = BPF_REGISTER_MIN_RANGE; + if (max_val == BPF_REGISTER_MAX_RANGE) + dst_reg->max_value = BPF_REGISTER_MAX_RANGE; + } switch (opcode) { case BPF_ADD: @@ -1879,10 +1881,17 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, dst_reg->min_align = min(src_align, dst_align); break; case BPF_SUB: + /* If one of our values was at the end of our ranges, then the + * _opposite_ value in the dst_reg goes to the end of our range. + */ + if (min_val == BPF_REGISTER_MIN_RANGE) + dst_reg->max_value = BPF_REGISTER_MAX_RANGE; + if (max_val == BPF_REGISTER_MAX_RANGE) + dst_reg->min_value = BPF_REGISTER_MIN_RANGE; if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) - dst_reg->min_value -= min_val; + dst_reg->min_value -= max_val; if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) - dst_reg->max_value -= max_val; + dst_reg->max_value -= min_val; dst_reg->min_align = min(src_align, dst_align); break; case BPF_MUL: -- cgit v1.2.3 From 8e6bcd9f7eac47104ce6c5d82c554c9b244b38e1 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 21 Jul 2017 02:07:54 +0200 Subject: PM / s2idle: Rearrange the main suspend-to-idle loop As a preparation for subsequent changes, rearrange the core suspend-to-idle code by moving the initial invocation of dpm_suspend_noirq() into s2idle_loop(). This also causes debug messages from that code to appear in a less confusing order. Signed-off-by: Rafael J. Wysocki --- kernel/power/power.h | 4 ++++ kernel/power/suspend.c | 26 +++++++++++++------------- 2 files changed, 17 insertions(+), 13 deletions(-) (limited to 'kernel') diff --git a/kernel/power/power.h b/kernel/power/power.h index 7fdc40d31b7d..6e3ac6a73d65 100644 --- a/kernel/power/power.h +++ b/kernel/power/power.h @@ -245,7 +245,11 @@ enum { #define TEST_FIRST TEST_NONE #define TEST_MAX (__TEST_AFTER_LAST - 1) +#ifdef CONFIG_PM_DEBUG extern int pm_test_level; +#else +#define pm_test_level (TEST_NONE) +#endif #ifdef CONFIG_SUSPEND_FREEZER static inline int suspend_freeze_processes(void) diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 18cdb1596d27..0c61713b6e5c 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -108,7 +108,13 @@ static void s2idle_loop(void) { pm_pr_dbg("suspend-to-idle\n"); - do { + while (!dpm_suspend_noirq(PMSG_SUSPEND)) { + /* + * Suspend-to-idle equals + * frozen processes + suspended devices + idle processors. + * Thus freeze_enter() should be called right after + * all devices have been suspended. + */ freeze_enter(); if (freeze_ops && freeze_ops->wake) @@ -122,7 +128,7 @@ static void s2idle_loop(void) break; pm_wakeup_clear(false); - } while (!dpm_suspend_noirq(PMSG_SUSPEND)); + } pm_pr_dbg("resume from suspend-to-idle\n"); } @@ -379,6 +385,11 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) if (error) goto Devices_early_resume; + if (state == PM_SUSPEND_FREEZE && pm_test_level != TEST_PLATFORM) { + s2idle_loop(); + goto Platform_early_resume; + } + error = dpm_suspend_noirq(PMSG_SUSPEND); if (error) { pr_err("PM: noirq suspend of devices failed\n"); @@ -391,17 +402,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) if (suspend_test(TEST_PLATFORM)) goto Platform_wake; - /* - * PM_SUSPEND_FREEZE equals - * frozen processes + suspended devices + idle processors. - * Thus we should invoke freeze_enter() soon after - * all the devices are suspended. - */ - if (state == PM_SUSPEND_FREEZE) { - s2idle_loop(); - goto Platform_early_resume; - } - error = disable_nonboot_cpus(); if (error || suspend_test(TEST_CPUS)) goto Enable_cpus; -- cgit v1.2.3 From 9a3ebe3523cc8297301d5d95332536ad123856bf Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 21 Jul 2017 02:12:10 +0200 Subject: PM / sleep: Check pm_wakeup_pending() in __device_suspend_noirq() Restore the pm_wakeup_pending() check in __device_suspend_noirq() removed by commit eed4d47efe95 (ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idle) as that allows the function to return earlier if there's a wakeup event pending already (so that it may spend less time on carrying out operations that will be reversed shortly anyway) and rework the main suspend-to-idle loop to take that optimization into account. Signed-off-by: Rafael J. Wysocki --- kernel/power/suspend.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 0c61713b6e5c..5cf232795318 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -108,19 +108,32 @@ static void s2idle_loop(void) { pm_pr_dbg("suspend-to-idle\n"); - while (!dpm_suspend_noirq(PMSG_SUSPEND)) { + for (;;) { + int error; + + dpm_noirq_begin(); + /* * Suspend-to-idle equals * frozen processes + suspended devices + idle processors. * Thus freeze_enter() should be called right after * all devices have been suspended. */ - freeze_enter(); + error = dpm_noirq_suspend_devices(PMSG_SUSPEND); + if (!error) + freeze_enter(); + + dpm_noirq_resume_devices(PMSG_RESUME); + if (error && (error != -EBUSY || !pm_wakeup_pending())) { + dpm_noirq_end(); + break; + } if (freeze_ops && freeze_ops->wake) freeze_ops->wake(); - dpm_resume_noirq(PMSG_RESUME); + dpm_noirq_end(); + if (freeze_ops && freeze_ops->sync) freeze_ops->sync(); -- cgit v1.2.3 From e516a1db43cea397cf63d395534236d9869f0310 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 21 Jul 2017 14:44:02 +0200 Subject: PM / sleep: Put pm_test under CONFIG_PM_SLEEP_DEBUG The pm_test sysfs attribute is under CONFIG_PM_DEBUG, but it doesn't make sense to provide it if CONFIG_PM_SLEEP is unset, so put it under CONFIG_PM_SLEEP_DEBUG instead. Signed-off-by: Rafael J. Wysocki --- kernel/power/main.c | 8 +++----- kernel/power/power.h | 2 +- 2 files changed, 4 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/power/main.c b/kernel/power/main.c index b7876eaf83f3..3074ea4cec0a 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -150,7 +150,7 @@ static ssize_t mem_sleep_store(struct kobject *kobj, struct kobj_attribute *attr power_attr(mem_sleep); #endif /* CONFIG_SUSPEND */ -#ifdef CONFIG_PM_DEBUG +#ifdef CONFIG_PM_SLEEP_DEBUG int pm_test_level = TEST_NONE; static const char * const pm_tests[__TEST_AFTER_LAST] = { @@ -211,7 +211,7 @@ static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr, } power_attr(pm_test); -#endif /* CONFIG_PM_DEBUG */ +#endif /* CONFIG_PM_SLEEP_DEBUG */ #ifdef CONFIG_DEBUG_FS static char *suspend_step_name(enum suspend_stat_step step) @@ -746,10 +746,8 @@ static struct attribute * g[] = { &wake_lock_attr.attr, &wake_unlock_attr.attr, #endif -#ifdef CONFIG_PM_DEBUG - &pm_test_attr.attr, -#endif #ifdef CONFIG_PM_SLEEP_DEBUG + &pm_test_attr.attr, &pm_print_times_attr.attr, &pm_wakeup_irq_attr.attr, &pm_debug_messages_attr.attr, diff --git a/kernel/power/power.h b/kernel/power/power.h index 6e3ac6a73d65..268c1b0afc28 100644 --- a/kernel/power/power.h +++ b/kernel/power/power.h @@ -245,7 +245,7 @@ enum { #define TEST_FIRST TEST_NONE #define TEST_MAX (__TEST_AFTER_LAST - 1) -#ifdef CONFIG_PM_DEBUG +#ifdef CONFIG_PM_SLEEP_DEBUG extern int pm_test_level; #else #define pm_test_level (TEST_NONE) -- cgit v1.2.3 From bebcdae3ec13b2171ff91594787ab37b3fdb3306 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 21 Jul 2017 14:49:51 +0200 Subject: PM / suspend: Use mem_sleep_labels[] strings in messages Some messages in suspend.c currently print state names from pm_states[], but that may be confusing if the mem_sleep sysfs attribute is changed to anything different from "mem", because in those cases the messages will say either "freeze" or "standby" after writing "mem" to /sys/power/state. To avoid the confusion, use mem_sleep_labels[] strings in those messages instead. Signed-off-by: Rafael J. Wysocki Reviewed-by: Andy Shevchenko --- kernel/power/suspend.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 5cf232795318..a3d270e2e313 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -560,7 +560,7 @@ static int enter_state(suspend_state_t state) trace_suspend_resume(TPS("sync_filesystems"), 0, false); #endif - pm_pr_dbg("Preparing system for sleep (%s)\n", pm_states[state]); + pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]); pm_suspend_clear_flags(); error = suspend_prepare(state); if (error) @@ -570,7 +570,7 @@ static int enter_state(suspend_state_t state) goto Finish; trace_suspend_resume(TPS("suspend_enter"), state, false); - pm_pr_dbg("Suspending system (%s)\n", pm_states[state]); + pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]); pm_restrict_gfp_mask(); error = suspend_devices_and_enter(state); pm_restore_gfp_mask(); @@ -597,7 +597,7 @@ int pm_suspend(suspend_state_t state) if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX) return -EINVAL; - pr_info("PM: suspend entry (%s)\n", pm_states[state]); + pr_info("PM: suspend entry (%s)\n", mem_sleep_labels[state]); error = enter_state(state); if (error) { suspend_stats.fail++; -- cgit v1.2.3 From 142bce74fd141913b2127970a9bd90f33c5b7653 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 21 Jul 2017 14:50:48 +0200 Subject: PM / suspend: Define pr_fmt() in suspend.c Define a common prefix ("PM:") for messages printed by the code in kernel/power/suspend.c. Signed-off-by: Rafael J. Wysocki Reviewed-by: Andy Shevchenko --- kernel/power/suspend.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index a3d270e2e313..4bce46ddc2cd 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -8,6 +8,8 @@ * This file is released under the GPLv2. */ +#define pr_fmt(fmt) "PM: " fmt + #include #include #include @@ -391,7 +393,7 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) error = dpm_suspend_late(PMSG_SUSPEND); if (error) { - pr_err("PM: late suspend of devices failed\n"); + pr_err("late suspend of devices failed\n"); goto Platform_finish; } error = platform_suspend_prepare_late(state); @@ -405,7 +407,7 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) error = dpm_suspend_noirq(PMSG_SUSPEND); if (error) { - pr_err("PM: noirq suspend of devices failed\n"); + pr_err("noirq suspend of devices failed\n"); goto Platform_early_resume; } error = platform_suspend_prepare_noirq(state); @@ -481,7 +483,7 @@ int suspend_devices_and_enter(suspend_state_t state) suspend_test_start(); error = dpm_suspend_start(PMSG_SUSPEND); if (error) { - pr_err("PM: Some devices failed to suspend, or early wake event detected\n"); + pr_err("Some devices failed to suspend, or early wake event detected\n"); goto Recover_platform; } suspend_test_finish("suspend devices"); @@ -539,7 +541,7 @@ static int enter_state(suspend_state_t state) if (state == PM_SUSPEND_FREEZE) { #ifdef CONFIG_PM_DEBUG if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) { - pr_warn("PM: Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n"); + pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n"); return -EAGAIN; } #endif @@ -554,7 +556,7 @@ static int enter_state(suspend_state_t state) #ifndef CONFIG_SUSPEND_SKIP_SYNC trace_suspend_resume(TPS("sync_filesystems"), 0, true); - pr_info("PM: Syncing filesystems ... "); + pr_info("Syncing filesystems ... "); sys_sync(); pr_cont("done.\n"); trace_suspend_resume(TPS("sync_filesystems"), 0, false); @@ -597,7 +599,7 @@ int pm_suspend(suspend_state_t state) if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX) return -EINVAL; - pr_info("PM: suspend entry (%s)\n", mem_sleep_labels[state]); + pr_info("suspend entry (%s)\n", mem_sleep_labels[state]); error = enter_state(state); if (error) { suspend_stats.fail++; @@ -605,7 +607,7 @@ int pm_suspend(suspend_state_t state) } else { suspend_stats.success++; } - pr_info("PM: suspend exit\n"); + pr_info("suspend exit\n"); return error; } EXPORT_SYMBOL(pm_suspend); -- cgit v1.2.3 From 825c5bd2fd47d30148db15fc121216c483682b01 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 26 May 2017 16:16:40 -0700 Subject: srcu: Move rcu_scheduler_starting() from Tiny RCU to Tiny SRCU Other than lockdep support, Tiny RCU has no need for the scheduler status. However, Tiny SRCU will need this to control boot-time behavior independent of lockdep. Therefore, this commit moves rcu_scheduler_starting() from kernel/rcu/tiny_plugin.h to kernel/rcu/srcutiny.c. This in turn allows the complete removal of kernel/rcu/tiny_plugin.h. Signed-off-by: Paul E. McKenney --- kernel/rcu/srcutiny.c | 8 ++++++++ kernel/rcu/tiny.c | 2 -- kernel/rcu/tiny_plugin.h | 47 ----------------------------------------------- 3 files changed, 8 insertions(+), 49 deletions(-) delete mode 100644 kernel/rcu/tiny_plugin.h (limited to 'kernel') diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c index 1a1c1047d2ed..76ac5f50b2c7 100644 --- a/kernel/rcu/srcutiny.c +++ b/kernel/rcu/srcutiny.c @@ -33,6 +33,8 @@ #include "rcu_segcblist.h" #include "rcu.h" +int rcu_scheduler_active __read_mostly; + static int init_srcu_struct_fields(struct srcu_struct *sp) { sp->srcu_lock_nesting[0] = 0; @@ -193,3 +195,9 @@ void synchronize_srcu(struct srcu_struct *sp) destroy_rcu_head_on_stack(&rs.head); } EXPORT_SYMBOL_GPL(synchronize_srcu); + +/* Lockdep diagnostics. */ +void __init rcu_scheduler_starting(void) +{ + rcu_scheduler_active = RCU_SCHEDULER_RUNNING; +} diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c index f8488965250f..a64eee0db39e 100644 --- a/kernel/rcu/tiny.c +++ b/kernel/rcu/tiny.c @@ -56,8 +56,6 @@ static struct rcu_ctrlblk rcu_bh_ctrlblk = { .curtail = &rcu_bh_ctrlblk.rcucblist, }; -#include "tiny_plugin.h" - void rcu_barrier_bh(void) { wait_rcu_gp(call_rcu_bh); diff --git a/kernel/rcu/tiny_plugin.h b/kernel/rcu/tiny_plugin.h deleted file mode 100644 index f0a01b2a3062..000000000000 --- a/kernel/rcu/tiny_plugin.h +++ /dev/null @@ -1,47 +0,0 @@ -/* - * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition - * Internal non-public definitions that provide either classic - * or preemptible semantics. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, you can access it online at - * http://www.gnu.org/licenses/gpl-2.0.html. - * - * Copyright (c) 2010 Linaro - * - * Author: Paul E. McKenney - */ - -#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU) -#include - -int rcu_scheduler_active __read_mostly; -EXPORT_SYMBOL_GPL(rcu_scheduler_active); - -/* - * During boot, we forgive RCU lockdep issues. After this function is - * invoked, we start taking RCU lockdep issues seriously. Note that unlike - * Tree RCU, Tiny RCU transitions directly from RCU_SCHEDULER_INACTIVE - * to RCU_SCHEDULER_RUNNING, skipping the RCU_SCHEDULER_INIT stage. - * The reason for this is that Tiny RCU does not need kthreads, so does - * not have to care about the fact that the scheduler is half-initialized - * at a certain phase of the boot process. Unless SRCU is in the mix. - */ -void __init rcu_scheduler_starting(void) -{ - WARN_ON(nr_context_switches() > 0); - rcu_scheduler_active = IS_ENABLED(CONFIG_SRCU) - ? RCU_SCHEDULER_INIT : RCU_SCHEDULER_RUNNING; -} - -#endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU) */ -- cgit v1.2.3 From 0d8a1e831e21d955af68f4ae5658b58b7ec25557 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 15 Jun 2017 17:06:38 -0700 Subject: srcu: Make process_srcu() be static The function process_srcu() is not invoked outside of srcutree.c, so this commit makes it static and drops the EXPORT_SYMBOL_GPL(). Signed-off-by: Paul E. McKenney --- kernel/rcu/srcutree.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index d0ca524bf042..94bd6ed43ea3 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -51,6 +51,7 @@ module_param(counter_wrap_check, ulong, 0444); static void srcu_invoke_callbacks(struct work_struct *work); static void srcu_reschedule(struct srcu_struct *sp, unsigned long delay); +static void process_srcu(struct work_struct *work); /* * Initialize SRCU combining tree. Note that statically allocated @@ -1194,7 +1195,7 @@ static void srcu_reschedule(struct srcu_struct *sp, unsigned long delay) /* * This is the work-queue function that handles SRCU grace periods. */ -void process_srcu(struct work_struct *work) +static void process_srcu(struct work_struct *work) { struct srcu_struct *sp; @@ -1203,7 +1204,6 @@ void process_srcu(struct work_struct *work) srcu_advance_state(sp); srcu_reschedule(sp, srcu_get_delay(sp)); } -EXPORT_SYMBOL_GPL(process_srcu); void srcutorture_get_gp_data(enum rcutorture_type test_type, struct srcu_struct *sp, int *flags, -- cgit v1.2.3 From 115a1a5285664f1931c30457081b4ae1e648f1f9 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 22 May 2017 13:31:03 -0700 Subject: rcutorture: Move SRCU status printing to SRCU implementations This commit gets rid of some ugly #ifdefs in rcutorture.c by moving the SRCU status printing to the SRCU implementations. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcutorture.c | 39 +-------------------------------------- kernel/rcu/srcutree.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 35 insertions(+), 38 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index b8f7f8ce8575..aedc8f2ad955 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -561,44 +561,7 @@ static void srcu_torture_barrier(void) static void srcu_torture_stats(void) { - int __maybe_unused cpu; - int idx; - -#ifdef CONFIG_TREE_SRCU - idx = srcu_ctlp->srcu_idx & 0x1; - pr_alert("%s%s Tree SRCU per-CPU(idx=%d):", - torture_type, TORTURE_FLAG, idx); - for_each_possible_cpu(cpu) { - unsigned long l0, l1; - unsigned long u0, u1; - long c0, c1; - struct srcu_data *counts; - - counts = per_cpu_ptr(srcu_ctlp->sda, cpu); - u0 = counts->srcu_unlock_count[!idx]; - u1 = counts->srcu_unlock_count[idx]; - - /* - * Make sure that a lock is always counted if the corresponding - * unlock is counted. - */ - smp_rmb(); - - l0 = counts->srcu_lock_count[!idx]; - l1 = counts->srcu_lock_count[idx]; - - c0 = l0 - u0; - c1 = l1 - u1; - pr_cont(" %d(%ld,%ld)", cpu, c0, c1); - } - pr_cont("\n"); -#elif defined(CONFIG_TINY_SRCU) - idx = READ_ONCE(srcu_ctlp->srcu_idx) & 0x1; - pr_alert("%s%s Tiny SRCU per-CPU(idx=%d): (%hd,%hd)\n", - torture_type, TORTURE_FLAG, idx, - READ_ONCE(srcu_ctlp->srcu_lock_nesting[!idx]), - READ_ONCE(srcu_ctlp->srcu_lock_nesting[idx])); -#endif + srcu_torture_stats_print(srcu_ctlp, torture_type, TORTURE_FLAG); } static void srcu_torture_synchronize_expedited(void) diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index d0ca524bf042..8f6fd11c338a 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -1217,6 +1217,40 @@ void srcutorture_get_gp_data(enum rcutorture_type test_type, } EXPORT_SYMBOL_GPL(srcutorture_get_gp_data); +void srcu_torture_stats_print(struct srcu_struct *sp, char *tt, char *tf) +{ + int cpu; + int idx; + + idx = sp->srcu_idx & 0x1; + pr_alert("%s%s Tree SRCU per-CPU(idx=%d):", tt, tf, idx); + for_each_possible_cpu(cpu) { + unsigned long l0, l1; + unsigned long u0, u1; + long c0, c1; + struct srcu_data *counts; + + counts = per_cpu_ptr(sp->sda, cpu); + u0 = counts->srcu_unlock_count[!idx]; + u1 = counts->srcu_unlock_count[idx]; + + /* + * Make sure that a lock is always counted if the corresponding + * unlock is counted. + */ + smp_rmb(); + + l0 = counts->srcu_lock_count[!idx]; + l1 = counts->srcu_lock_count[idx]; + + c0 = l0 - u0; + c1 = l1 - u1; + pr_cont(" %d(%ld,%ld)", cpu, c0, c1); + } + pr_cont("\n"); +} +EXPORT_SYMBOL_GPL(srcu_torture_stats_print); + static int __init srcu_bootup_announce(void) { pr_info("Hierarchical SRCU implementation.\n"); -- cgit v1.2.3 From ac3748c60426602c091c8c9281c95fadb781fcc0 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 22 May 2017 13:59:52 -0700 Subject: rcutorture: Print SRCU lock/unlock totals This commit adds printing of SRCU lock/unlock totals, which are just the sums of the per-CPU counts. Saves a bit of mental arithmetic. Signed-off-by: Paul E. McKenney --- kernel/rcu/srcutree.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 8f6fd11c338a..b4f491b06ee0 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -1221,6 +1221,7 @@ void srcu_torture_stats_print(struct srcu_struct *sp, char *tt, char *tf) { int cpu; int idx; + unsigned long s0 = 0, s1 = 0; idx = sp->srcu_idx & 0x1; pr_alert("%s%s Tree SRCU per-CPU(idx=%d):", tt, tf, idx); @@ -1246,8 +1247,10 @@ void srcu_torture_stats_print(struct srcu_struct *sp, char *tt, char *tf) c0 = l0 - u0; c1 = l1 - u1; pr_cont(" %d(%ld,%ld)", cpu, c0, c1); + s0 += c0; + s1 += c1; } - pr_cont("\n"); + pr_cont(" T(%ld,%ld)\n", s0, s1); } EXPORT_SYMBOL_GPL(srcu_torture_stats_print); -- cgit v1.2.3 From f1dbc54b929c5917c57b6661c9e37e42868b26a4 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 25 May 2017 08:23:06 -0700 Subject: rcu: Remove CONFIG_TASKS_RCU ifdef from rcuperf.c The synchronize_rcu_tasks() and call_rcu_tasks() APIs are now available regardless of kernel configuration, so this commit removes the CONFIG_TASKS_RCU ifdef from rcuperf.c. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcuperf.c | 17 +---------------- 1 file changed, 1 insertion(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c index 3cc18110b612..1f87a02c3399 100644 --- a/kernel/rcu/rcuperf.c +++ b/kernel/rcu/rcuperf.c @@ -317,8 +317,6 @@ static struct rcu_perf_ops sched_ops = { .name = "sched" }; -#ifdef CONFIG_TASKS_RCU - /* * Definitions for RCU-tasks perf testing. */ @@ -346,24 +344,11 @@ static struct rcu_perf_ops tasks_ops = { .name = "tasks" }; -#define RCUPERF_TASKS_OPS &tasks_ops, - static bool __maybe_unused torturing_tasks(void) { return cur_ops == &tasks_ops; } -#else /* #ifdef CONFIG_TASKS_RCU */ - -#define RCUPERF_TASKS_OPS - -static bool __maybe_unused torturing_tasks(void) -{ - return false; -} - -#endif /* #else #ifdef CONFIG_TASKS_RCU */ - /* * If performance tests complete, wait for shutdown to commence. */ @@ -658,7 +643,7 @@ rcu_perf_init(void) int firsterr = 0; static struct rcu_perf_ops *perf_ops[] = { &rcu_ops, &rcu_bh_ops, &srcu_ops, &srcud_ops, &sched_ops, - RCUPERF_TASKS_OPS + &tasks_ops, }; if (!torture_init_begin(perf_type, verbose, &perf_runnable)) -- cgit v1.2.3 From 5e741fa9e9698f4010bb85eff252186f7a4071f4 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 6 Jun 2017 12:52:44 -0700 Subject: rcutorture: Enable SRCU readers from timer handler Now that it is legal to invoke srcu_read_lock() and srcu_read_unlock() for a given srcu_struct from both process context and {soft,}irq handlers, it is time to test it. This commit therefore enables testing of SRCU readers from rcutorture's timer handler, using in_task() to determine whether or not it is safe to sleep in the SRCU read-side critical sections. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcutorture.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index aedc8f2ad955..8d59c82bec0b 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -522,7 +522,7 @@ static void srcu_read_delay(struct torture_random_state *rrsp) delay = torture_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick); - if (!delay) + if (!delay && in_task()) schedule_timeout_interruptible(longdelay); else rcu_read_delay(rrsp); @@ -583,6 +583,7 @@ static struct rcu_torture_ops srcu_ops = { .call = srcu_torture_call, .cb_barrier = srcu_torture_barrier, .stats = srcu_torture_stats, + .irq_capable = 1, .name = "srcu" }; @@ -615,6 +616,7 @@ static struct rcu_torture_ops srcud_ops = { .call = srcu_torture_call, .cb_barrier = srcu_torture_barrier, .stats = srcu_torture_stats, + .irq_capable = 1, .name = "srcud" }; -- cgit v1.2.3 From b3c983142d4584c9d506b1ed31b65f4292b4aea8 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 6 Jun 2017 16:39:00 -0700 Subject: rcutorture: Place event-traced strings into trace buffer Strings used in event tracing need to be specially handled, for example, being copied to the trace buffer instead of being pointed to by the trace buffer. Although the TPS() macro can be used to "launder" pointed-to strings, this might not be all that effective within a loadable module. This commit therefore copies rcutorture's strings to the trace buffer. Signed-off-by: Paul E. McKenney Cc: Steven Rostedt --- kernel/rcu/rcutorture.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 8d59c82bec0b..b48d2107f176 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -496,7 +496,7 @@ static struct rcu_torture_ops rcu_busted_ops = { .fqs = NULL, .stats = NULL, .irq_capable = 1, - .name = "rcu_busted" + .name = "busted" }; /* -- cgit v1.2.3 From 808de39cf422aa08dffd29510d841848ea18e215 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 19 Jun 2017 10:03:22 -0700 Subject: rcutorture: Add task's CPU for rcutorture writer stalls It appears that at least some of the rcutorture writer stall messages coincide with unusually long CPU-online operations, for example, no fewer than 205 seconds in a recent test. It is of course possible that the writer stall is not unrelated to this unusually long CPU-hotplug operation, and so this commit adds the rcutorture writer task's CPU to the stall message to gain more information about this possible connection. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcutorture.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index b48d2107f176..75ac749ced7c 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1319,11 +1319,12 @@ rcu_torture_stats_print(void) srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gpnum, &completed); wtp = READ_ONCE(writer_task); - pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x ->state %#lx\n", + pr_alert("??? Writer stall state %s(%d) g%lu c%lu f%#x ->state %#lx cpu %d\n", rcu_torture_writer_state_getname(), rcu_torture_writer_state, gpnum, completed, flags, - wtp == NULL ? ~0UL : wtp->state); + wtp == NULL ? ~0UL : wtp->state, + wtp == NULL ? -1 : (int)task_cpu(wtp)); show_rcu_gp_kthreads(); rcu_ftrace_dump(DUMP_ALL); } -- cgit v1.2.3 From a3b7b6c2739caf996b95a0164b5b4541c27630c3 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 23 Jun 2017 16:07:17 -0700 Subject: rcutorture: Eliminate unused ts_rem local from rcu_trace_clock_local() This commit removes an unused local variable named ts_rem that is marked __maybe_unused. Yes, the variable was assigned to, but it was never used beyond that point, hence not needed. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcutorture.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 75ac749ced7c..6e3f644280ee 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -199,7 +199,8 @@ MODULE_PARM_DESC(torture_runnable, "Start rcutorture at boot"); static u64 notrace rcu_trace_clock_local(void) { u64 ts = trace_clock_local(); - unsigned long __maybe_unused ts_rem = do_div(ts, NSEC_PER_USEC); + + (void)do_div(ts, NSEC_PER_USEC); return ts; } #else /* #ifdef CONFIG_RCU_TRACE */ -- cgit v1.2.3 From 96036c43066a04c99353abb4a342cc38a52d36f2 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 18 Jul 2017 13:52:18 -0700 Subject: rcu: Add last-CPU to GP-kthread starvation messages This commit augments the grace-period-kthread starvation debugging messages by adding the last CPU that ran the kthread. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 51d4c3acf32d..48c6ab5ca164 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1358,12 +1358,13 @@ static void rcu_check_gp_kthread_starvation(struct rcu_state *rsp) j = jiffies; gpa = READ_ONCE(rsp->gp_activity); if (j - gpa > 2 * HZ) { - pr_err("%s kthread starved for %ld jiffies! g%lu c%lu f%#x %s(%d) ->state=%#lx\n", + pr_err("%s kthread starved for %ld jiffies! g%lu c%lu f%#x %s(%d) ->state=%#lx ->cpu=%d\n", rsp->name, j - gpa, rsp->gpnum, rsp->completed, rsp->gp_flags, gp_state_getname(rsp->gp_state), rsp->gp_state, - rsp->gp_kthread ? rsp->gp_kthread->state : ~0); + rsp->gp_kthread ? rsp->gp_kthread->state : ~0, + rsp->gp_kthread ? task_cpu(rsp->gp_kthread) : -1); if (rsp->gp_kthread) { sched_show_task(rsp->gp_kthread); wake_up_process(rsp->gp_kthread); -- cgit v1.2.3 From f34c8585ed70f0f9b5ff9cf59c0dd533cddb975f Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 20 Jul 2017 15:27:32 -0700 Subject: rcutorture: Invoke call_rcu() from timer handler The Linux kernel invokes call_rcu() from various interrupt/softirq handlers, but rcutorture does not. This commit therefore adds this behavior to rcutorture's repertoire. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcutorture.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'kernel') diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 6e3f644280ee..0efd69b2fb8c 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1080,6 +1080,11 @@ rcu_torture_fakewriter(void *arg) return 0; } +static void rcu_torture_timer_cb(struct rcu_head *rhp) +{ + kfree(rhp); +} + /* * RCU torture reader from timer handler. Dereferences rcu_torture_current, * incrementing the corresponding element of the pipeline array. The @@ -1142,6 +1147,14 @@ static void rcu_torture_timer(unsigned long unused) __this_cpu_inc(rcu_torture_batch[completed]); preempt_enable(); cur_ops->readunlock(idx); + + /* Test call_rcu() invocation from interrupt handler. */ + if (cur_ops->call) { + struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_NOWAIT); + + if (rhp) + cur_ops->call(rhp, rcu_torture_timer_cb); + } } /* -- cgit v1.2.3 From 241a974ba2c0d98e2104012cb80ed4494c0e66a7 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Sat, 22 Jul 2017 10:40:04 +0300 Subject: bpf: dev_map_alloc() shouldn't return NULL We forgot to set the error code on two error paths which means that we return ERR_PTR(0) which is NULL. The caller, find_and_alloc_map(), is not expecting that and will have a NULL dereference. Fixes: 546ac1ffb70d ("bpf: add devmap, a map for storing net device references") Signed-off-by: Dan Carpenter Acked-by: Daniel Borkmann Acked-by: John Fastabend Signed-off-by: David S. Miller --- kernel/bpf/devmap.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 899364d097f5..d439ee0eadb1 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -114,6 +114,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) if (err) goto free_dtab; + err = -ENOMEM; /* A per cpu bitfield with a bit per possible net device */ dtab->flush_needed = __alloc_percpu( BITS_TO_LONGS(attr->max_entries) * -- cgit v1.2.3 From bf50f0e8a03005d19de66d01261d855cdeedf572 Mon Sep 17 00:00:00 2001 From: Jonathan Corbet Date: Mon, 24 Jul 2017 13:56:28 -0600 Subject: sched/core: Fix some documentation build warnings The kerneldoc comments for try_to_wake_up_local() were out of date, leading to these documentation build warnings: ./kernel/sched/core.c:2080: warning: No description found for parameter 'rf' ./kernel/sched/core.c:2080: warning: Excess function parameter 'cookie' description in 'try_to_wake_up_local' Update the comment to reflect current reality and give us some peace and quiet. Signed-off-by: Jonathan Corbet Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/20170724135628.695cecfc@lwn.net Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 17c667b427b4..0869b20fba81 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2069,7 +2069,7 @@ out: /** * try_to_wake_up_local - try to wake up a local task with rq lock held * @p: the thread to be awakened - * @cookie: context's cookie for pinning + * @rf: request-queue flags for pinning * * Put @p on the run-queue if it's not already there. The caller must * ensure that this_rq() is locked, @p is bound to this_rq() and not -- cgit v1.2.3 From 5279631271b32201243c60308a8987bd585e4460 Mon Sep 17 00:00:00 2001 From: Zhou Chengming Date: Fri, 7 Jul 2017 11:15:58 +0800 Subject: module: fix ddebug_remove_module() ddebug_remove_module() use mod->name to find the ddebug_table of the module and remove it. But dynamic_debug_setup() use the first _ddebug->modname to create ddebug_table for the module. It's ok when the _ddebug->modname is the same with the mod->name. But livepatch module is special, it may contain _ddebugs of other modules, the modname of which is different from the name of livepatch module. So ddebug_remove_module() can't use mod->name to find the right ddebug_table and remove it. It can cause kernel crash when we cat the file /dynamic_debug/control. Signed-off-by: Zhou Chengming Signed-off-by: Jessica Yu --- kernel/module.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index 40f983cbea81..de66ec825992 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2707,21 +2707,21 @@ static void add_kallsyms(struct module *mod, const struct load_info *info) } #endif /* CONFIG_KALLSYMS */ -static void dynamic_debug_setup(struct _ddebug *debug, unsigned int num) +static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num) { if (!debug) return; #ifdef CONFIG_DYNAMIC_DEBUG - if (ddebug_add_module(debug, num, debug->modname)) + if (ddebug_add_module(debug, num, mod->name)) pr_err("dynamic debug error adding module: %s\n", debug->modname); #endif } -static void dynamic_debug_remove(struct _ddebug *debug) +static void dynamic_debug_remove(struct module *mod, struct _ddebug *debug) { if (debug) - ddebug_remove_module(debug->modname); + ddebug_remove_module(mod->name); } void * __weak module_alloc(unsigned long size) @@ -3715,7 +3715,7 @@ static int load_module(struct load_info *info, const char __user *uargs, goto free_arch_cleanup; } - dynamic_debug_setup(info->debug, info->num_debug); + dynamic_debug_setup(mod, info->debug, info->num_debug); /* Ftrace init must be called in the MODULE_STATE_UNFORMED state */ ftrace_module_init(mod); @@ -3779,7 +3779,7 @@ static int load_module(struct load_info *info, const char __user *uargs, module_disable_nx(mod); ddebug_cleanup: - dynamic_debug_remove(info->debug); + dynamic_debug_remove(mod, info->debug); synchronize_sched(); kfree(mod->args); free_arch_cleanup: -- cgit v1.2.3 From 8be6e1b15c54402106e6ba9bc706e685458b2d2d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sat, 29 Apr 2017 20:03:20 -0700 Subject: rcu: Use timer as backstop for NOCB deferred wakeups The handling of RCU's no-CBs CPUs has a maintenance headache, namely that if call_rcu() is invoked with interrupts disabled, the rcuo kthread wakeup must be defered to a point where we can be sure that scheduler locks are not held. Of course, there are a lot of code paths leading from an interrupts-disabled invocation of call_rcu(), and missing any one of these can result in excessive callback-invocation latency, and potentially even system hangs. This commit therefore uses a timer to guarantee that the wakeup will eventually occur. If one of the deferred-wakeup points kicks in, then the timer is simply cancelled. This commit also fixes up an incomplete removal of commits that were intended to plug remaining exit paths, which should have the added benefit of reducing the overhead of RCU's context-switch hooks. In addition, it simplifies leader-to-follower callback-list handoff by introducing locking. The call_rcu()-to-leader handoff continues to use atomic operations in order to maintain good real-time latency for common-case use of call_rcu(). Signed-off-by: Paul E. McKenney [ paulmck: Dan Carpenter fix for mod_timer() usage bug found by smatch. ] --- kernel/rcu/tree.h | 2 + kernel/rcu/tree_plugin.h | 179 +++++++++++++++++++++++++++++------------------ 2 files changed, 111 insertions(+), 70 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 9af0f31d6847..fe83f684ddcd 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -268,7 +268,9 @@ struct rcu_data { struct rcu_head **nocb_follower_tail; struct swait_queue_head nocb_wq; /* For nocb kthreads to sleep on. */ struct task_struct *nocb_kthread; + raw_spinlock_t nocb_lock; /* Guard following pair of fields. */ int nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */ + struct timer_list nocb_timer; /* Enforce finite deferral. */ /* The following fields are used by the leader, hence own cacheline. */ struct rcu_head *nocb_gp_head ____cacheline_internodealigned_in_smp; diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 908b309d60d7..bb9e6e43130f 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -1788,22 +1788,61 @@ bool rcu_is_nocb_cpu(int cpu) } /* - * Kick the leader kthread for this NOCB group. + * Kick the leader kthread for this NOCB group. Caller holds ->nocb_lock + * and this function releases it. */ -static void wake_nocb_leader(struct rcu_data *rdp, bool force) +static void __wake_nocb_leader(struct rcu_data *rdp, bool force, + unsigned long flags) + __releases(rdp->nocb_lock) { struct rcu_data *rdp_leader = rdp->nocb_leader; - if (!READ_ONCE(rdp_leader->nocb_kthread)) + lockdep_assert_held(&rdp->nocb_lock); + if (!READ_ONCE(rdp_leader->nocb_kthread)) { + raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags); return; - if (READ_ONCE(rdp_leader->nocb_leader_sleep) || force) { + } + if (rdp_leader->nocb_leader_sleep || force) { /* Prior smp_mb__after_atomic() orders against prior enqueue. */ WRITE_ONCE(rdp_leader->nocb_leader_sleep, false); + del_timer(&rdp->nocb_timer); + raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags); smp_mb(); /* ->nocb_leader_sleep before swake_up(). */ swake_up(&rdp_leader->nocb_wq); + } else { + raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags); } } +/* + * Kick the leader kthread for this NOCB group, but caller has not + * acquired locks. + */ +static void wake_nocb_leader(struct rcu_data *rdp, bool force) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&rdp->nocb_lock, flags); + __wake_nocb_leader(rdp, force, flags); +} + +/* + * Arrange to wake the leader kthread for this NOCB group at some + * future time when it is safe to do so. + */ +static void wake_nocb_leader_defer(struct rcu_data *rdp, int waketype, + const char *reason) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&rdp->nocb_lock, flags); + if (rdp->nocb_defer_wakeup == RCU_NOCB_WAKE_NOT) + mod_timer(&rdp->nocb_timer, jiffies + 1); + WRITE_ONCE(rdp->nocb_defer_wakeup, waketype); + trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, reason); + raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags); +} + /* * Does the specified CPU need an RCU callback for the specified flavor * of rcu_barrier()? @@ -1891,11 +1930,8 @@ static void __call_rcu_nocb_enqueue(struct rcu_data *rdp, trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WakeEmpty")); } else { - WRITE_ONCE(rdp->nocb_defer_wakeup, RCU_NOCB_WAKE); - /* Store ->nocb_defer_wakeup before ->rcu_urgent_qs. */ - smp_store_release(this_cpu_ptr(&rcu_dynticks.rcu_urgent_qs), true); - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, - TPS("WakeEmptyIsDeferred")); + wake_nocb_leader_defer(rdp, RCU_NOCB_WAKE, + TPS("WakeEmptyIsDeferred")); } rdp->qlen_last_fqs_check = 0; } else if (len > rdp->qlen_last_fqs_check + qhimark) { @@ -1905,11 +1941,8 @@ static void __call_rcu_nocb_enqueue(struct rcu_data *rdp, trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WakeOvf")); } else { - WRITE_ONCE(rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_FORCE); - /* Store ->nocb_defer_wakeup before ->rcu_urgent_qs. */ - smp_store_release(this_cpu_ptr(&rcu_dynticks.rcu_urgent_qs), true); - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, - TPS("WakeOvfIsDeferred")); + wake_nocb_leader_defer(rdp, RCU_NOCB_WAKE, + TPS("WakeOvfIsDeferred")); } rdp->qlen_last_fqs_check = LONG_MAX / 2; } else { @@ -2031,6 +2064,7 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp) static void nocb_leader_wait(struct rcu_data *my_rdp) { bool firsttime = true; + unsigned long flags; bool gotcbs; struct rcu_data *rdp; struct rcu_head **tail; @@ -2042,7 +2076,11 @@ wait_again: trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "Sleep"); swait_event_interruptible(my_rdp->nocb_wq, !READ_ONCE(my_rdp->nocb_leader_sleep)); - /* Memory barrier handled by smp_mb() calls below and repoll. */ + raw_spin_lock_irqsave(&my_rdp->nocb_lock, flags); + my_rdp->nocb_leader_sleep = true; + WRITE_ONCE(my_rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_NOT); + del_timer(&my_rdp->nocb_timer); + raw_spin_unlock_irqrestore(&my_rdp->nocb_lock, flags); } else if (firsttime) { firsttime = false; /* Don't drown trace log with "Poll"! */ trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "Poll"); @@ -2054,7 +2092,7 @@ wait_again: * nocb_gp_head, where they await a grace period. */ gotcbs = false; - smp_mb(); /* wakeup before ->nocb_head reads. */ + smp_mb(); /* wakeup and _sleep before ->nocb_head reads. */ for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower) { rdp->nocb_gp_head = READ_ONCE(rdp->nocb_head); if (!rdp->nocb_gp_head) @@ -2066,56 +2104,41 @@ wait_again: gotcbs = true; } - /* - * If there were no callbacks, sleep a bit, rescan after a - * memory barrier, and go retry. - */ + /* No callbacks? Sleep a bit if polling, and go retry. */ if (unlikely(!gotcbs)) { - if (!rcu_nocb_poll) + WARN_ON(signal_pending(current)); + if (rcu_nocb_poll) { + schedule_timeout_interruptible(1); + } else { trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "WokeEmpty"); - WARN_ON(signal_pending(current)); - schedule_timeout_interruptible(1); - - /* Rescan in case we were a victim of memory ordering. */ - my_rdp->nocb_leader_sleep = true; - smp_mb(); /* Ensure _sleep true before scan. */ - for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower) - if (READ_ONCE(rdp->nocb_head)) { - /* Found CB, so short-circuit next wait. */ - my_rdp->nocb_leader_sleep = false; - break; - } + } goto wait_again; } /* Wait for one grace period. */ rcu_nocb_wait_gp(my_rdp); - /* - * We left ->nocb_leader_sleep unset to reduce cache thrashing. - * We set it now, but recheck for new callbacks while - * traversing our follower list. - */ - my_rdp->nocb_leader_sleep = true; - smp_mb(); /* Ensure _sleep true before scan of ->nocb_head. */ - /* Each pass through the following loop wakes a follower, if needed. */ for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower) { - if (READ_ONCE(rdp->nocb_head)) + if (!rcu_nocb_poll && + READ_ONCE(rdp->nocb_head) && + READ_ONCE(my_rdp->nocb_leader_sleep)) { + raw_spin_lock_irqsave(&my_rdp->nocb_lock, flags); my_rdp->nocb_leader_sleep = false;/* No need to sleep.*/ + raw_spin_unlock_irqrestore(&my_rdp->nocb_lock, flags); + } if (!rdp->nocb_gp_head) continue; /* No CBs, so no need to wake follower. */ /* Append callbacks to follower's "done" list. */ - tail = xchg(&rdp->nocb_follower_tail, rdp->nocb_gp_tail); + raw_spin_lock_irqsave(&rdp->nocb_lock, flags); + tail = rdp->nocb_follower_tail; + rdp->nocb_follower_tail = rdp->nocb_gp_tail; *tail = rdp->nocb_gp_head; - smp_mb__after_atomic(); /* Store *tail before wakeup. */ + raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags); if (rdp != my_rdp && tail == &rdp->nocb_follower_head) { - /* - * List was empty, wake up the follower. - * Memory barriers supplied by atomic_long_add(). - */ + /* List was empty, so wake up the follower. */ swake_up(&rdp->nocb_wq); } } @@ -2131,28 +2154,16 @@ wait_again: */ static void nocb_follower_wait(struct rcu_data *rdp) { - bool firsttime = true; - for (;;) { - if (!rcu_nocb_poll) { - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, - "FollowerSleep"); - swait_event_interruptible(rdp->nocb_wq, - READ_ONCE(rdp->nocb_follower_head)); - } else if (firsttime) { - /* Don't drown trace log with "Poll"! */ - firsttime = false; - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "Poll"); - } + trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "FollowerSleep"); + swait_event_interruptible(rdp->nocb_wq, + READ_ONCE(rdp->nocb_follower_head)); if (smp_load_acquire(&rdp->nocb_follower_head)) { /* ^^^ Ensure CB invocation follows _head test. */ return; } - if (!rcu_nocb_poll) - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, - "WokeEmpty"); WARN_ON(signal_pending(current)); - schedule_timeout_interruptible(1); + trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "WokeEmpty"); } } @@ -2165,6 +2176,7 @@ static void nocb_follower_wait(struct rcu_data *rdp) static int rcu_nocb_kthread(void *arg) { int c, cl; + unsigned long flags; struct rcu_head *list; struct rcu_head *next; struct rcu_head **tail; @@ -2179,11 +2191,14 @@ static int rcu_nocb_kthread(void *arg) nocb_follower_wait(rdp); /* Pull the ready-to-invoke callbacks onto local list. */ - list = READ_ONCE(rdp->nocb_follower_head); + raw_spin_lock_irqsave(&rdp->nocb_lock, flags); + list = rdp->nocb_follower_head; + rdp->nocb_follower_head = NULL; + tail = rdp->nocb_follower_tail; + rdp->nocb_follower_tail = &rdp->nocb_follower_head; + raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags); BUG_ON(!list); trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "WokeNonEmpty"); - WRITE_ONCE(rdp->nocb_follower_head, NULL); - tail = xchg(&rdp->nocb_follower_tail, &rdp->nocb_follower_head); /* Each pass through the following loop invokes a callback. */ trace_rcu_batch_start(rdp->rsp->name, @@ -2226,18 +2241,39 @@ static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp) } /* Do a deferred wakeup of rcu_nocb_kthread(). */ -static void do_nocb_deferred_wakeup(struct rcu_data *rdp) +static void do_nocb_deferred_wakeup_common(struct rcu_data *rdp) { + unsigned long flags; int ndw; - if (!rcu_nocb_need_deferred_wakeup(rdp)) + raw_spin_lock_irqsave(&rdp->nocb_lock, flags); + if (!rcu_nocb_need_deferred_wakeup(rdp)) { + raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags); return; + } ndw = READ_ONCE(rdp->nocb_defer_wakeup); WRITE_ONCE(rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_NOT); - wake_nocb_leader(rdp, ndw == RCU_NOCB_WAKE_FORCE); + __wake_nocb_leader(rdp, ndw == RCU_NOCB_WAKE_FORCE, flags); trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("DeferredWake")); } +/* Do a deferred wakeup of rcu_nocb_kthread() from a timer handler. */ +static void do_nocb_deferred_wakeup_timer(unsigned long x) +{ + do_nocb_deferred_wakeup_common((struct rcu_data *)x); +} + +/* + * Do a deferred wakeup of rcu_nocb_kthread() from fastpath. + * This means we do an inexact common-case check. Note that if + * we miss, ->nocb_timer will eventually clean things up. + */ +static void do_nocb_deferred_wakeup(struct rcu_data *rdp) +{ + if (rcu_nocb_need_deferred_wakeup(rdp)) + do_nocb_deferred_wakeup_common(rdp); +} + void __init rcu_init_nohz(void) { int cpu; @@ -2287,6 +2323,9 @@ static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp) rdp->nocb_tail = &rdp->nocb_head; init_swait_queue_head(&rdp->nocb_wq); rdp->nocb_follower_tail = &rdp->nocb_follower_head; + raw_spin_lock_init(&rdp->nocb_lock); + setup_timer(&rdp->nocb_timer, do_nocb_deferred_wakeup_timer, + (unsigned long)rdp); } /* -- cgit v1.2.3 From f274f1e72d7171c80c8c790040e47a23a74796b6 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 30 Jun 2017 13:13:59 -0700 Subject: task_work: Replace spin_unlock_wait() with lock/unlock pair There is no agreed-upon definition of spin_unlock_wait()'s semantics, and it appears that all callers could do just as well with a lock/unlock pair. This commit therefore replaces the spin_unlock_wait() call in task_work_run() with a spin_lock_irq() and a spin_unlock_irq() aruond the cmpxchg() dequeue loop. This should be safe from a performance perspective because ->pi_lock is local to the task and because calls to the other side of the race, task_work_cancel(), should be rare. Signed-off-by: Oleg Nesterov Signed-off-by: Paul E. McKenney --- kernel/task_work.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/task_work.c b/kernel/task_work.c index d513051fcca2..836a72a66fba 100644 --- a/kernel/task_work.c +++ b/kernel/task_work.c @@ -96,20 +96,16 @@ void task_work_run(void) * work->func() can do task_work_add(), do not set * work_exited unless the list is empty. */ + raw_spin_lock_irq(&task->pi_lock); do { work = READ_ONCE(task->task_works); head = !work && (task->flags & PF_EXITING) ? &work_exited : NULL; } while (cmpxchg(&task->task_works, work, head) != work); + raw_spin_unlock_irq(&task->pi_lock); if (!work) break; - /* - * Synchronize with task_work_cancel(). It can't remove - * the first entry == work, cmpxchg(task_works) should - * fail, but it can play with *work and other entries. - */ - raw_spin_unlock_wait(&task->pi_lock); do { next = work->next; -- cgit v1.2.3 From 918a8c2c4ea4fab8b7855b8da48bbaf0a733ebb0 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 23 Jul 2017 08:18:26 -0400 Subject: cgroup: remove unnecessary empty check when enabling threaded mode cgroup_enable_threaded() checks that the cgroup doesn't have any tasks or children and fails the operation if so. This test is unnecessary because the first part is already checked by cgroup_can_be_thread_root() and the latter is unnecessary. The latter actually cause a behavioral oddity. Please consider the following hierarchy. All cgroups are domains. A / \ B C \ D If B is made threaded, C and D becomes invalid domains. Due to the no children restriction, threaded mode can't be enabled on C. For C and D, the only thing the user can do is removal. There is no reason for this restriction. Remove it. Acked-by: Waiman Long Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 7 ------- 1 file changed, 7 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index e9a377dc5bdb..e0a558c4d358 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3146,13 +3146,6 @@ static int cgroup_enable_threaded(struct cgroup *cgrp) !cgroup_can_be_thread_root(dom_cgrp)) return -EOPNOTSUPP; - /* - * Allow enabling thread mode only on empty cgroups to avoid - * implicit migrations and recursive operations. - */ - if (cgroup_has_tasks(cgrp) || css_has_online_children(&cgrp->self)) - return -EBUSY; - /* * The following shouldn't cause actual migrations and should * always succeed. -- cgit v1.2.3 From c705a00d77457b44ba3790fdf0627ecb8593a254 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 25 Jul 2017 13:20:18 -0400 Subject: cgroup: add comment to cgroup_enable_threaded() Explain cgroup_enable_threaded() and note that the function can never be called on the root cgroup. Signed-off-by: Tejun Heo Suggested-by: Waiman Long --- kernel/cgroup/cgroup.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index e0a558c4d358..85f6a112344b 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3129,6 +3129,15 @@ out_unlock: return ret ?: nbytes; } +/** + * cgroup_enable_threaded - make @cgrp threaded + * @cgrp: the target cgroup + * + * Called when "threaded" is written to the cgroup.type interface file and + * tries to make @cgrp threaded and join the parent's resource domain. + * This function is never called on the root cgroup as cgroup.type doesn't + * exist on it. + */ static int cgroup_enable_threaded(struct cgroup *cgrp) { struct cgroup *parent = cgroup_parent(cgrp); -- cgit v1.2.3 From 0a94efb5acbb6980d7c9ab604372d93cd507e4d8 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 23 Jul 2017 08:36:15 -0400 Subject: workqueue: implicit ordered attribute should be overridable 5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered") automatically enabled ordered attribute for unbound workqueues w/ max_active == 1. Because ordered workqueues reject max_active and some attribute changes, this implicit ordered mode broke cases where the user creates an unbound workqueue w/ max_active == 1 and later explicitly changes the related attributes. This patch distinguishes explicit and implicit ordered setting and overrides from attribute changes if implict. Signed-off-by: Tejun Heo Fixes: 5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered") --- kernel/workqueue.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index abe4a4971c24..7146ea70a62d 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3744,8 +3744,12 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, return -EINVAL; /* creating multiple pwqs breaks ordering guarantee */ - if (WARN_ON((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs))) - return -EINVAL; + if (!list_empty(&wq->pwqs)) { + if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT)) + return -EINVAL; + + wq->flags &= ~__WQ_ORDERED; + } ctx = apply_wqattrs_prepare(wq, attrs); if (!ctx) @@ -4129,13 +4133,14 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) struct pool_workqueue *pwq; /* disallow meddling with max_active for ordered workqueues */ - if (WARN_ON(wq->flags & __WQ_ORDERED)) + if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT)) return; max_active = wq_clamp_max_active(max_active, wq->flags, wq->name); mutex_lock(&wq->mutex); + wq->flags &= ~__WQ_ORDERED; wq->saved_max_active = max_active; for_each_pwq(pwq, wq) @@ -5263,7 +5268,7 @@ int workqueue_sysfs_register(struct workqueue_struct *wq) * attributes breaks ordering guarantee. Disallow exposing ordered * workqueues. */ - if (WARN_ON(wq->flags & __WQ_ORDERED)) + if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT)) return -EINVAL; wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL); -- cgit v1.2.3 From a58163d8ca2c8d288ee9f95989712f98473a5ac2 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 20 Jun 2017 12:11:34 -0700 Subject: rcu: Migrate callbacks earlier in the CPU-offline timeline RCU callbacks must be migrated away from an outgoing CPU, and this is done near the end of the CPU-hotplug operation, after the outgoing CPU is long gone. Unfortunately, this means that other CPU-hotplug callbacks can execute while the outgoing CPU's callbacks are still immobilized on the long-gone CPU's callback lists. If any of these CPU-hotplug callbacks must wait, either directly or indirectly, for the invocation of any of the immobilized RCU callbacks, the system will hang. This commit avoids such hangs by migrating the callbacks away from the outgoing CPU immediately upon its departure, shortly after the return from __cpu_die() in takedown_cpu(). Thus, RCU is able to advance these callbacks and invoke them, which allows all the after-the-fact CPU-hotplug callbacks to wait on these RCU callbacks without risk of a hang. While in the neighborhood, this commit also moves rcu_send_cbs_to_orphanage() and rcu_adopt_orphan_cbs() under a pre-existing #ifdef to avoid including dead code on the one hand and to avoid define-without-use warnings on the other hand. Reported-by: Jeffrey Hugo Link: http://lkml.kernel.org/r/db9c91f6-1b17-6136-84f0-03c3c2581ab4@codeaurora.org Signed-off-by: Paul E. McKenney Cc: Thomas Gleixner Cc: Sebastian Andrzej Siewior Cc: Ingo Molnar Cc: Anna-Maria Gleixner Cc: Boris Ostrovsky Cc: Richard Weinberger --- kernel/cpu.c | 1 + kernel/rcu/tree.c | 209 +++++++++++++++++++++++++++++------------------------- 2 files changed, 114 insertions(+), 96 deletions(-) (limited to 'kernel') diff --git a/kernel/cpu.c b/kernel/cpu.c index eee033134262..bfbd649ccdc8 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -650,6 +650,7 @@ static int takedown_cpu(unsigned int cpu) __cpu_die(cpu); tick_cleanup_dead_cpu(cpu); + rcutree_migrate_callbacks(cpu); return 0; } diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 51d4c3acf32d..9bb5dff50815 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2562,85 +2562,6 @@ rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp) rcu_report_qs_rdp(rdp->cpu, rsp, rdp); } -/* - * Send the specified CPU's RCU callbacks to the orphanage. The - * specified CPU must be offline, and the caller must hold the - * ->orphan_lock. - */ -static void -rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp, - struct rcu_node *rnp, struct rcu_data *rdp) -{ - lockdep_assert_held(&rsp->orphan_lock); - - /* No-CBs CPUs do not have orphanable callbacks. */ - if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) || rcu_is_nocb_cpu(rdp->cpu)) - return; - - /* - * Orphan the callbacks. First adjust the counts. This is safe - * because _rcu_barrier() excludes CPU-hotplug operations, so it - * cannot be running now. Thus no memory barrier is required. - */ - rdp->n_cbs_orphaned += rcu_segcblist_n_cbs(&rdp->cblist); - rcu_segcblist_extract_count(&rdp->cblist, &rsp->orphan_done); - - /* - * Next, move those callbacks still needing a grace period to - * the orphanage, where some other CPU will pick them up. - * Some of the callbacks might have gone partway through a grace - * period, but that is too bad. They get to start over because we - * cannot assume that grace periods are synchronized across CPUs. - */ - rcu_segcblist_extract_pend_cbs(&rdp->cblist, &rsp->orphan_pend); - - /* - * Then move the ready-to-invoke callbacks to the orphanage, - * where some other CPU will pick them up. These will not be - * required to pass though another grace period: They are done. - */ - rcu_segcblist_extract_done_cbs(&rdp->cblist, &rsp->orphan_done); - - /* Finally, disallow further callbacks on this CPU. */ - rcu_segcblist_disable(&rdp->cblist); -} - -/* - * Adopt the RCU callbacks from the specified rcu_state structure's - * orphanage. The caller must hold the ->orphan_lock. - */ -static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags) -{ - struct rcu_data *rdp = raw_cpu_ptr(rsp->rda); - - lockdep_assert_held(&rsp->orphan_lock); - - /* No-CBs CPUs are handled specially. */ - if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) || - rcu_nocb_adopt_orphan_cbs(rsp, rdp, flags)) - return; - - /* Do the accounting first. */ - rdp->n_cbs_adopted += rsp->orphan_done.len; - if (rsp->orphan_done.len_lazy != rsp->orphan_done.len) - rcu_idle_count_callbacks_posted(); - rcu_segcblist_insert_count(&rdp->cblist, &rsp->orphan_done); - - /* - * We do not need a memory barrier here because the only way we - * can get here if there is an rcu_barrier() in flight is if - * we are the task doing the rcu_barrier(). - */ - - /* First adopt the ready-to-invoke callbacks, then the done ones. */ - rcu_segcblist_insert_done_cbs(&rdp->cblist, &rsp->orphan_done); - WARN_ON_ONCE(rsp->orphan_done.head); - rcu_segcblist_insert_pend_cbs(&rdp->cblist, &rsp->orphan_pend); - WARN_ON_ONCE(rsp->orphan_pend.head); - WARN_ON_ONCE(rcu_segcblist_empty(&rdp->cblist) != - !rcu_segcblist_n_cbs(&rdp->cblist)); -} - /* * Trace the fact that this CPU is going offline. */ @@ -2704,14 +2625,12 @@ static void rcu_cleanup_dead_rnp(struct rcu_node *rnp_leaf) /* * The CPU has been completely removed, and some other CPU is reporting - * this fact from process context. Do the remainder of the cleanup, - * including orphaning the outgoing CPU's RCU callbacks, and also - * adopting them. There can only be one CPU hotplug operation at a time, - * so no other CPU can be attempting to update rcu_cpu_kthread_task. + * this fact from process context. Do the remainder of the cleanup. + * There can only be one CPU hotplug operation at a time, so no need for + * explicit locking. */ static void rcu_cleanup_dead_cpu(int cpu, struct rcu_state *rsp) { - unsigned long flags; struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */ @@ -2720,18 +2639,6 @@ static void rcu_cleanup_dead_cpu(int cpu, struct rcu_state *rsp) /* Adjust any no-longer-needed kthreads. */ rcu_boost_kthread_setaffinity(rnp, -1); - - /* Orphan the dead CPU's callbacks, and adopt them if appropriate. */ - raw_spin_lock_irqsave(&rsp->orphan_lock, flags); - rcu_send_cbs_to_orphanage(cpu, rsp, rnp, rdp); - rcu_adopt_orphan_cbs(rsp, flags); - raw_spin_unlock_irqrestore(&rsp->orphan_lock, flags); - - WARN_ONCE(rcu_segcblist_n_cbs(&rdp->cblist) != 0 || - !rcu_segcblist_empty(&rdp->cblist), - "rcu_cleanup_dead_cpu: Callbacks on offline CPU %d: qlen=%lu, 1stCB=%p\n", - cpu, rcu_segcblist_n_cbs(&rdp->cblist), - rcu_segcblist_first_cb(&rdp->cblist)); } /* @@ -3937,6 +3844,116 @@ void rcu_report_dead(unsigned int cpu) for_each_rcu_flavor(rsp) rcu_cleanup_dying_idle_cpu(cpu, rsp); } + +/* + * Send the specified CPU's RCU callbacks to the orphanage. The + * specified CPU must be offline, and the caller must hold the + * ->orphan_lock. + */ +static void +rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp, + struct rcu_node *rnp, struct rcu_data *rdp) +{ + lockdep_assert_held(&rsp->orphan_lock); + + /* No-CBs CPUs do not have orphanable callbacks. */ + if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) || rcu_is_nocb_cpu(rdp->cpu)) + return; + + /* + * Orphan the callbacks. First adjust the counts. This is safe + * because _rcu_barrier() excludes CPU-hotplug operations, so it + * cannot be running now. Thus no memory barrier is required. + */ + rdp->n_cbs_orphaned += rcu_segcblist_n_cbs(&rdp->cblist); + rcu_segcblist_extract_count(&rdp->cblist, &rsp->orphan_done); + + /* + * Next, move those callbacks still needing a grace period to + * the orphanage, where some other CPU will pick them up. + * Some of the callbacks might have gone partway through a grace + * period, but that is too bad. They get to start over because we + * cannot assume that grace periods are synchronized across CPUs. + */ + rcu_segcblist_extract_pend_cbs(&rdp->cblist, &rsp->orphan_pend); + + /* + * Then move the ready-to-invoke callbacks to the orphanage, + * where some other CPU will pick them up. These will not be + * required to pass though another grace period: They are done. + */ + rcu_segcblist_extract_done_cbs(&rdp->cblist, &rsp->orphan_done); + + /* Finally, disallow further callbacks on this CPU. */ + rcu_segcblist_disable(&rdp->cblist); +} + +/* + * Adopt the RCU callbacks from the specified rcu_state structure's + * orphanage. The caller must hold the ->orphan_lock. + */ +static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags) +{ + struct rcu_data *rdp = raw_cpu_ptr(rsp->rda); + + lockdep_assert_held(&rsp->orphan_lock); + + /* No-CBs CPUs are handled specially. */ + if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) || + rcu_nocb_adopt_orphan_cbs(rsp, rdp, flags)) + return; + + /* Do the accounting first. */ + rdp->n_cbs_adopted += rsp->orphan_done.len; + if (rsp->orphan_done.len_lazy != rsp->orphan_done.len) + rcu_idle_count_callbacks_posted(); + rcu_segcblist_insert_count(&rdp->cblist, &rsp->orphan_done); + + /* + * We do not need a memory barrier here because the only way we + * can get here if there is an rcu_barrier() in flight is if + * we are the task doing the rcu_barrier(). + */ + + /* First adopt the ready-to-invoke callbacks, then the done ones. */ + rcu_segcblist_insert_done_cbs(&rdp->cblist, &rsp->orphan_done); + WARN_ON_ONCE(rsp->orphan_done.head); + rcu_segcblist_insert_pend_cbs(&rdp->cblist, &rsp->orphan_pend); + WARN_ON_ONCE(rsp->orphan_pend.head); + WARN_ON_ONCE(rcu_segcblist_empty(&rdp->cblist) != + !rcu_segcblist_n_cbs(&rdp->cblist)); +} + +/* Orphan the dead CPU's callbacks, and then adopt them. */ +static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp) +{ + unsigned long flags; + struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); + struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */ + + raw_spin_lock_irqsave(&rsp->orphan_lock, flags); + rcu_send_cbs_to_orphanage(cpu, rsp, rnp, rdp); + rcu_adopt_orphan_cbs(rsp, flags); + raw_spin_unlock_irqrestore(&rsp->orphan_lock, flags); + WARN_ONCE(rcu_segcblist_n_cbs(&rdp->cblist) != 0 || + !rcu_segcblist_empty(&rdp->cblist), + "rcu_cleanup_dead_cpu: Callbacks on offline CPU %d: qlen=%lu, 1stCB=%p\n", + cpu, rcu_segcblist_n_cbs(&rdp->cblist), + rcu_segcblist_first_cb(&rdp->cblist)); +} + +/* + * The outgoing CPU has just passed through the dying-idle state, + * and we are being invoked from the CPU that was IPIed to continue the + * offline operation. We need to migrate the outgoing CPU's callbacks. + */ +void rcutree_migrate_callbacks(int cpu) +{ + struct rcu_state *rsp; + + for_each_rcu_flavor(rsp) + rcu_migrate_callbacks(cpu, rsp); +} #endif /* -- cgit v1.2.3 From 313517fc44fb2d8403654b2d3e511da7d1c78cd6 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 8 Jun 2017 16:55:40 -0700 Subject: rcu: Make expedited GPs correctly handle hardware CPU insertion The update of the ->expmaskinitnext and of ->ncpus are unsynchronized, with the value of ->ncpus being incremented long before the corresponding ->expmaskinitnext mask is updated. If an RCU expedited grace period sees ->ncpus change, it will update the ->expmaskinit masks from the new ->expmaskinitnext masks. But it is possible that ->ncpus has already been updated, but the ->expmaskinitnext masks still have their old values. For the current expedited grace period, no harm done. The CPU could not have been online before the grace period started, so there is no need to wait for its non-existent pre-existing readers. But the next RCU expedited grace period is in a world of hurt. The value of ->ncpus has already been updated, so this grace period will assume that the ->expmaskinitnext masks have not changed. But they have, and they won't be taken into account until the next never-been-online CPU comes online. This means that RCU will be ignoring some CPUs that it should be paying attention to. The solution is to update ->ncpus and ->expmaskinitnext while holding the ->lock for the rcu_node structure containing the ->expmaskinitnext mask. Because smp_store_release() is now used to update ->ncpus and smp_load_acquire() is now used to locklessly read it, if the expedited grace period sees ->ncpus change, then the updating CPU has to already be holding the corresponding ->lock. Therefore, when the expedited grace period later acquires that ->lock, it is guaranteed to see the new value of ->expmaskinitnext. On the other hand, if the expedited grace period loads ->ncpus just before an update, earlier full memory barriers guarantee that the incoming CPU isn't far enough along to be running any RCU readers. This commit therefore makes the required change. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 10 ++++++++-- kernel/rcu/tree_exp.h | 2 +- 2 files changed, 9 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 9bb5dff50815..f431114bc06a 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3684,8 +3684,6 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp) */ rnp = rdp->mynode; raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */ - if (!rdp->beenonline) - WRITE_ONCE(rsp->ncpus, READ_ONCE(rsp->ncpus) + 1); rdp->beenonline = true; /* We have now been online. */ rdp->gpnum = rnp->completed; /* Make CPU later note any new GP. */ rdp->completed = rnp->completed; @@ -3789,6 +3787,8 @@ void rcu_cpu_starting(unsigned int cpu) { unsigned long flags; unsigned long mask; + int nbits; + unsigned long oldmask; struct rcu_data *rdp; struct rcu_node *rnp; struct rcu_state *rsp; @@ -3799,9 +3799,15 @@ void rcu_cpu_starting(unsigned int cpu) mask = rdp->grpmask; raw_spin_lock_irqsave_rcu_node(rnp, flags); rnp->qsmaskinitnext |= mask; + oldmask = rnp->expmaskinitnext; rnp->expmaskinitnext |= mask; + oldmask ^= rnp->expmaskinitnext; + nbits = bitmap_weight(&oldmask, BITS_PER_LONG); + /* Allow lockless access for expedited grace periods. */ + smp_store_release(&rsp->ncpus, rsp->ncpus + nbits); /* ^^^ */ raw_spin_unlock_irqrestore_rcu_node(rnp, flags); } + smp_mb(); /* Ensure RCU read-side usage follows above initialization. */ } #ifdef CONFIG_HOTPLUG_CPU diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index dd21ca47e4b4..46d61b597731 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -73,7 +73,7 @@ static void sync_exp_reset_tree_hotplug(struct rcu_state *rsp) unsigned long flags; unsigned long mask; unsigned long oldmask; - int ncpus = READ_ONCE(rsp->ncpus); + int ncpus = smp_load_acquire(&rsp->ncpus); /* Order against locking. */ struct rcu_node *rnp; struct rcu_node *rnp_up; -- cgit v1.2.3 From a2b2df207acff1e3f965ff2c7c38255b06d583cb Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 22 Jun 2017 15:38:26 -0700 Subject: torture: Fix typo suppressing CPU-hotplug statistics The torture status line contains a series of values preceded by "onoff:". The last value in that line, the one preceding the "HZ=" string, is always zero. The reason that it is always zero is that torture_offline() was incrementing the sum_offl pointer instead of the value that this pointer referenced. This commit therefore makes this increment operate on the statistic rather than the pointer to the statistic. Signed-off-by: Paul E. McKenney --- kernel/torture.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/torture.c b/kernel/torture.c index 55de96529287..637e172835d8 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -117,7 +117,7 @@ bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes, torture_type, cpu); (*n_offl_successes)++; delta = jiffies - starttime; - sum_offl += delta; + *sum_offl += delta; if (*min_offl < 0) { *min_offl = delta; *max_offl = delta; -- cgit v1.2.3 From c47e067a3c57835fe5ce24d50482f5c325a64efd Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 23 Jun 2017 20:30:08 -0700 Subject: rcu: Remove orphan/adopt event-tracing fields The rcu_node structure's ->n_cbs_orphaned and ->n_cbs_adopted fields are updated, but never read. This commit therefore removes them. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 2 -- kernel/rcu/tree.h | 2 -- 2 files changed, 4 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index f431114bc06a..f5acf34247fb 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3871,7 +3871,6 @@ rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp, * because _rcu_barrier() excludes CPU-hotplug operations, so it * cannot be running now. Thus no memory barrier is required. */ - rdp->n_cbs_orphaned += rcu_segcblist_n_cbs(&rdp->cblist); rcu_segcblist_extract_count(&rdp->cblist, &rsp->orphan_done); /* @@ -3910,7 +3909,6 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags) return; /* Do the accounting first. */ - rdp->n_cbs_adopted += rsp->orphan_done.len; if (rsp->orphan_done.len_lazy != rsp->orphan_done.len) rcu_idle_count_callbacks_posted(); rcu_segcblist_insert_count(&rdp->cblist, &rsp->orphan_done); diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 9af0f31d6847..aec53c4d4aec 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -219,8 +219,6 @@ struct rcu_data { /* qlen at last check for QS forcing */ unsigned long n_cbs_invoked; /* count of RCU cbs invoked. */ unsigned long n_nocbs_invoked; /* count of no-CBs RCU cbs invoked. */ - unsigned long n_cbs_orphaned; /* RCU cbs orphaned by dying CPU */ - unsigned long n_cbs_adopted; /* RCU cbs adopted from dying CPU */ unsigned long n_force_qs_snap; /* did other CPU force QS recently? */ long blimit; /* Upper limit on a processed batch */ -- cgit v1.2.3 From 95335c0355834c16cc11f041a981ee6782dba2e9 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 26 Jun 2017 10:49:50 -0700 Subject: rcu: Check for NOCB CPUs and empty lists earlier in CB migration The current CPU-hotplug RCU-callback-migration code checks for the source (newly offlined) CPU being a NOCBs CPU down in rcu_send_cbs_to_orphanage(). This commit simplifies callback migration a bit by moving this check up to rcu_migrate_callbacks(). This commit also adds a check for the source CPU having no callbacks, which eases analysis of the rcu_send_cbs_to_orphanage() and rcu_adopt_orphan_cbs() functions. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index f5acf34247fb..aeea697d6f9f 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3862,10 +3862,6 @@ rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp, { lockdep_assert_held(&rsp->orphan_lock); - /* No-CBs CPUs do not have orphanable callbacks. */ - if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) || rcu_is_nocb_cpu(rdp->cpu)) - return; - /* * Orphan the callbacks. First adjust the counts. This is safe * because _rcu_barrier() excludes CPU-hotplug operations, so it @@ -3935,6 +3931,9 @@ static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp) struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */ + if (rcu_is_nocb_cpu(cpu) || rcu_segcblist_empty(&rdp->cblist)) + return; /* No callbacks to migrate. */ + raw_spin_lock_irqsave(&rsp->orphan_lock, flags); rcu_send_cbs_to_orphanage(cpu, rsp, rnp, rdp); rcu_adopt_orphan_cbs(rsp, flags); -- cgit v1.2.3 From b1a2d79fe7d210c114003362d93d529912d244df Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 26 Jun 2017 12:23:46 -0700 Subject: rcu: Make NOCB CPUs migrate CBs directly from outgoing CPU RCU's CPU-hotplug callback-migration code first moves the outgoing CPU's callbacks to ->orphan_done and ->orphan_pend, and only then moves them to the NOCB callback list. This commit avoids the extra step (and simplifies the code) by moving the callbacks directly from the outgoing CPU's callback list to the NOCB callback list. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 14 ++++++++------ kernel/rcu/tree.h | 2 +- kernel/rcu/tree_plugin.h | 31 ++++++++++--------------------- 3 files changed, 19 insertions(+), 28 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index aeea697d6f9f..4ea28e820f4a 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3899,11 +3899,6 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags) lockdep_assert_held(&rsp->orphan_lock); - /* No-CBs CPUs are handled specially. */ - if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) || - rcu_nocb_adopt_orphan_cbs(rsp, rdp, flags)) - return; - /* Do the accounting first. */ if (rsp->orphan_done.len_lazy != rsp->orphan_done.len) rcu_idle_count_callbacks_posted(); @@ -3928,13 +3923,20 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags) static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp) { unsigned long flags; + struct rcu_data *my_rdp; struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */ if (rcu_is_nocb_cpu(cpu) || rcu_segcblist_empty(&rdp->cblist)) return; /* No callbacks to migrate. */ - raw_spin_lock_irqsave(&rsp->orphan_lock, flags); + local_irq_save(flags); + my_rdp = this_cpu_ptr(rsp->rda); + if (rcu_nocb_adopt_orphan_cbs(my_rdp, rdp, flags)) { + local_irq_restore(flags); + return; + } + raw_spin_lock(&rsp->orphan_lock); /* irqs already disabled. */ rcu_send_cbs_to_orphanage(cpu, rsp, rnp, rdp); rcu_adopt_orphan_cbs(rsp, flags); raw_spin_unlock_irqrestore(&rsp->orphan_lock, flags); diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index aec53c4d4aec..574513cf49b4 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -493,7 +493,7 @@ static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq); static void rcu_init_one_nocb(struct rcu_node *rnp); static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp, bool lazy, unsigned long flags); -static bool rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp, +static bool rcu_nocb_adopt_orphan_cbs(struct rcu_data *my_rdp, struct rcu_data *rdp, unsigned long flags); static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp); diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 908b309d60d7..ff7d5ee49816 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -1961,30 +1961,19 @@ static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp, * Adopt orphaned callbacks on a no-CBs CPU, or return 0 if this is * not a no-CBs CPU. */ -static bool __maybe_unused rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp, +static bool __maybe_unused rcu_nocb_adopt_orphan_cbs(struct rcu_data *my_rdp, struct rcu_data *rdp, unsigned long flags) { - long ql = rsp->orphan_done.len; - long qll = rsp->orphan_done.len_lazy; - - /* If this is not a no-CBs CPU, tell the caller to do it the old way. */ + RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_nocb_adopt_orphan_cbs() invoked with irqs enabled!!!"); if (!rcu_is_nocb_cpu(smp_processor_id())) - return false; - - /* First, enqueue the donelist, if any. This preserves CB ordering. */ - if (rsp->orphan_done.head) { - __call_rcu_nocb_enqueue(rdp, rcu_cblist_head(&rsp->orphan_done), - rcu_cblist_tail(&rsp->orphan_done), - ql, qll, flags); - } - if (rsp->orphan_pend.head) { - __call_rcu_nocb_enqueue(rdp, rcu_cblist_head(&rsp->orphan_pend), - rcu_cblist_tail(&rsp->orphan_pend), - ql, qll, flags); - } - rcu_cblist_init(&rsp->orphan_done); - rcu_cblist_init(&rsp->orphan_pend); + return false; /* Not NOCBs CPU, caller must migrate CBs. */ + __call_rcu_nocb_enqueue(my_rdp, rcu_segcblist_head(&rdp->cblist), + rcu_segcblist_tail(&rdp->cblist), + rcu_segcblist_n_cbs(&rdp->cblist), + rcu_segcblist_n_lazy_cbs(&rdp->cblist), flags); + rcu_segcblist_init(&rdp->cblist); + rcu_segcblist_disable(&rdp->cblist); return true; } @@ -2459,7 +2448,7 @@ static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp, return false; } -static bool __maybe_unused rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp, +static bool __maybe_unused rcu_nocb_adopt_orphan_cbs(struct rcu_data *my_rdp, struct rcu_data *rdp, unsigned long flags) { -- cgit v1.2.3 From 9fa46fb8c9c6dfad30487fb3d905c2ff04b379b7 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 26 Jun 2017 15:43:27 -0700 Subject: rcu: Advance outgoing CPU's callbacks before migrating them It is possible that the outgoing CPU is unaware of recent grace periods, and so it is also possible that some of its pending callbacks are actually ready to be invoked. The current callback-migration code would needlessly force these callbacks to pass through another grace period. This commit therefore invokes rcu_advance_cbs() on the outgoing CPU's callbacks in order to give them full credit for having passed through any recent grace periods. This also fixes an odd theoretical bug where there are no callbacks in the system except for those on the outgoing CPU, none of those callbacks have yet been associated with a grace-period number, there is never again another callback registered, and the surviving CPU never again takes a scheduling-clock interrupt, never goes idle, and never enters nohz_full userspace execution. Yes, this is (just barely) possible. It requires that the surviving CPU be a nohz_full CPU, that its scheduler-clock interrupt be shut off, and that it loop forever in the kernel. You get bonus points if you can make this one happen! ;-) Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 4ea28e820f4a..c080c6ed66af 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3926,6 +3926,7 @@ static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp) struct rcu_data *my_rdp; struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */ + struct rcu_node *rnp_root = rcu_get_root(rdp->rsp); if (rcu_is_nocb_cpu(cpu) || rcu_segcblist_empty(&rdp->cblist)) return; /* No callbacks to migrate. */ @@ -3936,7 +3937,11 @@ static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp) local_irq_restore(flags); return; } - raw_spin_lock(&rsp->orphan_lock); /* irqs already disabled. */ + raw_spin_lock_rcu_node(rnp_root); /* irqs already disabled. */ + rcu_advance_cbs(rsp, rnp_root, rdp); /* Leverage recent GPs. */ + raw_spin_unlock_rcu_node(rnp_root); + + raw_spin_lock(&rsp->orphan_lock); rcu_send_cbs_to_orphanage(cpu, rsp, rnp, rdp); rcu_adopt_orphan_cbs(rsp, flags); raw_spin_unlock_irqrestore(&rsp->orphan_lock, flags); -- cgit v1.2.3 From 537b85c870babacc1cf13235e92bee9de86210e0 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 26 Jun 2017 17:59:02 -0700 Subject: rcu: Eliminate rcu_state ->orphan_lock The ->orphan_lock is acquired and released only within the rcu_migrate_callbacks() function, which now acquires the root rcu_node structure's ->lock. This commit therefore eliminates the ->orphan_lock in favor of the root rcu_node structure's ->lock. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 15 +++------------ kernel/rcu/tree.h | 3 --- 2 files changed, 3 insertions(+), 15 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index c080c6ed66af..58ab489eca66 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -97,7 +97,6 @@ struct rcu_state sname##_state = { \ .gp_state = RCU_GP_IDLE, \ .gpnum = 0UL - 300UL, \ .completed = 0UL - 300UL, \ - .orphan_lock = __RAW_SPIN_LOCK_UNLOCKED(&sname##_state.orphan_lock), \ .orphan_pend = RCU_CBLIST_INITIALIZER(sname##_state.orphan_pend), \ .orphan_done = RCU_CBLIST_INITIALIZER(sname##_state.orphan_done), \ .barrier_mutex = __MUTEX_INITIALIZER(sname##_state.barrier_mutex), \ @@ -3853,15 +3852,12 @@ void rcu_report_dead(unsigned int cpu) /* * Send the specified CPU's RCU callbacks to the orphanage. The - * specified CPU must be offline, and the caller must hold the - * ->orphan_lock. + * specified CPU must be offline. */ static void rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) { - lockdep_assert_held(&rsp->orphan_lock); - /* * Orphan the callbacks. First adjust the counts. This is safe * because _rcu_barrier() excludes CPU-hotplug operations, so it @@ -3891,14 +3887,12 @@ rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp, /* * Adopt the RCU callbacks from the specified rcu_state structure's - * orphanage. The caller must hold the ->orphan_lock. + * orphanage. */ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags) { struct rcu_data *rdp = raw_cpu_ptr(rsp->rda); - lockdep_assert_held(&rsp->orphan_lock); - /* Do the accounting first. */ if (rsp->orphan_done.len_lazy != rsp->orphan_done.len) rcu_idle_count_callbacks_posted(); @@ -3939,12 +3933,9 @@ static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp) } raw_spin_lock_rcu_node(rnp_root); /* irqs already disabled. */ rcu_advance_cbs(rsp, rnp_root, rdp); /* Leverage recent GPs. */ - raw_spin_unlock_rcu_node(rnp_root); - - raw_spin_lock(&rsp->orphan_lock); rcu_send_cbs_to_orphanage(cpu, rsp, rnp, rdp); rcu_adopt_orphan_cbs(rsp, flags); - raw_spin_unlock_irqrestore(&rsp->orphan_lock, flags); + raw_spin_unlock_irqrestore_rcu_node(rnp_root, flags); WARN_ONCE(rcu_segcblist_n_cbs(&rdp->cblist) != 0 || !rcu_segcblist_empty(&rdp->cblist), "rcu_cleanup_dead_cpu: Callbacks on offline CPU %d: qlen=%lu, 1stCB=%p\n", diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 574513cf49b4..62b1d0b0d47c 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -348,14 +348,11 @@ struct rcu_state { /* End of fields guarded by root rcu_node's lock. */ - raw_spinlock_t orphan_lock ____cacheline_internodealigned_in_smp; - /* Protect following fields. */ struct rcu_cblist orphan_pend; /* Orphaned callbacks that */ /* need a grace period. */ struct rcu_cblist orphan_done; /* Orphaned callbacks that */ /* are ready to invoke. */ /* (Contains counts.) */ - /* End of fields guarded by orphan_lock. */ struct mutex barrier_mutex; /* Guards barrier fields. */ atomic_t barrier_cpu_count; /* # CPUs waiting on. */ -- cgit v1.2.3 From 21cc248384aeb0375b3cac164c276c78c503291a Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 26 Jun 2017 20:37:51 -0700 Subject: rcu: Advance callbacks after migration When migrating callbacks from a newly offlined CPU, we are already holding the root rcu_node structure's lock, so it costs almost nothing to advance and accelerate the newly migrated callbacks. This patch therefore makes this advancing and acceleration happen. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 58ab489eca66..f9f01aeb5add 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3935,6 +3935,7 @@ static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp) rcu_advance_cbs(rsp, rnp_root, rdp); /* Leverage recent GPs. */ rcu_send_cbs_to_orphanage(cpu, rsp, rnp, rdp); rcu_adopt_orphan_cbs(rsp, flags); + rcu_advance_cbs(rsp, rnp_root, my_rdp); /* Assign GP to pending CBs. */ raw_spin_unlock_irqrestore_rcu_node(rnp_root, flags); WARN_ONCE(rcu_segcblist_n_cbs(&rdp->cblist) != 0 || !rcu_segcblist_empty(&rdp->cblist), -- cgit v1.2.3 From f2dbe4a562d4f17cc1bad3e36a9d1ccb19c86604 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 27 Jun 2017 07:44:06 -0700 Subject: rcu: Localize rcu_state ->orphan_pend and ->orphan_done Given that the rcu_state structure's >orphan_pend and ->orphan_done fields are used only during migration of callbacks from the recently offlined CPU to a surviving CPU, if rcu_send_cbs_to_orphanage() and rcu_adopt_orphan_cbs() are combined, these fields can become local variables in the combined function. This commit therefore combines rcu_send_cbs_to_orphanage() and rcu_adopt_orphan_cbs() into a new rcu_segcblist_merge() function and removes the ->orphan_pend and ->orphan_done fields. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcu_segcblist.c | 24 +++++++++++++++ kernel/rcu/rcu_segcblist.h | 2 ++ kernel/rcu/tree.c | 73 +++------------------------------------------- kernel/rcu/tree.h | 6 ---- 4 files changed, 30 insertions(+), 75 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/rcu_segcblist.c b/kernel/rcu/rcu_segcblist.c index 2b62a38b080f..7091d824b893 100644 --- a/kernel/rcu/rcu_segcblist.c +++ b/kernel/rcu/rcu_segcblist.c @@ -503,3 +503,27 @@ bool rcu_segcblist_future_gp_needed(struct rcu_segcblist *rsclp, return true; return false; } + +/* + * Merge the source rcu_segcblist structure into the destination + * rcu_segcblist structure, then initialize the source. Any pending + * callbacks from the source get to start over. It is best to + * advance and accelerate both the destination and the source + * before merging. + */ +void rcu_segcblist_merge(struct rcu_segcblist *dst_rsclp, + struct rcu_segcblist *src_rsclp) +{ + struct rcu_cblist donecbs; + struct rcu_cblist pendcbs; + + rcu_cblist_init(&donecbs); + rcu_cblist_init(&pendcbs); + rcu_segcblist_extract_count(src_rsclp, &donecbs); + rcu_segcblist_extract_done_cbs(src_rsclp, &donecbs); + rcu_segcblist_extract_pend_cbs(src_rsclp, &pendcbs); + rcu_segcblist_insert_count(dst_rsclp, &donecbs); + rcu_segcblist_insert_done_cbs(dst_rsclp, &donecbs); + rcu_segcblist_insert_pend_cbs(dst_rsclp, &pendcbs); + rcu_segcblist_init(src_rsclp); +} diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h index 6e36e36478cd..c2f319f3f06a 100644 --- a/kernel/rcu/rcu_segcblist.h +++ b/kernel/rcu/rcu_segcblist.h @@ -162,3 +162,5 @@ void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq); bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq); bool rcu_segcblist_future_gp_needed(struct rcu_segcblist *rsclp, unsigned long seq); +void rcu_segcblist_merge(struct rcu_segcblist *dst_rsclp, + struct rcu_segcblist *src_rsclp); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index f9f01aeb5add..d330c17c8df4 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -97,8 +97,6 @@ struct rcu_state sname##_state = { \ .gp_state = RCU_GP_IDLE, \ .gpnum = 0UL - 300UL, \ .completed = 0UL - 300UL, \ - .orphan_pend = RCU_CBLIST_INITIALIZER(sname##_state.orphan_pend), \ - .orphan_done = RCU_CBLIST_INITIALIZER(sname##_state.orphan_done), \ .barrier_mutex = __MUTEX_INITIALIZER(sname##_state.barrier_mutex), \ .name = RCU_STATE_NAME(sname), \ .abbr = sabbr, \ @@ -3850,76 +3848,12 @@ void rcu_report_dead(unsigned int cpu) rcu_cleanup_dying_idle_cpu(cpu, rsp); } -/* - * Send the specified CPU's RCU callbacks to the orphanage. The - * specified CPU must be offline. - */ -static void -rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp, - struct rcu_node *rnp, struct rcu_data *rdp) -{ - /* - * Orphan the callbacks. First adjust the counts. This is safe - * because _rcu_barrier() excludes CPU-hotplug operations, so it - * cannot be running now. Thus no memory barrier is required. - */ - rcu_segcblist_extract_count(&rdp->cblist, &rsp->orphan_done); - - /* - * Next, move those callbacks still needing a grace period to - * the orphanage, where some other CPU will pick them up. - * Some of the callbacks might have gone partway through a grace - * period, but that is too bad. They get to start over because we - * cannot assume that grace periods are synchronized across CPUs. - */ - rcu_segcblist_extract_pend_cbs(&rdp->cblist, &rsp->orphan_pend); - - /* - * Then move the ready-to-invoke callbacks to the orphanage, - * where some other CPU will pick them up. These will not be - * required to pass though another grace period: They are done. - */ - rcu_segcblist_extract_done_cbs(&rdp->cblist, &rsp->orphan_done); - - /* Finally, disallow further callbacks on this CPU. */ - rcu_segcblist_disable(&rdp->cblist); -} - -/* - * Adopt the RCU callbacks from the specified rcu_state structure's - * orphanage. - */ -static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags) -{ - struct rcu_data *rdp = raw_cpu_ptr(rsp->rda); - - /* Do the accounting first. */ - if (rsp->orphan_done.len_lazy != rsp->orphan_done.len) - rcu_idle_count_callbacks_posted(); - rcu_segcblist_insert_count(&rdp->cblist, &rsp->orphan_done); - - /* - * We do not need a memory barrier here because the only way we - * can get here if there is an rcu_barrier() in flight is if - * we are the task doing the rcu_barrier(). - */ - - /* First adopt the ready-to-invoke callbacks, then the done ones. */ - rcu_segcblist_insert_done_cbs(&rdp->cblist, &rsp->orphan_done); - WARN_ON_ONCE(rsp->orphan_done.head); - rcu_segcblist_insert_pend_cbs(&rdp->cblist, &rsp->orphan_pend); - WARN_ON_ONCE(rsp->orphan_pend.head); - WARN_ON_ONCE(rcu_segcblist_empty(&rdp->cblist) != - !rcu_segcblist_n_cbs(&rdp->cblist)); -} - -/* Orphan the dead CPU's callbacks, and then adopt them. */ +/* Migrate the dead CPU's callbacks to the current CPU. */ static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp) { unsigned long flags; struct rcu_data *my_rdp; struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu); - struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */ struct rcu_node *rnp_root = rcu_get_root(rdp->rsp); if (rcu_is_nocb_cpu(cpu) || rcu_segcblist_empty(&rdp->cblist)) @@ -3933,15 +3867,16 @@ static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp) } raw_spin_lock_rcu_node(rnp_root); /* irqs already disabled. */ rcu_advance_cbs(rsp, rnp_root, rdp); /* Leverage recent GPs. */ - rcu_send_cbs_to_orphanage(cpu, rsp, rnp, rdp); - rcu_adopt_orphan_cbs(rsp, flags); rcu_advance_cbs(rsp, rnp_root, my_rdp); /* Assign GP to pending CBs. */ + rcu_segcblist_merge(&my_rdp->cblist, &rdp->cblist); raw_spin_unlock_irqrestore_rcu_node(rnp_root, flags); WARN_ONCE(rcu_segcblist_n_cbs(&rdp->cblist) != 0 || !rcu_segcblist_empty(&rdp->cblist), "rcu_cleanup_dead_cpu: Callbacks on offline CPU %d: qlen=%lu, 1stCB=%p\n", cpu, rcu_segcblist_n_cbs(&rdp->cblist), rcu_segcblist_first_cb(&rdp->cblist)); + WARN_ON_ONCE(rcu_segcblist_empty(&my_rdp->cblist) != + !rcu_segcblist_n_cbs(&my_rdp->cblist)); } /* diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 62b1d0b0d47c..b99f31c2b0c3 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -348,12 +348,6 @@ struct rcu_state { /* End of fields guarded by root rcu_node's lock. */ - struct rcu_cblist orphan_pend; /* Orphaned callbacks that */ - /* need a grace period. */ - struct rcu_cblist orphan_done; /* Orphaned callbacks that */ - /* are ready to invoke. */ - /* (Contains counts.) */ - struct mutex barrier_mutex; /* Guards barrier fields. */ atomic_t barrier_cpu_count; /* # CPUs waiting on. */ struct completion barrier_completion; /* Wake at barrier end. */ -- cgit v1.2.3 From aed4e046863820e6d06ebf7c079e9ad924608edf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 27 Jun 2017 08:38:45 -0700 Subject: rcu: Remove unused RCU list functions Given changes to callback migration, rcu_cblist_head(), rcu_cblist_tail(), rcu_cblist_count_cbs(), rcu_segcblist_segempty(), rcu_segcblist_dequeued_lazy(), and rcu_segcblist_new_cbs() are no longer used. This commit therefore removes them. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcu_segcblist.c | 84 ---------------------------------------------- kernel/rcu/rcu_segcblist.h | 26 -------------- 2 files changed, 110 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/rcu_segcblist.c b/kernel/rcu/rcu_segcblist.c index 7091d824b893..7649fcd2c4c7 100644 --- a/kernel/rcu/rcu_segcblist.c +++ b/kernel/rcu/rcu_segcblist.c @@ -35,24 +35,6 @@ void rcu_cblist_init(struct rcu_cblist *rclp) rclp->len_lazy = 0; } -/* - * Debug function to actually count the number of callbacks. - * If the number exceeds the limit specified, return -1. - */ -long rcu_cblist_count_cbs(struct rcu_cblist *rclp, long lim) -{ - int cnt = 0; - struct rcu_head **rhpp = &rclp->head; - - for (;;) { - if (!*rhpp) - return cnt; - if (++cnt > lim) - return -1; - rhpp = &(*rhpp)->next; - } -} - /* * Dequeue the oldest rcu_head structure from the specified callback * list. This function assumes that the callback is non-lazy, but @@ -102,17 +84,6 @@ void rcu_segcblist_disable(struct rcu_segcblist *rsclp) rsclp->tails[RCU_NEXT_TAIL] = NULL; } -/* - * Is the specified segment of the specified rcu_segcblist structure - * empty of callbacks? - */ -bool rcu_segcblist_segempty(struct rcu_segcblist *rsclp, int seg) -{ - if (seg == RCU_DONE_TAIL) - return &rsclp->head == rsclp->tails[RCU_DONE_TAIL]; - return rsclp->tails[seg - 1] == rsclp->tails[seg]; -} - /* * Does the specified rcu_segcblist structure contain callbacks that * are ready to be invoked? @@ -133,50 +104,6 @@ bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp) !rcu_segcblist_restempty(rsclp, RCU_DONE_TAIL); } -/* - * Dequeue and return the first ready-to-invoke callback. If there - * are no ready-to-invoke callbacks, return NULL. Disables interrupts - * to avoid interference. Does not protect from interference from other - * CPUs or tasks. - */ -struct rcu_head *rcu_segcblist_dequeue(struct rcu_segcblist *rsclp) -{ - unsigned long flags; - int i; - struct rcu_head *rhp; - - local_irq_save(flags); - if (!rcu_segcblist_ready_cbs(rsclp)) { - local_irq_restore(flags); - return NULL; - } - rhp = rsclp->head; - BUG_ON(!rhp); - rsclp->head = rhp->next; - for (i = RCU_DONE_TAIL; i < RCU_CBLIST_NSEGS; i++) { - if (rsclp->tails[i] != &rhp->next) - break; - rsclp->tails[i] = &rsclp->head; - } - smp_mb(); /* Dequeue before decrement for rcu_barrier(). */ - WRITE_ONCE(rsclp->len, rsclp->len - 1); - local_irq_restore(flags); - return rhp; -} - -/* - * Account for the fact that a previously dequeued callback turned out - * to be marked as lazy. - */ -void rcu_segcblist_dequeued_lazy(struct rcu_segcblist *rsclp) -{ - unsigned long flags; - - local_irq_save(flags); - rsclp->len_lazy--; - local_irq_restore(flags); -} - /* * Return a pointer to the first callback in the specified rcu_segcblist * structure. This is useful for diagnostics. @@ -202,17 +129,6 @@ struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp) return NULL; } -/* - * Does the specified rcu_segcblist structure contain callbacks that - * have not yet been processed beyond having been posted, that is, - * does it contain callbacks in its last segment? - */ -bool rcu_segcblist_new_cbs(struct rcu_segcblist *rsclp) -{ - return rcu_segcblist_is_enabled(rsclp) && - !rcu_segcblist_restempty(rsclp, RCU_NEXT_READY_TAIL); -} - /* * Enqueue the specified callback onto the specified rcu_segcblist * structure, updating accounting as needed. Note that the ->len diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h index c2f319f3f06a..581c12b63544 100644 --- a/kernel/rcu/rcu_segcblist.h +++ b/kernel/rcu/rcu_segcblist.h @@ -31,29 +31,7 @@ static inline void rcu_cblist_dequeued_lazy(struct rcu_cblist *rclp) rclp->len_lazy--; } -/* - * Interim function to return rcu_cblist head pointer. Longer term, the - * rcu_cblist will be used more pervasively, removing the need for this - * function. - */ -static inline struct rcu_head *rcu_cblist_head(struct rcu_cblist *rclp) -{ - return rclp->head; -} - -/* - * Interim function to return rcu_cblist head pointer. Longer term, the - * rcu_cblist will be used more pervasively, removing the need for this - * function. - */ -static inline struct rcu_head **rcu_cblist_tail(struct rcu_cblist *rclp) -{ - WARN_ON_ONCE(!rclp->head); - return rclp->tail; -} - void rcu_cblist_init(struct rcu_cblist *rclp); -long rcu_cblist_count_cbs(struct rcu_cblist *rclp, long lim); struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp); /* @@ -134,14 +112,10 @@ static inline struct rcu_head **rcu_segcblist_tail(struct rcu_segcblist *rsclp) void rcu_segcblist_init(struct rcu_segcblist *rsclp); void rcu_segcblist_disable(struct rcu_segcblist *rsclp); -bool rcu_segcblist_segempty(struct rcu_segcblist *rsclp, int seg); bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp); bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp); -struct rcu_head *rcu_segcblist_dequeue(struct rcu_segcblist *rsclp); -void rcu_segcblist_dequeued_lazy(struct rcu_segcblist *rsclp); struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp); struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp); -bool rcu_segcblist_new_cbs(struct rcu_segcblist *rsclp); void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp, struct rcu_head *rhp, bool lazy); bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp, -- cgit v1.2.3 From 09efeeee173e9f541b15157d30658cd8b23ec4f3 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 19 Jul 2017 10:56:46 -0700 Subject: rcu: Move callback-list warning to irq-disable region After adopting callbacks from a newly offlined CPU, the adopting CPU checks to make sure that its callback list's count is zero only if the list has no callbacks and vice versa. Unfortunately, it does so after enabling interrupts, which means that false positives are possible due to interrupt handlers invoking call_rcu(). Although these false positives are improbable, rcutorture did make it happen once. This commit therefore moves this check to an irq-disabled region of code, thus suppressing the false positive. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index d330c17c8df4..4b03bddbca3c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3869,14 +3869,14 @@ static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp) rcu_advance_cbs(rsp, rnp_root, rdp); /* Leverage recent GPs. */ rcu_advance_cbs(rsp, rnp_root, my_rdp); /* Assign GP to pending CBs. */ rcu_segcblist_merge(&my_rdp->cblist, &rdp->cblist); + WARN_ON_ONCE(rcu_segcblist_empty(&my_rdp->cblist) != + !rcu_segcblist_n_cbs(&my_rdp->cblist)); raw_spin_unlock_irqrestore_rcu_node(rnp_root, flags); WARN_ONCE(rcu_segcblist_n_cbs(&rdp->cblist) != 0 || !rcu_segcblist_empty(&rdp->cblist), "rcu_cleanup_dead_cpu: Callbacks on offline CPU %d: qlen=%lu, 1stCB=%p\n", cpu, rcu_segcblist_n_cbs(&rdp->cblist), rcu_segcblist_first_cb(&rdp->cblist)); - WARN_ON_ONCE(rcu_segcblist_empty(&my_rdp->cblist) != - !rcu_segcblist_n_cbs(&my_rdp->cblist)); } /* -- cgit v1.2.3 From 560c6e452d8fa1e98cc50674d3408924387a983e Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 19 Jul 2017 15:42:47 +0530 Subject: cpufreq: schedutil: Set dynamic_switching to true Set dynamic_switching to 'true' to disallow use of schedutil governor for platforms with transition_latency set to CPUFREQ_ETERNAL, as they may not want to do automatic dynamic frequency switching. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- kernel/sched/cpufreq_schedutil.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 89c4dd9777bb..45fcf21ad685 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -646,6 +646,7 @@ static void sugov_limits(struct cpufreq_policy *policy) static struct cpufreq_governor schedutil_gov = { .name = "schedutil", .owner = THIS_MODULE, + .dynamic_switching = true, .init = sugov_init, .exit = sugov_exit, .start = sugov_start, -- cgit v1.2.3 From b6eb66fd3430a1a0d1c89cf4bdb01062bdb9b738 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 26 Jul 2017 02:19:35 +0200 Subject: device property: export irqchip_fwnode_ops The newly added irqchip_fwnode_ops structure is not exported, which can lead to link errors: ERROR: "irqchip_fwnode_ops" [drivers/gpio/gpio-xgene-sb.ko] undefined! I checked that all other such symbols that were introduced are exported if they need to be, this is the only missing one. Fixes: db3e50f3234b (device property: Get rid of struct fwnode_handle type field) Signed-off-by: Arnd Bergmann Signed-off-by: Rafael J. Wysocki --- kernel/irq/irqdomain.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index e064fd1390f1..9e8a075117a3 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -42,6 +42,7 @@ static inline void debugfs_remove_domain_dir(struct irq_domain *d) { } #endif const struct fwnode_operations irqchip_fwnode_ops; +EXPORT_SYMBOL_GPL(irqchip_fwnode_ops); /** * irq_domain_alloc_fwnode - Allocate a fwnode_handle suitable for -- cgit v1.2.3 From a5a0809bc58e133d674e45175b052c9bdf002f1d Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Sun, 23 Jul 2017 08:54:25 -0700 Subject: cpufreq: schedutil: Make iowait boost more energy efficient Currently the iowait_boost feature in schedutil makes the frequency go to max on iowait wakeups. This feature was added to handle a case that Peter described where the throughput of operations involving continuous I/O requests [1] is reduced due to running at a lower frequency, however the lower throughput itself causes utilization to be low and hence causing frequency to be low hence its "stuck". Instead of going to max, its also possible to achieve the same effect by ramping up to max if there are repeated in_iowait wakeups happening. This patch is an attempt to do that. We start from a lower frequency (policy->min) and double the boost for every consecutive iowait update until we reach the maximum iowait boost frequency (iowait_boost_max). I ran a synthetic test (continuous O_DIRECT writes in a loop) on an x86 machine with intel_pstate in passive mode using schedutil. In this test the iowait_boost value ramped from 800MHz to 4GHz in 60ms. The patch achieves the desired improved throughput as the existing behavior. [1] https://patchwork.kernel.org/patch/9735885/ Suggested-by: Peter Zijlstra Suggested-by: Viresh Kumar Signed-off-by: Joel Fernandes Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- kernel/sched/cpufreq_schedutil.c | 38 ++++++++++++++++++++++++++++++++------ 1 file changed, 32 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 29a397067ffa..148844a995a8 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -53,6 +53,7 @@ struct sugov_cpu { struct update_util_data update_util; struct sugov_policy *sg_policy; + bool iowait_boost_pending; unsigned long iowait_boost; unsigned long iowait_boost_max; u64 last_update; @@ -169,30 +170,54 @@ static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time, unsigned int flags) { if (flags & SCHED_CPUFREQ_IOWAIT) { - sg_cpu->iowait_boost = sg_cpu->iowait_boost_max; + if (sg_cpu->iowait_boost_pending) + return; + + sg_cpu->iowait_boost_pending = true; + + if (sg_cpu->iowait_boost) { + sg_cpu->iowait_boost <<= 1; + if (sg_cpu->iowait_boost > sg_cpu->iowait_boost_max) + sg_cpu->iowait_boost = sg_cpu->iowait_boost_max; + } else { + sg_cpu->iowait_boost = sg_cpu->sg_policy->policy->min; + } } else if (sg_cpu->iowait_boost) { s64 delta_ns = time - sg_cpu->last_update; /* Clear iowait_boost if the CPU apprears to have been idle. */ - if (delta_ns > TICK_NSEC) + if (delta_ns > TICK_NSEC) { sg_cpu->iowait_boost = 0; + sg_cpu->iowait_boost_pending = false; + } } } static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, unsigned long *util, unsigned long *max) { - unsigned long boost_util = sg_cpu->iowait_boost; - unsigned long boost_max = sg_cpu->iowait_boost_max; + unsigned long boost_util, boost_max; - if (!boost_util) + if (!sg_cpu->iowait_boost) return; + if (sg_cpu->iowait_boost_pending) { + sg_cpu->iowait_boost_pending = false; + } else { + sg_cpu->iowait_boost >>= 1; + if (sg_cpu->iowait_boost < sg_cpu->sg_policy->policy->min) { + sg_cpu->iowait_boost = 0; + return; + } + } + + boost_util = sg_cpu->iowait_boost; + boost_max = sg_cpu->iowait_boost_max; + if (*util * boost_max < *max * boost_util) { *util = boost_util; *max = boost_max; } - sg_cpu->iowait_boost >>= 1; } #ifdef CONFIG_NO_HZ_COMMON @@ -264,6 +289,7 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time) delta_ns = time - j_sg_cpu->last_update; if (delta_ns > TICK_NSEC) { j_sg_cpu->iowait_boost = 0; + j_sg_cpu->iowait_boost_pending = false; continue; } if (j_sg_cpu->flags & SCHED_CPUFREQ_RT_DL) -- cgit v1.2.3 From 251accf98591d7f59f7a2bac2e05c66d16bf2811 Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Sun, 23 Jul 2017 08:54:26 -0700 Subject: cpufreq: schedutil: Use unsigned int for iowait boost Make iowait_boost and iowait_boost_max as unsigned int since its unit is kHz and this is consistent with struct cpufreq_policy. Also change the local variables in sugov_iowait_boost() to match this. Signed-off-by: Joel Fernandes Signed-off-by: Rafael J. Wysocki --- kernel/sched/cpufreq_schedutil.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 148844a995a8..ddd385f2a985 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -54,8 +54,8 @@ struct sugov_cpu { struct sugov_policy *sg_policy; bool iowait_boost_pending; - unsigned long iowait_boost; - unsigned long iowait_boost_max; + unsigned int iowait_boost; + unsigned int iowait_boost_max; u64 last_update; /* The fields below are only needed when sharing a policy. */ @@ -196,7 +196,7 @@ static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time, static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, unsigned long *util, unsigned long *max) { - unsigned long boost_util, boost_max; + unsigned int boost_util, boost_max; if (!sg_cpu->iowait_boost) return; -- cgit v1.2.3 From aec47caa747e1e15a3363dc0b0db37e51b8d4f15 Mon Sep 17 00:00:00 2001 From: Pierre Kuo Date: Tue, 11 Jul 2017 14:40:55 +0800 Subject: printk: Modify operators of printed_len and text_len With commit ("printk: report lost messages in printk safe/nmi contexts") and commit <8b1742c9c207> ("printk: remove zap_locks() function"), it seems we can remove initialization, "=0", of text_len and directly assign result of log_output to printed_len. Link: http://lkml.kernel.org/r/1499755255-6258-1-git-send-email-vichy.kuo@gmail.com Cc: rostedt@goodmis.org Cc: linux-kernel@vger.kernel.org Cc: joe@perches.com Signed-off-by: Pierre Kuo Reviewed-by: Sergey Senozhatsky Signed-off-by: Petr Mladek --- kernel/printk/printk.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index fc47863f629c..229fbdcbe6ef 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1698,10 +1698,10 @@ asmlinkage int vprintk_emit(int facility, int level, { static char textbuf[LOG_LINE_MAX]; char *text = textbuf; - size_t text_len = 0; + size_t text_len; enum log_flags lflags = 0; unsigned long flags; - int printed_len = 0; + int printed_len; bool in_sched = false; if (level == LOGLEVEL_SCHED) { @@ -1754,7 +1754,7 @@ asmlinkage int vprintk_emit(int facility, int level, if (dict) lflags |= LOG_PREFIX|LOG_NEWLINE; - printed_len += log_output(facility, level, lflags, dict, dictlen, text, text_len); + printed_len = log_output(facility, level, lflags, dict, dictlen, text, text_len); logbuf_unlock_irqrestore(flags); -- cgit v1.2.3 From 2b1be689f3aadcfe0a768314c80e43483c784659 Mon Sep 17 00:00:00 2001 From: Matt Redfearn Date: Fri, 14 Jul 2017 14:51:12 +0200 Subject: printk/console: Always disable boot consoles that use init memory before it is freed Commit 4c30c6f566c0 ("kernel/printk: do not turn off bootconsole in printk_late_init() if keep_bootcon") added a check on keep_bootcon to ensure that boot consoles were kept around until the real console is registered. This can lead to problems if the boot console data and code are in the init section, since it can be freed before the boot console is unregistered. Commit 81cc26f2bd11 ("printk: only unregister boot consoles when necessary") fixed this a better way. It allowed to keep boot consoles that did not use init data. Unfortunately it did not remove the check of keep_bootcon. This can lead to crashes and weird panics when the bootconsole is accessed after free, especially if page poisoning is in use and the code / data have been overwritten with a poison value. To prevent this, always free the boot console if it is within the init section. In addition, print a warning about that the console is removed prematurely. Finally there is a new comment how to avoid the warning. It replaced an explanation that duplicated a more comprehensive function description few lines above. Fixes: 4c30c6f566c0 ("kernel/printk: do not turn off bootconsole in printk_late_init() if keep_bootcon") Link: http://lkml.kernel.org/r/1500036673-7122-2-git-send-email-pmladek@suse.com Cc: Steven Rostedt Cc: Andrew Morton Cc: Peter Zijlstra Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: "David S. Miller" Cc: Alan Cox Cc: "Fabio M. Di Nitto" Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Matt Redfearn [pmladek@suse.com: print the warning, code and comments clean up] Reviewed-by: Sergey Senozhatsky Signed-off-by: Petr Mladek --- kernel/printk/printk.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 229fbdcbe6ef..76985ee3dfff 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2650,9 +2650,8 @@ void __init console_init(void) * makes it difficult to diagnose problems that occur during this time. * * To mitigate this problem somewhat, only unregister consoles whose memory - * intersects with the init section. Note that code exists elsewhere to get - * rid of the boot console as soon as the proper console shows up, so there - * won't be side-effects from postponing the removal. + * intersects with the init section. Note that all other boot consoles will + * get unregistred when the real preferred console is registered. */ static int __init printk_late_init(void) { @@ -2660,16 +2659,15 @@ static int __init printk_late_init(void) int ret; for_each_console(con) { - if (!keep_bootcon && con->flags & CON_BOOT) { + if ((con->flags & CON_BOOT) && + init_section_intersects(con, sizeof(*con))) { /* - * Make sure to unregister boot consoles whose data - * resides in the init section before the init section - * is discarded. Boot consoles whose data will stick - * around will automatically be unregistered when the - * proper console replaces them. + * Please, consider moving the reported consoles out + * of the init section. */ - if (init_section_intersects(con, sizeof(*con))) - unregister_console(con); + pr_warn("bootconsole [%s%d] uses init memory and must be disabled even before the real one is ready\n", + con->name, con->index); + unregister_console(con); } } ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL, -- cgit v1.2.3 From 5a814231ae3d4f248a8ecb668a072a1da471c656 Mon Sep 17 00:00:00 2001 From: Petr Mladek Date: Fri, 14 Jul 2017 14:51:13 +0200 Subject: printk/console: Enhance the check for consoles using init memory printk_late_init() is responsible for disabling boot consoles that use init memory. It checks the address of struct console for this. But this is not enough. For example, there are several early consoles that have write() method in the init section and struct console in the normal section. They are not disabled and could cause fancy and hard to debug system states. It is even more complicated by the macros EARLYCON_DECLARE() and OF_EARLYCON_DECLARE() where various struct members are set at runtime by the provided setup() function. I have tried to reproduce this problem and forced the classic uart early console to stay using keep_bootcon parameter. In particular I used earlycon=uart,io,0x3f8 keep_bootcon console=ttyS0,115200. The system did not boot: [ 1.570496] PM: Image not found (code -22) [ 1.570496] PM: Image not found (code -22) [ 1.571886] PM: Hibernation image not present or could not be loaded. [ 1.571886] PM: Hibernation image not present or could not be loaded. [ 1.576407] Freeing unused kernel memory: 2528K [ 1.577244] kernel tried to execute NX-protected page - exploit attempt? (uid: 0) The double lines are caused by having both early uart console and ttyS0 console enabled at the same time. The early console stopped working when the init memory was freed. Fortunately, the invalid call was caught by the NX-protexted page check and did not cause any silent fancy problems. This patch adds a check for many other addresses stored in struct console. It omits setup() and match() that are used only when the console is registered. Therefore they have already been used at this point and there is no reason to use them again. Link: http://lkml.kernel.org/r/1500036673-7122-3-git-send-email-pmladek@suse.com Cc: Steven Rostedt Cc: Andrew Morton Cc: Peter Zijlstra Cc: Matt Redfearn Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: "David S. Miller" Cc: Alan Cox Cc: "Fabio M. Di Nitto" Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Sergey Senozhatsky Signed-off-by: Petr Mladek --- kernel/printk/printk.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 76985ee3dfff..87f1a8f4e0f9 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2659,8 +2659,16 @@ static int __init printk_late_init(void) int ret; for_each_console(con) { - if ((con->flags & CON_BOOT) && - init_section_intersects(con, sizeof(*con))) { + if (!(con->flags & CON_BOOT)) + continue; + + /* Check addresses that might be used for enabled consoles. */ + if (init_section_intersects(con, sizeof(*con)) || + init_section_contains(con->write, 0) || + init_section_contains(con->read, 0) || + init_section_contains(con->device, 0) || + init_section_contains(con->unblank, 0) || + init_section_contains(con->data, 0)) { /* * Please, consider moving the reported consoles out * of the init section. -- cgit v1.2.3 From 8397913303abc9333f376a518a8368fa22ca5e6e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 27 Jul 2017 12:21:11 +0200 Subject: genirq/cpuhotplug: Revert "Set force affinity flag on hotplug migration" That commit was part of the changes moving x86 to the generic CPU hotplug interrupt migration code. The force flag was required on x86 before the hierarchical irqdomain rework, but invoking set_affinity() with force=true stayed and had no side effects. At some point in the past, the force flag got repurposed to support the exynos timer interrupt affinity setting to a not yet online CPU, so the interrupt controller callback does not verify the supplied affinity mask against cpu_online_mask. Setting the flag in the CPU hotplug code causes the cpu online masking to be blocked on these irq controllers and results in potentially affining an interrupt to the CPU which is unplugged, i.e. instead of moving it away, it's just reassigned to it. As the force flags is not longer needed on x86, it's safe to revert that patch so the ARM irqchips which use the force flag work again. Add comments to that effect, so this won't happen again. Note: The online mask handling should be done in the generic code and the force flag and the masking in the irq chips removed all together, but that's not a change possible for 4.13. Fixes: 77f85e66aa8b ("genirq/cpuhotplug: Set force affinity flag on hotplug migration") Reported-by: Will Deacon Signed-off-by: Thomas Gleixner Acked-by: Will Deacon Cc: Marc Zyngier Cc: Russell King Cc: LAK Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1707271217590.3109@nanos Signed-off-by: Thomas Gleixner --- kernel/irq/cpuhotplug.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c index aee8f7ec40af..638eb9c83d9f 100644 --- a/kernel/irq/cpuhotplug.c +++ b/kernel/irq/cpuhotplug.c @@ -95,8 +95,13 @@ static bool migrate_one_irq(struct irq_desc *desc) affinity = cpu_online_mask; brokeaff = true; } - - err = irq_do_set_affinity(d, affinity, true); + /* + * Do not set the force argument of irq_do_set_affinity() as this + * disables the masking of offline CPUs from the supplied affinity + * mask and therefore might keep/reassign the irq to the outgoing + * CPU. + */ + err = irq_do_set_affinity(d, affinity, false); if (err) { pr_warn_ratelimited("IRQ%u: set affinity failed(%d).\n", d->irq, err); -- cgit v1.2.3 From 35732cf9dd38b1efb0f2f22c91c61b51337d1ac3 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 5 Jul 2017 13:30:21 -0700 Subject: srcu: Provide ordering for CPU not involved in grace period Tree RCU guarantees that every online CPU has a memory barrier between any given grace period and any of that CPU's RCU read-side sections that must be ordered against that grace period. Since RCU doesn't always know where read-side critical sections are, the actual implementation guarantees order against prior and subsequent non-idle non-offline code, whether in an RCU read-side critical section or not. As a result, there does not need to be a memory barrier at the end of synchronize_rcu() and friends because the ordering internal to the grace period has ordered every CPU's post-grace-period execution against each CPU's pre-grace-period execution, again for all non-idle online CPUs. In contrast, SRCU can have non-idle online CPUs that are completely uninvolved in a given SRCU grace period, for example, a CPU that never runs any SRCU read-side critical sections and took no part in the grace-period processing. It is in theory possible for a given synchronize_srcu()'s wakeup to be delivered to a CPU that was completely uninvolved in the prior SRCU grace period, which could mean that the code following that synchronize_srcu() would end up being unordered with respect to both the grace period and any pre-existing SRCU read-side critical sections. This commit therefore adds an smp_mb() to the end of __synchronize_srcu(), which prevents this scenario from occurring. Reported-by: Lance Roy Signed-off-by: Paul E. McKenney Acked-by: Lance Roy Cc: # 4.12.x --- kernel/rcu/srcutree.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'kernel') diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 94bd6ed43ea3..c1c0ee3cce3b 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -897,6 +897,15 @@ static void __synchronize_srcu(struct srcu_struct *sp, bool do_norm) __call_srcu(sp, &rcu.head, wakeme_after_rcu, do_norm); wait_for_completion(&rcu.completion); destroy_rcu_head_on_stack(&rcu.head); + + /* + * Make sure that later code is ordered after the SRCU grace + * period. This pairs with the raw_spin_lock_irq_rcu_node() + * in srcu_invoke_callbacks(). Unlike Tree RCU, this is needed + * because the current CPU might have been totally uninvolved with + * (and thus unordered against) that grace period. + */ + smp_mb(); } /** -- cgit v1.2.3 From 1ad0f0a7aa1bf3bd42dcd108a96713d255eacd9f Mon Sep 17 00:00:00 2001 From: Michael Bringmann Date: Thu, 27 Jul 2017 16:27:14 -0500 Subject: workqueue: Work around edge cases for calc of pool's cpumask There is an underlying assumption/trade-off in many layers of the Linux system that CPU <-> node mapping is static. This is despite the presence of features like NUMA and 'hotplug' that support the dynamic addition/ removal of fundamental system resources like CPUs and memory. PowerPC systems, however, do provide extensive features for the dynamic change of resources available to a system. Currently, there is little or no synchronization protection around the updating of the CPU <-> node mapping, and the export/update of this information for other layers / modules. In systems which can change this mapping during 'hotplug', like PowerPC, the information is changing underneath all layers that might reference it. This patch attempts to ensure that a valid, usable cpumask attribute is used by the workqueue infrastructure when setting up new resource pools. It prevents a crash that has been observed when an 'empty' cpumask is passed along to the worker/task scheduling code. It is intended as a temporary workaround until a more fundamental review and correction of the issue can be done. [With additions to the patch provided by Tejun Hao ] Signed-off-by: Michael Bringmann Signed-off-by: Tejun Heo --- kernel/workqueue.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 7146ea70a62d..ca937b0c3a96 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3577,6 +3577,13 @@ static bool wq_calc_node_cpumask(const struct workqueue_attrs *attrs, int node, /* yeap, return possible CPUs in @node that @attrs wants */ cpumask_and(cpumask, attrs->cpumask, wq_numa_possible_cpumask[node]); + + if (cpumask_empty(cpumask)) { + pr_warn_once("WARNING: workqueue cpumask: online intersect > " + "possible intersect\n"); + return false; + } + return !cpumask_equal(cpumask, attrs->cpumask); use_dfl: -- cgit v1.2.3 From 955dbdf4ce87fd9be4bc8378e26b8c2eb8b3d184 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 17 Jun 2017 08:10:08 -0400 Subject: sched: Allow migrating kthreads into online but inactive CPUs Per-cpu workqueues have been tripping CPU affinity sanity checks while a CPU is being offlined. A per-cpu kworker ends up running on a CPU which isn't its target CPU while the CPU is online but inactive. While the scheduler allows kthreads to wake up on an online but inactive CPU, it doesn't allow a running kthread to be migrated to such a CPU, which leads to an odd situation where setting affinity on a sleeping and running kthread leads to different results. Each mem-reclaim workqueue has one rescuer which guarantees forward progress and the rescuer needs to bind itself to the CPU which needs help in making forward progress; however, due to the above issue, while set_cpus_allowed_ptr() succeeds, the rescuer doesn't end up on the correct CPU if the CPU is in the process of going offline, tripping the sanity check and executing the work item on the wrong CPU. This patch updates __migrate_task() so that kthreads can be migrated into an inactive but online CPU. Signed-off-by: Tejun Heo Reported-by: "Paul E. McKenney" Reported-by: Steven Rostedt Signed-off-by: Paul E. McKenney --- kernel/sched/core.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 17c667b427b4..bfee6ea7db49 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -951,8 +951,13 @@ struct migration_arg { static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf, struct task_struct *p, int dest_cpu) { - if (unlikely(!cpu_active(dest_cpu))) - return rq; + if (p->flags & PF_KTHREAD) { + if (unlikely(!cpu_online(dest_cpu))) + return rq; + } else { + if (unlikely(!cpu_active(dest_cpu))) + return rq; + } /* Affinity changed (again). */ if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed)) -- cgit v1.2.3 From aa8188253474b4053bc2900d9fcb545ce68bdf5c Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Wed, 12 Jul 2017 11:49:51 -0700 Subject: kernfs: add exportfs operations Now we have the facilities to implement exportfs operations. The idea is cgroup can export the fhandle info to userspace, then userspace uses fhandle to find the cgroup name. Another example is userspace can get fhandle for a cgroup and BPF uses the fhandle to filter info for the cgroup. Acked-by: Greg Kroah-Hartman Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe --- kernel/cgroup/cgroup.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 620794a20a33..6cefa277f39c 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1737,7 +1737,8 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags) &cgroup_kf_syscall_ops : &cgroup1_kf_syscall_ops; root->kf_root = kernfs_create_root(kf_sops, - KERNFS_ROOT_CREATE_DEACTIVATED, + KERNFS_ROOT_CREATE_DEACTIVATED | + KERNFS_ROOT_SUPPORT_EXPORTOP, root_cgrp); if (IS_ERR(root->kf_root)) { ret = PTR_ERR(root->kf_root); -- cgit v1.2.3 From ca1136c99b66b1566781ff12ecddc635d570f932 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Wed, 12 Jul 2017 11:49:53 -0700 Subject: blktrace: export cgroup info in trace Currently blktrace isn't cgroup aware. blktrace prints out task name of current context, but the task of current context isn't always in the cgroup where the BIO comes from. We can't use task name to find out IO cgroup. For example, Writeback BIOs always comes from flusher thread but the BIOs are for different blk cgroups. Request could be requeued and dispatched from completely different tasks. MD/DM are another examples. This patch tries to fix the gap. We print out cgroup fhandle info in blktrace. Userspace can use open_by_handle_at() syscall to find the cgroup by fhandle. Or userspace can use name_to_handle_at() syscall to find fhandle for a cgroup and use a BPF program to filter out blktrace for a specific cgroup. We add a new 'blk_cgroup' trace option for blk tracer. It's default off. Application which doesn't know the new option isn't affected. When it's on, we output fhandle info right after blk_io_trace with an extra bit set in event action. So from application point of view, blktrace with the option will output new actions. I didn't change blk trace event yet, since I'm not sure if changing the trace event output is an ABI issue. If not, I'll do it later. Acked-by: Steven Rostedt (VMware) Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe --- kernel/trace/blktrace.c | 231 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 158 insertions(+), 73 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index bc364f86100a..f393d7a43695 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -27,6 +27,7 @@ #include #include #include +#include #include "../../block/blk.h" @@ -46,10 +47,14 @@ static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock); /* Select an alternative, minimalistic output than the original one */ #define TRACE_BLK_OPT_CLASSIC 0x1 +#define TRACE_BLK_OPT_CGROUP 0x2 static struct tracer_opt blk_tracer_opts[] = { /* Default disable the minimalistic output */ { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, +#ifdef CONFIG_BLK_CGROUP + { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) }, +#endif { } }; @@ -68,7 +73,8 @@ static void blk_unregister_tracepoints(void); * Send out a notify message. */ static void trace_note(struct blk_trace *bt, pid_t pid, int action, - const void *data, size_t len) + const void *data, size_t len, + union kernfs_node_id *cgid) { struct blk_io_trace *t; struct ring_buffer_event *event = NULL; @@ -76,12 +82,13 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action, int pc = 0; int cpu = smp_processor_id(); bool blk_tracer = blk_tracer_enabled; + ssize_t cgid_len = cgid ? sizeof(*cgid) : 0; if (blk_tracer) { buffer = blk_tr->trace_buffer.buffer; pc = preempt_count(); event = trace_buffer_lock_reserve(buffer, TRACE_BLK, - sizeof(*t) + len, + sizeof(*t) + len + cgid_len, 0, pc); if (!event) return; @@ -92,17 +99,19 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action, if (!bt->rchan) return; - t = relay_reserve(bt->rchan, sizeof(*t) + len); + t = relay_reserve(bt->rchan, sizeof(*t) + len + cgid_len); if (t) { t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; t->time = ktime_to_ns(ktime_get()); record_it: t->device = bt->dev; - t->action = action; + t->action = action | (cgid ? __BLK_TN_CGROUP : 0); t->pid = pid; t->cpu = cpu; - t->pdu_len = len; - memcpy((void *) t + sizeof(*t), data, len); + t->pdu_len = len + cgid_len; + if (cgid) + memcpy((void *)t + sizeof(*t), cgid, cgid_len); + memcpy((void *) t + sizeof(*t) + cgid_len, data, len); if (blk_tracer) trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc); @@ -122,7 +131,7 @@ static void trace_note_tsk(struct task_struct *tsk) spin_lock_irqsave(&running_trace_lock, flags); list_for_each_entry(bt, &running_trace_list, running_list) { trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, - sizeof(tsk->comm)); + sizeof(tsk->comm), NULL); } spin_unlock_irqrestore(&running_trace_lock, flags); } @@ -139,7 +148,7 @@ static void trace_note_time(struct blk_trace *bt) words[1] = now.tv_nsec; local_irq_save(flags); - trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words)); + trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words), NULL); local_irq_restore(flags); } @@ -167,7 +176,7 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); va_end(args); - trace_note(bt, 0, BLK_TN_MESSAGE, buf, n); + trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, NULL); local_irq_restore(flags); } EXPORT_SYMBOL_GPL(__trace_note_message); @@ -204,7 +213,7 @@ static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ), */ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, int op, int op_flags, u32 what, int error, int pdu_len, - void *pdu_data) + void *pdu_data, union kernfs_node_id *cgid) { struct task_struct *tsk = current; struct ring_buffer_event *event = NULL; @@ -215,6 +224,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, pid_t pid; int cpu, pc = 0; bool blk_tracer = blk_tracer_enabled; + ssize_t cgid_len = cgid ? sizeof(*cgid) : 0; if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer)) return; @@ -229,6 +239,8 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, what |= BLK_TC_ACT(BLK_TC_DISCARD); if (op == REQ_OP_FLUSH) what |= BLK_TC_ACT(BLK_TC_FLUSH); + if (cgid) + what |= __BLK_TA_CGROUP; pid = tsk->pid; if (act_log_check(bt, what, sector, pid)) @@ -241,7 +253,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, buffer = blk_tr->trace_buffer.buffer; pc = preempt_count(); event = trace_buffer_lock_reserve(buffer, TRACE_BLK, - sizeof(*t) + pdu_len, + sizeof(*t) + pdu_len + cgid_len, 0, pc); if (!event) return; @@ -258,7 +270,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, * from coming in and stepping on our toes. */ local_irq_save(flags); - t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len); + t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len); if (t) { sequence = per_cpu_ptr(bt->sequence, cpu); @@ -280,10 +292,12 @@ record_it: t->action = what; t->device = bt->dev; t->error = error; - t->pdu_len = pdu_len; + t->pdu_len = pdu_len + cgid_len; + if (cgid_len) + memcpy((void *)t + sizeof(*t), cgid, cgid_len); if (pdu_len) - memcpy((void *) t + sizeof(*t), pdu_data, pdu_len); + memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len); if (blk_tracer) { trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc); @@ -684,6 +698,36 @@ void blk_trace_shutdown(struct request_queue *q) } } +#ifdef CONFIG_BLK_CGROUP +static union kernfs_node_id * +blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) +{ + struct blk_trace *bt = q->blk_trace; + + if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP)) + return NULL; + + if (!bio->bi_css) + return NULL; + return cgroup_get_kernfs_id(bio->bi_css->cgroup); +} +#else +static union kernfs_node_id * +blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio) +{ + return NULL; +} +#endif + +static union kernfs_node_id * +blk_trace_request_get_cgid(struct request_queue *q, struct request *rq) +{ + if (!rq->bio) + return NULL; + /* Use the first bio */ + return blk_trace_bio_get_cgid(q, rq->bio); +} + /* * blktrace probes */ @@ -694,13 +738,15 @@ void blk_trace_shutdown(struct request_queue *q) * @error: return status to log * @nr_bytes: number of completed bytes * @what: the action + * @cgid: the cgroup info * * Description: * Records an action against a request. Will log the bio offset + size. * **/ static void blk_add_trace_rq(struct request *rq, int error, - unsigned int nr_bytes, u32 what) + unsigned int nr_bytes, u32 what, + union kernfs_node_id *cgid) { struct blk_trace *bt = rq->q->blk_trace; @@ -713,32 +759,36 @@ static void blk_add_trace_rq(struct request *rq, int error, what |= BLK_TC_ACT(BLK_TC_FS); __blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq), - rq->cmd_flags, what, error, 0, NULL); + rq->cmd_flags, what, error, 0, NULL, cgid); } static void blk_add_trace_rq_insert(void *ignore, struct request_queue *q, struct request *rq) { - blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT); + blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_INSERT, + blk_trace_request_get_cgid(q, rq)); } static void blk_add_trace_rq_issue(void *ignore, struct request_queue *q, struct request *rq) { - blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE); + blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_ISSUE, + blk_trace_request_get_cgid(q, rq)); } static void blk_add_trace_rq_requeue(void *ignore, struct request_queue *q, struct request *rq) { - blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE); + blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_REQUEUE, + blk_trace_request_get_cgid(q, rq)); } static void blk_add_trace_rq_complete(void *ignore, struct request *rq, int error, unsigned int nr_bytes) { - blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE); + blk_add_trace_rq(rq, error, nr_bytes, BLK_TA_COMPLETE, + blk_trace_request_get_cgid(rq->q, rq)); } /** @@ -753,7 +803,7 @@ static void blk_add_trace_rq_complete(void *ignore, struct request *rq, * **/ static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, - u32 what, int error) + u32 what, int error, union kernfs_node_id *cgid) { struct blk_trace *bt = q->blk_trace; @@ -761,20 +811,22 @@ static void blk_add_trace_bio(struct request_queue *q, struct bio *bio, return; __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, - bio_op(bio), bio->bi_opf, what, error, 0, NULL); + bio_op(bio), bio->bi_opf, what, error, 0, NULL, cgid); } static void blk_add_trace_bio_bounce(void *ignore, struct request_queue *q, struct bio *bio) { - blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0); + blk_add_trace_bio(q, bio, BLK_TA_BOUNCE, 0, + blk_trace_bio_get_cgid(q, bio)); } static void blk_add_trace_bio_complete(void *ignore, struct request_queue *q, struct bio *bio, int error) { - blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error); + blk_add_trace_bio(q, bio, BLK_TA_COMPLETE, error, + blk_trace_bio_get_cgid(q, bio)); } static void blk_add_trace_bio_backmerge(void *ignore, @@ -782,7 +834,8 @@ static void blk_add_trace_bio_backmerge(void *ignore, struct request *rq, struct bio *bio) { - blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0); + blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE, 0, + blk_trace_bio_get_cgid(q, bio)); } static void blk_add_trace_bio_frontmerge(void *ignore, @@ -790,13 +843,15 @@ static void blk_add_trace_bio_frontmerge(void *ignore, struct request *rq, struct bio *bio) { - blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0); + blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE, 0, + blk_trace_bio_get_cgid(q, bio)); } static void blk_add_trace_bio_queue(void *ignore, struct request_queue *q, struct bio *bio) { - blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0); + blk_add_trace_bio(q, bio, BLK_TA_QUEUE, 0, + blk_trace_bio_get_cgid(q, bio)); } static void blk_add_trace_getrq(void *ignore, @@ -804,13 +859,14 @@ static void blk_add_trace_getrq(void *ignore, struct bio *bio, int rw) { if (bio) - blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0); + blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0, + blk_trace_bio_get_cgid(q, bio)); else { struct blk_trace *bt = q->blk_trace; if (bt) __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0, - NULL); + NULL, NULL); } } @@ -820,13 +876,14 @@ static void blk_add_trace_sleeprq(void *ignore, struct bio *bio, int rw) { if (bio) - blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0); + blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0, + blk_trace_bio_get_cgid(q, bio)); else { struct blk_trace *bt = q->blk_trace; if (bt) __blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ, - 0, 0, NULL); + 0, 0, NULL, NULL); } } @@ -835,7 +892,7 @@ static void blk_add_trace_plug(void *ignore, struct request_queue *q) struct blk_trace *bt = q->blk_trace; if (bt) - __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); + __blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, NULL); } static void blk_add_trace_unplug(void *ignore, struct request_queue *q, @@ -852,7 +909,7 @@ static void blk_add_trace_unplug(void *ignore, struct request_queue *q, else what = BLK_TA_UNPLUG_TIMER; - __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu); + __blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, NULL); } } @@ -868,7 +925,7 @@ static void blk_add_trace_split(void *ignore, __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf, BLK_TA_SPLIT, bio->bi_status, sizeof(rpdu), - &rpdu); + &rpdu, blk_trace_bio_get_cgid(q, bio)); } } @@ -901,7 +958,7 @@ static void blk_add_trace_bio_remap(void *ignore, __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status, - sizeof(r), &r); + sizeof(r), &r, blk_trace_bio_get_cgid(q, bio)); } /** @@ -934,7 +991,7 @@ static void blk_add_trace_rq_remap(void *ignore, __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rq_data_dir(rq), 0, BLK_TA_REMAP, 0, - sizeof(r), &r); + sizeof(r), &r, blk_trace_request_get_cgid(q, rq)); } /** @@ -958,7 +1015,8 @@ void blk_add_driver_data(struct request_queue *q, return; __blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0, - BLK_TA_DRV_DATA, 0, len, data); + BLK_TA_DRV_DATA, 0, len, data, + blk_trace_request_get_cgid(q, rq)); } EXPORT_SYMBOL_GPL(blk_add_driver_data); @@ -1031,7 +1089,7 @@ static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) int i = 0; int tc = t->action >> BLK_TC_SHIFT; - if (t->action == BLK_TN_MESSAGE) { + if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) { rwbs[i++] = 'N'; goto out; } @@ -1066,9 +1124,21 @@ const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent) return (const struct blk_io_trace *)ent; } -static inline const void *pdu_start(const struct trace_entry *ent) +static inline const void *pdu_start(const struct trace_entry *ent, bool has_cg) { - return te_blk_io_trace(ent) + 1; + return (void *)(te_blk_io_trace(ent) + 1) + + (has_cg ? sizeof(union kernfs_node_id) : 0); +} + +static inline const void *cgid_start(const struct trace_entry *ent) +{ + return (void *)(te_blk_io_trace(ent) + 1); +} + +static inline int pdu_real_len(const struct trace_entry *ent, bool has_cg) +{ + return te_blk_io_trace(ent)->pdu_len - + (has_cg ? sizeof(union kernfs_node_id) : 0); } static inline u32 t_action(const struct trace_entry *ent) @@ -1096,16 +1166,16 @@ static inline __u16 t_error(const struct trace_entry *ent) return te_blk_io_trace(ent)->error; } -static __u64 get_pdu_int(const struct trace_entry *ent) +static __u64 get_pdu_int(const struct trace_entry *ent, bool has_cg) { - const __u64 *val = pdu_start(ent); + const __u64 *val = pdu_start(ent, has_cg); return be64_to_cpu(*val); } static void get_pdu_remap(const struct trace_entry *ent, - struct blk_io_trace_remap *r) + struct blk_io_trace_remap *r, bool has_cg) { - const struct blk_io_trace_remap *__r = pdu_start(ent); + const struct blk_io_trace_remap *__r = pdu_start(ent, has_cg); __u64 sector_from = __r->sector_from; r->device_from = be32_to_cpu(__r->device_from); @@ -1113,9 +1183,11 @@ static void get_pdu_remap(const struct trace_entry *ent, r->sector_from = be64_to_cpu(sector_from); } -typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act); +typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act, + bool has_cg); -static void blk_log_action_classic(struct trace_iterator *iter, const char *act) +static void blk_log_action_classic(struct trace_iterator *iter, const char *act, + bool has_cg) { char rwbs[RWBS_LEN]; unsigned long long ts = iter->ts; @@ -1131,24 +1203,33 @@ static void blk_log_action_classic(struct trace_iterator *iter, const char *act) secs, nsec_rem, iter->ent->pid, act, rwbs); } -static void blk_log_action(struct trace_iterator *iter, const char *act) +static void blk_log_action(struct trace_iterator *iter, const char *act, + bool has_cg) { char rwbs[RWBS_LEN]; const struct blk_io_trace *t = te_blk_io_trace(iter->ent); fill_rwbs(rwbs, t); - trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", - MAJOR(t->device), MINOR(t->device), act, rwbs); + if (has_cg) { + const union kernfs_node_id *id = cgid_start(iter->ent); + + trace_seq_printf(&iter->seq, "%3d,%-3d %x,%-x %2s %3s ", + MAJOR(t->device), MINOR(t->device), + id->ino, id->generation, act, rwbs); + } else + trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ", + MAJOR(t->device), MINOR(t->device), act, rwbs); } -static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_dump_pdu(struct trace_seq *s, + const struct trace_entry *ent, bool has_cg) { const unsigned char *pdu_buf; int pdu_len; int i, end; - pdu_buf = pdu_start(ent); - pdu_len = te_blk_io_trace(ent)->pdu_len; + pdu_buf = pdu_start(ent, has_cg); + pdu_len = pdu_real_len(ent, has_cg); if (!pdu_len) return; @@ -1179,7 +1260,7 @@ static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent) trace_seq_puts(s, ") "); } -static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) { char cmd[TASK_COMM_LEN]; @@ -1187,7 +1268,7 @@ static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { trace_seq_printf(s, "%u ", t_bytes(ent)); - blk_log_dump_pdu(s, ent); + blk_log_dump_pdu(s, ent, has_cg); trace_seq_printf(s, "[%s]\n", cmd); } else { if (t_sec(ent)) @@ -1199,10 +1280,10 @@ static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent) } static void blk_log_with_error(struct trace_seq *s, - const struct trace_entry *ent) + const struct trace_entry *ent, bool has_cg) { if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) { - blk_log_dump_pdu(s, ent); + blk_log_dump_pdu(s, ent, has_cg); trace_seq_printf(s, "[%d]\n", t_error(ent)); } else { if (t_sec(ent)) @@ -1215,18 +1296,18 @@ static void blk_log_with_error(struct trace_seq *s, } } -static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) { struct blk_io_trace_remap r = { .device_from = 0, }; - get_pdu_remap(ent, &r); + get_pdu_remap(ent, &r, has_cg); trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n", t_sector(ent), t_sec(ent), MAJOR(r.device_from), MINOR(r.device_from), (unsigned long long)r.sector_from); } -static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) { char cmd[TASK_COMM_LEN]; @@ -1235,30 +1316,31 @@ static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent) trace_seq_printf(s, "[%s]\n", cmd); } -static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) { char cmd[TASK_COMM_LEN]; trace_find_cmdline(ent->pid, cmd); - trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent)); + trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent, has_cg)); } -static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent, bool has_cg) { char cmd[TASK_COMM_LEN]; trace_find_cmdline(ent->pid, cmd); trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent), - get_pdu_int(ent), cmd); + get_pdu_int(ent, has_cg), cmd); } -static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent) +static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent, + bool has_cg) { - const struct blk_io_trace *t = te_blk_io_trace(ent); - trace_seq_putmem(s, t + 1, t->pdu_len); + trace_seq_putmem(s, pdu_start(ent, has_cg), + pdu_real_len(ent, has_cg)); trace_seq_putc(s, '\n'); } @@ -1298,7 +1380,8 @@ static void blk_tracer_reset(struct trace_array *tr) static const struct { const char *act[2]; - void (*print)(struct trace_seq *s, const struct trace_entry *ent); + void (*print)(struct trace_seq *s, const struct trace_entry *ent, + bool has_cg); } what2act[] = { [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic }, [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic }, @@ -1326,23 +1409,25 @@ static enum print_line_t print_one_line(struct trace_iterator *iter, u16 what; bool long_act; blk_log_action_t *log_action; + bool has_cg; t = te_blk_io_trace(iter->ent); - what = t->action & ((1 << BLK_TC_SHIFT) - 1); + what = (t->action & ((1 << BLK_TC_SHIFT) - 1)) & ~__BLK_TA_CGROUP; long_act = !!(tr->trace_flags & TRACE_ITER_VERBOSE); log_action = classic ? &blk_log_action_classic : &blk_log_action; + has_cg = t->action & __BLK_TA_CGROUP; - if (t->action == BLK_TN_MESSAGE) { - log_action(iter, long_act ? "message" : "m"); - blk_log_msg(s, iter->ent); + if ((t->action & ~__BLK_TN_CGROUP) == BLK_TN_MESSAGE) { + log_action(iter, long_act ? "message" : "m", has_cg); + blk_log_msg(s, iter->ent, has_cg); return trace_handle_return(s); } if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act))) trace_seq_printf(s, "Unknown action %x\n", what); else { - log_action(iter, what2act[what].act[long_act]); - what2act[what].print(s, iter->ent); + log_action(iter, what2act[what].act[long_act], has_cg); + what2act[what].print(s, iter->ent, has_cg); } return trace_handle_return(s); -- cgit v1.2.3 From 69fd5c391763bd94a40dd152bc72a7f230137150 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Wed, 12 Jul 2017 11:49:55 -0700 Subject: blktrace: add an option to allow displaying cgroup path By default we output cgroup id in blktrace. This adds an option to display cgroup path. Since get cgroup path is a relativly heavy operation, we don't enable it by default. with the option enabled, blktrace will output something like this: dd-1353 [007] d..2 293.015252: 8,0 /test/level D R 24 + 8 [dd] Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe --- kernel/cgroup/cgroup.c | 12 ++++++++++++ kernel/trace/blktrace.c | 14 +++++++++++++- 2 files changed, 25 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 6cefa277f39c..2aba1c519138 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4701,6 +4701,18 @@ static int __init cgroup_wq_init(void) } core_initcall(cgroup_wq_init); +void cgroup_path_from_kernfs_id(const union kernfs_node_id *id, + char *buf, size_t buflen) +{ + struct kernfs_node *kn; + + kn = kernfs_get_node_by_id(cgrp_dfl_root.kf_root, id); + if (!kn) + return; + kernfs_path(kn, buf, buflen); + kernfs_put(kn); +} + /* * proc_cgroup_show() * - Print task's cgroup paths into seq_file, one line for each hierarchy diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index f393d7a43695..e90974ed4532 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -48,12 +48,14 @@ static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock); /* Select an alternative, minimalistic output than the original one */ #define TRACE_BLK_OPT_CLASSIC 0x1 #define TRACE_BLK_OPT_CGROUP 0x2 +#define TRACE_BLK_OPT_CGNAME 0x4 static struct tracer_opt blk_tracer_opts[] = { /* Default disable the minimalistic output */ { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) }, #ifdef CONFIG_BLK_CGROUP { TRACER_OPT(blk_cgroup, TRACE_BLK_OPT_CGROUP) }, + { TRACER_OPT(blk_cgname, TRACE_BLK_OPT_CGNAME) }, #endif { } }; @@ -1213,7 +1215,17 @@ static void blk_log_action(struct trace_iterator *iter, const char *act, if (has_cg) { const union kernfs_node_id *id = cgid_start(iter->ent); - trace_seq_printf(&iter->seq, "%3d,%-3d %x,%-x %2s %3s ", + if (blk_tracer_flags.val & TRACE_BLK_OPT_CGNAME) { + char blkcg_name_buf[NAME_MAX + 1] = "<...>"; + + cgroup_path_from_kernfs_id(id, blkcg_name_buf, + sizeof(blkcg_name_buf)); + trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ", + MAJOR(t->device), MINOR(t->device), + blkcg_name_buf, act, rwbs); + } else + trace_seq_printf(&iter->seq, + "%3d,%-3d %x,%-x %2s %3s ", MAJOR(t->device), MINOR(t->device), id->ino, id->generation, act, rwbs); } else -- cgit v1.2.3 From 35fe6d763229e8fc0eb5f9b93a401673cfcb5e1e Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Wed, 12 Jul 2017 11:49:56 -0700 Subject: block: use standard blktrace API to output cgroup info for debug notes Currently cfq/bfq/blk-throttle output cgroup info in trace in their own way. Now we have standard blktrace API for this, so convert them to use it. Note, this changes the behavior a little bit. cgroup info isn't output by default, we only do this with 'blk_cgroup' option enabled. cgroup info isn't output as a string by default too, we only do this with 'blk_cgname' option enabled. Also cgroup info is output in different position of the note string. I think these behavior changes aren't a big issue (actually we make trace data shorter which is good), since the blktrace note is solely for debugging. Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe --- kernel/trace/blktrace.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index e90974ed4532..7724de18d2fe 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -154,7 +154,8 @@ static void trace_note_time(struct blk_trace *bt) local_irq_restore(flags); } -void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) +void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg, + const char *fmt, ...) { int n; va_list args; @@ -178,7 +179,14 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args); va_end(args); + if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP)) + blkcg = NULL; +#ifdef CONFIG_BLK_CGROUP + trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, + blkcg ? cgroup_get_kernfs_id(blkcg->css.cgroup) : NULL); +#else trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, NULL); +#endif local_irq_restore(flags); } EXPORT_SYMBOL_GPL(__trace_note_message); @@ -375,7 +383,7 @@ static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, return PTR_ERR(msg); bt = filp->private_data; - __trace_note_message(bt, "%s", msg); + __trace_note_message(bt, NULL, "%s", msg); kfree(msg); return count; -- cgit v1.2.3 From 89b096898a8450b0a5b97d521e000ae9f94f81f9 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 27 Jul 2017 21:02:46 +0200 Subject: bpf: don't indicate success when copy_from_user fails err in bpf_prog_get_info_by_fd() still holds 0 at that time from prior check_uarg_tail_zero() check. Explicitly return -EFAULT instead, so user space can be notified of buggy behavior. Fixes: 1e2709769086 ("bpf: Add BPF_OBJ_GET_INFO_BY_FD") Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller --- kernel/bpf/syscall.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 045646da97cc..84bb39975ad4 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1289,7 +1289,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, info_len = min_t(u32, sizeof(info), info_len); if (copy_from_user(&info, uinfo, info_len)) - return err; + return -EFAULT; info.type = prog->type; info.id = prog->aux->id; -- cgit v1.2.3 From 9975a54b3c9ecf029cbf5dd7a8c9701b1d74029e Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 28 Jul 2017 17:05:25 +0200 Subject: bpf: fix bpf_prog_get_info_by_fd to dump correct xlated_prog_len bpf_prog_size(prog->len) is not the correct length we want to dump back to user space. The code in bpf_prog_get_info_by_fd() uses this to copy prog->insnsi to user space, but bpf_prog_size(prog->len) also includes the size of struct bpf_prog itself plus program instructions and is usually used either in context of accounting or for bpf_prog_alloc() et al, thus we copy out of bounds in bpf_prog_get_info_by_fd() potentially. Use the correct bpf_prog_insn_size() instead. Fixes: 1e2709769086 ("bpf: Add BPF_OBJ_GET_INFO_BY_FD") Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller --- kernel/bpf/syscall.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 84bb39975ad4..6c772adabad2 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1312,7 +1312,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, } ulen = info.xlated_prog_len; - info.xlated_prog_len = bpf_prog_size(prog->len); + info.xlated_prog_len = bpf_prog_insn_size(prog); if (info.xlated_prog_len && ulen) { uinsns = u64_to_user_ptr(info.xlated_prog_insns); ulen = min_t(u32, info.xlated_prog_len, ulen); -- cgit v1.2.3 From 313c8c16ee62b32b8b40c6b00637b401dc19050e Mon Sep 17 00:00:00 2001 From: Alex Shi Date: Fri, 28 Jul 2017 15:09:25 +0800 Subject: PM / CPU: replace raw_notifier with atomic_notifier This patch replaces an rwlock and raw notifier by an atomic notifier protected by a spin_lock and RCU. The main reason for this change is due to a 'scheduling while atomic' bug with RT kernels on ARM/ARM64. On ARM/ARM64, the rwlock cpu_pm_notifier_lock in cpu_pm_enter/exit() causes a potential schedule after IRQ disable in the idle call chain: cpu_startup_entry cpu_idle_loop local_irq_disable() cpuidle_idle_call call_cpuidle cpuidle_enter cpuidle_enter_state ->enter :arm_enter_idle_state cpu_pm_enter/exit CPU_PM_CPU_IDLE_ENTER read_lock(&cpu_pm_notifier_lock); <-- sleep in idle __rt_spin_lock(); schedule(); The kernel panic is here: [ 4.609601] BUG: scheduling while atomic: swapper/1/0/0x00000002 [ 4.609608] [] arm_enter_idle_state+0x18/0x70 [ 4.609614] Modules linked in: [ 4.609615] [] cpuidle_enter_state+0xf0/0x218 [ 4.609620] [] cpuidle_enter+0x18/0x20 [ 4.609626] Preemption disabled at: [ 4.609627] [] call_cpuidle+0x24/0x40 [ 4.609635] [] schedule_preempt_disabled+0x1c/0x28 [ 4.609639] [] cpu_startup_entry+0x154/0x1f8 [ 4.609645] [] secondary_start_kernel+0x15c/0x1a0 Daniel Lezcano said this notification is needed on arm/arm64 platforms. Sebastian suggested using atomic_notifier instead of rwlock, which is not only removing the sleeping in idle, but also improving latency. Tony Lindgren found a miss use that rcu_read_lock used after rcu_idle_enter Paul McKenney suggested trying RCU_NONIDLE. Signed-off-by: Alex Shi Tested-by: Tony Lindgren Acked-by: Sebastian Andrzej Siewior [ rjw: Subject & changelog ] Signed-off-by: Rafael J. Wysocki --- kernel/cpu_pm.c | 50 +++++++++++++------------------------------------- 1 file changed, 13 insertions(+), 37 deletions(-) (limited to 'kernel') diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c index 009cc9a17d95..67b02e138a47 100644 --- a/kernel/cpu_pm.c +++ b/kernel/cpu_pm.c @@ -22,15 +22,21 @@ #include #include -static DEFINE_RWLOCK(cpu_pm_notifier_lock); -static RAW_NOTIFIER_HEAD(cpu_pm_notifier_chain); +static ATOMIC_NOTIFIER_HEAD(cpu_pm_notifier_chain); static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls) { int ret; - ret = __raw_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL, + /* + * __atomic_notifier_call_chain has a RCU read critical section, which + * could be disfunctional in cpu idle. Copy RCU_NONIDLE code to let + * RCU know this. + */ + rcu_irq_enter_irqson(); + ret = __atomic_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL, nr_to_call, nr_calls); + rcu_irq_exit_irqson(); return notifier_to_errno(ret); } @@ -47,14 +53,7 @@ static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls) */ int cpu_pm_register_notifier(struct notifier_block *nb) { - unsigned long flags; - int ret; - - write_lock_irqsave(&cpu_pm_notifier_lock, flags); - ret = raw_notifier_chain_register(&cpu_pm_notifier_chain, nb); - write_unlock_irqrestore(&cpu_pm_notifier_lock, flags); - - return ret; + return atomic_notifier_chain_register(&cpu_pm_notifier_chain, nb); } EXPORT_SYMBOL_GPL(cpu_pm_register_notifier); @@ -69,14 +68,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_register_notifier); */ int cpu_pm_unregister_notifier(struct notifier_block *nb) { - unsigned long flags; - int ret; - - write_lock_irqsave(&cpu_pm_notifier_lock, flags); - ret = raw_notifier_chain_unregister(&cpu_pm_notifier_chain, nb); - write_unlock_irqrestore(&cpu_pm_notifier_lock, flags); - - return ret; + return atomic_notifier_chain_unregister(&cpu_pm_notifier_chain, nb); } EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier); @@ -100,7 +92,6 @@ int cpu_pm_enter(void) int nr_calls; int ret = 0; - read_lock(&cpu_pm_notifier_lock); ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls); if (ret) /* @@ -108,7 +99,6 @@ int cpu_pm_enter(void) * PM entry who are notified earlier to prepare for it. */ cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL); - read_unlock(&cpu_pm_notifier_lock); return ret; } @@ -128,13 +118,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_enter); */ int cpu_pm_exit(void) { - int ret; - - read_lock(&cpu_pm_notifier_lock); - ret = cpu_pm_notify(CPU_PM_EXIT, -1, NULL); - read_unlock(&cpu_pm_notifier_lock); - - return ret; + return cpu_pm_notify(CPU_PM_EXIT, -1, NULL); } EXPORT_SYMBOL_GPL(cpu_pm_exit); @@ -159,7 +143,6 @@ int cpu_cluster_pm_enter(void) int nr_calls; int ret = 0; - read_lock(&cpu_pm_notifier_lock); ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls); if (ret) /* @@ -167,7 +150,6 @@ int cpu_cluster_pm_enter(void) * PM entry who are notified earlier to prepare for it. */ cpu_pm_notify(CPU_CLUSTER_PM_ENTER_FAILED, nr_calls - 1, NULL); - read_unlock(&cpu_pm_notifier_lock); return ret; } @@ -190,13 +172,7 @@ EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); */ int cpu_cluster_pm_exit(void) { - int ret; - - read_lock(&cpu_pm_notifier_lock); - ret = cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL); - read_unlock(&cpu_pm_notifier_lock); - - return ret; + return cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL); } EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit); -- cgit v1.2.3 From 34f41c0316ed52b0b44542491d89278efdaa70e4 Mon Sep 17 00:00:00 2001 From: Matija Glavinic Pecotic Date: Tue, 1 Aug 2017 09:11:52 +0200 Subject: timers: Fix overflow in get_next_timer_interrupt For e.g. HZ=100, timer being 430 jiffies in the future, and 32 bit unsigned int, there is an overflow on unsigned int right-hand side of the expression which results with wrong values being returned. Type cast the multiplier to 64bit to avoid that issue. Fixes: 46c8f0b077a8 ("timers: Fix get_next_timer_interrupt() computation") Signed-off-by: Matija Glavinic Pecotic Signed-off-by: Thomas Gleixner Reviewed-by: Alexander Sverdlin Cc: khilman@baylibre.com Cc: akpm@linux-foundation.org Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/a7900f04-2a21-c9fd-67be-ab334d459ee5@nokia.com --- kernel/time/timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 71ce3f4eead3..8f5d1bf18854 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1495,7 +1495,7 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) base->is_idle = false; } else { if (!is_max_delta) - expires = basem + (nextevt - basej) * TICK_NSEC; + expires = basem + (u64)(nextevt - basej) * TICK_NSEC; /* * If we expect to sleep more than a tick, mark the base idle: */ -- cgit v1.2.3 From 674e75411fc260b0d4532701228cfe12fc090da8 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Fri, 28 Jul 2017 12:16:38 +0530 Subject: sched: cpufreq: Allow remote cpufreq callbacks With Android UI and benchmarks the latency of cpufreq response to certain scheduling events can become very critical. Currently, callbacks into cpufreq governors are only made from the scheduler if the target CPU of the event is the same as the current CPU. This means there are certain situations where a target CPU may not run the cpufreq governor for some time. One testcase to show this behavior is where a task starts running on CPU0, then a new task is also spawned on CPU0 by a task on CPU1. If the system is configured such that the new tasks should receive maximum demand initially, this should result in CPU0 increasing frequency immediately. But because of the above mentioned limitation though, this does not occur. This patch updates the scheduler core to call the cpufreq callbacks for remote CPUs as well. The schedutil, ondemand and conservative governors are updated to process cpufreq utilization update hooks called for remote CPUs where the remote CPU is managed by the cpufreq policy of the local CPU. The intel_pstate driver is updated to always reject remote callbacks. This is tested with couple of usecases (Android: hackbench, recentfling, galleryfling, vellamo, Ubuntu: hackbench) on ARM hikey board (64 bit octa-core, single policy). Only galleryfling showed minor improvements, while others didn't had much deviation. The reason being that this patch only targets a corner case, where following are required to be true to improve performance and that doesn't happen too often with these tests: - Task is migrated to another CPU. - The task has high demand, and should take the target CPU to higher OPPs. - And the target CPU doesn't call into the cpufreq governor until the next tick. Based on initial work from Steve Muckle. Signed-off-by: Viresh Kumar Acked-by: Saravana Kannan Acked-by: Peter Zijlstra (Intel) Signed-off-by: Rafael J. Wysocki --- kernel/sched/cpufreq_schedutil.c | 31 ++++++++++++++++++++++++++----- kernel/sched/deadline.c | 2 +- kernel/sched/fair.c | 8 +++++--- kernel/sched/rt.c | 2 +- kernel/sched/sched.h | 10 ++-------- 5 files changed, 35 insertions(+), 18 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index ddd385f2a985..7dbc76801f86 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -52,6 +52,7 @@ struct sugov_policy { struct sugov_cpu { struct update_util_data update_util; struct sugov_policy *sg_policy; + unsigned int cpu; bool iowait_boost_pending; unsigned int iowait_boost; @@ -77,6 +78,21 @@ static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time) { s64 delta_ns; + /* + * Since cpufreq_update_util() is called with rq->lock held for + * the @target_cpu, our per-cpu data is fully serialized. + * + * However, drivers cannot in general deal with cross-cpu + * requests, so while get_next_freq() will work, our + * sugov_update_commit() call may not. + * + * Hence stop here for remote requests if they aren't supported + * by the hardware, as calculating the frequency is pointless if + * we cannot in fact act on it. + */ + if (!cpufreq_can_do_remote_dvfs(sg_policy->policy)) + return false; + if (sg_policy->work_in_progress) return false; @@ -155,12 +171,12 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy, return cpufreq_driver_resolve_freq(policy, freq); } -static void sugov_get_util(unsigned long *util, unsigned long *max) +static void sugov_get_util(unsigned long *util, unsigned long *max, int cpu) { - struct rq *rq = this_rq(); + struct rq *rq = cpu_rq(cpu); unsigned long cfs_max; - cfs_max = arch_scale_cpu_capacity(NULL, smp_processor_id()); + cfs_max = arch_scale_cpu_capacity(NULL, cpu); *util = min(rq->cfs.avg.util_avg, cfs_max); *max = cfs_max; @@ -254,7 +270,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, if (flags & SCHED_CPUFREQ_RT_DL) { next_f = policy->cpuinfo.max_freq; } else { - sugov_get_util(&util, &max); + sugov_get_util(&util, &max, sg_cpu->cpu); sugov_iowait_boost(sg_cpu, &util, &max); next_f = get_next_freq(sg_policy, util, max); /* @@ -316,7 +332,7 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time, unsigned long util, max; unsigned int next_f; - sugov_get_util(&util, &max); + sugov_get_util(&util, &max, sg_cpu->cpu); raw_spin_lock(&sg_policy->update_lock); @@ -697,6 +713,11 @@ struct cpufreq_governor *cpufreq_default_governor(void) static int __init sugov_register(void) { + int cpu; + + for_each_possible_cpu(cpu) + per_cpu(sugov_cpu, cpu).cpu = cpu; + return cpufreq_register_governor(&schedutil_gov); } fs_initcall(sugov_register); diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 755bd3f1a1a9..5c3bf4bd0327 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1136,7 +1136,7 @@ static void update_curr_dl(struct rq *rq) } /* kick cpufreq (see the comment in kernel/sched/sched.h). */ - cpufreq_update_this_cpu(rq, SCHED_CPUFREQ_DL); + cpufreq_update_util(rq, SCHED_CPUFREQ_DL); schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec)); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c95880e216f6..d378d02fdfcb 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3278,7 +3278,9 @@ static inline void set_tg_cfs_propagate(struct cfs_rq *cfs_rq) {} static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq) { - if (&this_rq()->cfs == cfs_rq) { + struct rq *rq = rq_of(cfs_rq); + + if (&rq->cfs == cfs_rq) { /* * There are a few boundary cases this might miss but it should * get called often enough that that should (hopefully) not be @@ -3295,7 +3297,7 @@ static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq) * * See cpu_util(). */ - cpufreq_update_util(rq_of(cfs_rq), 0); + cpufreq_update_util(rq, 0); } } @@ -4875,7 +4877,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) * passed. */ if (p->in_iowait) - cpufreq_update_this_cpu(rq, SCHED_CPUFREQ_IOWAIT); + cpufreq_update_util(rq, SCHED_CPUFREQ_IOWAIT); for_each_sched_entity(se) { if (se->on_rq) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 45caf937ef90..0af5ca9e3e3f 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -970,7 +970,7 @@ static void update_curr_rt(struct rq *rq) return; /* Kick cpufreq (see the comment in kernel/sched/sched.h). */ - cpufreq_update_this_cpu(rq, SCHED_CPUFREQ_RT); + cpufreq_update_util(rq, SCHED_CPUFREQ_RT); schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec)); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index eeef1a3086d1..aa9d5b87b4f8 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2070,19 +2070,13 @@ static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) { struct update_util_data *data; - data = rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data)); + data = rcu_dereference_sched(*per_cpu_ptr(&cpufreq_update_util_data, + cpu_of(rq))); if (data) data->func(data, rq_clock(rq), flags); } - -static inline void cpufreq_update_this_cpu(struct rq *rq, unsigned int flags) -{ - if (cpu_of(rq) == smp_processor_id()) - cpufreq_update_util(rq, flags); -} #else static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {} -static inline void cpufreq_update_this_cpu(struct rq *rq, unsigned int flags) {} #endif /* CONFIG_CPU_FREQ */ #ifdef arch_scale_freq_capacity -- cgit v1.2.3 From bc2eecd7ecce40af43b6eb3d256b6076257df846 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Tue, 1 Aug 2017 00:31:32 -0400 Subject: futex: Allow for compiling out PI support This makes it possible to preserve basic futex support and compile out the PI support when RT mutexes are not available. Signed-off-by: Nicolas Pitre Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: Darren Hart Link: http://lkml.kernel.org/r/alpine.LFD.2.20.1708010024190.5981@knanqh.ubzr --- kernel/futex.c | 22 ++++++++++++++++++++++ kernel/locking/rtmutex_common.h | 29 +++++++++++++++++++++++++++++ 2 files changed, 51 insertions(+) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index 16dbe4c93895..ad0af4df1b9d 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -875,6 +875,8 @@ static struct task_struct *futex_find_get_task(pid_t pid) return p; } +#ifdef CONFIG_FUTEX_PI + /* * This task is holding PI mutexes at exit time => bad. * Kernel cleans up PI-state, but userspace is likely hosed. @@ -932,6 +934,8 @@ void exit_pi_state_list(struct task_struct *curr) raw_spin_unlock_irq(&curr->pi_lock); } +#endif + /* * We need to check the following states: * @@ -1799,6 +1803,15 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags, struct futex_q *this, *next; DEFINE_WAKE_Q(wake_q); + /* + * When PI not supported: return -ENOSYS if requeue_pi is true, + * consequently the compiler knows requeue_pi is always false past + * this point which will optimize away all the conditional code + * further down. + */ + if (!IS_ENABLED(CONFIG_FUTEX_PI) && requeue_pi) + return -ENOSYS; + if (requeue_pi) { /* * Requeue PI only works on two distinct uaddrs. This @@ -2594,6 +2607,9 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags, struct futex_q q = futex_q_init; int res, ret; + if (!IS_ENABLED(CONFIG_FUTEX_PI)) + return -ENOSYS; + if (refill_pi_state_cache()) return -ENOMEM; @@ -2773,6 +2789,9 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags) struct futex_q *top_waiter; int ret; + if (!IS_ENABLED(CONFIG_FUTEX_PI)) + return -ENOSYS; + retry: if (get_user(uval, uaddr)) return -EFAULT; @@ -2983,6 +3002,9 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, struct futex_q q = futex_q_init; int res, ret; + if (!IS_ENABLED(CONFIG_FUTEX_PI)) + return -ENOSYS; + if (uaddr == uaddr2) return -EINVAL; diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h index 72ad45a9a794..8d039b928d61 100644 --- a/kernel/locking/rtmutex_common.h +++ b/kernel/locking/rtmutex_common.h @@ -40,6 +40,9 @@ struct rt_mutex_waiter { /* * Various helpers to access the waiters-tree: */ + +#ifdef CONFIG_RT_MUTEXES + static inline int rt_mutex_has_waiters(struct rt_mutex *lock) { return !RB_EMPTY_ROOT(&lock->waiters); @@ -69,6 +72,32 @@ task_top_pi_waiter(struct task_struct *p) pi_tree_entry); } +#else + +static inline int rt_mutex_has_waiters(struct rt_mutex *lock) +{ + return false; +} + +static inline struct rt_mutex_waiter * +rt_mutex_top_waiter(struct rt_mutex *lock) +{ + return NULL; +} + +static inline int task_has_pi_waiters(struct task_struct *p) +{ + return false; +} + +static inline struct rt_mutex_waiter * +task_top_pi_waiter(struct task_struct *p) +{ + return NULL; +} + +#endif + /* * lock->owner state tracking: */ -- cgit v1.2.3 From c39a0e2c8850f08249383f2425dbd8dbe4baad69 Mon Sep 17 00:00:00 2001 From: Vikas Shivappa Date: Tue, 25 Jul 2017 14:14:20 -0700 Subject: x86/perf/cqm: Wipe out perf based cqm 'perf cqm' never worked due to the incompatibility between perf infrastructure and cqm hardware support. The hardware uses RMIDs to track the llc occupancy of tasks and these RMIDs are per package. This makes monitoring a hierarchy like cgroup along with monitoring of tasks separately difficult and several patches sent to lkml to fix them were NACKed. Further more, the following issues in the current perf cqm make it almost unusable: 1. No support to monitor the same group of tasks for which we do allocation using resctrl. 2. It gives random and inaccurate data (mostly 0s) once we run out of RMIDs due to issues in Recycling. 3. Recycling results in inaccuracy of data because we cannot guarantee that the RMID was stolen from a task when it was not pulling data into cache or even when it pulled the least data. Also for monitoring llc_occupancy, if we stop using an RMID_x and then start using an RMID_y after we reclaim an RMID from an other event, we miss accounting all the occupancy that was tagged to RMID_x at a later perf_count. 2. Recycling code makes the monitoring code complex including scheduling because the event can lose RMID any time. Since MBM counters count bandwidth for a period of time by taking snap shot of total bytes at two different times, recycling complicates the way we count MBM in a hierarchy. Also we need a spin lock while we do the processing to account for MBM counter overflow. We also currently use a spin lock in scheduling to prevent the RMID from being taken away. 4. Lack of support when we run different kind of event like task, system-wide and cgroup events together. Data mostly prints 0s. This is also because we can have only one RMID tied to a cpu as defined by the cqm hardware but a perf can at the same time tie multiple events during one sched_in. 5. No support of monitoring a group of tasks. There is partial support for cgroup but it does not work once there is a hierarchy of cgroups or if we want to monitor a task in a cgroup and the cgroup itself. 6. No support for monitoring tasks for the lifetime without perf overhead. 7. It reported the aggregate cache occupancy or memory bandwidth over all sockets. But most cloud and VMM based use cases want to know the individual per-socket usage. Signed-off-by: Vikas Shivappa Signed-off-by: Thomas Gleixner Cc: ravi.v.shankar@intel.com Cc: tony.luck@intel.com Cc: fenghua.yu@intel.com Cc: peterz@infradead.org Cc: eranian@google.com Cc: vikas.shivappa@intel.com Cc: ak@linux.intel.com Cc: davidcc@google.com Cc: reinette.chatre@intel.com Link: http://lkml.kernel.org/r/1501017287-28083-2-git-send-email-vikas.shivappa@linux.intel.com --- kernel/events/core.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 426c2ffba16d..6e171540c0af 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3625,10 +3625,7 @@ unlock: static inline u64 perf_event_count(struct perf_event *event) { - if (event->pmu->count) - return event->pmu->count(event); - - return __perf_event_count(event); + return local64_read(&event->count) + atomic64_read(&event->child_count); } /* @@ -3659,15 +3656,6 @@ int perf_event_read_local(struct perf_event *event, u64 *value) goto out; } - /* - * It must not have a pmu::count method, those are not - * NMI safe. - */ - if (event->pmu->count) { - ret = -EOPNOTSUPP; - goto out; - } - /* If this is a per-task event, it must be for current */ if ((event->attach_state & PERF_ATTACH_TASK) && event->hw.target != current) { -- cgit v1.2.3 From 4bb0f0e73c8c30917d169c4a0f1ac083690c545b Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 1 Aug 2017 12:01:52 -0400 Subject: tracing: Call clear_boot_tracer() at lateinit_sync The clear_boot_tracer function is used to reset the default_bootup_tracer string to prevent it from being accessed after boot, as it originally points to init data. But since clear_boot_tracer() is called via the init_lateinit() call, it races with the initcall for registering the hwlat tracer. If someone adds "ftrace=hwlat" to the kernel command line, depending on how the linker sets up the text, the saved command line may be cleared, and the hwlat tracer never is initialized. Simply have the clear_boot_tracer() be called by initcall_lateinit_sync() as that's for tasks to be called after lateinit. Link: https://bugzilla.kernel.org/show_bug.cgi?id=196551 Cc: stable@vger.kernel.org Fixes: e7c15cd8a ("tracing: Added hardware latency tracer") Reported-by: Zamir SUN Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 42b9355033d4..784fb43b2abe 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8407,4 +8407,4 @@ __init static int clear_boot_tracer(void) } fs_initcall(tracer_init_tracefs); -late_initcall(clear_boot_tracer); +late_initcall_sync(clear_boot_tracer); -- cgit v1.2.3 From 147d88e0b5eb90191bc5c12ca0a3c410b75a13d2 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Tue, 1 Aug 2017 14:02:01 +0300 Subject: tracing: Missing error code in tracer_alloc_buffers() If ring_buffer_alloc() or one of the next couple function calls fail then we should return -ENOMEM but the current code returns success. Link: http://lkml.kernel.org/r/20170801110201.ajdkct7vwzixahvx@mwanda Cc: Sebastian Andrzej Siewior Cc: Ingo Molnar Cc: stable@vger.kernel.org Fixes: b32614c03413 ('tracing/rb: Convert to hotplug state machine') Signed-off-by: Dan Carpenter Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 784fb43b2abe..d815fc317e9d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8293,6 +8293,7 @@ __init static int tracer_alloc_buffers(void) if (ret < 0) goto out_free_cpumask; /* Used for event triggers */ + ret = -ENOMEM; temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE); if (!temp_buffer) goto out_rm_hp_state; -- cgit v1.2.3 From a7e52ad7ed82e21273eccff93d1477a7b313aabb Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Wed, 2 Aug 2017 14:20:54 -0400 Subject: ring-buffer: Have ring_buffer_alloc_read_page() return error on offline CPU Chunyu Hu reported: "per_cpu trace directories and files are created for all possible cpus, but only the cpus which have ever been on-lined have their own per cpu ring buffer (allocated by cpuhp threads). While trace_buffers_open, the open handler for trace file 'trace_pipe_raw' is always trying to access field of ring_buffer_per_cpu, and would panic with the NULL pointer. Align the behavior of trace_pipe_raw with trace_pipe, that returns -NODEV when openning it if that cpu does not have trace ring buffer. Reproduce: cat /sys/kernel/debug/tracing/per_cpu/cpu31/trace_pipe_raw (cpu31 is never on-lined, this is a 16 cores x86_64 box) Tested with: 1) boot with maxcpus=14, read trace_pipe_raw of cpu15. Got -NODEV. 2) oneline cpu15, read trace_pipe_raw of cpu15. Get the raw trace data. Call trace: [ 5760.950995] RIP: 0010:ring_buffer_alloc_read_page+0x32/0xe0 [ 5760.961678] tracing_buffers_read+0x1f6/0x230 [ 5760.962695] __vfs_read+0x37/0x160 [ 5760.963498] ? __vfs_read+0x5/0x160 [ 5760.964339] ? security_file_permission+0x9d/0xc0 [ 5760.965451] ? __vfs_read+0x5/0x160 [ 5760.966280] vfs_read+0x8c/0x130 [ 5760.967070] SyS_read+0x55/0xc0 [ 5760.967779] do_syscall_64+0x67/0x150 [ 5760.968687] entry_SYSCALL64_slow_path+0x25/0x25" This was introduced by the addition of the feature to reuse reader pages instead of re-allocating them. The problem is that the allocation of a reader page (which is per cpu) does not check if the cpu is online and set up for the ring buffer. Link: http://lkml.kernel.org/r/1500880866-1177-1-git-send-email-chuhu@redhat.com Cc: stable@vger.kernel.org Fixes: 73a757e63114 ("ring-buffer: Return reader page back into existing ring buffer") Reported-by: Chunyu Hu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ring_buffer.c | 14 +++++++++----- kernel/trace/ring_buffer_benchmark.c | 2 +- kernel/trace/trace.c | 16 +++++++++++----- 3 files changed, 21 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 529cc50d7243..81279c6602ff 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -4386,15 +4386,19 @@ EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu); * the page that was allocated, with the read page of the buffer. * * Returns: - * The page allocated, or NULL on error. + * The page allocated, or ERR_PTR */ void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu) { - struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu]; + struct ring_buffer_per_cpu *cpu_buffer; struct buffer_data_page *bpage = NULL; unsigned long flags; struct page *page; + if (!cpumask_test_cpu(cpu, buffer->cpumask)) + return ERR_PTR(-ENODEV); + + cpu_buffer = buffer->buffers[cpu]; local_irq_save(flags); arch_spin_lock(&cpu_buffer->lock); @@ -4412,7 +4416,7 @@ void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu) page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL | __GFP_NORETRY, 0); if (!page) - return NULL; + return ERR_PTR(-ENOMEM); bpage = page_address(page); @@ -4467,8 +4471,8 @@ EXPORT_SYMBOL_GPL(ring_buffer_free_read_page); * * for example: * rpage = ring_buffer_alloc_read_page(buffer, cpu); - * if (!rpage) - * return error; + * if (IS_ERR(rpage)) + * return PTR_ERR(rpage); * ret = ring_buffer_read_page(buffer, &rpage, len, cpu, 0); * if (ret >= 0) * process_page(rpage, ret); diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c index 9fbcaf567886..68ee79afe31c 100644 --- a/kernel/trace/ring_buffer_benchmark.c +++ b/kernel/trace/ring_buffer_benchmark.c @@ -113,7 +113,7 @@ static enum event_status read_page(int cpu) int i; bpage = ring_buffer_alloc_read_page(buffer, cpu); - if (!bpage) + if (IS_ERR(bpage)) return EVENT_DROPPED; ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d815fc317e9d..44004d8aa3b3 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6598,7 +6598,7 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, { struct ftrace_buffer_info *info = filp->private_data; struct trace_iterator *iter = &info->iter; - ssize_t ret; + ssize_t ret = 0; ssize_t size; if (!count) @@ -6612,10 +6612,15 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, if (!info->spare) { info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer, iter->cpu_file); - info->spare_cpu = iter->cpu_file; + if (IS_ERR(info->spare)) { + ret = PTR_ERR(info->spare); + info->spare = NULL; + } else { + info->spare_cpu = iter->cpu_file; + } } if (!info->spare) - return -ENOMEM; + return ret; /* Do we have previous read data to read? */ if (info->read < PAGE_SIZE) @@ -6790,8 +6795,9 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, ref->ref = 1; ref->buffer = iter->trace_buffer->buffer; ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file); - if (!ref->page) { - ret = -ENOMEM; + if (IS_ERR(ref->page)) { + ret = PTR_ERR(ref->page); + ref->page = NULL; kfree(ref); break; } -- cgit v1.2.3 From 0679dee03c6d706d57145ea92c23d08fa10a1999 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Wed, 2 Aug 2017 17:55:29 +0100 Subject: cgroup: keep track of number of descent cgroups Keep track of the number of online and dying descent cgroups. This data will be used later to add an ability to control cgroup hierarchy (limit the depth and the number of descent cgroups) and display hierarchy stats. Signed-off-by: Roman Gushchin Suggested-by: Tejun Heo Signed-off-by: Tejun Heo Cc: Zefan Li Cc: Waiman Long Cc: Johannes Weiner Cc: kernel-team@fb.com Cc: cgroups@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- kernel/cgroup/cgroup.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 85f6a112344b..cfdbb1e780de 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4408,9 +4408,15 @@ static void css_release_work_fn(struct work_struct *work) if (ss->css_released) ss->css_released(css); } else { + struct cgroup *tcgrp; + /* cgroup release path */ trace_cgroup_release(cgrp); + for (tcgrp = cgroup_parent(cgrp); tcgrp; + tcgrp = cgroup_parent(tcgrp)) + tcgrp->nr_dying_descendants--; + cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id); cgrp->id = -1; @@ -4609,9 +4615,13 @@ static struct cgroup *cgroup_create(struct cgroup *parent) cgrp->root = root; cgrp->level = level; - for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) + for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) { cgrp->ancestor_ids[tcgrp->level] = tcgrp->id; + if (tcgrp != cgrp) + tcgrp->nr_descendants++; + } + if (notify_on_release(parent)) set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); @@ -4817,7 +4827,7 @@ static void kill_css(struct cgroup_subsys_state *css) static int cgroup_destroy_locked(struct cgroup *cgrp) __releases(&cgroup_mutex) __acquires(&cgroup_mutex) { - struct cgroup *parent = cgroup_parent(cgrp); + struct cgroup *tcgrp, *parent = cgroup_parent(cgrp); struct cgroup_subsys_state *css; struct cgrp_cset_link *link; int ssid; @@ -4865,6 +4875,11 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) if (parent && cgroup_is_threaded(cgrp)) parent->nr_threaded_children--; + for (tcgrp = cgroup_parent(cgrp); tcgrp; tcgrp = cgroup_parent(tcgrp)) { + tcgrp->nr_descendants--; + tcgrp->nr_dying_descendants++; + } + cgroup1_check_for_release(cgroup_parent(cgrp)); /* put the base reference */ -- cgit v1.2.3 From 1a926e0bbab83bae8207d05a533173425e0496d1 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Fri, 28 Jul 2017 18:28:44 +0100 Subject: cgroup: implement hierarchy limits Creating cgroup hierearchies of unreasonable size can affect overall system performance. A user might want to limit the size of cgroup hierarchy. This is especially important if a user is delegating some cgroup sub-tree. To address this issue, introduce an ability to control the size of cgroup hierarchy. The cgroup.max.descendants control file allows to set the maximum allowed number of descendant cgroups. The cgroup.max.depth file controls the maximum depth of the cgroup tree. Both are single value r/w files, with "max" default value. The control files exist on each hierarchy level (including root). When a new cgroup is created, we check the total descendants and depth limits on each level, and if none of them are exceeded, a new cgroup is created. Only alive cgroups are counted, removed (dying) cgroups are ignored. Signed-off-by: Roman Gushchin Suggested-by: Tejun Heo Signed-off-by: Tejun Heo Cc: Zefan Li Cc: Waiman Long Cc: Johannes Weiner Cc: kernel-team@fb.com Cc: cgroups@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- kernel/cgroup/cgroup.c | 126 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 126 insertions(+) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index cfdbb1e780de..0fd9134e1720 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1827,6 +1827,8 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp) cgrp->self.cgroup = cgrp; cgrp->self.flags |= CSS_ONLINE; cgrp->dom_cgrp = cgrp; + cgrp->max_descendants = INT_MAX; + cgrp->max_depth = INT_MAX; for_each_subsys(ss, ssid) INIT_LIST_HEAD(&cgrp->e_csets[ssid]); @@ -3209,6 +3211,92 @@ static ssize_t cgroup_type_write(struct kernfs_open_file *of, char *buf, return ret ?: nbytes; } +static int cgroup_max_descendants_show(struct seq_file *seq, void *v) +{ + struct cgroup *cgrp = seq_css(seq)->cgroup; + int descendants = READ_ONCE(cgrp->max_descendants); + + if (descendants == INT_MAX) + seq_puts(seq, "max\n"); + else + seq_printf(seq, "%d\n", descendants); + + return 0; +} + +static ssize_t cgroup_max_descendants_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct cgroup *cgrp; + int descendants; + ssize_t ret; + + buf = strstrip(buf); + if (!strcmp(buf, "max")) { + descendants = INT_MAX; + } else { + ret = kstrtoint(buf, 0, &descendants); + if (ret) + return ret; + } + + if (descendants < 0 || descendants > INT_MAX) + return -ERANGE; + + cgrp = cgroup_kn_lock_live(of->kn, false); + if (!cgrp) + return -ENOENT; + + cgrp->max_descendants = descendants; + + cgroup_kn_unlock(of->kn); + + return nbytes; +} + +static int cgroup_max_depth_show(struct seq_file *seq, void *v) +{ + struct cgroup *cgrp = seq_css(seq)->cgroup; + int depth = READ_ONCE(cgrp->max_depth); + + if (depth == INT_MAX) + seq_puts(seq, "max\n"); + else + seq_printf(seq, "%d\n", depth); + + return 0; +} + +static ssize_t cgroup_max_depth_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct cgroup *cgrp; + ssize_t ret; + int depth; + + buf = strstrip(buf); + if (!strcmp(buf, "max")) { + depth = INT_MAX; + } else { + ret = kstrtoint(buf, 0, &depth); + if (ret) + return ret; + } + + if (depth < 0 || depth > INT_MAX) + return -ERANGE; + + cgrp = cgroup_kn_lock_live(of->kn, false); + if (!cgrp) + return -ENOENT; + + cgrp->max_depth = depth; + + cgroup_kn_unlock(of->kn); + + return nbytes; +} + static int cgroup_events_show(struct seq_file *seq, void *v) { seq_printf(seq, "populated %d\n", @@ -4309,6 +4397,16 @@ static struct cftype cgroup_base_files[] = { .file_offset = offsetof(struct cgroup, events_file), .seq_show = cgroup_events_show, }, + { + .name = "cgroup.max.descendants", + .seq_show = cgroup_max_descendants_show, + .write = cgroup_max_descendants_write, + }, + { + .name = "cgroup.max.depth", + .seq_show = cgroup_max_depth_show, + .write = cgroup_max_depth_write, + }, { } /* terminate */ }; @@ -4662,6 +4760,29 @@ out_free_cgrp: return ERR_PTR(ret); } +static bool cgroup_check_hierarchy_limits(struct cgroup *parent) +{ + struct cgroup *cgroup; + int ret = false; + int level = 1; + + lockdep_assert_held(&cgroup_mutex); + + for (cgroup = parent; cgroup; cgroup = cgroup_parent(cgroup)) { + if (cgroup->nr_descendants >= cgroup->max_descendants) + goto fail; + + if (level > cgroup->max_depth) + goto fail; + + level++; + } + + ret = true; +fail: + return ret; +} + int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode) { struct cgroup *parent, *cgrp; @@ -4676,6 +4797,11 @@ int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode) if (!parent) return -ENODEV; + if (!cgroup_check_hierarchy_limits(parent)) { + ret = -EAGAIN; + goto out_unlock; + } + cgrp = cgroup_create(parent); if (IS_ERR(cgrp)) { ret = PTR_ERR(cgrp); -- cgit v1.2.3 From ec39225cca42c05ac36853d11d28f877fde5c42e Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Wed, 2 Aug 2017 17:55:31 +0100 Subject: cgroup: add cgroup.stat interface with basic hierarchy stats A cgroup can consume resources even after being deleted by a user. For example, writing back dirty pages should be accounted and limited, despite the corresponding cgroup might contain no processes and being deleted by a user. In the current implementation a cgroup can remain in such "dying" state for an undefined amount of time. For instance, if a memory cgroup contains a pge, mlocked by a process belonging to an other cgroup. Although the lifecycle of a dying cgroup is out of user's control, it's important to have some insight of what's going on under the hood. In particular, it's handy to have a counter which will allow to detect css leaks. To solve this problem, add a cgroup.stat interface to the base cgroup control files with the following metrics: nr_descendants total number of visible descendant cgroups nr_dying_descendants total number of dying descendant cgroups Signed-off-by: Roman Gushchin Suggested-by: Tejun Heo Signed-off-by: Tejun Heo Cc: Zefan Li Cc: Waiman Long Cc: Johannes Weiner Cc: kernel-team@fb.com Cc: cgroups@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- kernel/cgroup/cgroup.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 0fd9134e1720..a06755a610e1 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3304,6 +3304,18 @@ static int cgroup_events_show(struct seq_file *seq, void *v) return 0; } +static int cgroup_stats_show(struct seq_file *seq, void *v) +{ + struct cgroup *cgroup = seq_css(seq)->cgroup; + + seq_printf(seq, "nr_descendants %d\n", + cgroup->nr_descendants); + seq_printf(seq, "nr_dying_descendants %d\n", + cgroup->nr_dying_descendants); + + return 0; +} + static int cgroup_file_open(struct kernfs_open_file *of) { struct cftype *cft = of->kn->priv; @@ -4407,6 +4419,10 @@ static struct cftype cgroup_base_files[] = { .seq_show = cgroup_max_depth_show, .write = cgroup_max_depth_write, }, + { + .name = "cgroup.stat", + .seq_show = cgroup_stats_show, + }, { } /* terminate */ }; -- cgit v1.2.3 From 5a621e6c958e057c727a30c502f28bf2bc04adfd Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Wed, 2 Aug 2017 17:55:32 +0100 Subject: cgroup: re-use the parent pointer in cgroup_destroy_locked() As we already have a pointer to the parent cgroup in cgroup_destroy_locked(), we don't need to calculate it again to pass as an argument for cgroup1_check_for_release(). Signed-off-by: Roman Gushchin Suggested-by: Tejun Heo Signed-off-by: Tejun Heo Cc: Zefan Li Cc: Waiman Long Cc: Johannes Weiner Cc: kernel-team@fb.com Cc: linux-kernel@vger.kernel.org --- kernel/cgroup/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index a06755a610e1..92e599796220 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -5022,7 +5022,7 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) tcgrp->nr_dying_descendants++; } - cgroup1_check_for_release(cgroup_parent(cgrp)); + cgroup1_check_for_release(parent); /* put the base reference */ percpu_ref_kill(&cgrp->self.refcnt); -- cgit v1.2.3 From 13d82fb77abb9625f3ca74f5c4cbedde0f412f01 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 2 Aug 2017 15:39:38 -0700 Subject: cgroup: short-circuit cset_cgroup_from_root() on the default hierarchy Each css_set directly points to the default cgroup it belongs to, so there's no reason to walk the cgrp_links list on the default hierarchy. Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 92e599796220..f5ca55db1fe1 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1311,6 +1311,8 @@ static struct cgroup *cset_cgroup_from_root(struct css_set *cset, if (cset == &init_css_set) { res = &root->cgrp; + } else if (root == &cgrp_dfl_root) { + res = cset->dfl_cgrp; } else { struct cgrp_cset_link *link; -- cgit v1.2.3 From 27e37d84e55f47bf28f7072fadf8fa2cbc3d9375 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 2 Aug 2017 13:31:50 -0700 Subject: pid: kill pidhash_size in pidhash_init() After commit 3d375d78593c ("mm: update callers to use HASH_ZERO flag"), drop unused pidhash_size in pidhash_init(). Link: http://lkml.kernel.org/r/1500389267-49222-1-git-send-email-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Pavel Tatashin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/pid.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'kernel') diff --git a/kernel/pid.c b/kernel/pid.c index 731c4e528f4e..c69c30d827e5 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -575,13 +575,10 @@ struct pid *find_ge_pid(int nr, struct pid_namespace *ns) */ void __init pidhash_init(void) { - unsigned int pidhash_size; - pid_hash = alloc_large_system_hash("PID", sizeof(*pid_hash), 0, 18, HASH_EARLY | HASH_SMALL | HASH_ZERO, &pidhash_shift, NULL, 0, 4096); - pidhash_size = 1U << pidhash_shift; } void __init pidmap_init(void) -- cgit v1.2.3 From 89affbf5d9ebb15c6460596822e8857ea2f9e735 Mon Sep 17 00:00:00 2001 From: Dima Zavin Date: Wed, 2 Aug 2017 13:32:18 -0700 Subject: cpuset: fix a deadlock due to incomplete patching of cpusets_enabled() In codepaths that use the begin/retry interface for reading mems_allowed_seq with irqs disabled, there exists a race condition that stalls the patch process after only modifying a subset of the static_branch call sites. This problem manifested itself as a deadlock in the slub allocator, inside get_any_partial. The loop reads mems_allowed_seq value (via read_mems_allowed_begin), performs the defrag operation, and then verifies the consistency of mem_allowed via the read_mems_allowed_retry and the cookie returned by xxx_begin. The issue here is that both begin and retry first check if cpusets are enabled via cpusets_enabled() static branch. This branch can be rewritted dynamically (via cpuset_inc) if a new cpuset is created. The x86 jump label code fully synchronizes across all CPUs for every entry it rewrites. If it rewrites only one of the callsites (specifically the one in read_mems_allowed_retry) and then waits for the smp_call_function(do_sync_core) to complete while a CPU is inside the begin/retry section with IRQs off and the mems_allowed value is changed, we can hang. This is because begin() will always return 0 (since it wasn't patched yet) while retry() will test the 0 against the actual value of the seq counter. The fix is to use two different static keys: one for begin (pre_enable_key) and one for retry (enable_key). In cpuset_inc(), we first bump the pre_enable key to ensure that cpuset_mems_allowed_begin() always return a valid seqcount if are enabling cpusets. Similarly, when disabling cpusets via cpuset_dec(), we first ensure that callers of cpuset_mems_allowed_retry() will start ignoring the seqcount value before we let cpuset_mems_allowed_begin() return 0. The relevant stack traces of the two stuck threads: CPU: 1 PID: 1415 Comm: mkdir Tainted: G L 4.9.36-00104-g540c51286237 #4 Hardware name: Default string Default string/Hardware, BIOS 4.29.1-20170526215256 05/26/2017 task: ffff8817f9c28000 task.stack: ffffc9000ffa4000 RIP: smp_call_function_many+0x1f9/0x260 Call Trace: smp_call_function+0x3b/0x70 on_each_cpu+0x2f/0x90 text_poke_bp+0x87/0xd0 arch_jump_label_transform+0x93/0x100 __jump_label_update+0x77/0x90 jump_label_update+0xaa/0xc0 static_key_slow_inc+0x9e/0xb0 cpuset_css_online+0x70/0x2e0 online_css+0x2c/0xa0 cgroup_apply_control_enable+0x27f/0x3d0 cgroup_mkdir+0x2b7/0x420 kernfs_iop_mkdir+0x5a/0x80 vfs_mkdir+0xf6/0x1a0 SyS_mkdir+0xb7/0xe0 entry_SYSCALL_64_fastpath+0x18/0xad ... CPU: 2 PID: 1 Comm: init Tainted: G L 4.9.36-00104-g540c51286237 #4 Hardware name: Default string Default string/Hardware, BIOS 4.29.1-20170526215256 05/26/2017 task: ffff8818087c0000 task.stack: ffffc90000030000 RIP: int3+0x39/0x70 Call Trace: <#DB> ? ___slab_alloc+0x28b/0x5a0 ? copy_process.part.40+0xf7/0x1de0 __slab_alloc.isra.80+0x54/0x90 copy_process.part.40+0xf7/0x1de0 copy_process.part.40+0xf7/0x1de0 kmem_cache_alloc_node+0x8a/0x280 copy_process.part.40+0xf7/0x1de0 _do_fork+0xe7/0x6c0 _raw_spin_unlock_irq+0x2d/0x60 trace_hardirqs_on_caller+0x136/0x1d0 entry_SYSCALL_64_fastpath+0x5/0xad do_syscall_64+0x27/0x350 SyS_clone+0x19/0x20 do_syscall_64+0x60/0x350 entry_SYSCALL64_slow_path+0x25/0x25 Link: http://lkml.kernel.org/r/20170731040113.14197-1-dmitriyz@waymo.com Fixes: 46e700abc44c ("mm, page_alloc: remove unnecessary taking of a seqlock when cpusets are disabled") Signed-off-by: Dima Zavin Reported-by: Cliff Spradlin Acked-by: Vlastimil Babka Cc: Peter Zijlstra Cc: Christopher Lameter Cc: Li Zefan Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Mel Gorman Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cgroup/cpuset.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index ca8376e5008c..8d5151688504 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -63,6 +63,7 @@ #include #include +DEFINE_STATIC_KEY_FALSE(cpusets_pre_enable_key); DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key); /* See "Frequency meter" comments, below. */ -- cgit v1.2.3 From e870c6c87cf9484090d28f2a68aa29e008960c93 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 31 Jul 2017 23:43:18 +0200 Subject: ACPI / PM: Prefer suspend-to-idle over S3 on some systems Modify the ACPI system sleep support setup code to select suspend-to-idle as the default system sleep state if (1) the ACPI_FADT_LOW_POWER_S0 flag is set in the FADT and (2) the Low Power Idle S0 _DSM interface has been discovered and (3) the default sleep state was not selected from the kernel command line. The main motivation for this change is that systems where the (1) and (2) conditions are met typically ship with OSes that don't exercise the S3 path in the platform firmware which remains untested and turns out to be non-functional at least in some cases. Signed-off-by: Rafael J. Wysocki Tested-by: Mario Limonciello --- kernel/power/power.h | 1 - kernel/power/suspend.c | 4 ++-- 2 files changed, 2 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/power/power.h b/kernel/power/power.h index 268c1b0afc28..1d2d761e3c25 100644 --- a/kernel/power/power.h +++ b/kernel/power/power.h @@ -192,7 +192,6 @@ extern void swsusp_show_speed(ktime_t, ktime_t, unsigned int, char *); extern const char * const pm_labels[]; extern const char *pm_states[]; extern const char *mem_sleep_states[]; -extern suspend_state_t mem_sleep_current; extern int suspend_devices_and_enter(suspend_state_t state); #else /* !CONFIG_SUSPEND */ diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 4bce46ddc2cd..0639d3a79852 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -48,7 +48,7 @@ static const char * const mem_sleep_labels[] = { const char *mem_sleep_states[PM_SUSPEND_MAX]; suspend_state_t mem_sleep_current = PM_SUSPEND_FREEZE; -static suspend_state_t mem_sleep_default = PM_SUSPEND_MEM; +suspend_state_t mem_sleep_default = PM_SUSPEND_MAX; suspend_state_t pm_suspend_target_state; EXPORT_SYMBOL_GPL(pm_suspend_target_state); @@ -216,7 +216,7 @@ void suspend_set_ops(const struct platform_suspend_ops *ops) } if (valid_state(PM_SUSPEND_MEM)) { mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM]; - if (mem_sleep_default == PM_SUSPEND_MEM) + if (mem_sleep_default >= PM_SUSPEND_MEM) mem_sleep_current = PM_SUSPEND_MEM; } -- cgit v1.2.3 From fbb77611e95d3d5b2af86a59754a3130877cb667 Mon Sep 17 00:00:00 2001 From: "Dmitry V. Levin" Date: Sat, 5 Aug 2017 23:00:50 +0300 Subject: Fix compat_sys_sigpending breakage The latest change of compat_sys_sigpending in commit 8f13621abced ("sigpending(): move compat to native") has broken it in two ways. First, it tries to write 4 bytes more than userspace expects: sizeof(old_sigset_t) == sizeof(long) == 8 instead of sizeof(compat_old_sigset_t) == sizeof(u32) == 4. Second, on big endian architectures these bytes are being written in the wrong order. This bug was found by strace test suite. Reported-by: Anatoly Pugachev Inspired-by: Eugene Syromyatnikov Fixes: 8f13621abced ("sigpending(): move compat to native") Signed-off-by: Dmitry V. Levin Acked-by: Al Viro Signed-off-by: Linus Torvalds --- kernel/signal.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/signal.c b/kernel/signal.c index caed9133ae52..7e33f8c583e6 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3303,12 +3303,15 @@ SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) #ifdef CONFIG_COMPAT COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32) { +#ifdef __BIG_ENDIAN sigset_t set; - int err = do_sigpending(&set, sizeof(old_sigset_t)); - if (err == 0) - if (copy_to_user(set32, &set, sizeof(old_sigset_t))) - err = -EFAULT; + int err = do_sigpending(&set, sizeof(set.sig[0])); + if (!err) + err = put_user(set.sig[0], set32); return err; +#else + return sys_rt_sigpending((sigset_t __user *)set32, sizeof(*set32)); +#endif } #endif -- cgit v1.2.3 From 9a2614916ac564d6ea1d0a5cb986298bc508c3bf Mon Sep 17 00:00:00 2001 From: Benjamin Peterson Date: Sun, 6 Aug 2017 19:33:22 -0700 Subject: workqueue: fix path to documentation Signed-off-by: Benjamin Peterson Signed-off-by: Tejun Heo --- kernel/workqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index a86688fabc55..4fa6c7650f09 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -21,7 +21,7 @@ * pools for workqueues which are not bound to any specific CPU - the * number of these backing pools is dynamic. * - * Please read Documentation/workqueue.txt for details. + * Please read Documentation/core-api/workqueue.rst for details. */ #include -- cgit v1.2.3 From cf5f5cea270655dd49370760576c64b228583b79 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Fri, 4 Aug 2017 16:00:09 -0700 Subject: bpf: add support for sys_enter_* and sys_exit_* tracepoints Currently, bpf programs cannot be attached to sys_enter_* and sys_exit_* style tracepoints. The iovisor/bcc issue #748 (https://github.com/iovisor/bcc/issues/748) documents this issue. For example, if you try to attach a bpf program to tracepoints syscalls/sys_enter_newfstat, you will get the following error: # ./tools/trace.py t:syscalls:sys_enter_newfstat Ioctl(PERF_EVENT_IOC_SET_BPF): Invalid argument Failed to attach BPF to tracepoint The main reason is that syscalls/sys_enter_* and syscalls/sys_exit_* tracepoints are treated differently from other tracepoints and there is no bpf hook to it. This patch adds bpf support for these syscalls tracepoints by . permitting bpf attachment in ioctl PERF_EVENT_IOC_SET_BPF . calling bpf programs in perf_syscall_enter and perf_syscall_exit The legality of bpf program ctx access is also checked. Function trace_event_get_offsets returns correct max offset for each specific syscall tracepoint, which is compared against the maximum offset access in bpf program. Signed-off-by: Yonghong Song Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/events/core.c | 10 ++++---- kernel/trace/trace_syscalls.c | 53 +++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 57 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 426c2ffba16d..a7a6c1d19a49 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8050,7 +8050,7 @@ static void perf_event_free_bpf_handler(struct perf_event *event) static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) { - bool is_kprobe, is_tracepoint; + bool is_kprobe, is_tracepoint, is_syscall_tp; struct bpf_prog *prog; if (event->attr.type != PERF_TYPE_TRACEPOINT) @@ -8061,7 +8061,8 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE; is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; - if (!is_kprobe && !is_tracepoint) + is_syscall_tp = is_syscall_trace_event(event->tp_event); + if (!is_kprobe && !is_tracepoint && !is_syscall_tp) /* bpf programs can only be attached to u/kprobe or tracepoint */ return -EINVAL; @@ -8070,13 +8071,14 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) return PTR_ERR(prog); if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) || - (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) { + (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) || + (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) { /* valid fd, but invalid bpf program type */ bpf_prog_put(prog); return -EINVAL; } - if (is_tracepoint) { + if (is_tracepoint || is_syscall_tp) { int off = trace_event_get_offsets(event->tp_event); if (prog->aux->max_ctx_offset > off) { diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 5e10395da88e..7a1a92036563 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -559,11 +559,29 @@ static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls); static int sys_perf_refcount_enter; static int sys_perf_refcount_exit; +static int perf_call_bpf_enter(struct bpf_prog *prog, struct pt_regs *regs, + struct syscall_metadata *sys_data, + struct syscall_trace_enter *rec) { + struct syscall_tp_t { + unsigned long long regs; + unsigned long syscall_nr; + unsigned long args[sys_data->nb_args]; + } param; + int i; + + *(struct pt_regs **)¶m = regs; + param.syscall_nr = rec->nr; + for (i = 0; i < sys_data->nb_args; i++) + param.args[i] = rec->args[i]; + return trace_call_bpf(prog, ¶m); +} + static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) { struct syscall_metadata *sys_data; struct syscall_trace_enter *rec; struct hlist_head *head; + struct bpf_prog *prog; int syscall_nr; int rctx; int size; @@ -578,8 +596,9 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) if (!sys_data) return; + prog = READ_ONCE(sys_data->enter_event->prog); head = this_cpu_ptr(sys_data->enter_event->perf_events); - if (hlist_empty(head)) + if (!prog && hlist_empty(head)) return; /* get the size after alignment with the u32 buffer size field */ @@ -594,6 +613,13 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) rec->nr = syscall_nr; syscall_get_arguments(current, regs, 0, sys_data->nb_args, (unsigned long *)&rec->args); + + if ((prog && !perf_call_bpf_enter(prog, regs, sys_data, rec)) || + hlist_empty(head)) { + perf_swevent_put_recursion_context(rctx); + return; + } + perf_trace_buf_submit(rec, size, rctx, sys_data->enter_event->event.type, 1, regs, head, NULL); @@ -633,11 +659,26 @@ static void perf_sysenter_disable(struct trace_event_call *call) mutex_unlock(&syscall_trace_lock); } +static int perf_call_bpf_exit(struct bpf_prog *prog, struct pt_regs *regs, + struct syscall_trace_exit *rec) { + struct syscall_tp_t { + unsigned long long regs; + unsigned long syscall_nr; + unsigned long ret; + } param; + + *(struct pt_regs **)¶m = regs; + param.syscall_nr = rec->nr; + param.ret = rec->ret; + return trace_call_bpf(prog, ¶m); +} + static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret) { struct syscall_metadata *sys_data; struct syscall_trace_exit *rec; struct hlist_head *head; + struct bpf_prog *prog; int syscall_nr; int rctx; int size; @@ -652,8 +693,9 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret) if (!sys_data) return; + prog = READ_ONCE(sys_data->exit_event->prog); head = this_cpu_ptr(sys_data->exit_event->perf_events); - if (hlist_empty(head)) + if (!prog && hlist_empty(head)) return; /* We can probably do that at build time */ @@ -666,6 +708,13 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret) rec->nr = syscall_nr; rec->ret = syscall_get_return_value(current, regs); + + if ((prog && !perf_call_bpf_exit(prog, regs, rec)) || + hlist_empty(head)) { + perf_swevent_put_recursion_context(rctx); + return; + } + perf_trace_buf_submit(rec, size, rctx, sys_data->exit_event->event.type, 1, regs, head, NULL); } -- cgit v1.2.3 From 4cc7b9544b9a904add353406ed1bacbf56f75c52 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Fri, 4 Aug 2017 22:02:19 -0700 Subject: bpf: devmap fix mutex in rcu critical section Originally we used a mutex to protect concurrent devmap update and delete operations from racing with netdev unregister notifier callbacks. The notifier hook is needed because we increment the netdev ref count when a dev is added to the devmap. This ensures the netdev reference is valid in the datapath. However, we don't want to block unregister events, hence the initial mutex and notifier handler. The concern was in the notifier hook we search the map for dev entries that hold a refcnt on the net device being torn down. But, in order to do this we require two steps, (i) dereference the netdev: dev = rcu_dereference(map[i]) (ii) test ifindex: dev->ifindex == removing_ifindex and then finally we can swap in the NULL dev in the map via an xchg operation, xchg(map[i], NULL) The danger here is a concurrent update could run a different xchg op concurrently leading us to replace the new dev with a NULL dev incorrectly. CPU 1 CPU 2 notifier hook bpf devmap update dev = rcu_dereference(map[i]) dev = rcu_dereference(map[i]) xchg(map[i]), new_dev); rcu_call(dev,...) xchg(map[i], NULL) The above flow would create the incorrect state with the dev reference in the update path being lost. To resolve this the original code used a mutex around the above block. However, updates, deletes, and lookups occur inside rcu critical sections so we can't use a mutex in this context safely. Fortunately, by writing slightly better code we can avoid the mutex altogether. If CPU 1 in the above example uses a cmpxchg and _only_ replaces the dev reference in the map when it is in fact the expected dev the race is removed completely. The two cases being illustrated here, first the race condition, CPU 1 CPU 2 notifier hook bpf devmap update dev = rcu_dereference(map[i]) dev = rcu_dereference(map[i]) xchg(map[i]), new_dev); rcu_call(dev,...) odev = cmpxchg(map[i], dev, NULL) Now we can test the cmpxchg return value, detect odev != dev and abort. Or in the good case, CPU 1 CPU 2 notifier hook bpf devmap update dev = rcu_dereference(map[i]) odev = cmpxchg(map[i], dev, NULL) [...] Now 'odev == dev' and we can do proper cleanup. And viola the original race we tried to solve with a mutex is corrected and the trace noted by Sasha below is resolved due to removal of the mutex. Note: When walking the devmap and removing dev references as needed we depend on the core to fail any calls to dev_get_by_index() using the ifindex of the device being removed. This way we do not race with the user while searching the devmap. Additionally, the mutex was also protecting list add/del/read on the list of maps in-use. This patch converts this to an RCU list and spinlock implementation. This protects the list from concurrent alloc/free operations. The notifier hook walks this list so it uses RCU read semantics. BUG: sleeping function called from invalid context at kernel/locking/mutex.c:747 in_atomic(): 1, irqs_disabled(): 0, pid: 16315, name: syz-executor1 1 lock held by syz-executor1/16315: #0: (rcu_read_lock){......}, at: [] map_delete_elem kernel/bpf/syscall.c:577 [inline] #0: (rcu_read_lock){......}, at: [] SYSC_bpf kernel/bpf/syscall.c:1427 [inline] #0: (rcu_read_lock){......}, at: [] SyS_bpf+0x1d32/0x4ba0 kernel/bpf/syscall.c:1388 Fixes: 2ddf71e23cc2 ("net: add notifier hooks for devmap bpf map") Reported-by: Sasha Levin Signed-off-by: Daniel Borkmann Signed-off-by: John Fastabend Signed-off-by: David S. Miller --- kernel/bpf/devmap.c | 48 +++++++++++++++++++++++++----------------------- 1 file changed, 25 insertions(+), 23 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index d439ee0eadb1..7192fb67d4de 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -40,11 +40,12 @@ * contain a reference to the net device and remove them. This is a two step * process (a) dereference the bpf_dtab_netdev object in netdev_map and (b) * check to see if the ifindex is the same as the net_device being removed. - * Unfortunately, the xchg() operations do not protect against this. To avoid - * potentially removing incorrect objects the dev_map_list_mutex protects - * conflicting netdev unregister and BPF syscall operations. Updates and - * deletes from a BPF program (done in rcu critical section) are blocked - * because of this mutex. + * When removing the dev a cmpxchg() is used to ensure the correct dev is + * removed, in the case of a concurrent update or delete operation it is + * possible that the initially referenced dev is no longer in the map. As the + * notifier hook walks the map we know that new dev references can not be + * added by the user because core infrastructure ensures dev_get_by_index() + * calls will fail at this point. */ #include #include @@ -68,7 +69,7 @@ struct bpf_dtab { struct list_head list; }; -static DEFINE_MUTEX(dev_map_list_mutex); +static DEFINE_SPINLOCK(dev_map_lock); static LIST_HEAD(dev_map_list); static struct bpf_map *dev_map_alloc(union bpf_attr *attr) @@ -128,9 +129,9 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) if (!dtab->netdev_map) goto free_dtab; - mutex_lock(&dev_map_list_mutex); - list_add_tail(&dtab->list, &dev_map_list); - mutex_unlock(&dev_map_list_mutex); + spin_lock(&dev_map_lock); + list_add_tail_rcu(&dtab->list, &dev_map_list); + spin_unlock(&dev_map_lock); return &dtab->map; free_dtab: @@ -169,7 +170,6 @@ static void dev_map_free(struct bpf_map *map) * at this point we we can still race with netdev notifier, hence the * lock. */ - mutex_lock(&dev_map_list_mutex); for (i = 0; i < dtab->map.max_entries; i++) { struct bpf_dtab_netdev *dev; @@ -184,8 +184,9 @@ static void dev_map_free(struct bpf_map *map) /* At this point bpf program is detached and all pending operations * _must_ be complete */ - list_del(&dtab->list); - mutex_unlock(&dev_map_list_mutex); + spin_lock(&dev_map_lock); + list_del_rcu(&dtab->list); + spin_unlock(&dev_map_lock); free_percpu(dtab->flush_needed); bpf_map_area_free(dtab->netdev_map); kfree(dtab); @@ -322,11 +323,9 @@ static int dev_map_delete_elem(struct bpf_map *map, void *key) * the driver tear down ensures all soft irqs are complete before * removing the net device in the case of dev_put equals zero. */ - mutex_lock(&dev_map_list_mutex); old_dev = xchg(&dtab->netdev_map[k], NULL); if (old_dev) call_rcu(&old_dev->rcu, __dev_map_entry_free); - mutex_unlock(&dev_map_list_mutex); return 0; } @@ -369,11 +368,9 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value, * Remembering the driver side flush operation will happen before the * net device is removed. */ - mutex_lock(&dev_map_list_mutex); old_dev = xchg(&dtab->netdev_map[i], dev); if (old_dev) call_rcu(&old_dev->rcu, __dev_map_entry_free); - mutex_unlock(&dev_map_list_mutex); return 0; } @@ -396,22 +393,27 @@ static int dev_map_notification(struct notifier_block *notifier, switch (event) { case NETDEV_UNREGISTER: - mutex_lock(&dev_map_list_mutex); - list_for_each_entry(dtab, &dev_map_list, list) { + /* This rcu_read_lock/unlock pair is needed because + * dev_map_list is an RCU list AND to ensure a delete + * operation does not free a netdev_map entry while we + * are comparing it against the netdev being unregistered. + */ + rcu_read_lock(); + list_for_each_entry_rcu(dtab, &dev_map_list, list) { for (i = 0; i < dtab->map.max_entries; i++) { - struct bpf_dtab_netdev *dev; + struct bpf_dtab_netdev *dev, *odev; - dev = dtab->netdev_map[i]; + dev = READ_ONCE(dtab->netdev_map[i]); if (!dev || dev->dev->ifindex != netdev->ifindex) continue; - dev = xchg(&dtab->netdev_map[i], NULL); - if (dev) + odev = cmpxchg(&dtab->netdev_map[i], dev, NULL); + if (dev == odev) call_rcu(&dev->rcu, __dev_map_entry_free); } } - mutex_unlock(&dev_map_list_mutex); + rcu_read_unlock(); break; default: break; -- cgit v1.2.3 From f1174f77b50c94eecaa658fdc56fa69b421de4b8 Mon Sep 17 00:00:00 2001 From: Edward Cree Date: Mon, 7 Aug 2017 15:26:19 +0100 Subject: bpf/verifier: rework value tracking Unifies adjusted and unadjusted register value types (e.g. FRAME_POINTER is now just a PTR_TO_STACK with zero offset). Tracks value alignment by means of tracking known & unknown bits. This also replaces the 'reg->imm' (leading zero bits) calculations for (what were) UNKNOWN_VALUEs. If pointer leaks are allowed, and adjust_ptr_min_max_vals returns -EACCES, treat the pointer as an unknown scalar and try again, because we might be able to conclude something about the result (e.g. pointer & 0x40 is either 0 or 0x40). Verifier hooks in the netronome/nfp driver were changed to match the new data structures. Signed-off-by: Edward Cree Signed-off-by: David S. Miller --- kernel/bpf/Makefile | 2 +- kernel/bpf/tnum.c | 164 +++++ kernel/bpf/verifier.c | 1780 +++++++++++++++++++++++++++---------------------- 3 files changed, 1139 insertions(+), 807 deletions(-) create mode 100644 kernel/bpf/tnum.c (limited to 'kernel') diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 48e92705be59..2f0bcda40e90 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -1,6 +1,6 @@ obj-y := core.o -obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o +obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o ifeq ($(CONFIG_NET),y) obj-$(CONFIG_BPF_SYSCALL) += devmap.o diff --git a/kernel/bpf/tnum.c b/kernel/bpf/tnum.c new file mode 100644 index 000000000000..92eeeb1974a2 --- /dev/null +++ b/kernel/bpf/tnum.c @@ -0,0 +1,164 @@ +/* tnum: tracked (or tristate) numbers + * + * A tnum tracks knowledge about the bits of a value. Each bit can be either + * known (0 or 1), or unknown (x). Arithmetic operations on tnums will + * propagate the unknown bits such that the tnum result represents all the + * possible results for possible values of the operands. + */ +#include +#include + +#define TNUM(_v, _m) (struct tnum){.value = _v, .mask = _m} +/* A completely unknown value */ +const struct tnum tnum_unknown = { .value = 0, .mask = -1 }; + +struct tnum tnum_const(u64 value) +{ + return TNUM(value, 0); +} + +struct tnum tnum_lshift(struct tnum a, u8 shift) +{ + return TNUM(a.value << shift, a.mask << shift); +} + +struct tnum tnum_rshift(struct tnum a, u8 shift) +{ + return TNUM(a.value >> shift, a.mask >> shift); +} + +struct tnum tnum_add(struct tnum a, struct tnum b) +{ + u64 sm, sv, sigma, chi, mu; + + sm = a.mask + b.mask; + sv = a.value + b.value; + sigma = sm + sv; + chi = sigma ^ sv; + mu = chi | a.mask | b.mask; + return TNUM(sv & ~mu, mu); +} + +struct tnum tnum_sub(struct tnum a, struct tnum b) +{ + u64 dv, alpha, beta, chi, mu; + + dv = a.value - b.value; + alpha = dv + a.mask; + beta = dv - b.mask; + chi = alpha ^ beta; + mu = chi | a.mask | b.mask; + return TNUM(dv & ~mu, mu); +} + +struct tnum tnum_and(struct tnum a, struct tnum b) +{ + u64 alpha, beta, v; + + alpha = a.value | a.mask; + beta = b.value | b.mask; + v = a.value & b.value; + return TNUM(v, alpha & beta & ~v); +} + +struct tnum tnum_or(struct tnum a, struct tnum b) +{ + u64 v, mu; + + v = a.value | b.value; + mu = a.mask | b.mask; + return TNUM(v, mu & ~v); +} + +struct tnum tnum_xor(struct tnum a, struct tnum b) +{ + u64 v, mu; + + v = a.value ^ b.value; + mu = a.mask | b.mask; + return TNUM(v & ~mu, mu); +} + +/* half-multiply add: acc += (unknown * mask * value). + * An intermediate step in the multiply algorithm. + */ +static struct tnum hma(struct tnum acc, u64 value, u64 mask) +{ + while (mask) { + if (mask & 1) + acc = tnum_add(acc, TNUM(0, value)); + mask >>= 1; + value <<= 1; + } + return acc; +} + +struct tnum tnum_mul(struct tnum a, struct tnum b) +{ + struct tnum acc; + u64 pi; + + pi = a.value * b.value; + acc = hma(TNUM(pi, 0), a.mask, b.mask | b.value); + return hma(acc, b.mask, a.value); +} + +/* Note that if a and b disagree - i.e. one has a 'known 1' where the other has + * a 'known 0' - this will return a 'known 1' for that bit. + */ +struct tnum tnum_intersect(struct tnum a, struct tnum b) +{ + u64 v, mu; + + v = a.value | b.value; + mu = a.mask & b.mask; + return TNUM(v & ~mu, mu); +} + +struct tnum tnum_cast(struct tnum a, u8 size) +{ + a.value &= (1ULL << (size * 8)) - 1; + a.mask &= (1ULL << (size * 8)) - 1; + return a; +} + +bool tnum_is_aligned(struct tnum a, u64 size) +{ + if (!size) + return true; + return !((a.value | a.mask) & (size - 1)); +} + +bool tnum_in(struct tnum a, struct tnum b) +{ + if (b.mask & ~a.mask) + return false; + b.value &= ~a.mask; + return a.value == b.value; +} + +int tnum_strn(char *str, size_t size, struct tnum a) +{ + return snprintf(str, size, "(%#llx; %#llx)", a.value, a.mask); +} +EXPORT_SYMBOL_GPL(tnum_strn); + +int tnum_sbin(char *str, size_t size, struct tnum a) +{ + size_t n; + + for (n = 64; n; n--) { + if (n < size) { + if (a.mask & 1) + str[n - 1] = 'x'; + else if (a.value & 1) + str[n - 1] = '1'; + else + str[n - 1] = '0'; + } + a.mask >>= 1; + a.value >>= 1; + } + str[min(size - 1, (size_t)64)] = 0; + return 64; +} diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f6e8b3887eab..c3f88b466c30 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -61,12 +61,12 @@ * (and -20 constant is saved for further stack bounds checking). * Meaning that this reg is a pointer to stack plus known immediate constant. * - * Most of the time the registers have UNKNOWN_VALUE type, which + * Most of the time the registers have SCALAR_VALUE type, which * means the register has some value, but it's not a valid pointer. - * (like pointer plus pointer becomes UNKNOWN_VALUE type) + * (like pointer plus pointer becomes SCALAR_VALUE type) * * When verifier sees load or store instructions the type of base register - * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, FRAME_PTR. These are three pointer + * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK. These are three pointer * types recognized by check_mem_access() function. * * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value' @@ -180,15 +180,12 @@ static __printf(1, 2) void verbose(const char *fmt, ...) /* string representation of 'enum bpf_reg_type' */ static const char * const reg_type_str[] = { [NOT_INIT] = "?", - [UNKNOWN_VALUE] = "inv", + [SCALAR_VALUE] = "inv", [PTR_TO_CTX] = "ctx", [CONST_PTR_TO_MAP] = "map_ptr", [PTR_TO_MAP_VALUE] = "map_value", [PTR_TO_MAP_VALUE_OR_NULL] = "map_value_or_null", - [PTR_TO_MAP_VALUE_ADJ] = "map_value_adj", - [FRAME_PTR] = "fp", [PTR_TO_STACK] = "fp", - [CONST_IMM] = "imm", [PTR_TO_PACKET] = "pkt", [PTR_TO_PACKET_END] = "pkt_end", }; @@ -221,32 +218,36 @@ static void print_verifier_state(struct bpf_verifier_state *state) if (t == NOT_INIT) continue; verbose(" R%d=%s", i, reg_type_str[t]); - if (t == CONST_IMM || t == PTR_TO_STACK) - verbose("%lld", reg->imm); - else if (t == PTR_TO_PACKET) - verbose("(id=%d,off=%d,r=%d)", - reg->id, reg->off, reg->range); - else if (t == UNKNOWN_VALUE && reg->imm) - verbose("%lld", reg->imm); - else if (t == CONST_PTR_TO_MAP || t == PTR_TO_MAP_VALUE || - t == PTR_TO_MAP_VALUE_OR_NULL || - t == PTR_TO_MAP_VALUE_ADJ) - verbose("(ks=%d,vs=%d,id=%u)", - reg->map_ptr->key_size, - reg->map_ptr->value_size, - reg->id); - if (reg->min_value != BPF_REGISTER_MIN_RANGE) - verbose(",min_value=%lld", - (long long)reg->min_value); - if (reg->max_value != BPF_REGISTER_MAX_RANGE) - verbose(",max_value=%llu", - (unsigned long long)reg->max_value); - if (reg->min_align) - verbose(",min_align=%u", reg->min_align); - if (reg->aux_off) - verbose(",aux_off=%u", reg->aux_off); - if (reg->aux_off_align) - verbose(",aux_off_align=%u", reg->aux_off_align); + if ((t == SCALAR_VALUE || t == PTR_TO_STACK) && + tnum_is_const(reg->var_off)) { + /* reg->off should be 0 for SCALAR_VALUE */ + verbose("%lld", reg->var_off.value + reg->off); + } else { + verbose("(id=%d", reg->id); + if (t != SCALAR_VALUE) + verbose(",off=%d", reg->off); + if (t == PTR_TO_PACKET) + verbose(",r=%d", reg->range); + else if (t == CONST_PTR_TO_MAP || + t == PTR_TO_MAP_VALUE || + t == PTR_TO_MAP_VALUE_OR_NULL) + verbose(",ks=%d,vs=%d", + reg->map_ptr->key_size, + reg->map_ptr->value_size); + if (reg->min_value != BPF_REGISTER_MIN_RANGE) + verbose(",min_value=%lld", + (long long)reg->min_value); + if (reg->max_value != BPF_REGISTER_MAX_RANGE) + verbose(",max_value=%llu", + (unsigned long long)reg->max_value); + if (!tnum_is_unknown(reg->var_off)) { + char tn_buf[48]; + + tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); + verbose(",var_off=%s", tn_buf); + } + verbose(")"); + } } for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) { if (state->stack_slot_type[i] == STACK_SPILL) @@ -463,14 +464,69 @@ static const int caller_saved[CALLER_SAVED_REGS] = { BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5 }; -static void mark_reg_not_init(struct bpf_reg_state *regs, u32 regno) +static void __mark_reg_not_init(struct bpf_reg_state *reg); + +/* Mark the 'variable offset' part of a register as zero. This should be + * used only on registers holding a pointer type. + */ +static void __mark_reg_known_zero(struct bpf_reg_state *reg) { - BUG_ON(regno >= MAX_BPF_REG); + reg->var_off = tnum_const(0); + reg->min_value = 0; + reg->max_value = 0; +} - memset(®s[regno], 0, sizeof(regs[regno])); - regs[regno].type = NOT_INIT; - regs[regno].min_value = BPF_REGISTER_MIN_RANGE; - regs[regno].max_value = BPF_REGISTER_MAX_RANGE; +static void mark_reg_known_zero(struct bpf_reg_state *regs, u32 regno) +{ + if (WARN_ON(regno >= MAX_BPF_REG)) { + verbose("mark_reg_known_zero(regs, %u)\n", regno); + /* Something bad happened, let's kill all regs */ + for (regno = 0; regno < MAX_BPF_REG; regno++) + __mark_reg_not_init(regs + regno); + return; + } + __mark_reg_known_zero(regs + regno); +} + +/* Mark a register as having a completely unknown (scalar) value. */ +static void __mark_reg_unknown(struct bpf_reg_state *reg) +{ + reg->type = SCALAR_VALUE; + reg->id = 0; + reg->off = 0; + reg->var_off = tnum_unknown; + reg->min_value = BPF_REGISTER_MIN_RANGE; + reg->max_value = BPF_REGISTER_MAX_RANGE; +} + +static void mark_reg_unknown(struct bpf_reg_state *regs, u32 regno) +{ + if (WARN_ON(regno >= MAX_BPF_REG)) { + verbose("mark_reg_unknown(regs, %u)\n", regno); + /* Something bad happened, let's kill all regs */ + for (regno = 0; regno < MAX_BPF_REG; regno++) + __mark_reg_not_init(regs + regno); + return; + } + __mark_reg_unknown(regs + regno); +} + +static void __mark_reg_not_init(struct bpf_reg_state *reg) +{ + __mark_reg_unknown(reg); + reg->type = NOT_INIT; +} + +static void mark_reg_not_init(struct bpf_reg_state *regs, u32 regno) +{ + if (WARN_ON(regno >= MAX_BPF_REG)) { + verbose("mark_reg_not_init(regs, %u)\n", regno); + /* Something bad happened, let's kill all regs */ + for (regno = 0; regno < MAX_BPF_REG; regno++) + __mark_reg_not_init(regs + regno); + return; + } + __mark_reg_not_init(regs + regno); } static void init_reg_state(struct bpf_reg_state *regs) @@ -481,23 +537,12 @@ static void init_reg_state(struct bpf_reg_state *regs) mark_reg_not_init(regs, i); /* frame pointer */ - regs[BPF_REG_FP].type = FRAME_PTR; + regs[BPF_REG_FP].type = PTR_TO_STACK; + mark_reg_known_zero(regs, BPF_REG_FP); /* 1st arg to a function */ regs[BPF_REG_1].type = PTR_TO_CTX; -} - -static void __mark_reg_unknown_value(struct bpf_reg_state *regs, u32 regno) -{ - regs[regno].type = UNKNOWN_VALUE; - regs[regno].id = 0; - regs[regno].imm = 0; -} - -static void mark_reg_unknown_value(struct bpf_reg_state *regs, u32 regno) -{ - BUG_ON(regno >= MAX_BPF_REG); - __mark_reg_unknown_value(regs, regno); + mark_reg_known_zero(regs, BPF_REG_1); } static void reset_reg_range_values(struct bpf_reg_state *regs, u32 regno) @@ -505,14 +550,6 @@ static void reset_reg_range_values(struct bpf_reg_state *regs, u32 regno) regs[regno].min_value = BPF_REGISTER_MIN_RANGE; regs[regno].max_value = BPF_REGISTER_MAX_RANGE; regs[regno].value_from_signed = false; - regs[regno].min_align = 0; -} - -static void mark_reg_unknown_value_and_range(struct bpf_reg_state *regs, - u32 regno) -{ - mark_reg_unknown_value(regs, regno); - reset_reg_range_values(regs, regno); } enum reg_arg_type { @@ -542,7 +579,7 @@ static int check_reg_arg(struct bpf_reg_state *regs, u32 regno, return -EACCES; } if (t == DST_OP) - mark_reg_unknown_value(regs, regno); + mark_reg_unknown(regs, regno); } return 0; } @@ -552,12 +589,10 @@ static bool is_spillable_regtype(enum bpf_reg_type type) switch (type) { case PTR_TO_MAP_VALUE: case PTR_TO_MAP_VALUE_OR_NULL: - case PTR_TO_MAP_VALUE_ADJ: case PTR_TO_STACK: case PTR_TO_CTX: case PTR_TO_PACKET: case PTR_TO_PACKET_END: - case FRAME_PTR: case CONST_PTR_TO_MAP: return true; default: @@ -637,14 +672,13 @@ static int check_stack_read(struct bpf_verifier_state *state, int off, int size, } if (value_regno >= 0) /* have read misc data from the stack */ - mark_reg_unknown_value_and_range(state->regs, - value_regno); + mark_reg_unknown(state->regs, value_regno); return 0; } } /* check read/write into map element returned by bpf_map_lookup_elem() */ -static int check_map_access(struct bpf_verifier_env *env, u32 regno, int off, +static int __check_map_access(struct bpf_verifier_env *env, u32 regno, int off, int size) { struct bpf_map *map = env->cur_state.regs[regno].map_ptr; @@ -657,22 +691,25 @@ static int check_map_access(struct bpf_verifier_env *env, u32 regno, int off, return 0; } -/* check read/write into an adjusted map element */ -static int check_map_access_adj(struct bpf_verifier_env *env, u32 regno, +/* check read/write into a map element with possible variable offset */ +static int check_map_access(struct bpf_verifier_env *env, u32 regno, int off, int size) { struct bpf_verifier_state *state = &env->cur_state; struct bpf_reg_state *reg = &state->regs[regno]; int err; - /* We adjusted the register to this map value, so we - * need to change off and size to min_value and max_value - * respectively to make sure our theoretical access will be - * safe. + /* We may have adjusted the register to this map value, so we + * need to try adding each of min_value and max_value to off + * to make sure our theoretical access will be safe. */ if (log_level) print_verifier_state(state); - env->varlen_map_value_access = true; + /* If the offset is variable, we will need to be stricter in state + * pruning from now on. + */ + if (!tnum_is_const(reg->var_off)) + env->varlen_map_value_access = true; /* The minimum value is only important with signed * comparisons where we can't assume the floor of a * value is 0. If we are using signed variables for our @@ -684,10 +721,9 @@ static int check_map_access_adj(struct bpf_verifier_env *env, u32 regno, regno); return -EACCES; } - err = check_map_access(env, regno, reg->min_value + off, size); + err = __check_map_access(env, regno, reg->min_value + off, size); if (err) { - verbose("R%d min value is outside of the array range\n", - regno); + verbose("R%d min value is outside of the array range\n", regno); return err; } @@ -699,7 +735,10 @@ static int check_map_access_adj(struct bpf_verifier_env *env, u32 regno, regno); return -EACCES; } - return check_map_access(env, regno, reg->max_value + off, size); + err = __check_map_access(env, regno, reg->max_value + off, size); + if (err) + verbose("R%d max value is outside of the array range\n", regno); + return err; } #define MAX_PACKET_OFF 0xffff @@ -729,14 +768,13 @@ static bool may_access_direct_pkt_data(struct bpf_verifier_env *env, } } -static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, - int size) +static int __check_packet_access(struct bpf_verifier_env *env, u32 regno, + int off, int size) { struct bpf_reg_state *regs = env->cur_state.regs; struct bpf_reg_state *reg = ®s[regno]; - off += reg->off; - if (off < 0 || size <= 0 || off + size > reg->range) { + if (off < 0 || size <= 0 || (u64)off + size > reg->range) { verbose("invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n", off, size, regno, reg->id, reg->off, reg->range); return -EACCES; @@ -744,7 +782,35 @@ static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, return 0; } -/* check access to 'struct bpf_context' fields */ +static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, + int size) +{ + struct bpf_reg_state *regs = env->cur_state.regs; + struct bpf_reg_state *reg = ®s[regno]; + int err; + + /* We may have added a variable offset to the packet pointer; but any + * reg->range we have comes after that. We are only checking the fixed + * offset. + */ + + /* We don't allow negative numbers, because we aren't tracking enough + * detail to prove they're safe. + */ + if (reg->min_value < 0) { + verbose("R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", + regno); + return -EACCES; + } + err = __check_packet_access(env, regno, off, size); + if (err) { + verbose("R%d offset is outside of the packet\n", regno); + return err; + } + return err; +} + +/* check access to 'struct bpf_context' fields. Supports fixed offsets only */ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size, enum bpf_access_type t, enum bpf_reg_type *reg_type) { @@ -784,13 +850,7 @@ static bool __is_pointer_value(bool allow_ptr_leaks, if (allow_ptr_leaks) return false; - switch (reg->type) { - case UNKNOWN_VALUE: - case CONST_IMM: - return false; - default: - return true; - } + return reg->type != SCALAR_VALUE; } static bool is_pointer_value(struct bpf_verifier_env *env, int regno) @@ -801,23 +861,13 @@ static bool is_pointer_value(struct bpf_verifier_env *env, int regno) static int check_pkt_ptr_alignment(const struct bpf_reg_state *reg, int off, int size, bool strict) { + struct tnum reg_off; int ip_align; - int reg_off; /* Byte size accesses are always allowed. */ if (!strict || size == 1) return 0; - reg_off = reg->off; - if (reg->id) { - if (reg->aux_off_align % size) { - verbose("Packet access is only %u byte aligned, %d byte access not allowed\n", - reg->aux_off_align, size); - return -EACCES; - } - reg_off += reg->aux_off; - } - /* For platforms that do not have a Kconfig enabling * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of * NET_IP_ALIGN is universally set to '2'. And on platforms @@ -827,20 +877,37 @@ static int check_pkt_ptr_alignment(const struct bpf_reg_state *reg, * unconditional IP align value of '2'. */ ip_align = 2; - if ((ip_align + reg_off + off) % size != 0) { - verbose("misaligned packet access off %d+%d+%d size %d\n", - ip_align, reg_off, off, size); + + reg_off = tnum_add(reg->var_off, tnum_const(ip_align + reg->off + off)); + if (!tnum_is_aligned(reg_off, size)) { + char tn_buf[48]; + + tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); + verbose("misaligned packet access off %d+%s+%d+%d size %d\n", + ip_align, tn_buf, reg->off, off, size); return -EACCES; } return 0; } -static int check_val_ptr_alignment(const struct bpf_reg_state *reg, - int size, bool strict) +static int check_generic_ptr_alignment(const struct bpf_reg_state *reg, + const char *pointer_desc, + int off, int size, bool strict) { - if (strict && size != 1) { - verbose("Unknown alignment. Only byte-sized access allowed in value access.\n"); + struct tnum reg_off; + + /* Byte size accesses are always allowed. */ + if (!strict || size == 1) + return 0; + + reg_off = tnum_add(reg->var_off, tnum_const(reg->off + off)); + if (!tnum_is_aligned(reg_off, size)) { + char tn_buf[48]; + + tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); + verbose("misaligned %saccess off %s+%d+%d size %d\n", + pointer_desc, tn_buf, reg->off, off, size); return -EACCES; } @@ -852,21 +919,25 @@ static int check_ptr_alignment(struct bpf_verifier_env *env, int off, int size) { bool strict = env->strict_alignment; + const char *pointer_desc = ""; switch (reg->type) { case PTR_TO_PACKET: + /* special case, because of NET_IP_ALIGN */ return check_pkt_ptr_alignment(reg, off, size, strict); - case PTR_TO_MAP_VALUE_ADJ: - return check_val_ptr_alignment(reg, size, strict); + case PTR_TO_MAP_VALUE: + pointer_desc = "value "; + break; + case PTR_TO_CTX: + pointer_desc = "context "; + break; + case PTR_TO_STACK: + pointer_desc = "stack "; + break; default: - if (off % size != 0) { - verbose("misaligned access off %d size %d\n", - off, size); - return -EACCES; - } - - return 0; + break; } + return check_generic_ptr_alignment(reg, pointer_desc, off, size, strict); } /* check whether memory at (regno + off) is accessible for t = (read | write) @@ -883,52 +954,79 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn struct bpf_reg_state *reg = &state->regs[regno]; int size, err = 0; - if (reg->type == PTR_TO_STACK) - off += reg->imm; - size = bpf_size_to_bytes(bpf_size); if (size < 0) return size; + /* alignment checks will add in reg->off themselves */ err = check_ptr_alignment(env, reg, off, size); if (err) return err; - if (reg->type == PTR_TO_MAP_VALUE || - reg->type == PTR_TO_MAP_VALUE_ADJ) { + /* for access checks, reg->off is just part of off */ + off += reg->off; + + if (reg->type == PTR_TO_MAP_VALUE) { if (t == BPF_WRITE && value_regno >= 0 && is_pointer_value(env, value_regno)) { verbose("R%d leaks addr into map\n", value_regno); return -EACCES; } - if (reg->type == PTR_TO_MAP_VALUE_ADJ) - err = check_map_access_adj(env, regno, off, size); - else - err = check_map_access(env, regno, off, size); + err = check_map_access(env, regno, off, size); if (!err && t == BPF_READ && value_regno >= 0) - mark_reg_unknown_value_and_range(state->regs, - value_regno); + mark_reg_unknown(state->regs, value_regno); } else if (reg->type == PTR_TO_CTX) { - enum bpf_reg_type reg_type = UNKNOWN_VALUE; + enum bpf_reg_type reg_type = SCALAR_VALUE; if (t == BPF_WRITE && value_regno >= 0 && is_pointer_value(env, value_regno)) { verbose("R%d leaks addr into ctx\n", value_regno); return -EACCES; } + /* ctx accesses must be at a fixed offset, so that we can + * determine what type of data were returned. + */ + if (!tnum_is_const(reg->var_off)) { + char tn_buf[48]; + + tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); + verbose("variable ctx access var_off=%s off=%d size=%d", + tn_buf, off, size); + return -EACCES; + } + off += reg->var_off.value; err = check_ctx_access(env, insn_idx, off, size, t, ®_type); if (!err && t == BPF_READ && value_regno >= 0) { - mark_reg_unknown_value_and_range(state->regs, - value_regno); - /* note that reg.[id|off|range] == 0 */ + /* ctx access returns either a scalar, or a + * PTR_TO_PACKET[_END]. In the latter case, we know + * the offset is zero. + */ + if (reg_type == SCALAR_VALUE) + mark_reg_unknown(state->regs, value_regno); + else + mark_reg_known_zero(state->regs, value_regno); + state->regs[value_regno].id = 0; + state->regs[value_regno].off = 0; + state->regs[value_regno].range = 0; state->regs[value_regno].type = reg_type; - state->regs[value_regno].aux_off = 0; - state->regs[value_regno].aux_off_align = 0; } - } else if (reg->type == FRAME_PTR || reg->type == PTR_TO_STACK) { + } else if (reg->type == PTR_TO_STACK) { + /* stack accesses must be at a fixed offset, so that we can + * determine what type of data were returned. + * See check_stack_read(). + */ + if (!tnum_is_const(reg->var_off)) { + char tn_buf[48]; + + tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); + verbose("variable stack access var_off=%s off=%d size=%d", + tn_buf, off, size); + return -EACCES; + } + off += reg->var_off.value; if (off >= 0 || off < -MAX_BPF_STACK) { verbose("invalid stack off=%d size=%d\n", off, size); return -EACCES; @@ -948,7 +1046,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn } else { err = check_stack_read(state, off, size, value_regno); } - } else if (state->regs[regno].type == PTR_TO_PACKET) { + } else if (reg->type == PTR_TO_PACKET) { if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) { verbose("cannot write into packet\n"); return -EACCES; @@ -960,21 +1058,24 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn } err = check_packet_access(env, regno, off, size); if (!err && t == BPF_READ && value_regno >= 0) - mark_reg_unknown_value_and_range(state->regs, - value_regno); + mark_reg_unknown(state->regs, value_regno); } else { verbose("R%d invalid mem access '%s'\n", regno, reg_type_str[reg->type]); return -EACCES; } - if (!err && size <= 2 && value_regno >= 0 && env->allow_ptr_leaks && - state->regs[value_regno].type == UNKNOWN_VALUE) { - /* 1 or 2 byte load zero-extends, determine the number of - * zero upper bits. Not doing it fo 4 byte load, since - * such values cannot be added to ptr_to_packet anyway. - */ - state->regs[value_regno].imm = 64 - size * 8; + if (!err && size < BPF_REG_SIZE && value_regno >= 0 && t == BPF_READ && + state->regs[value_regno].type == SCALAR_VALUE) { + /* b/h/w load zero-extends, mark upper bits as known 0 */ + state->regs[value_regno].var_off = tnum_cast( + state->regs[value_regno].var_off, size); + /* sign bit is known zero, so we can bound the value */ + state->regs[value_regno].min_value = 0; + state->regs[value_regno].max_value = min_t(u64, + state->regs[value_regno].var_off.value | + state->regs[value_regno].var_off.mask, + BPF_REGISTER_MAX_RANGE); } return err; } @@ -1016,9 +1117,17 @@ static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_ins BPF_SIZE(insn->code), BPF_WRITE, -1); } +/* Does this register contain a constant zero? */ +static bool register_is_null(struct bpf_reg_state reg) +{ + return reg.type == SCALAR_VALUE && tnum_equals_const(reg.var_off, 0); +} + /* when register 'regno' is passed into function that will read 'access_size' * bytes from that pointer, make sure that it's within stack boundary - * and all elements of stack are initialized + * and all elements of stack are initialized. + * Unlike most pointer bounds-checking functions, this one doesn't take an + * 'off' argument, so it has to add in reg->off itself. */ static int check_stack_boundary(struct bpf_verifier_env *env, int regno, int access_size, bool zero_size_allowed, @@ -1029,9 +1138,9 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno, int off, i; if (regs[regno].type != PTR_TO_STACK) { + /* Allow zero-byte read from NULL, regardless of pointer type */ if (zero_size_allowed && access_size == 0 && - regs[regno].type == CONST_IMM && - regs[regno].imm == 0) + register_is_null(regs[regno])) return 0; verbose("R%d type=%s expected=%s\n", regno, @@ -1040,7 +1149,15 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno, return -EACCES; } - off = regs[regno].imm; + /* Only allow fixed-offset stack reads */ + if (!tnum_is_const(regs[regno].var_off)) { + char tn_buf[48]; + + tnum_strn(tn_buf, sizeof(tn_buf), regs[regno].var_off); + verbose("invalid variable stack read R%d var_off=%s\n", + regno, tn_buf); + } + off = regs[regno].off + regs[regno].var_off.value; if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 || access_size <= 0) { verbose("invalid stack type R%d off=%d access_size=%d\n", @@ -1071,16 +1188,14 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, int access_size, bool zero_size_allowed, struct bpf_call_arg_meta *meta) { - struct bpf_reg_state *regs = env->cur_state.regs; + struct bpf_reg_state *regs = env->cur_state.regs, *reg = ®s[regno]; - switch (regs[regno].type) { + switch (reg->type) { case PTR_TO_PACKET: - return check_packet_access(env, regno, 0, access_size); + return check_packet_access(env, regno, reg->off, access_size); case PTR_TO_MAP_VALUE: - return check_map_access(env, regno, 0, access_size); - case PTR_TO_MAP_VALUE_ADJ: - return check_map_access_adj(env, regno, 0, access_size); - default: /* const_imm|ptr_to_stack or invalid ptr */ + return check_map_access(env, regno, reg->off, access_size); + default: /* scalar_value|ptr_to_stack or invalid ptr */ return check_stack_boundary(env, regno, access_size, zero_size_allowed, meta); } @@ -1123,11 +1238,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, goto err_type; } else if (arg_type == ARG_CONST_SIZE || arg_type == ARG_CONST_SIZE_OR_ZERO) { - expected_type = CONST_IMM; - /* One exception. Allow UNKNOWN_VALUE registers when the - * boundaries are known and don't cause unsafe memory accesses - */ - if (type != UNKNOWN_VALUE && type != expected_type) + expected_type = SCALAR_VALUE; + if (type != expected_type) goto err_type; } else if (arg_type == ARG_CONST_MAP_PTR) { expected_type = CONST_PTR_TO_MAP; @@ -1141,13 +1253,13 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, arg_type == ARG_PTR_TO_UNINIT_MEM) { expected_type = PTR_TO_STACK; /* One exception here. In case function allows for NULL to be - * passed in as argument, it's a CONST_IMM type. Final test + * passed in as argument, it's a SCALAR_VALUE type. Final test * happens during stack boundary checking. */ - if (type == CONST_IMM && reg->imm == 0) + if (register_is_null(*reg)) /* final test in check_stack_boundary() */; else if (type != PTR_TO_PACKET && type != PTR_TO_MAP_VALUE && - type != PTR_TO_MAP_VALUE_ADJ && type != expected_type) + type != expected_type) goto err_type; meta->raw_mode = arg_type == ARG_PTR_TO_UNINIT_MEM; } else { @@ -1173,7 +1285,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, return -EACCES; } if (type == PTR_TO_PACKET) - err = check_packet_access(env, regno, 0, + err = check_packet_access(env, regno, reg->off, meta->map_ptr->key_size); else err = check_stack_boundary(env, regno, @@ -1189,7 +1301,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, return -EACCES; } if (type == PTR_TO_PACKET) - err = check_packet_access(env, regno, 0, + err = check_packet_access(env, regno, reg->off, meta->map_ptr->value_size); else err = check_stack_boundary(env, regno, @@ -1209,10 +1321,11 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, return -EACCES; } - /* If the register is UNKNOWN_VALUE, the access check happens - * using its boundaries. Otherwise, just use its imm + /* The register is SCALAR_VALUE; the access check + * happens using its boundaries. */ - if (type == UNKNOWN_VALUE) { + + if (!tnum_is_const(reg->var_off)) /* For unprivileged variable accesses, disable raw * mode so that the program is required to * initialize all the memory that the helper could @@ -1220,35 +1333,28 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, */ meta = NULL; - if (reg->min_value < 0) { - verbose("R%d min value is negative, either use unsigned or 'var &= const'\n", - regno); - return -EACCES; - } - - if (reg->min_value == 0) { - err = check_helper_mem_access(env, regno - 1, 0, - zero_size_allowed, - meta); - if (err) - return err; - } + if (reg->min_value < 0) { + verbose("R%d min value is negative, either use unsigned or 'var &= const'\n", + regno); + return -EACCES; + } - if (reg->max_value == BPF_REGISTER_MAX_RANGE) { - verbose("R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n", - regno); - return -EACCES; - } - err = check_helper_mem_access(env, regno - 1, - reg->max_value, - zero_size_allowed, meta); + if (reg->min_value == 0) { + err = check_helper_mem_access(env, regno - 1, 0, + zero_size_allowed, + meta); if (err) return err; - } else { - /* register is CONST_IMM */ - err = check_helper_mem_access(env, regno - 1, reg->imm, - zero_size_allowed, meta); } + + if (reg->max_value == BPF_REGISTER_MAX_RANGE) { + verbose("R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n", + regno); + return -EACCES; + } + err = check_helper_mem_access(env, regno - 1, + reg->max_value, + zero_size_allowed, meta); } return err; @@ -1352,6 +1458,9 @@ static int check_raw_mode(const struct bpf_func_proto *fn) return count > 1 ? -EINVAL : 0; } +/* Packet data might have moved, any old PTR_TO_PACKET[_END] are now invalid, + * so turn them into unknown SCALAR_VALUE. + */ static void clear_all_pkt_pointers(struct bpf_verifier_env *env) { struct bpf_verifier_state *state = &env->cur_state; @@ -1361,7 +1470,7 @@ static void clear_all_pkt_pointers(struct bpf_verifier_env *env) for (i = 0; i < MAX_BPF_REG; i++) if (regs[i].type == PTR_TO_PACKET || regs[i].type == PTR_TO_PACKET_END) - mark_reg_unknown_value(regs, i); + mark_reg_unknown(regs, i); for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) { if (state->stack_slot_type[i] != STACK_SPILL) @@ -1370,8 +1479,7 @@ static void clear_all_pkt_pointers(struct bpf_verifier_env *env) if (reg->type != PTR_TO_PACKET && reg->type != PTR_TO_PACKET_END) continue; - __mark_reg_unknown_value(state->spilled_regs, - i / BPF_REG_SIZE); + __mark_reg_unknown(reg); } } @@ -1451,14 +1559,17 @@ static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx) /* update return register */ if (fn->ret_type == RET_INTEGER) { - regs[BPF_REG_0].type = UNKNOWN_VALUE; + /* sets type to SCALAR_VALUE */ + mark_reg_unknown(regs, BPF_REG_0); } else if (fn->ret_type == RET_VOID) { regs[BPF_REG_0].type = NOT_INIT; } else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL) { struct bpf_insn_aux_data *insn_aux; regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL; - regs[BPF_REG_0].max_value = regs[BPF_REG_0].min_value = 0; + /* There is no offset yet applied, variable or fixed */ + mark_reg_known_zero(regs, BPF_REG_0); + regs[BPF_REG_0].off = 0; /* remember map_ptr, so that check_map_access() * can check 'value_size' boundary of memory access * to map element returned from bpf_map_lookup_elem() @@ -1489,456 +1600,337 @@ static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx) return 0; } -static int check_packet_ptr_add(struct bpf_verifier_env *env, - struct bpf_insn *insn) +static void check_reg_overflow(struct bpf_reg_state *reg) { - struct bpf_reg_state *regs = env->cur_state.regs; - struct bpf_reg_state *dst_reg = ®s[insn->dst_reg]; - struct bpf_reg_state *src_reg = ®s[insn->src_reg]; - struct bpf_reg_state tmp_reg; - s32 imm; - - if (BPF_SRC(insn->code) == BPF_K) { - /* pkt_ptr += imm */ - imm = insn->imm; - -add_imm: - if (imm < 0) { - verbose("addition of negative constant to packet pointer is not allowed\n"); - return -EACCES; - } - if (imm >= MAX_PACKET_OFF || - imm + dst_reg->off >= MAX_PACKET_OFF) { - verbose("constant %d is too large to add to packet pointer\n", - imm); - return -EACCES; - } - /* a constant was added to pkt_ptr. - * Remember it while keeping the same 'id' - */ - dst_reg->off += imm; - } else { - bool had_id; - - if (src_reg->type == PTR_TO_PACKET) { - /* R6=pkt(id=0,off=0,r=62) R7=imm22; r7 += r6 */ - tmp_reg = *dst_reg; /* save r7 state */ - *dst_reg = *src_reg; /* copy pkt_ptr state r6 into r7 */ - src_reg = &tmp_reg; /* pretend it's src_reg state */ - /* if the checks below reject it, the copy won't matter, - * since we're rejecting the whole program. If all ok, - * then imm22 state will be added to r7 - * and r7 will be pkt(id=0,off=22,r=62) while - * r6 will stay as pkt(id=0,off=0,r=62) - */ - } - - if (src_reg->type == CONST_IMM) { - /* pkt_ptr += reg where reg is known constant */ - imm = src_reg->imm; - goto add_imm; - } - /* disallow pkt_ptr += reg - * if reg is not uknown_value with guaranteed zero upper bits - * otherwise pkt_ptr may overflow and addition will become - * subtraction which is not allowed - */ - if (src_reg->type != UNKNOWN_VALUE) { - verbose("cannot add '%s' to ptr_to_packet\n", - reg_type_str[src_reg->type]); - return -EACCES; - } - if (src_reg->imm < 48) { - verbose("cannot add integer value with %lld upper zero bits to ptr_to_packet\n", - src_reg->imm); - return -EACCES; - } - - had_id = (dst_reg->id != 0); + if (reg->max_value > BPF_REGISTER_MAX_RANGE) + reg->max_value = BPF_REGISTER_MAX_RANGE; + if (reg->min_value < BPF_REGISTER_MIN_RANGE || + reg->min_value > BPF_REGISTER_MAX_RANGE) + reg->min_value = BPF_REGISTER_MIN_RANGE; +} - /* dst_reg stays as pkt_ptr type and since some positive - * integer value was added to the pointer, increment its 'id' - */ - dst_reg->id = ++env->id_gen; - - /* something was added to pkt_ptr, set range to zero */ - dst_reg->aux_off += dst_reg->off; - dst_reg->off = 0; - dst_reg->range = 0; - if (had_id) - dst_reg->aux_off_align = min(dst_reg->aux_off_align, - src_reg->min_align); - else - dst_reg->aux_off_align = src_reg->min_align; +static void coerce_reg_to_32(struct bpf_reg_state *reg) +{ + /* 32-bit values can't be negative as an s64 */ + if (reg->min_value < 0) + reg->min_value = 0; + /* clear high 32 bits */ + reg->var_off = tnum_cast(reg->var_off, 4); + /* Did value become known? Then update bounds */ + if (tnum_is_const(reg->var_off)) { + if ((s64)reg->var_off.value > BPF_REGISTER_MIN_RANGE) + reg->min_value = reg->var_off.value; + if (reg->var_off.value < BPF_REGISTER_MAX_RANGE) + reg->max_value = reg->var_off.value; } - return 0; } -static int evaluate_reg_alu(struct bpf_verifier_env *env, struct bpf_insn *insn) +/* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off. + * Caller must check_reg_overflow all argument regs beforehand. + * Caller should also handle BPF_MOV case separately. + * If we return -EACCES, caller may want to try again treating pointer as a + * scalar. So we only emit a diagnostic if !env->allow_ptr_leaks. + */ +static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, + struct bpf_insn *insn, + const struct bpf_reg_state *ptr_reg, + const struct bpf_reg_state *off_reg) { - struct bpf_reg_state *regs = env->cur_state.regs; - struct bpf_reg_state *dst_reg = ®s[insn->dst_reg]; + struct bpf_reg_state *regs = env->cur_state.regs, *dst_reg; + bool known = tnum_is_const(off_reg->var_off); + s64 min_val = off_reg->min_value; + u64 max_val = off_reg->max_value; u8 opcode = BPF_OP(insn->code); - s64 imm_log2; + u32 dst = insn->dst_reg; - /* for type == UNKNOWN_VALUE: - * imm > 0 -> number of zero upper bits - * imm == 0 -> don't track which is the same as all bits can be non-zero - */ + dst_reg = ®s[dst]; - if (BPF_SRC(insn->code) == BPF_X) { - struct bpf_reg_state *src_reg = ®s[insn->src_reg]; - - if (src_reg->type == UNKNOWN_VALUE && src_reg->imm > 0 && - dst_reg->imm && opcode == BPF_ADD) { - /* dreg += sreg - * where both have zero upper bits. Adding them - * can only result making one more bit non-zero - * in the larger value. - * Ex. 0xffff (imm=48) + 1 (imm=63) = 0x10000 (imm=47) - * 0xffff (imm=48) + 0xffff = 0x1fffe (imm=47) - */ - dst_reg->imm = min(dst_reg->imm, src_reg->imm); - dst_reg->imm--; - return 0; - } - if (src_reg->type == CONST_IMM && src_reg->imm > 0 && - dst_reg->imm && opcode == BPF_ADD) { - /* dreg += sreg - * where dreg has zero upper bits and sreg is const. - * Adding them can only result making one more bit - * non-zero in the larger value. - */ - imm_log2 = __ilog2_u64((long long)src_reg->imm); - dst_reg->imm = min(dst_reg->imm, 63 - imm_log2); - dst_reg->imm--; - return 0; - } - /* all other cases non supported yet, just mark dst_reg */ - dst_reg->imm = 0; - return 0; + if (WARN_ON_ONCE(known && (min_val != max_val))) { + print_verifier_state(&env->cur_state); + verbose("verifier internal error\n"); + return -EINVAL; + } + + if (BPF_CLASS(insn->code) != BPF_ALU64) { + /* 32-bit ALU ops on pointers produce (meaningless) scalars */ + if (!env->allow_ptr_leaks) + verbose("R%d 32-bit pointer arithmetic prohibited\n", + dst); + return -EACCES; } - /* sign extend 32-bit imm into 64-bit to make sure that - * negative values occupy bit 63. Note ilog2() would have - * been incorrect, since sizeof(insn->imm) == 4 + if (ptr_reg->type == PTR_TO_MAP_VALUE_OR_NULL) { + if (!env->allow_ptr_leaks) + verbose("R%d pointer arithmetic on PTR_TO_MAP_VALUE_OR_NULL prohibited, null-check it first\n", + dst); + return -EACCES; + } + if (ptr_reg->type == CONST_PTR_TO_MAP) { + if (!env->allow_ptr_leaks) + verbose("R%d pointer arithmetic on CONST_PTR_TO_MAP prohibited\n", + dst); + return -EACCES; + } + if (ptr_reg->type == PTR_TO_PACKET_END) { + if (!env->allow_ptr_leaks) + verbose("R%d pointer arithmetic on PTR_TO_PACKET_END prohibited\n", + dst); + return -EACCES; + } + + /* In case of 'scalar += pointer', dst_reg inherits pointer type and id. + * The id may be overwritten later if we create a new variable offset. */ - imm_log2 = __ilog2_u64((long long)insn->imm); + dst_reg->type = ptr_reg->type; + dst_reg->id = ptr_reg->id; - if (dst_reg->imm && opcode == BPF_LSH) { - /* reg <<= imm - * if reg was a result of 2 byte load, then its imm == 48 - * which means that upper 48 bits are zero and shifting this reg - * left by 4 would mean that upper 44 bits are still zero + switch (opcode) { + case BPF_ADD: + /* We can take a fixed offset as long as it doesn't overflow + * the s32 'off' field */ - dst_reg->imm -= insn->imm; - } else if (dst_reg->imm && opcode == BPF_MUL) { - /* reg *= imm - * if multiplying by 14 subtract 4 - * This is conservative calculation of upper zero bits. - * It's not trying to special case insn->imm == 1 or 0 cases + if (known && (ptr_reg->off + min_val == + (s64)(s32)(ptr_reg->off + min_val))) { + /* pointer += K. Accumulate it into fixed offset */ + dst_reg->min_value = ptr_reg->min_value; + dst_reg->max_value = ptr_reg->max_value; + dst_reg->var_off = ptr_reg->var_off; + dst_reg->off = ptr_reg->off + min_val; + dst_reg->range = ptr_reg->range; + break; + } + if (max_val == BPF_REGISTER_MAX_RANGE) { + if (!env->allow_ptr_leaks) + verbose("R%d tried to add unbounded value to pointer\n", + dst); + return -EACCES; + } + /* A new variable offset is created. Note that off_reg->off + * == 0, since it's a scalar. + * dst_reg gets the pointer type and since some positive + * integer value was added to the pointer, give it a new 'id' + * if it's a PTR_TO_PACKET. + * this creates a new 'base' pointer, off_reg (variable) gets + * added into the variable offset, and we copy the fixed offset + * from ptr_reg. */ - dst_reg->imm -= imm_log2 + 1; - } else if (opcode == BPF_AND) { - /* reg &= imm */ - dst_reg->imm = 63 - imm_log2; - } else if (dst_reg->imm && opcode == BPF_ADD) { - /* reg += imm */ - dst_reg->imm = min(dst_reg->imm, 63 - imm_log2); - dst_reg->imm--; - } else if (opcode == BPF_RSH) { - /* reg >>= imm - * which means that after right shift, upper bits will be zero - * note that verifier already checked that - * 0 <= imm < 64 for shift insn + if (min_val <= BPF_REGISTER_MIN_RANGE) + dst_reg->min_value = BPF_REGISTER_MIN_RANGE; + if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) + dst_reg->min_value += min_val; + if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) + dst_reg->max_value += max_val; + dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off); + dst_reg->off = ptr_reg->off; + if (ptr_reg->type == PTR_TO_PACKET) { + dst_reg->id = ++env->id_gen; + /* something was added to pkt_ptr, set range to zero */ + dst_reg->range = 0; + } + break; + case BPF_SUB: + if (dst_reg == off_reg) { + /* scalar -= pointer. Creates an unknown scalar */ + if (!env->allow_ptr_leaks) + verbose("R%d tried to subtract pointer from scalar\n", + dst); + return -EACCES; + } + /* We don't allow subtraction from FP, because (according to + * test_verifier.c test "invalid fp arithmetic", JITs might not + * be able to deal with it. */ - dst_reg->imm += insn->imm; - if (unlikely(dst_reg->imm > 64)) - /* some dumb code did: - * r2 = *(u32 *)mem; - * r2 >>= 32; - * and all bits are zero now */ - dst_reg->imm = 64; - } else { - /* all other alu ops, means that we don't know what will - * happen to the value, mark it with unknown number of zero bits + if (ptr_reg->type == PTR_TO_STACK) { + if (!env->allow_ptr_leaks) + verbose("R%d subtraction from stack pointer prohibited\n", + dst); + return -EACCES; + } + if (known && (ptr_reg->off - min_val == + (s64)(s32)(ptr_reg->off - min_val))) { + /* pointer -= K. Subtract it from fixed offset */ + dst_reg->min_value = ptr_reg->min_value; + dst_reg->max_value = ptr_reg->max_value; + dst_reg->var_off = ptr_reg->var_off; + dst_reg->id = ptr_reg->id; + dst_reg->off = ptr_reg->off - min_val; + dst_reg->range = ptr_reg->range; + break; + } + /* Subtracting a negative value will just confuse everything. + * This can happen if off_reg is an immediate. */ - dst_reg->imm = 0; - } - - if (dst_reg->imm < 0) { - /* all 64 bits of the register can contain non-zero bits - * and such value cannot be added to ptr_to_packet, since it - * may overflow, mark it as unknown to avoid further eval + if ((s64)max_val < 0) { + if (!env->allow_ptr_leaks) + verbose("R%d tried to subtract negative max_val %lld from pointer\n", + dst, (s64)max_val); + return -EACCES; + } + /* A new variable offset is created. If the subtrahend is known + * nonnegative, then any reg->range we had before is still good. */ - dst_reg->imm = 0; - } - return 0; -} - -static int evaluate_reg_imm_alu_unknown(struct bpf_verifier_env *env, - struct bpf_insn *insn) -{ - struct bpf_reg_state *regs = env->cur_state.regs; - struct bpf_reg_state *dst_reg = ®s[insn->dst_reg]; - struct bpf_reg_state *src_reg = ®s[insn->src_reg]; - u8 opcode = BPF_OP(insn->code); - s64 imm_log2 = __ilog2_u64((long long)dst_reg->imm); - - /* BPF_X code with src_reg->type UNKNOWN_VALUE here. */ - if (src_reg->imm > 0 && dst_reg->imm) { - switch (opcode) { - case BPF_ADD: - /* dreg += sreg - * where both have zero upper bits. Adding them - * can only result making one more bit non-zero - * in the larger value. - * Ex. 0xffff (imm=48) + 1 (imm=63) = 0x10000 (imm=47) - * 0xffff (imm=48) + 0xffff = 0x1fffe (imm=47) - */ - dst_reg->imm = min(src_reg->imm, 63 - imm_log2); - dst_reg->imm--; - break; - case BPF_AND: - /* dreg &= sreg - * AND can not extend zero bits only shrink - * Ex. 0x00..00ffffff - * & 0x0f..ffffffff - * ---------------- - * 0x00..00ffffff - */ - dst_reg->imm = max(src_reg->imm, 63 - imm_log2); - break; - case BPF_OR: - /* dreg |= sreg - * OR can only extend zero bits - * Ex. 0x00..00ffffff - * | 0x0f..ffffffff - * ---------------- - * 0x0f..00ffffff - */ - dst_reg->imm = min(src_reg->imm, 63 - imm_log2); - break; - case BPF_SUB: - case BPF_MUL: - case BPF_RSH: - case BPF_LSH: - /* These may be flushed out later */ - default: - mark_reg_unknown_value(regs, insn->dst_reg); + if (max_val >= BPF_REGISTER_MAX_RANGE) + dst_reg->min_value = BPF_REGISTER_MIN_RANGE; + if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) + dst_reg->min_value -= max_val; + if (min_val <= BPF_REGISTER_MIN_RANGE) + dst_reg->max_value = BPF_REGISTER_MAX_RANGE; + if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) + dst_reg->max_value -= min_val; + dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off); + dst_reg->off = ptr_reg->off; + if (ptr_reg->type == PTR_TO_PACKET) { + dst_reg->id = ++env->id_gen; + /* something was added to pkt_ptr, set range to zero */ + if (min_val < 0) + dst_reg->range = 0; } - } else { - mark_reg_unknown_value(regs, insn->dst_reg); + break; + case BPF_AND: + case BPF_OR: + case BPF_XOR: + /* bitwise ops on pointers are troublesome, prohibit for now. + * (However, in principle we could allow some cases, e.g. + * ptr &= ~3 which would reduce min_value by 3.) + */ + if (!env->allow_ptr_leaks) + verbose("R%d bitwise operator %s on pointer prohibited\n", + dst, bpf_alu_string[opcode >> 4]); + return -EACCES; + default: + /* other operators (e.g. MUL,LSH) produce non-pointer results */ + if (!env->allow_ptr_leaks) + verbose("R%d pointer arithmetic with %s operator prohibited\n", + dst, bpf_alu_string[opcode >> 4]); + return -EACCES; } - dst_reg->type = UNKNOWN_VALUE; + check_reg_overflow(dst_reg); return 0; } -static int evaluate_reg_imm_alu(struct bpf_verifier_env *env, - struct bpf_insn *insn) +static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, + struct bpf_insn *insn, + struct bpf_reg_state *dst_reg, + struct bpf_reg_state src_reg) { struct bpf_reg_state *regs = env->cur_state.regs; - struct bpf_reg_state *dst_reg = ®s[insn->dst_reg]; - struct bpf_reg_state *src_reg = ®s[insn->src_reg]; - u8 opcode = BPF_OP(insn->code); - u64 dst_imm = dst_reg->imm; - - if (BPF_SRC(insn->code) == BPF_X && src_reg->type == UNKNOWN_VALUE) - return evaluate_reg_imm_alu_unknown(env, insn); - - /* dst_reg->type == CONST_IMM here. Simulate execution of insns - * containing ALU ops. Don't care about overflow or negative - * values, just add/sub/... them; registers are in u64. - */ - if (opcode == BPF_ADD && BPF_SRC(insn->code) == BPF_K) { - dst_imm += insn->imm; - } else if (opcode == BPF_ADD && BPF_SRC(insn->code) == BPF_X && - src_reg->type == CONST_IMM) { - dst_imm += src_reg->imm; - } else if (opcode == BPF_SUB && BPF_SRC(insn->code) == BPF_K) { - dst_imm -= insn->imm; - } else if (opcode == BPF_SUB && BPF_SRC(insn->code) == BPF_X && - src_reg->type == CONST_IMM) { - dst_imm -= src_reg->imm; - } else if (opcode == BPF_MUL && BPF_SRC(insn->code) == BPF_K) { - dst_imm *= insn->imm; - } else if (opcode == BPF_MUL && BPF_SRC(insn->code) == BPF_X && - src_reg->type == CONST_IMM) { - dst_imm *= src_reg->imm; - } else if (opcode == BPF_OR && BPF_SRC(insn->code) == BPF_K) { - dst_imm |= insn->imm; - } else if (opcode == BPF_OR && BPF_SRC(insn->code) == BPF_X && - src_reg->type == CONST_IMM) { - dst_imm |= src_reg->imm; - } else if (opcode == BPF_AND && BPF_SRC(insn->code) == BPF_K) { - dst_imm &= insn->imm; - } else if (opcode == BPF_AND && BPF_SRC(insn->code) == BPF_X && - src_reg->type == CONST_IMM) { - dst_imm &= src_reg->imm; - } else if (opcode == BPF_RSH && BPF_SRC(insn->code) == BPF_K) { - dst_imm >>= insn->imm; - } else if (opcode == BPF_RSH && BPF_SRC(insn->code) == BPF_X && - src_reg->type == CONST_IMM) { - dst_imm >>= src_reg->imm; - } else if (opcode == BPF_LSH && BPF_SRC(insn->code) == BPF_K) { - dst_imm <<= insn->imm; - } else if (opcode == BPF_LSH && BPF_SRC(insn->code) == BPF_X && - src_reg->type == CONST_IMM) { - dst_imm <<= src_reg->imm; - } else { - mark_reg_unknown_value(regs, insn->dst_reg); - goto out; - } - - dst_reg->imm = dst_imm; -out: - return 0; -} - -static void check_reg_overflow(struct bpf_reg_state *reg) -{ - if (reg->max_value > BPF_REGISTER_MAX_RANGE) - reg->max_value = BPF_REGISTER_MAX_RANGE; - if (reg->min_value < BPF_REGISTER_MIN_RANGE || - reg->min_value > BPF_REGISTER_MAX_RANGE) - reg->min_value = BPF_REGISTER_MIN_RANGE; -} - -static u32 calc_align(u32 imm) -{ - if (!imm) - return 1U << 31; - return imm - ((imm - 1) & imm); -} - -static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, - struct bpf_insn *insn) -{ - struct bpf_reg_state *regs = env->cur_state.regs, *dst_reg; s64 min_val = BPF_REGISTER_MIN_RANGE; u64 max_val = BPF_REGISTER_MAX_RANGE; u8 opcode = BPF_OP(insn->code); - u32 dst_align, src_align; + bool src_known, dst_known; - dst_reg = ®s[insn->dst_reg]; - src_align = 0; - if (BPF_SRC(insn->code) == BPF_X) { - check_reg_overflow(®s[insn->src_reg]); - min_val = regs[insn->src_reg].min_value; - max_val = regs[insn->src_reg].max_value; - - /* If the source register is a random pointer then the - * min_value/max_value values represent the range of the known - * accesses into that value, not the actual min/max value of the - * register itself. In this case we have to reset the reg range - * values so we know it is not safe to look at. - */ - if (regs[insn->src_reg].type != CONST_IMM && - regs[insn->src_reg].type != UNKNOWN_VALUE) { - min_val = BPF_REGISTER_MIN_RANGE; - max_val = BPF_REGISTER_MAX_RANGE; - src_align = 0; - } else { - src_align = regs[insn->src_reg].min_align; - } - } else if (insn->imm < BPF_REGISTER_MAX_RANGE && - (s64)insn->imm > BPF_REGISTER_MIN_RANGE) { - min_val = max_val = insn->imm; - src_align = calc_align(insn->imm); - } - - dst_align = dst_reg->min_align; - - /* We don't know anything about what was done to this register, mark it - * as unknown. Also, if both derived bounds came from signed/unsigned - * mixed compares and one side is unbounded, we cannot really do anything - * with them as boundaries cannot be trusted. Thus, arithmetic of two - * regs of such kind will get invalidated bounds on the dst side. - */ - if ((min_val == BPF_REGISTER_MIN_RANGE && - max_val == BPF_REGISTER_MAX_RANGE) || - (BPF_SRC(insn->code) == BPF_X && - ((min_val != BPF_REGISTER_MIN_RANGE && - max_val == BPF_REGISTER_MAX_RANGE) || - (min_val == BPF_REGISTER_MIN_RANGE && - max_val != BPF_REGISTER_MAX_RANGE) || - (dst_reg->min_value != BPF_REGISTER_MIN_RANGE && - dst_reg->max_value == BPF_REGISTER_MAX_RANGE) || - (dst_reg->min_value == BPF_REGISTER_MIN_RANGE && - dst_reg->max_value != BPF_REGISTER_MAX_RANGE)) && - regs[insn->dst_reg].value_from_signed != - regs[insn->src_reg].value_from_signed)) { - reset_reg_range_values(regs, insn->dst_reg); - return; - } - - /* If one of our values was at the end of our ranges then we can't just - * do our normal operations to the register, we need to set the values - * to the min/max since they are undefined. - */ - if (opcode != BPF_SUB) { - if (min_val == BPF_REGISTER_MIN_RANGE) - dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - if (max_val == BPF_REGISTER_MAX_RANGE) - dst_reg->max_value = BPF_REGISTER_MAX_RANGE; + if (BPF_CLASS(insn->code) != BPF_ALU64) { + /* 32-bit ALU ops are (32,32)->64 */ + coerce_reg_to_32(dst_reg); + coerce_reg_to_32(&src_reg); } + min_val = src_reg.min_value; + max_val = src_reg.max_value; + src_known = tnum_is_const(src_reg.var_off); + dst_known = tnum_is_const(dst_reg->var_off); switch (opcode) { case BPF_ADD: + if (min_val == BPF_REGISTER_MIN_RANGE) + dst_reg->min_value = BPF_REGISTER_MIN_RANGE; if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) dst_reg->min_value += min_val; + /* if max_val is MAX_RANGE, this will saturate dst->max */ if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) dst_reg->max_value += max_val; - dst_reg->min_align = min(src_align, dst_align); + dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off); break; case BPF_SUB: - /* If one of our values was at the end of our ranges, then the - * _opposite_ value in the dst_reg goes to the end of our range. - */ - if (min_val == BPF_REGISTER_MIN_RANGE) - dst_reg->max_value = BPF_REGISTER_MAX_RANGE; if (max_val == BPF_REGISTER_MAX_RANGE) dst_reg->min_value = BPF_REGISTER_MIN_RANGE; if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) dst_reg->min_value -= max_val; + if (min_val == BPF_REGISTER_MIN_RANGE) + dst_reg->max_value = BPF_REGISTER_MAX_RANGE; if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) dst_reg->max_value -= min_val; - dst_reg->min_align = min(src_align, dst_align); + dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off); break; case BPF_MUL: - if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) - dst_reg->min_value *= min_val; + if (min_val < 0 || dst_reg->min_value < 0) { + /* Ain't nobody got time to multiply that sign */ + __mark_reg_unknown(dst_reg); + break; + } + dst_reg->min_value *= min_val; + /* if max_val is MAX_RANGE, this will saturate dst->max. + * We know MAX_RANGE ** 2 won't overflow a u64, because + * MAX_RANGE itself fits in a u32. + */ + BUILD_BUG_ON(BPF_REGISTER_MAX_RANGE > (u32)-1); if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) dst_reg->max_value *= max_val; - dst_reg->min_align = max(src_align, dst_align); + dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off); break; case BPF_AND: - /* Disallow AND'ing of negative numbers, ain't nobody got time - * for that. Otherwise the minimum is 0 and the max is the max - * value we could AND against. + if (src_known && dst_known) { + u64 value = dst_reg->var_off.value & src_reg.var_off.value; + + dst_reg->var_off = tnum_const(value); + dst_reg->min_value = dst_reg->max_value = min_t(u64, + value, BPF_REGISTER_MAX_RANGE); + break; + } + /* Lose min_value when AND'ing negative numbers, ain't nobody + * got time for that. Otherwise we get our minimum from the + * var_off, since that's inherently bitwise. + * Our maximum is the minimum of the operands' maxima. */ - if (min_val < 0) + dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg.var_off); + if (min_val < 0 && dst_reg->min_value < 0) dst_reg->min_value = BPF_REGISTER_MIN_RANGE; else - dst_reg->min_value = 0; - dst_reg->max_value = max_val; - dst_reg->min_align = max(src_align, dst_align); + dst_reg->min_value = dst_reg->var_off.value; + dst_reg->max_value = min(dst_reg->max_value, max_val); + break; + case BPF_OR: + if (src_known && dst_known) { + u64 value = dst_reg->var_off.value | src_reg.var_off.value; + + dst_reg->var_off = tnum_const(value); + dst_reg->min_value = dst_reg->max_value = min_t(u64, + value, BPF_REGISTER_MAX_RANGE); + break; + } + /* Lose ranges when OR'ing negative numbers, ain't nobody got + * time for that. Otherwise we get our maximum from the var_off, + * and our minimum is the maximum of the operands' minima. + */ + dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg.var_off); + if (min_val < 0 || dst_reg->min_value < 0) { + dst_reg->min_value = BPF_REGISTER_MIN_RANGE; + dst_reg->max_value = BPF_REGISTER_MAX_RANGE; + } else { + dst_reg->min_value = max(dst_reg->min_value, min_val); + dst_reg->max_value = dst_reg->var_off.value | dst_reg->var_off.mask; + } break; case BPF_LSH: + if (min_val < 0) { + /* LSH by a negative number is undefined */ + mark_reg_unknown(regs, insn->dst_reg); + break; + } /* Gotta have special overflow logic here, if we're shifting * more than MAX_RANGE then just assume we have an invalid * range. */ if (min_val > ilog2(BPF_REGISTER_MAX_RANGE)) { dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - dst_reg->min_align = 1; + dst_reg->var_off = tnum_unknown; } else { if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) dst_reg->min_value <<= min_val; - if (!dst_reg->min_align) - dst_reg->min_align = 1; - dst_reg->min_align <<= min_val; + if (src_known) + dst_reg->var_off = tnum_lshift(dst_reg->var_off, min_val); + else + dst_reg->var_off = tnum_lshift(tnum_unknown, min_val); } if (max_val > ilog2(BPF_REGISTER_MAX_RANGE)) dst_reg->max_value = BPF_REGISTER_MAX_RANGE; @@ -1946,37 +1938,139 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, dst_reg->max_value <<= max_val; break; case BPF_RSH: - /* RSH by a negative number is undefined, and the BPF_RSH is an - * unsigned shift, so make the appropriate casts. - */ - if (min_val < 0 || dst_reg->min_value < 0) { - dst_reg->min_value = BPF_REGISTER_MIN_RANGE; + if (min_val < 0) { + /* RSH by a negative number is undefined */ + mark_reg_unknown(regs, insn->dst_reg); + break; + } + /* BPF_RSH is an unsigned shift, so make the appropriate casts */ + if (dst_reg->min_value < 0) { + if (min_val) + /* Sign bit will be cleared */ + dst_reg->min_value = 0; } else { dst_reg->min_value = (u64)(dst_reg->min_value) >> min_val; } - if (min_val < 0) { - dst_reg->min_align = 1; - } else { - dst_reg->min_align >>= (u64) min_val; - if (!dst_reg->min_align) - dst_reg->min_align = 1; - } - if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) - dst_reg->max_value >>= max_val; + if (src_known) + dst_reg->var_off = tnum_rshift(dst_reg->var_off, min_val); + else + dst_reg->var_off = tnum_rshift(tnum_unknown, min_val); + if (dst_reg->max_value == BPF_REGISTER_MAX_RANGE) + dst_reg->max_value = ~0; + dst_reg->max_value >>= max_val; break; default: - reset_reg_range_values(regs, insn->dst_reg); + mark_reg_unknown(regs, insn->dst_reg); break; } check_reg_overflow(dst_reg); + return 0; +} + +/* Handles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max + * and var_off. + */ +static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, + struct bpf_insn *insn) +{ + struct bpf_reg_state *regs = env->cur_state.regs, *dst_reg, *src_reg; + struct bpf_reg_state *ptr_reg = NULL, off_reg = {0}; + u8 opcode = BPF_OP(insn->code); + int rc; + + dst_reg = ®s[insn->dst_reg]; + check_reg_overflow(dst_reg); + src_reg = NULL; + if (dst_reg->type != SCALAR_VALUE) + ptr_reg = dst_reg; + if (BPF_SRC(insn->code) == BPF_X) { + src_reg = ®s[insn->src_reg]; + check_reg_overflow(src_reg); + + if (src_reg->type != SCALAR_VALUE) { + if (dst_reg->type != SCALAR_VALUE) { + /* Combining two pointers by any ALU op yields + * an arbitrary scalar. + */ + if (!env->allow_ptr_leaks) { + verbose("R%d pointer %s pointer prohibited\n", + insn->dst_reg, + bpf_alu_string[opcode >> 4]); + return -EACCES; + } + mark_reg_unknown(regs, insn->dst_reg); + return 0; + } else { + /* scalar += pointer + * This is legal, but we have to reverse our + * src/dest handling in computing the range + */ + rc = adjust_ptr_min_max_vals(env, insn, + src_reg, dst_reg); + if (rc == -EACCES && env->allow_ptr_leaks) { + /* scalar += unknown scalar */ + __mark_reg_unknown(&off_reg); + return adjust_scalar_min_max_vals( + env, insn, + dst_reg, off_reg); + } + return rc; + } + } else if (ptr_reg) { + /* pointer += scalar */ + rc = adjust_ptr_min_max_vals(env, insn, + dst_reg, src_reg); + if (rc == -EACCES && env->allow_ptr_leaks) { + /* unknown scalar += scalar */ + __mark_reg_unknown(dst_reg); + return adjust_scalar_min_max_vals( + env, insn, dst_reg, *src_reg); + } + return rc; + } + } else { + /* Pretend the src is a reg with a known value, since we only + * need to be able to read from this state. + */ + off_reg.type = SCALAR_VALUE; + off_reg.var_off = tnum_const(insn->imm); + off_reg.min_value = insn->imm; + off_reg.max_value = insn->imm; + src_reg = &off_reg; + check_reg_overflow(src_reg); + if (ptr_reg) { /* pointer += K */ + rc = adjust_ptr_min_max_vals(env, insn, + ptr_reg, src_reg); + if (rc == -EACCES && env->allow_ptr_leaks) { + /* unknown scalar += K */ + __mark_reg_unknown(dst_reg); + return adjust_scalar_min_max_vals( + env, insn, dst_reg, off_reg); + } + return rc; + } + } + + /* Got here implies adding two SCALAR_VALUEs */ + if (WARN_ON_ONCE(ptr_reg)) { + print_verifier_state(&env->cur_state); + verbose("verifier internal error: unexpected ptr_reg\n"); + return -EINVAL; + } + if (WARN_ON(!src_reg)) { + print_verifier_state(&env->cur_state); + verbose("verifier internal error: no src_reg\n"); + return -EINVAL; + } + return adjust_scalar_min_max_vals(env, insn, dst_reg, *src_reg); } /* check validity of 32-bit and 64-bit arithmetic operations */ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) { - struct bpf_reg_state *regs = env->cur_state.regs, *dst_reg; + struct bpf_reg_state *regs = env->cur_state.regs; u8 opcode = BPF_OP(insn->code); int err; @@ -2036,11 +2130,6 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) if (err) return err; - /* we are setting our register to something new, we need to - * reset its range values. - */ - reset_reg_range_values(regs, insn->dst_reg); - if (BPF_SRC(insn->code) == BPF_X) { if (BPF_CLASS(insn->code) == BPF_ALU64) { /* case: R1 = R2 @@ -2048,24 +2137,29 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) */ regs[insn->dst_reg] = regs[insn->src_reg]; } else { + /* R1 = (u32) R2 */ if (is_pointer_value(env, insn->src_reg)) { verbose("R%d partial copy of pointer\n", insn->src_reg); return -EACCES; } - mark_reg_unknown_value(regs, insn->dst_reg); + mark_reg_unknown(regs, insn->dst_reg); + /* high 32 bits are known zero. But this is + * still out of range for max_value, so leave + * that. + */ + regs[insn->dst_reg].var_off = tnum_cast( + regs[insn->dst_reg].var_off, 4); } } else { /* case: R = imm * remember the value we stored into this reg */ - regs[insn->dst_reg].type = CONST_IMM; - regs[insn->dst_reg].imm = insn->imm; - regs[insn->dst_reg].id = 0; + regs[insn->dst_reg].type = SCALAR_VALUE; + regs[insn->dst_reg].var_off = tnum_const(insn->imm); regs[insn->dst_reg].max_value = insn->imm; regs[insn->dst_reg].min_value = insn->imm; - regs[insn->dst_reg].min_align = calc_align(insn->imm); - regs[insn->dst_reg].value_from_signed = false; + regs[insn->dst_reg].id = 0; } } else if (opcode > BPF_END) { @@ -2116,68 +2210,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) if (err) return err; - dst_reg = ®s[insn->dst_reg]; - - /* first we want to adjust our ranges. */ - adjust_reg_min_max_vals(env, insn); - - /* pattern match 'bpf_add Rx, imm' instruction */ - if (opcode == BPF_ADD && BPF_CLASS(insn->code) == BPF_ALU64 && - dst_reg->type == FRAME_PTR && BPF_SRC(insn->code) == BPF_K) { - dst_reg->type = PTR_TO_STACK; - dst_reg->imm = insn->imm; - return 0; - } else if (opcode == BPF_ADD && - BPF_CLASS(insn->code) == BPF_ALU64 && - dst_reg->type == PTR_TO_STACK && - ((BPF_SRC(insn->code) == BPF_X && - regs[insn->src_reg].type == CONST_IMM) || - BPF_SRC(insn->code) == BPF_K)) { - if (BPF_SRC(insn->code) == BPF_X) - dst_reg->imm += regs[insn->src_reg].imm; - else - dst_reg->imm += insn->imm; - return 0; - } else if (opcode == BPF_ADD && - BPF_CLASS(insn->code) == BPF_ALU64 && - (dst_reg->type == PTR_TO_PACKET || - (BPF_SRC(insn->code) == BPF_X && - regs[insn->src_reg].type == PTR_TO_PACKET))) { - /* ptr_to_packet += K|X */ - return check_packet_ptr_add(env, insn); - } else if (BPF_CLASS(insn->code) == BPF_ALU64 && - dst_reg->type == UNKNOWN_VALUE && - env->allow_ptr_leaks) { - /* unknown += K|X */ - return evaluate_reg_alu(env, insn); - } else if (BPF_CLASS(insn->code) == BPF_ALU64 && - dst_reg->type == CONST_IMM && - env->allow_ptr_leaks) { - /* reg_imm += K|X */ - return evaluate_reg_imm_alu(env, insn); - } else if (is_pointer_value(env, insn->dst_reg)) { - verbose("R%d pointer arithmetic prohibited\n", - insn->dst_reg); - return -EACCES; - } else if (BPF_SRC(insn->code) == BPF_X && - is_pointer_value(env, insn->src_reg)) { - verbose("R%d pointer arithmetic prohibited\n", - insn->src_reg); - return -EACCES; - } - - /* If we did pointer math on a map value then just set it to our - * PTR_TO_MAP_VALUE_ADJ type so we can deal with any stores or - * loads to this register appropriately, otherwise just mark the - * register as unknown. - */ - if (env->allow_ptr_leaks && - BPF_CLASS(insn->code) == BPF_ALU64 && opcode == BPF_ADD && - (dst_reg->type == PTR_TO_MAP_VALUE || - dst_reg->type == PTR_TO_MAP_VALUE_ADJ)) - dst_reg->type = PTR_TO_MAP_VALUE_ADJ; - else - mark_reg_unknown_value(regs, insn->dst_reg); + return adjust_reg_min_max_vals(env, insn); } return 0; @@ -2189,6 +2222,17 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *state, struct bpf_reg_state *regs = state->regs, *reg; int i; + if (dst_reg->off < 0) + /* This doesn't give us any range */ + return; + + if (dst_reg->max_value > MAX_PACKET_OFF || + dst_reg->max_value + dst_reg->off > MAX_PACKET_OFF) + /* Risk of overflow. For instance, ptr + (1<<63) may be less + * than pkt_end, but that's because it's also less than pkt. + */ + return; + /* LLVM can generate two kind of checks: * * Type 1: @@ -2219,30 +2263,44 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *state, * so that range of bytes [r3, r3 + 8) is safe to access. */ + /* If our ids match, then we must have the same max_value. And we + * don't care about the other reg's fixed offset, since if it's too big + * the range won't allow anything. + * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16. + */ for (i = 0; i < MAX_BPF_REG; i++) if (regs[i].type == PTR_TO_PACKET && regs[i].id == dst_reg->id) /* keep the maximum range already checked */ - regs[i].range = max(regs[i].range, dst_reg->off); + regs[i].range = max_t(u16, regs[i].range, dst_reg->off); for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) { if (state->stack_slot_type[i] != STACK_SPILL) continue; reg = &state->spilled_regs[i / BPF_REG_SIZE]; if (reg->type == PTR_TO_PACKET && reg->id == dst_reg->id) - reg->range = max(reg->range, dst_reg->off); + reg->range = max_t(u16, reg->range, dst_reg->off); } } /* Adjusts the register min/max values in the case that the dst_reg is the * variable register that we are working on, and src_reg is a constant or we're * simply doing a BPF_K check. + * In JEQ/JNE cases we also adjust the var_off values. */ static void reg_set_min_max(struct bpf_reg_state *true_reg, struct bpf_reg_state *false_reg, u64 val, u8 opcode) { bool value_from_signed = true; - bool is_range = true; + + /* If the dst_reg is a pointer, we can't learn anything about its + * variable offset from the compare (unless src_reg were a pointer into + * the same object, but we don't bother with that. + * Since false_reg and true_reg have the same type by construction, we + * only need to check one of them for pointerness. + */ + if (__is_pointer_value(false, false_reg)) + return; switch (opcode) { case BPF_JEQ: @@ -2250,14 +2308,14 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, * true then we know for sure. */ true_reg->max_value = true_reg->min_value = val; - is_range = false; + true_reg->var_off = tnum_const(val); break; case BPF_JNE: /* If this is true we know nothing Jon Snow, but if it is false * we know the value for sure; */ false_reg->max_value = false_reg->min_value = val; - is_range = false; + false_reg->var_off = tnum_const(val); break; case BPF_JGT: value_from_signed = false; @@ -2305,23 +2363,19 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, check_reg_overflow(false_reg); check_reg_overflow(true_reg); - if (is_range) { - if (__is_pointer_value(false, false_reg)) - reset_reg_range_values(false_reg, 0); - if (__is_pointer_value(false, true_reg)) - reset_reg_range_values(true_reg, 0); - } } -/* Same as above, but for the case that dst_reg is a CONST_IMM reg and src_reg - * is the variable reg. +/* Same as above, but for the case that dst_reg holds a constant and src_reg is + * the variable reg. */ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, struct bpf_reg_state *false_reg, u64 val, u8 opcode) { bool value_from_signed = true; - bool is_range = true; + + if (__is_pointer_value(false, false_reg)) + return; switch (opcode) { case BPF_JEQ: @@ -2329,14 +2383,14 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, * true then we know for sure. */ true_reg->max_value = true_reg->min_value = val; - is_range = false; + true_reg->var_off = tnum_const(val); break; case BPF_JNE: /* If this is true we know nothing Jon Snow, but if it is false * we know the value for sure; */ false_reg->max_value = false_reg->min_value = val; - is_range = false; + false_reg->var_off = tnum_const(val); break; case BPF_JGT: value_from_signed = false; @@ -2385,27 +2439,60 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, check_reg_overflow(false_reg); check_reg_overflow(true_reg); - if (is_range) { - if (__is_pointer_value(false, false_reg)) - reset_reg_range_values(false_reg, 0); - if (__is_pointer_value(false, true_reg)) - reset_reg_range_values(true_reg, 0); +} + +/* Regs are known to be equal, so intersect their min/max/var_off */ +static void __reg_combine_min_max(struct bpf_reg_state *src_reg, + struct bpf_reg_state *dst_reg) +{ + src_reg->min_value = dst_reg->min_value = max(src_reg->min_value, + dst_reg->min_value); + src_reg->max_value = dst_reg->max_value = min(src_reg->max_value, + dst_reg->max_value); + src_reg->var_off = dst_reg->var_off = tnum_intersect(src_reg->var_off, + dst_reg->var_off); + check_reg_overflow(src_reg); + check_reg_overflow(dst_reg); +} + +static void reg_combine_min_max(struct bpf_reg_state *true_src, + struct bpf_reg_state *true_dst, + struct bpf_reg_state *false_src, + struct bpf_reg_state *false_dst, + u8 opcode) +{ + switch (opcode) { + case BPF_JEQ: + __reg_combine_min_max(true_src, true_dst); + break; + case BPF_JNE: + __reg_combine_min_max(false_src, false_dst); } } static void mark_map_reg(struct bpf_reg_state *regs, u32 regno, u32 id, - enum bpf_reg_type type) + bool is_null) { struct bpf_reg_state *reg = ®s[regno]; if (reg->type == PTR_TO_MAP_VALUE_OR_NULL && reg->id == id) { - if (type == UNKNOWN_VALUE) { - __mark_reg_unknown_value(regs, regno); + /* Old offset (both fixed and variable parts) should + * have been known-zero, because we don't allow pointer + * arithmetic on pointers that might be NULL. + */ + if (WARN_ON_ONCE(reg->min_value || reg->max_value || + reg->var_off.value || reg->var_off.mask || + reg->off)) { + reg->min_value = reg->max_value = reg->off = 0; + reg->var_off = tnum_const(0); + } + if (is_null) { + reg->type = SCALAR_VALUE; } else if (reg->map_ptr->inner_map_meta) { reg->type = CONST_PTR_TO_MAP; reg->map_ptr = reg->map_ptr->inner_map_meta; } else { - reg->type = type; + reg->type = PTR_TO_MAP_VALUE; } /* We don't need id from this point onwards anymore, thus we * should better reset it, so that state pruning has chances @@ -2419,19 +2506,19 @@ static void mark_map_reg(struct bpf_reg_state *regs, u32 regno, u32 id, * be folded together at some point. */ static void mark_map_regs(struct bpf_verifier_state *state, u32 regno, - enum bpf_reg_type type) + bool is_null) { struct bpf_reg_state *regs = state->regs; u32 id = regs[regno].id; int i; for (i = 0; i < MAX_BPF_REG; i++) - mark_map_reg(regs, i, id, type); + mark_map_reg(regs, i, id, is_null); for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) { if (state->stack_slot_type[i] != STACK_SPILL) continue; - mark_map_reg(state->spilled_regs, i / BPF_REG_SIZE, id, type); + mark_map_reg(state->spilled_regs, i / BPF_REG_SIZE, id, is_null); } } @@ -2481,7 +2568,8 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, /* detect if R == 0 where R was initialized to zero earlier */ if (BPF_SRC(insn->code) == BPF_K && (opcode == BPF_JEQ || opcode == BPF_JNE) && - dst_reg->type == CONST_IMM && dst_reg->imm == insn->imm) { + dst_reg->type == SCALAR_VALUE && + tnum_equals_const(dst_reg->var_off, insn->imm)) { if (opcode == BPF_JEQ) { /* if (imm == imm) goto pc+off; * only follow the goto, ignore fall-through @@ -2503,17 +2591,30 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, /* detect if we are comparing against a constant value so we can adjust * our min/max values for our dst register. + * this is only legit if both are scalars (or pointers to the same + * object, I suppose, but we don't support that right now), because + * otherwise the different base pointers mean the offsets aren't + * comparable. */ if (BPF_SRC(insn->code) == BPF_X) { - if (regs[insn->src_reg].type == CONST_IMM) - reg_set_min_max(&other_branch->regs[insn->dst_reg], - dst_reg, regs[insn->src_reg].imm, - opcode); - else if (dst_reg->type == CONST_IMM) - reg_set_min_max_inv(&other_branch->regs[insn->src_reg], - ®s[insn->src_reg], dst_reg->imm, - opcode); - } else { + if (dst_reg->type == SCALAR_VALUE && + regs[insn->src_reg].type == SCALAR_VALUE) { + if (tnum_is_const(regs[insn->src_reg].var_off)) + reg_set_min_max(&other_branch->regs[insn->dst_reg], + dst_reg, regs[insn->src_reg].var_off.value, + opcode); + else if (tnum_is_const(dst_reg->var_off)) + reg_set_min_max_inv(&other_branch->regs[insn->src_reg], + ®s[insn->src_reg], + dst_reg->var_off.value, opcode); + else if (opcode == BPF_JEQ || opcode == BPF_JNE) + /* Comparing for equality, we can combine knowledge */ + reg_combine_min_max(&other_branch->regs[insn->src_reg], + &other_branch->regs[insn->dst_reg], + ®s[insn->src_reg], + ®s[insn->dst_reg], opcode); + } + } else if (dst_reg->type == SCALAR_VALUE) { reg_set_min_max(&other_branch->regs[insn->dst_reg], dst_reg, insn->imm, opcode); } @@ -2525,10 +2626,8 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, /* Mark all identical map registers in each branch as either * safe or unknown depending R == 0 or R != 0 conditional. */ - mark_map_regs(this_branch, insn->dst_reg, - opcode == BPF_JEQ ? PTR_TO_MAP_VALUE : UNKNOWN_VALUE); - mark_map_regs(other_branch, insn->dst_reg, - opcode == BPF_JEQ ? UNKNOWN_VALUE : PTR_TO_MAP_VALUE); + mark_map_regs(this_branch, insn->dst_reg, opcode == BPF_JNE); + mark_map_regs(other_branch, insn->dst_reg, opcode == BPF_JEQ); } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGT && dst_reg->type == PTR_TO_PACKET && regs[insn->src_reg].type == PTR_TO_PACKET_END) { @@ -2576,8 +2675,11 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) if (insn->src_reg == 0) { u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; - regs[insn->dst_reg].type = CONST_IMM; - regs[insn->dst_reg].imm = imm; + regs[insn->dst_reg].type = SCALAR_VALUE; + regs[insn->dst_reg].min_value = imm; + regs[insn->dst_reg].max_value = imm; + check_reg_overflow(®s[insn->dst_reg]); + regs[insn->dst_reg].var_off = tnum_const(imm); regs[insn->dst_reg].id = 0; return 0; } @@ -2659,7 +2761,7 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) /* mark destination R0 register as readable, since it contains * the value fetched from the packet */ - regs[BPF_REG_0].type = UNKNOWN_VALUE; + mark_reg_unknown(regs, BPF_REG_0); return 0; } @@ -2862,57 +2964,145 @@ err_free: return ret; } -/* the following conditions reduce the number of explored insns - * from ~140k to ~80k for ultra large programs that use a lot of ptr_to_packet +/* check %cur's range satisfies %old's */ +static bool range_within(struct bpf_reg_state *old, + struct bpf_reg_state *cur) +{ + return old->min_value <= cur->min_value && + old->max_value >= cur->max_value; +} + +/* Maximum number of register states that can exist at once */ +#define ID_MAP_SIZE (MAX_BPF_REG + MAX_BPF_STACK / BPF_REG_SIZE) +struct idpair { + u32 old; + u32 cur; +}; + +/* If in the old state two registers had the same id, then they need to have + * the same id in the new state as well. But that id could be different from + * the old state, so we need to track the mapping from old to new ids. + * Once we have seen that, say, a reg with old id 5 had new id 9, any subsequent + * regs with old id 5 must also have new id 9 for the new state to be safe. But + * regs with a different old id could still have new id 9, we don't care about + * that. + * So we look through our idmap to see if this old id has been seen before. If + * so, we require the new id to match; otherwise, we add the id pair to the map. */ -static bool compare_ptrs_to_packet(struct bpf_verifier_env *env, - struct bpf_reg_state *old, - struct bpf_reg_state *cur) +static bool check_ids(u32 old_id, u32 cur_id, struct idpair *idmap) { - if (old->id != cur->id) - return false; + unsigned int i; + + for (i = 0; i < ID_MAP_SIZE; i++) { + if (!idmap[i].old) { + /* Reached an empty slot; haven't seen this id before */ + idmap[i].old = old_id; + idmap[i].cur = cur_id; + return true; + } + if (idmap[i].old == old_id) + return idmap[i].cur == cur_id; + } + /* We ran out of idmap slots, which should be impossible */ + WARN_ON_ONCE(1); + return false; +} - /* old ptr_to_packet is more conservative, since it allows smaller - * range. Ex: - * old(off=0,r=10) is equal to cur(off=0,r=20), because - * old(off=0,r=10) means that with range=10 the verifier proceeded - * further and found no issues with the program. Now we're in the same - * spot with cur(off=0,r=20), so we're safe too, since anything further - * will only be looking at most 10 bytes after this pointer. - */ - if (old->off == cur->off && old->range < cur->range) +/* Returns true if (rold safe implies rcur safe) */ +static bool regsafe(struct bpf_reg_state *rold, + struct bpf_reg_state *rcur, + bool varlen_map_access, struct idpair *idmap) +{ + if (memcmp(rold, rcur, sizeof(*rold)) == 0) return true; - /* old(off=20,r=10) is equal to cur(off=22,re=22 or 5 or 0) - * since both cannot be used for packet access and safe(old) - * pointer has smaller off that could be used for further - * 'if (ptr > data_end)' check - * Ex: - * old(off=20,r=10) and cur(off=22,r=22) and cur(off=22,r=0) mean - * that we cannot access the packet. - * The safe range is: - * [ptr, ptr + range - off) - * so whenever off >=range, it means no safe bytes from this pointer. - * When comparing old->off <= cur->off, it means that older code - * went with smaller offset and that offset was later - * used to figure out the safe range after 'if (ptr > data_end)' check - * Say, 'old' state was explored like: - * ... R3(off=0, r=0) - * R4 = R3 + 20 - * ... now R4(off=20,r=0) <-- here - * if (R4 > data_end) - * ... R4(off=20,r=20), R3(off=0,r=20) and R3 can be used to access. - * ... the code further went all the way to bpf_exit. - * Now the 'cur' state at the mark 'here' has R4(off=30,r=0). - * old_R4(off=20,r=0) equal to cur_R4(off=30,r=0), since if the verifier - * goes further, such cur_R4 will give larger safe packet range after - * 'if (R4 > data_end)' and all further insn were already good with r=20, - * so they will be good with r=30 and we can prune the search. - */ - if (!env->strict_alignment && old->off <= cur->off && - old->off >= old->range && cur->off >= cur->range) + if (rold->type == NOT_INIT) + /* explored state can't have used this */ return true; + if (rcur->type == NOT_INIT) + return false; + switch (rold->type) { + case SCALAR_VALUE: + if (rcur->type == SCALAR_VALUE) { + /* new val must satisfy old val knowledge */ + return range_within(rold, rcur) && + tnum_in(rold->var_off, rcur->var_off); + } else { + /* if we knew anything about the old value, we're not + * equal, because we can't know anything about the + * scalar value of the pointer in the new value. + */ + return rold->min_value == BPF_REGISTER_MIN_RANGE && + rold->max_value == BPF_REGISTER_MAX_RANGE && + tnum_is_unknown(rold->var_off); + } + case PTR_TO_MAP_VALUE: + if (varlen_map_access) { + /* If the new min/max/var_off satisfy the old ones and + * everything else matches, we are OK. + * We don't care about the 'id' value, because nothing + * uses it for PTR_TO_MAP_VALUE (only for ..._OR_NULL) + */ + return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 && + range_within(rold, rcur) && + tnum_in(rold->var_off, rcur->var_off); + } else { + /* If the ranges/var_off were not the same, but + * everything else was and we didn't do a variable + * access into a map then we are a-ok. + */ + return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0; + } + case PTR_TO_MAP_VALUE_OR_NULL: + /* a PTR_TO_MAP_VALUE could be safe to use as a + * PTR_TO_MAP_VALUE_OR_NULL into the same map. + * However, if the old PTR_TO_MAP_VALUE_OR_NULL then got NULL- + * checked, doing so could have affected others with the same + * id, and we can't check for that because we lost the id when + * we converted to a PTR_TO_MAP_VALUE. + */ + if (rcur->type != PTR_TO_MAP_VALUE_OR_NULL) + return false; + if (memcmp(rold, rcur, offsetof(struct bpf_reg_state, id))) + return false; + /* Check our ids match any regs they're supposed to */ + return check_ids(rold->id, rcur->id, idmap); + case PTR_TO_PACKET: + if (rcur->type != PTR_TO_PACKET) + return false; + /* We must have at least as much range as the old ptr + * did, so that any accesses which were safe before are + * still safe. This is true even if old range < old off, + * since someone could have accessed through (ptr - k), or + * even done ptr -= k in a register, to get a safe access. + */ + if (rold->range > rcur->range) + return false; + /* If the offsets don't match, we can't trust our alignment; + * nor can we be sure that we won't fall out of range. + */ + if (rold->off != rcur->off) + return false; + /* id relations must be preserved */ + if (rold->id && !check_ids(rold->id, rcur->id, idmap)) + return false; + /* new val must satisfy old val knowledge */ + return range_within(rold, rcur) && + tnum_in(rold->var_off, rcur->var_off); + case PTR_TO_CTX: + case CONST_PTR_TO_MAP: + case PTR_TO_STACK: + case PTR_TO_PACKET_END: + /* Only valid matches are exact, which memcmp() above + * would have accepted + */ + default: + /* Don't know what's going on, just say it's not safe */ + return false; + } + /* Shouldn't get here; if we do, say it's not safe */ + WARN_ON_ONCE(1); return false; } @@ -2947,43 +3137,19 @@ static bool states_equal(struct bpf_verifier_env *env, struct bpf_verifier_state *cur) { bool varlen_map_access = env->varlen_map_value_access; - struct bpf_reg_state *rold, *rcur; + struct idpair *idmap; + bool ret = false; int i; - for (i = 0; i < MAX_BPF_REG; i++) { - rold = &old->regs[i]; - rcur = &cur->regs[i]; - - if (memcmp(rold, rcur, sizeof(*rold)) == 0) - continue; - - /* If the ranges were not the same, but everything else was and - * we didn't do a variable access into a map then we are a-ok. - */ - if (!varlen_map_access && - memcmp(rold, rcur, offsetofend(struct bpf_reg_state, id)) == 0) - continue; - - /* If we didn't map access then again we don't care about the - * mismatched range values and it's ok if our old type was - * UNKNOWN and we didn't go to a NOT_INIT'ed reg. - */ - if (rold->type == NOT_INIT || - (!varlen_map_access && rold->type == UNKNOWN_VALUE && - rcur->type != NOT_INIT)) - continue; - - /* Don't care about the reg->id in this case. */ - if (rold->type == PTR_TO_MAP_VALUE_OR_NULL && - rcur->type == PTR_TO_MAP_VALUE_OR_NULL && - rold->map_ptr == rcur->map_ptr) - continue; - - if (rold->type == PTR_TO_PACKET && rcur->type == PTR_TO_PACKET && - compare_ptrs_to_packet(env, rold, rcur)) - continue; - + idmap = kcalloc(ID_MAP_SIZE, sizeof(struct idpair), GFP_KERNEL); + /* If we failed to allocate the idmap, just say it's not safe */ + if (!idmap) return false; + + for (i = 0; i < MAX_BPF_REG; i++) { + if (!regsafe(&old->regs[i], &cur->regs[i], varlen_map_access, + idmap)) + goto out_free; } for (i = 0; i < MAX_BPF_STACK; i++) { @@ -2995,29 +3161,32 @@ static bool states_equal(struct bpf_verifier_env *env, * this verifier states are not equivalent, * return false to continue verification of this path */ - return false; + goto out_free; if (i % BPF_REG_SIZE) continue; if (old->stack_slot_type[i] != STACK_SPILL) continue; - if (memcmp(&old->spilled_regs[i / BPF_REG_SIZE], - &cur->spilled_regs[i / BPF_REG_SIZE], - sizeof(old->spilled_regs[0]))) - /* when explored and current stack slot types are - * the same, check that stored pointers types + if (!regsafe(&old->spilled_regs[i / BPF_REG_SIZE], + &cur->spilled_regs[i / BPF_REG_SIZE], + varlen_map_access, idmap)) + /* when explored and current stack slot are both storing + * spilled registers, check that stored pointers types * are the same as well. * Ex: explored safe path could have stored - * (bpf_reg_state) {.type = PTR_TO_STACK, .imm = -8} + * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8} * but current path has stored: - * (bpf_reg_state) {.type = PTR_TO_STACK, .imm = -16} + * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16} * such verifier states are not equivalent. * return false to continue verification of this path */ - return false; + goto out_free; else continue; } - return true; + ret = true; +out_free: + kfree(idmap); + return ret; } static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) @@ -3331,7 +3500,6 @@ process_bpf_exit: verbose("invalid BPF_LD mode\n"); return -EINVAL; } - reset_reg_range_values(regs, insn->dst_reg); } else { verbose("unknown insn class %d\n", class); return -EINVAL; -- cgit v1.2.3 From b03c9f9fdc37dab81ea04d5dacdc5995d4c224c2 Mon Sep 17 00:00:00 2001 From: Edward Cree Date: Mon, 7 Aug 2017 15:26:36 +0100 Subject: bpf/verifier: track signed and unsigned min/max values Allows us to, sometimes, combine information from a signed check of one bound and an unsigned check of the other. We now track the full range of possible values, rather than restricting ourselves to [0, 1<<30) and considering anything beyond that as unknown. While this is probably not necessary, it makes the code more straightforward and symmetrical between signed and unsigned bounds. Signed-off-by: Edward Cree Signed-off-by: David S. Miller --- kernel/bpf/tnum.c | 16 ++ kernel/bpf/verifier.c | 737 +++++++++++++++++++++++++++++--------------------- 2 files changed, 445 insertions(+), 308 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/tnum.c b/kernel/bpf/tnum.c index 92eeeb1974a2..1f4bf68c12db 100644 --- a/kernel/bpf/tnum.c +++ b/kernel/bpf/tnum.c @@ -17,6 +17,22 @@ struct tnum tnum_const(u64 value) return TNUM(value, 0); } +struct tnum tnum_range(u64 min, u64 max) +{ + u64 chi = min ^ max, delta; + u8 bits = fls64(chi); + + /* special case, needed because 1ULL << 64 is undefined */ + if (bits > 63) + return tnum_unknown; + /* e.g. if chi = 4, bits = 3, delta = (1<<3) - 1 = 7. + * if chi = 0, bits = 0, delta = (1<<0) - 1 = 0, so we return + * constant min (since min == max). + */ + delta = (1ULL << bits) - 1; + return TNUM(min & ~delta, delta); +} + struct tnum tnum_lshift(struct tnum a, u8 shift) { return TNUM(a.value << shift, a.mask << shift); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c3f88b466c30..7557800bf7a7 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -234,12 +234,20 @@ static void print_verifier_state(struct bpf_verifier_state *state) verbose(",ks=%d,vs=%d", reg->map_ptr->key_size, reg->map_ptr->value_size); - if (reg->min_value != BPF_REGISTER_MIN_RANGE) - verbose(",min_value=%lld", - (long long)reg->min_value); - if (reg->max_value != BPF_REGISTER_MAX_RANGE) - verbose(",max_value=%llu", - (unsigned long long)reg->max_value); + if (reg->smin_value != reg->umin_value && + reg->smin_value != S64_MIN) + verbose(",smin_value=%lld", + (long long)reg->smin_value); + if (reg->smax_value != reg->umax_value && + reg->smax_value != S64_MAX) + verbose(",smax_value=%lld", + (long long)reg->smax_value); + if (reg->umin_value != 0) + verbose(",umin_value=%llu", + (unsigned long long)reg->umin_value); + if (reg->umax_value != U64_MAX) + verbose(",umax_value=%llu", + (unsigned long long)reg->umax_value); if (!tnum_is_unknown(reg->var_off)) { char tn_buf[48]; @@ -466,14 +474,25 @@ static const int caller_saved[CALLER_SAVED_REGS] = { static void __mark_reg_not_init(struct bpf_reg_state *reg); +/* Mark the unknown part of a register (variable offset or scalar value) as + * known to have the value @imm. + */ +static void __mark_reg_known(struct bpf_reg_state *reg, u64 imm) +{ + reg->id = 0; + reg->var_off = tnum_const(imm); + reg->smin_value = (s64)imm; + reg->smax_value = (s64)imm; + reg->umin_value = imm; + reg->umax_value = imm; +} + /* Mark the 'variable offset' part of a register as zero. This should be * used only on registers holding a pointer type. */ static void __mark_reg_known_zero(struct bpf_reg_state *reg) { - reg->var_off = tnum_const(0); - reg->min_value = 0; - reg->max_value = 0; + __mark_reg_known(reg, 0); } static void mark_reg_known_zero(struct bpf_reg_state *regs, u32 regno) @@ -488,6 +507,72 @@ static void mark_reg_known_zero(struct bpf_reg_state *regs, u32 regno) __mark_reg_known_zero(regs + regno); } +/* Attempts to improve min/max values based on var_off information */ +static void __update_reg_bounds(struct bpf_reg_state *reg) +{ + /* min signed is max(sign bit) | min(other bits) */ + reg->smin_value = max_t(s64, reg->smin_value, + reg->var_off.value | (reg->var_off.mask & S64_MIN)); + /* max signed is min(sign bit) | max(other bits) */ + reg->smax_value = min_t(s64, reg->smax_value, + reg->var_off.value | (reg->var_off.mask & S64_MAX)); + reg->umin_value = max(reg->umin_value, reg->var_off.value); + reg->umax_value = min(reg->umax_value, + reg->var_off.value | reg->var_off.mask); +} + +/* Uses signed min/max values to inform unsigned, and vice-versa */ +static void __reg_deduce_bounds(struct bpf_reg_state *reg) +{ + /* Learn sign from signed bounds. + * If we cannot cross the sign boundary, then signed and unsigned bounds + * are the same, so combine. This works even in the negative case, e.g. + * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff. + */ + if (reg->smin_value >= 0 || reg->smax_value < 0) { + reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value, + reg->umin_value); + reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value, + reg->umax_value); + return; + } + /* Learn sign from unsigned bounds. Signed bounds cross the sign + * boundary, so we must be careful. + */ + if ((s64)reg->umax_value >= 0) { + /* Positive. We can't learn anything from the smin, but smax + * is positive, hence safe. + */ + reg->smin_value = reg->umin_value; + reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value, + reg->umax_value); + } else if ((s64)reg->umin_value < 0) { + /* Negative. We can't learn anything from the smax, but smin + * is negative, hence safe. + */ + reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value, + reg->umin_value); + reg->smax_value = reg->umax_value; + } +} + +/* Attempts to improve var_off based on unsigned min/max information */ +static void __reg_bound_offset(struct bpf_reg_state *reg) +{ + reg->var_off = tnum_intersect(reg->var_off, + tnum_range(reg->umin_value, + reg->umax_value)); +} + +/* Reset the min/max bounds of a register */ +static void __mark_reg_unbounded(struct bpf_reg_state *reg) +{ + reg->smin_value = S64_MIN; + reg->smax_value = S64_MAX; + reg->umin_value = 0; + reg->umax_value = U64_MAX; +} + /* Mark a register as having a completely unknown (scalar) value. */ static void __mark_reg_unknown(struct bpf_reg_state *reg) { @@ -495,8 +580,7 @@ static void __mark_reg_unknown(struct bpf_reg_state *reg) reg->id = 0; reg->off = 0; reg->var_off = tnum_unknown; - reg->min_value = BPF_REGISTER_MIN_RANGE; - reg->max_value = BPF_REGISTER_MAX_RANGE; + __mark_reg_unbounded(reg); } static void mark_reg_unknown(struct bpf_reg_state *regs, u32 regno) @@ -545,13 +629,6 @@ static void init_reg_state(struct bpf_reg_state *regs) mark_reg_known_zero(regs, BPF_REG_1); } -static void reset_reg_range_values(struct bpf_reg_state *regs, u32 regno) -{ - regs[regno].min_value = BPF_REGISTER_MIN_RANGE; - regs[regno].max_value = BPF_REGISTER_MAX_RANGE; - regs[regno].value_from_signed = false; -} - enum reg_arg_type { SRC_OP, /* register is used as source operand */ DST_OP, /* register is used as destination operand */ @@ -716,26 +793,27 @@ static int check_map_access(struct bpf_verifier_env *env, u32 regno, * index'es we need to make sure that whatever we use * will have a set floor within our range. */ - if (reg->min_value < 0) { + if (reg->smin_value < 0) { verbose("R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", regno); return -EACCES; } - err = __check_map_access(env, regno, reg->min_value + off, size); + err = __check_map_access(env, regno, reg->smin_value + off, size); if (err) { verbose("R%d min value is outside of the array range\n", regno); return err; } - /* If we haven't set a max value then we need to bail - * since we can't be sure we won't do bad things. + /* If we haven't set a max value then we need to bail since we can't be + * sure we won't do bad things. + * If reg->umax_value + off could overflow, treat that as unbounded too. */ - if (reg->max_value == BPF_REGISTER_MAX_RANGE) { + if (reg->umax_value >= BPF_MAX_VAR_OFF) { verbose("R%d unbounded memory access, make sure to bounds check any array access into a map\n", regno); return -EACCES; } - err = __check_map_access(env, regno, reg->max_value + off, size); + err = __check_map_access(env, regno, reg->umax_value + off, size); if (err) verbose("R%d max value is outside of the array range\n", regno); return err; @@ -797,7 +875,7 @@ static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, /* We don't allow negative numbers, because we aren't tracking enough * detail to prove they're safe. */ - if (reg->min_value < 0) { + if (reg->smin_value < 0) { verbose("R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", regno); return -EACCES; @@ -1070,12 +1148,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn /* b/h/w load zero-extends, mark upper bits as known 0 */ state->regs[value_regno].var_off = tnum_cast( state->regs[value_regno].var_off, size); - /* sign bit is known zero, so we can bound the value */ - state->regs[value_regno].min_value = 0; - state->regs[value_regno].max_value = min_t(u64, - state->regs[value_regno].var_off.value | - state->regs[value_regno].var_off.mask, - BPF_REGISTER_MAX_RANGE); + __update_reg_bounds(&state->regs[value_regno]); } return err; } @@ -1333,13 +1406,13 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, */ meta = NULL; - if (reg->min_value < 0) { + if (reg->smin_value < 0) { verbose("R%d min value is negative, either use unsigned or 'var &= const'\n", regno); return -EACCES; } - if (reg->min_value == 0) { + if (reg->umin_value == 0) { err = check_helper_mem_access(env, regno - 1, 0, zero_size_allowed, meta); @@ -1347,13 +1420,13 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, return err; } - if (reg->max_value == BPF_REGISTER_MAX_RANGE) { + if (reg->umax_value >= BPF_MAX_VAR_SIZ) { verbose("R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n", regno); return -EACCES; } err = check_helper_mem_access(env, regno - 1, - reg->max_value, + reg->umax_value, zero_size_allowed, meta); } @@ -1600,33 +1673,35 @@ static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx) return 0; } -static void check_reg_overflow(struct bpf_reg_state *reg) -{ - if (reg->max_value > BPF_REGISTER_MAX_RANGE) - reg->max_value = BPF_REGISTER_MAX_RANGE; - if (reg->min_value < BPF_REGISTER_MIN_RANGE || - reg->min_value > BPF_REGISTER_MAX_RANGE) - reg->min_value = BPF_REGISTER_MIN_RANGE; -} - static void coerce_reg_to_32(struct bpf_reg_state *reg) { - /* 32-bit values can't be negative as an s64 */ - if (reg->min_value < 0) - reg->min_value = 0; /* clear high 32 bits */ reg->var_off = tnum_cast(reg->var_off, 4); - /* Did value become known? Then update bounds */ - if (tnum_is_const(reg->var_off)) { - if ((s64)reg->var_off.value > BPF_REGISTER_MIN_RANGE) - reg->min_value = reg->var_off.value; - if (reg->var_off.value < BPF_REGISTER_MAX_RANGE) - reg->max_value = reg->var_off.value; - } + /* Update bounds */ + __update_reg_bounds(reg); +} + +static bool signed_add_overflows(s64 a, s64 b) +{ + /* Do the add in u64, where overflow is well-defined */ + s64 res = (s64)((u64)a + (u64)b); + + if (b < 0) + return res > a; + return res < a; +} + +static bool signed_sub_overflows(s64 a, s64 b) +{ + /* Do the sub in u64, where overflow is well-defined */ + s64 res = (s64)((u64)a - (u64)b); + + if (b < 0) + return res < a; + return res > a; } /* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off. - * Caller must check_reg_overflow all argument regs beforehand. * Caller should also handle BPF_MOV case separately. * If we return -EACCES, caller may want to try again treating pointer as a * scalar. So we only emit a diagnostic if !env->allow_ptr_leaks. @@ -1638,16 +1713,23 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, { struct bpf_reg_state *regs = env->cur_state.regs, *dst_reg; bool known = tnum_is_const(off_reg->var_off); - s64 min_val = off_reg->min_value; - u64 max_val = off_reg->max_value; + s64 smin_val = off_reg->smin_value, smax_val = off_reg->smax_value, + smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value; + u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value, + umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value; u8 opcode = BPF_OP(insn->code); u32 dst = insn->dst_reg; dst_reg = ®s[dst]; - if (WARN_ON_ONCE(known && (min_val != max_val))) { + if (WARN_ON_ONCE(known && (smin_val != smax_val))) { + print_verifier_state(&env->cur_state); + verbose("verifier internal error: known but bad sbounds\n"); + return -EINVAL; + } + if (WARN_ON_ONCE(known && (umin_val != umax_val))) { print_verifier_state(&env->cur_state); - verbose("verifier internal error\n"); + verbose("verifier internal error: known but bad ubounds\n"); return -EINVAL; } @@ -1689,22 +1771,18 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, /* We can take a fixed offset as long as it doesn't overflow * the s32 'off' field */ - if (known && (ptr_reg->off + min_val == - (s64)(s32)(ptr_reg->off + min_val))) { + if (known && (ptr_reg->off + smin_val == + (s64)(s32)(ptr_reg->off + smin_val))) { /* pointer += K. Accumulate it into fixed offset */ - dst_reg->min_value = ptr_reg->min_value; - dst_reg->max_value = ptr_reg->max_value; + dst_reg->smin_value = smin_ptr; + dst_reg->smax_value = smax_ptr; + dst_reg->umin_value = umin_ptr; + dst_reg->umax_value = umax_ptr; dst_reg->var_off = ptr_reg->var_off; - dst_reg->off = ptr_reg->off + min_val; + dst_reg->off = ptr_reg->off + smin_val; dst_reg->range = ptr_reg->range; break; } - if (max_val == BPF_REGISTER_MAX_RANGE) { - if (!env->allow_ptr_leaks) - verbose("R%d tried to add unbounded value to pointer\n", - dst); - return -EACCES; - } /* A new variable offset is created. Note that off_reg->off * == 0, since it's a scalar. * dst_reg gets the pointer type and since some positive @@ -1714,12 +1792,22 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, * added into the variable offset, and we copy the fixed offset * from ptr_reg. */ - if (min_val <= BPF_REGISTER_MIN_RANGE) - dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) - dst_reg->min_value += min_val; - if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) - dst_reg->max_value += max_val; + if (signed_add_overflows(smin_ptr, smin_val) || + signed_add_overflows(smax_ptr, smax_val)) { + dst_reg->smin_value = S64_MIN; + dst_reg->smax_value = S64_MAX; + } else { + dst_reg->smin_value = smin_ptr + smin_val; + dst_reg->smax_value = smax_ptr + smax_val; + } + if (umin_ptr + umin_val < umin_ptr || + umax_ptr + umax_val < umax_ptr) { + dst_reg->umin_value = 0; + dst_reg->umax_value = U64_MAX; + } else { + dst_reg->umin_value = umin_ptr + umin_val; + dst_reg->umax_value = umax_ptr + umax_val; + } dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off); dst_reg->off = ptr_reg->off; if (ptr_reg->type == PTR_TO_PACKET) { @@ -1746,43 +1834,46 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, dst); return -EACCES; } - if (known && (ptr_reg->off - min_val == - (s64)(s32)(ptr_reg->off - min_val))) { + if (known && (ptr_reg->off - smin_val == + (s64)(s32)(ptr_reg->off - smin_val))) { /* pointer -= K. Subtract it from fixed offset */ - dst_reg->min_value = ptr_reg->min_value; - dst_reg->max_value = ptr_reg->max_value; + dst_reg->smin_value = smin_ptr; + dst_reg->smax_value = smax_ptr; + dst_reg->umin_value = umin_ptr; + dst_reg->umax_value = umax_ptr; dst_reg->var_off = ptr_reg->var_off; dst_reg->id = ptr_reg->id; - dst_reg->off = ptr_reg->off - min_val; + dst_reg->off = ptr_reg->off - smin_val; dst_reg->range = ptr_reg->range; break; } - /* Subtracting a negative value will just confuse everything. - * This can happen if off_reg is an immediate. - */ - if ((s64)max_val < 0) { - if (!env->allow_ptr_leaks) - verbose("R%d tried to subtract negative max_val %lld from pointer\n", - dst, (s64)max_val); - return -EACCES; - } /* A new variable offset is created. If the subtrahend is known * nonnegative, then any reg->range we had before is still good. */ - if (max_val >= BPF_REGISTER_MAX_RANGE) - dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) - dst_reg->min_value -= max_val; - if (min_val <= BPF_REGISTER_MIN_RANGE) - dst_reg->max_value = BPF_REGISTER_MAX_RANGE; - if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) - dst_reg->max_value -= min_val; + if (signed_sub_overflows(smin_ptr, smax_val) || + signed_sub_overflows(smax_ptr, smin_val)) { + /* Overflow possible, we know nothing */ + dst_reg->smin_value = S64_MIN; + dst_reg->smax_value = S64_MAX; + } else { + dst_reg->smin_value = smin_ptr - smax_val; + dst_reg->smax_value = smax_ptr - smin_val; + } + if (umin_ptr < umax_val) { + /* Overflow possible, we know nothing */ + dst_reg->umin_value = 0; + dst_reg->umax_value = U64_MAX; + } else { + /* Cannot overflow (as long as bounds are consistent) */ + dst_reg->umin_value = umin_ptr - umax_val; + dst_reg->umax_value = umax_ptr - umin_val; + } dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off); dst_reg->off = ptr_reg->off; if (ptr_reg->type == PTR_TO_PACKET) { dst_reg->id = ++env->id_gen; /* something was added to pkt_ptr, set range to zero */ - if (min_val < 0) + if (smin_val < 0) dst_reg->range = 0; } break; @@ -1805,7 +1896,9 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, return -EACCES; } - check_reg_overflow(dst_reg); + __update_reg_bounds(dst_reg); + __reg_deduce_bounds(dst_reg); + __reg_bound_offset(dst_reg); return 0; } @@ -1815,157 +1908,217 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, struct bpf_reg_state src_reg) { struct bpf_reg_state *regs = env->cur_state.regs; - s64 min_val = BPF_REGISTER_MIN_RANGE; - u64 max_val = BPF_REGISTER_MAX_RANGE; u8 opcode = BPF_OP(insn->code); bool src_known, dst_known; + s64 smin_val, smax_val; + u64 umin_val, umax_val; if (BPF_CLASS(insn->code) != BPF_ALU64) { /* 32-bit ALU ops are (32,32)->64 */ coerce_reg_to_32(dst_reg); coerce_reg_to_32(&src_reg); } - min_val = src_reg.min_value; - max_val = src_reg.max_value; + smin_val = src_reg.smin_value; + smax_val = src_reg.smax_value; + umin_val = src_reg.umin_value; + umax_val = src_reg.umax_value; src_known = tnum_is_const(src_reg.var_off); dst_known = tnum_is_const(dst_reg->var_off); switch (opcode) { case BPF_ADD: - if (min_val == BPF_REGISTER_MIN_RANGE) - dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) - dst_reg->min_value += min_val; - /* if max_val is MAX_RANGE, this will saturate dst->max */ - if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) - dst_reg->max_value += max_val; + if (signed_add_overflows(dst_reg->smin_value, smin_val) || + signed_add_overflows(dst_reg->smax_value, smax_val)) { + dst_reg->smin_value = S64_MIN; + dst_reg->smax_value = S64_MAX; + } else { + dst_reg->smin_value += smin_val; + dst_reg->smax_value += smax_val; + } + if (dst_reg->umin_value + umin_val < umin_val || + dst_reg->umax_value + umax_val < umax_val) { + dst_reg->umin_value = 0; + dst_reg->umax_value = U64_MAX; + } else { + dst_reg->umin_value += umin_val; + dst_reg->umax_value += umax_val; + } dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off); break; case BPF_SUB: - if (max_val == BPF_REGISTER_MAX_RANGE) - dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) - dst_reg->min_value -= max_val; - if (min_val == BPF_REGISTER_MIN_RANGE) - dst_reg->max_value = BPF_REGISTER_MAX_RANGE; - if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) - dst_reg->max_value -= min_val; + if (signed_sub_overflows(dst_reg->smin_value, smax_val) || + signed_sub_overflows(dst_reg->smax_value, smin_val)) { + /* Overflow possible, we know nothing */ + dst_reg->smin_value = S64_MIN; + dst_reg->smax_value = S64_MAX; + } else { + dst_reg->smin_value -= smax_val; + dst_reg->smax_value -= smin_val; + } + if (dst_reg->umin_value < umax_val) { + /* Overflow possible, we know nothing */ + dst_reg->umin_value = 0; + dst_reg->umax_value = U64_MAX; + } else { + /* Cannot overflow (as long as bounds are consistent) */ + dst_reg->umin_value -= umax_val; + dst_reg->umax_value -= umin_val; + } dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off); break; case BPF_MUL: - if (min_val < 0 || dst_reg->min_value < 0) { + dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off); + if (smin_val < 0 || dst_reg->smin_value < 0) { /* Ain't nobody got time to multiply that sign */ - __mark_reg_unknown(dst_reg); + __mark_reg_unbounded(dst_reg); + __update_reg_bounds(dst_reg); break; } - dst_reg->min_value *= min_val; - /* if max_val is MAX_RANGE, this will saturate dst->max. - * We know MAX_RANGE ** 2 won't overflow a u64, because - * MAX_RANGE itself fits in a u32. + /* Both values are positive, so we can work with unsigned and + * copy the result to signed (unless it exceeds S64_MAX). */ - BUILD_BUG_ON(BPF_REGISTER_MAX_RANGE > (u32)-1); - if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) - dst_reg->max_value *= max_val; - dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off); + if (umax_val > U32_MAX || dst_reg->umax_value > U32_MAX) { + /* Potential overflow, we know nothing */ + __mark_reg_unbounded(dst_reg); + /* (except what we can learn from the var_off) */ + __update_reg_bounds(dst_reg); + break; + } + dst_reg->umin_value *= umin_val; + dst_reg->umax_value *= umax_val; + if (dst_reg->umax_value > S64_MAX) { + /* Overflow possible, we know nothing */ + dst_reg->smin_value = S64_MIN; + dst_reg->smax_value = S64_MAX; + } else { + dst_reg->smin_value = dst_reg->umin_value; + dst_reg->smax_value = dst_reg->umax_value; + } break; case BPF_AND: if (src_known && dst_known) { - u64 value = dst_reg->var_off.value & src_reg.var_off.value; - - dst_reg->var_off = tnum_const(value); - dst_reg->min_value = dst_reg->max_value = min_t(u64, - value, BPF_REGISTER_MAX_RANGE); + __mark_reg_known(dst_reg, dst_reg->var_off.value & + src_reg.var_off.value); break; } - /* Lose min_value when AND'ing negative numbers, ain't nobody - * got time for that. Otherwise we get our minimum from the - * var_off, since that's inherently bitwise. - * Our maximum is the minimum of the operands' maxima. + /* We get our minimum from the var_off, since that's inherently + * bitwise. Our maximum is the minimum of the operands' maxima. */ dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg.var_off); - if (min_val < 0 && dst_reg->min_value < 0) - dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - else - dst_reg->min_value = dst_reg->var_off.value; - dst_reg->max_value = min(dst_reg->max_value, max_val); + dst_reg->umin_value = dst_reg->var_off.value; + dst_reg->umax_value = min(dst_reg->umax_value, umax_val); + if (dst_reg->smin_value < 0 || smin_val < 0) { + /* Lose signed bounds when ANDing negative numbers, + * ain't nobody got time for that. + */ + dst_reg->smin_value = S64_MIN; + dst_reg->smax_value = S64_MAX; + } else { + /* ANDing two positives gives a positive, so safe to + * cast result into s64. + */ + dst_reg->smin_value = dst_reg->umin_value; + dst_reg->smax_value = dst_reg->umax_value; + } + /* We may learn something more from the var_off */ + __update_reg_bounds(dst_reg); break; case BPF_OR: if (src_known && dst_known) { - u64 value = dst_reg->var_off.value | src_reg.var_off.value; - - dst_reg->var_off = tnum_const(value); - dst_reg->min_value = dst_reg->max_value = min_t(u64, - value, BPF_REGISTER_MAX_RANGE); + __mark_reg_known(dst_reg, dst_reg->var_off.value | + src_reg.var_off.value); break; } - /* Lose ranges when OR'ing negative numbers, ain't nobody got - * time for that. Otherwise we get our maximum from the var_off, - * and our minimum is the maximum of the operands' minima. + /* We get our maximum from the var_off, and our minimum is the + * maximum of the operands' minima */ dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg.var_off); - if (min_val < 0 || dst_reg->min_value < 0) { - dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - dst_reg->max_value = BPF_REGISTER_MAX_RANGE; + dst_reg->umin_value = max(dst_reg->umin_value, umin_val); + dst_reg->umax_value = dst_reg->var_off.value | + dst_reg->var_off.mask; + if (dst_reg->smin_value < 0 || smin_val < 0) { + /* Lose signed bounds when ORing negative numbers, + * ain't nobody got time for that. + */ + dst_reg->smin_value = S64_MIN; + dst_reg->smax_value = S64_MAX; } else { - dst_reg->min_value = max(dst_reg->min_value, min_val); - dst_reg->max_value = dst_reg->var_off.value | dst_reg->var_off.mask; + /* ORing two positives gives a positive, so safe to + * cast result into s64. + */ + dst_reg->smin_value = dst_reg->umin_value; + dst_reg->smax_value = dst_reg->umax_value; } + /* We may learn something more from the var_off */ + __update_reg_bounds(dst_reg); break; case BPF_LSH: - if (min_val < 0) { - /* LSH by a negative number is undefined */ + if (umax_val > 63) { + /* Shifts greater than 63 are undefined. This includes + * shifts by a negative number. + */ mark_reg_unknown(regs, insn->dst_reg); break; } - /* Gotta have special overflow logic here, if we're shifting - * more than MAX_RANGE then just assume we have an invalid - * range. + /* We lose all sign bit information (except what we can pick + * up from var_off) */ - if (min_val > ilog2(BPF_REGISTER_MAX_RANGE)) { - dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - dst_reg->var_off = tnum_unknown; + dst_reg->smin_value = S64_MIN; + dst_reg->smax_value = S64_MAX; + /* If we might shift our top bit out, then we know nothing */ + if (dst_reg->umax_value > 1ULL << (63 - umax_val)) { + dst_reg->umin_value = 0; + dst_reg->umax_value = U64_MAX; } else { - if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) - dst_reg->min_value <<= min_val; - if (src_known) - dst_reg->var_off = tnum_lshift(dst_reg->var_off, min_val); - else - dst_reg->var_off = tnum_lshift(tnum_unknown, min_val); + dst_reg->umin_value <<= umin_val; + dst_reg->umax_value <<= umax_val; } - if (max_val > ilog2(BPF_REGISTER_MAX_RANGE)) - dst_reg->max_value = BPF_REGISTER_MAX_RANGE; - else if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) - dst_reg->max_value <<= max_val; + if (src_known) + dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val); + else + dst_reg->var_off = tnum_lshift(tnum_unknown, umin_val); + /* We may learn something more from the var_off */ + __update_reg_bounds(dst_reg); break; case BPF_RSH: - if (min_val < 0) { - /* RSH by a negative number is undefined */ + if (umax_val > 63) { + /* Shifts greater than 63 are undefined. This includes + * shifts by a negative number. + */ mark_reg_unknown(regs, insn->dst_reg); break; } /* BPF_RSH is an unsigned shift, so make the appropriate casts */ - if (dst_reg->min_value < 0) { - if (min_val) + if (dst_reg->smin_value < 0) { + if (umin_val) { /* Sign bit will be cleared */ - dst_reg->min_value = 0; + dst_reg->smin_value = 0; + } else { + /* Lost sign bit information */ + dst_reg->smin_value = S64_MIN; + dst_reg->smax_value = S64_MAX; + } } else { - dst_reg->min_value = - (u64)(dst_reg->min_value) >> min_val; + dst_reg->smin_value = + (u64)(dst_reg->smin_value) >> umax_val; } if (src_known) - dst_reg->var_off = tnum_rshift(dst_reg->var_off, min_val); + dst_reg->var_off = tnum_rshift(dst_reg->var_off, + umin_val); else - dst_reg->var_off = tnum_rshift(tnum_unknown, min_val); - if (dst_reg->max_value == BPF_REGISTER_MAX_RANGE) - dst_reg->max_value = ~0; - dst_reg->max_value >>= max_val; + dst_reg->var_off = tnum_rshift(tnum_unknown, umin_val); + dst_reg->umin_value >>= umax_val; + dst_reg->umax_value >>= umin_val; + /* We may learn something more from the var_off */ + __update_reg_bounds(dst_reg); break; default: mark_reg_unknown(regs, insn->dst_reg); break; } - check_reg_overflow(dst_reg); + __reg_deduce_bounds(dst_reg); + __reg_bound_offset(dst_reg); return 0; } @@ -1981,14 +2134,11 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, int rc; dst_reg = ®s[insn->dst_reg]; - check_reg_overflow(dst_reg); src_reg = NULL; if (dst_reg->type != SCALAR_VALUE) ptr_reg = dst_reg; if (BPF_SRC(insn->code) == BPF_X) { src_reg = ®s[insn->src_reg]; - check_reg_overflow(src_reg); - if (src_reg->type != SCALAR_VALUE) { if (dst_reg->type != SCALAR_VALUE) { /* Combining two pointers by any ALU op yields @@ -2035,11 +2185,8 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, * need to be able to read from this state. */ off_reg.type = SCALAR_VALUE; - off_reg.var_off = tnum_const(insn->imm); - off_reg.min_value = insn->imm; - off_reg.max_value = insn->imm; + __mark_reg_known(&off_reg, insn->imm); src_reg = &off_reg; - check_reg_overflow(src_reg); if (ptr_reg) { /* pointer += K */ rc = adjust_ptr_min_max_vals(env, insn, ptr_reg, src_reg); @@ -2144,22 +2291,17 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) return -EACCES; } mark_reg_unknown(regs, insn->dst_reg); - /* high 32 bits are known zero. But this is - * still out of range for max_value, so leave - * that. - */ + /* high 32 bits are known zero. */ regs[insn->dst_reg].var_off = tnum_cast( regs[insn->dst_reg].var_off, 4); + __update_reg_bounds(®s[insn->dst_reg]); } } else { /* case: R = imm * remember the value we stored into this reg */ regs[insn->dst_reg].type = SCALAR_VALUE; - regs[insn->dst_reg].var_off = tnum_const(insn->imm); - regs[insn->dst_reg].max_value = insn->imm; - regs[insn->dst_reg].min_value = insn->imm; - regs[insn->dst_reg].id = 0; + __mark_reg_known(regs + insn->dst_reg, insn->imm); } } else if (opcode > BPF_END) { @@ -2226,8 +2368,8 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *state, /* This doesn't give us any range */ return; - if (dst_reg->max_value > MAX_PACKET_OFF || - dst_reg->max_value + dst_reg->off > MAX_PACKET_OFF) + if (dst_reg->umax_value > MAX_PACKET_OFF || + dst_reg->umax_value + dst_reg->off > MAX_PACKET_OFF) /* Risk of overflow. For instance, ptr + (1<<63) may be less * than pkt_end, but that's because it's also less than pkt. */ @@ -2291,8 +2433,6 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, struct bpf_reg_state *false_reg, u64 val, u8 opcode) { - bool value_from_signed = true; - /* If the dst_reg is a pointer, we can't learn anything about its * variable offset from the compare (unless src_reg were a pointer into * the same object, but we don't bother with that. @@ -2307,62 +2447,45 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, /* If this is false then we know nothing Jon Snow, but if it is * true then we know for sure. */ - true_reg->max_value = true_reg->min_value = val; - true_reg->var_off = tnum_const(val); + __mark_reg_known(true_reg, val); break; case BPF_JNE: /* If this is true we know nothing Jon Snow, but if it is false * we know the value for sure; */ - false_reg->max_value = false_reg->min_value = val; - false_reg->var_off = tnum_const(val); + __mark_reg_known(false_reg, val); break; case BPF_JGT: - value_from_signed = false; - /* fallthrough */ + false_reg->umax_value = min(false_reg->umax_value, val); + true_reg->umin_value = max(true_reg->umin_value, val + 1); + break; case BPF_JSGT: - if (true_reg->value_from_signed != value_from_signed) - reset_reg_range_values(true_reg, 0); - if (false_reg->value_from_signed != value_from_signed) - reset_reg_range_values(false_reg, 0); - if (opcode == BPF_JGT) { - /* Unsigned comparison, the minimum value is 0. */ - false_reg->min_value = 0; - } - /* If this is false then we know the maximum val is val, - * otherwise we know the min val is val+1. - */ - false_reg->max_value = val; - false_reg->value_from_signed = value_from_signed; - true_reg->min_value = val + 1; - true_reg->value_from_signed = value_from_signed; + false_reg->smax_value = min_t(s64, false_reg->smax_value, val); + true_reg->smin_value = max_t(s64, true_reg->smin_value, val + 1); break; case BPF_JGE: - value_from_signed = false; - /* fallthrough */ + false_reg->umax_value = min(false_reg->umax_value, val - 1); + true_reg->umin_value = max(true_reg->umin_value, val); + break; case BPF_JSGE: - if (true_reg->value_from_signed != value_from_signed) - reset_reg_range_values(true_reg, 0); - if (false_reg->value_from_signed != value_from_signed) - reset_reg_range_values(false_reg, 0); - if (opcode == BPF_JGE) { - /* Unsigned comparison, the minimum value is 0. */ - false_reg->min_value = 0; - } - /* If this is false then we know the maximum value is val - 1, - * otherwise we know the mimimum value is val. - */ - false_reg->max_value = val - 1; - false_reg->value_from_signed = value_from_signed; - true_reg->min_value = val; - true_reg->value_from_signed = value_from_signed; + false_reg->smax_value = min_t(s64, false_reg->smax_value, val - 1); + true_reg->smin_value = max_t(s64, true_reg->smin_value, val); break; default: break; } - check_reg_overflow(false_reg); - check_reg_overflow(true_reg); + __reg_deduce_bounds(false_reg); + __reg_deduce_bounds(true_reg); + /* We might have learned some bits from the bounds. */ + __reg_bound_offset(false_reg); + __reg_bound_offset(true_reg); + /* Intersecting with the old var_off might have improved our bounds + * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), + * then new var_off is (0; 0x7f...fc) which improves our umax. + */ + __update_reg_bounds(false_reg); + __update_reg_bounds(true_reg); } /* Same as above, but for the case that dst_reg holds a constant and src_reg is @@ -2372,8 +2495,6 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, struct bpf_reg_state *false_reg, u64 val, u8 opcode) { - bool value_from_signed = true; - if (__is_pointer_value(false, false_reg)) return; @@ -2382,77 +2503,76 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, /* If this is false then we know nothing Jon Snow, but if it is * true then we know for sure. */ - true_reg->max_value = true_reg->min_value = val; - true_reg->var_off = tnum_const(val); + __mark_reg_known(true_reg, val); break; case BPF_JNE: /* If this is true we know nothing Jon Snow, but if it is false * we know the value for sure; */ - false_reg->max_value = false_reg->min_value = val; - false_reg->var_off = tnum_const(val); + __mark_reg_known(false_reg, val); break; case BPF_JGT: - value_from_signed = false; - /* fallthrough */ + true_reg->umax_value = min(true_reg->umax_value, val - 1); + false_reg->umin_value = max(false_reg->umin_value, val); + break; case BPF_JSGT: - if (true_reg->value_from_signed != value_from_signed) - reset_reg_range_values(true_reg, 0); - if (false_reg->value_from_signed != value_from_signed) - reset_reg_range_values(false_reg, 0); - if (opcode == BPF_JGT) { - /* Unsigned comparison, the minimum value is 0. */ - true_reg->min_value = 0; - } - /* - * If this is false, then the val is <= the register, if it is - * true the register <= to the val. - */ - false_reg->min_value = val; - false_reg->value_from_signed = value_from_signed; - true_reg->max_value = val - 1; - true_reg->value_from_signed = value_from_signed; + true_reg->smax_value = min_t(s64, true_reg->smax_value, val - 1); + false_reg->smin_value = max_t(s64, false_reg->smin_value, val); break; case BPF_JGE: - value_from_signed = false; - /* fallthrough */ + true_reg->umax_value = min(true_reg->umax_value, val); + false_reg->umin_value = max(false_reg->umin_value, val + 1); + break; case BPF_JSGE: - if (true_reg->value_from_signed != value_from_signed) - reset_reg_range_values(true_reg, 0); - if (false_reg->value_from_signed != value_from_signed) - reset_reg_range_values(false_reg, 0); - if (opcode == BPF_JGE) { - /* Unsigned comparison, the minimum value is 0. */ - true_reg->min_value = 0; - } - /* If this is false then constant < register, if it is true then - * the register < constant. - */ - false_reg->min_value = val + 1; - false_reg->value_from_signed = value_from_signed; - true_reg->max_value = val; - true_reg->value_from_signed = value_from_signed; + true_reg->smax_value = min_t(s64, true_reg->smax_value, val); + false_reg->smin_value = max_t(s64, false_reg->smin_value, val + 1); break; default: break; } - check_reg_overflow(false_reg); - check_reg_overflow(true_reg); + __reg_deduce_bounds(false_reg); + __reg_deduce_bounds(true_reg); + /* We might have learned some bits from the bounds. */ + __reg_bound_offset(false_reg); + __reg_bound_offset(true_reg); + /* Intersecting with the old var_off might have improved our bounds + * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), + * then new var_off is (0; 0x7f...fc) which improves our umax. + */ + __update_reg_bounds(false_reg); + __update_reg_bounds(true_reg); } /* Regs are known to be equal, so intersect their min/max/var_off */ static void __reg_combine_min_max(struct bpf_reg_state *src_reg, struct bpf_reg_state *dst_reg) { - src_reg->min_value = dst_reg->min_value = max(src_reg->min_value, - dst_reg->min_value); - src_reg->max_value = dst_reg->max_value = min(src_reg->max_value, - dst_reg->max_value); + src_reg->umin_value = dst_reg->umin_value = max(src_reg->umin_value, + dst_reg->umin_value); + src_reg->umax_value = dst_reg->umax_value = min(src_reg->umax_value, + dst_reg->umax_value); + src_reg->smin_value = dst_reg->smin_value = max(src_reg->smin_value, + dst_reg->smin_value); + src_reg->smax_value = dst_reg->smax_value = min(src_reg->smax_value, + dst_reg->smax_value); src_reg->var_off = dst_reg->var_off = tnum_intersect(src_reg->var_off, dst_reg->var_off); - check_reg_overflow(src_reg); - check_reg_overflow(dst_reg); + /* We might have learned new bounds from the var_off. */ + __update_reg_bounds(src_reg); + __update_reg_bounds(dst_reg); + /* We might have learned something about the sign bit. */ + __reg_deduce_bounds(src_reg); + __reg_deduce_bounds(dst_reg); + /* We might have learned some bits from the bounds. */ + __reg_bound_offset(src_reg); + __reg_bound_offset(dst_reg); + /* Intersecting with the old var_off might have improved our bounds + * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), + * then new var_off is (0; 0x7f...fc) which improves our umax. + */ + __update_reg_bounds(src_reg); + __update_reg_bounds(dst_reg); } static void reg_combine_min_max(struct bpf_reg_state *true_src, @@ -2467,6 +2587,7 @@ static void reg_combine_min_max(struct bpf_reg_state *true_src, break; case BPF_JNE: __reg_combine_min_max(false_src, false_dst); + break; } } @@ -2480,11 +2601,11 @@ static void mark_map_reg(struct bpf_reg_state *regs, u32 regno, u32 id, * have been known-zero, because we don't allow pointer * arithmetic on pointers that might be NULL. */ - if (WARN_ON_ONCE(reg->min_value || reg->max_value || - reg->var_off.value || reg->var_off.mask || + if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || + !tnum_equals_const(reg->var_off, 0) || reg->off)) { - reg->min_value = reg->max_value = reg->off = 0; - reg->var_off = tnum_const(0); + __mark_reg_known_zero(reg); + reg->off = 0; } if (is_null) { reg->type = SCALAR_VALUE; @@ -2676,11 +2797,7 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; regs[insn->dst_reg].type = SCALAR_VALUE; - regs[insn->dst_reg].min_value = imm; - regs[insn->dst_reg].max_value = imm; - check_reg_overflow(®s[insn->dst_reg]); - regs[insn->dst_reg].var_off = tnum_const(imm); - regs[insn->dst_reg].id = 0; + __mark_reg_known(®s[insn->dst_reg], imm); return 0; } @@ -2968,8 +3085,10 @@ err_free: static bool range_within(struct bpf_reg_state *old, struct bpf_reg_state *cur) { - return old->min_value <= cur->min_value && - old->max_value >= cur->max_value; + return old->umin_value <= cur->umin_value && + old->umax_value >= cur->umax_value && + old->smin_value <= cur->smin_value && + old->smax_value >= cur->smax_value; } /* Maximum number of register states that can exist at once */ @@ -3032,8 +3151,10 @@ static bool regsafe(struct bpf_reg_state *rold, * equal, because we can't know anything about the * scalar value of the pointer in the new value. */ - return rold->min_value == BPF_REGISTER_MIN_RANGE && - rold->max_value == BPF_REGISTER_MAX_RANGE && + return rold->umin_value == 0 && + rold->umax_value == U64_MAX && + rold->smin_value == S64_MIN && + rold->smax_value == S64_MAX && tnum_is_unknown(rold->var_off); } case PTR_TO_MAP_VALUE: -- cgit v1.2.3 From 7d1238f21026e277936fff408b73bc19e89239a8 Mon Sep 17 00:00:00 2001 From: Edward Cree Date: Mon, 7 Aug 2017 15:26:56 +0100 Subject: bpf/verifier: more concise register state logs for constant var_off Signed-off-by: Edward Cree Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 46 +++++++++++++++++++++++++++------------------- 1 file changed, 27 insertions(+), 19 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 7557800bf7a7..08a6fa0369c2 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -234,25 +234,33 @@ static void print_verifier_state(struct bpf_verifier_state *state) verbose(",ks=%d,vs=%d", reg->map_ptr->key_size, reg->map_ptr->value_size); - if (reg->smin_value != reg->umin_value && - reg->smin_value != S64_MIN) - verbose(",smin_value=%lld", - (long long)reg->smin_value); - if (reg->smax_value != reg->umax_value && - reg->smax_value != S64_MAX) - verbose(",smax_value=%lld", - (long long)reg->smax_value); - if (reg->umin_value != 0) - verbose(",umin_value=%llu", - (unsigned long long)reg->umin_value); - if (reg->umax_value != U64_MAX) - verbose(",umax_value=%llu", - (unsigned long long)reg->umax_value); - if (!tnum_is_unknown(reg->var_off)) { - char tn_buf[48]; - - tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); - verbose(",var_off=%s", tn_buf); + if (tnum_is_const(reg->var_off)) { + /* Typically an immediate SCALAR_VALUE, but + * could be a pointer whose offset is too big + * for reg->off + */ + verbose(",imm=%llx", reg->var_off.value); + } else { + if (reg->smin_value != reg->umin_value && + reg->smin_value != S64_MIN) + verbose(",smin_value=%lld", + (long long)reg->smin_value); + if (reg->smax_value != reg->umax_value && + reg->smax_value != S64_MAX) + verbose(",smax_value=%lld", + (long long)reg->smax_value); + if (reg->umin_value != 0) + verbose(",umin_value=%llu", + (unsigned long long)reg->umin_value); + if (reg->umax_value != U64_MAX) + verbose(",umax_value=%llu", + (unsigned long long)reg->umax_value); + if (!tnum_is_unknown(reg->var_off)) { + char tn_buf[48]; + + tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); + verbose(",var_off=%s", tn_buf); + } } verbose(")"); } -- cgit v1.2.3 From 8e17c1b16277cba0e9426de6fe78817df378f45c Mon Sep 17 00:00:00 2001 From: Edward Cree Date: Mon, 7 Aug 2017 15:30:30 +0100 Subject: bpf/verifier: increase complexity limit to 128k The more detailed value tracking can reduce the effectiveness of pruning for some programs. So, to avoid rejecting previously valid programs, up the limit to 128kinsns. Hopefully we will be able to bring this back down later by improving pruning performance. Signed-off-by: Edward Cree Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 08a6fa0369c2..8160a81a40bf 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -140,7 +140,7 @@ struct bpf_verifier_stack_elem { struct bpf_verifier_stack_elem *next; }; -#define BPF_COMPLEXITY_LIMIT_INSNS 98304 +#define BPF_COMPLEXITY_LIMIT_INSNS 131072 #define BPF_COMPLEXITY_LIMIT_STACK 1024 #define BPF_MAP_PTR_POISON ((void *)0xeB9F + POISON_POINTER_DELTA) -- cgit v1.2.3 From 58291a7465f6b88248c9f34807c16705bd5698f8 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= Date: Mon, 7 Aug 2017 20:45:19 +0200 Subject: bpf: Move check_uarg_tail_zero() upward MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The function check_uarg_tail_zero() may be useful for other part of the code in the syscall.c file. Move this function at the beginning of the file. Signed-off-by: Mickaël Salaün Acked-by: Daniel Borkmann Cc: Alexei Starovoitov Cc: David S. Miller Cc: Kees Cook Cc: Martin KaFai Lau Signed-off-by: David S. Miller --- kernel/bpf/syscall.c | 52 ++++++++++++++++++++++++++-------------------------- 1 file changed, 26 insertions(+), 26 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 6c772adabad2..c653ee0bd162 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -48,6 +48,32 @@ static const struct bpf_map_ops * const bpf_map_types[] = { #undef BPF_MAP_TYPE }; +static int check_uarg_tail_zero(void __user *uaddr, + size_t expected_size, + size_t actual_size) +{ + unsigned char __user *addr; + unsigned char __user *end; + unsigned char val; + int err; + + if (actual_size <= expected_size) + return 0; + + addr = uaddr + expected_size; + end = uaddr + actual_size; + + for (; addr < end; addr++) { + err = get_user(val, addr); + if (err) + return err; + if (val) + return -E2BIG; + } + + return 0; +} + static struct bpf_map *find_and_alloc_map(union bpf_attr *attr) { struct bpf_map *map; @@ -1246,32 +1272,6 @@ static int bpf_map_get_fd_by_id(const union bpf_attr *attr) return fd; } -static int check_uarg_tail_zero(void __user *uaddr, - size_t expected_size, - size_t actual_size) -{ - unsigned char __user *addr; - unsigned char __user *end; - unsigned char val; - int err; - - if (actual_size <= expected_size) - return 0; - - addr = uaddr + expected_size; - end = uaddr + actual_size; - - for (; addr < end; addr++) { - err = get_user(val, addr); - if (err) - return err; - if (val) - return -E2BIG; - } - - return 0; -} - static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, const union bpf_attr *attr, union bpf_attr __user *uattr) -- cgit v1.2.3 From 752ba56fb130b27c32c2ae6c82c8ef246b22106c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= Date: Mon, 7 Aug 2017 20:45:20 +0200 Subject: bpf: Extend check_uarg_tail_zero() checks MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The function check_uarg_tail_zero() was created from bpf(2) for BPF_OBJ_GET_INFO_BY_FD without taking the access_ok() nor the PAGE_SIZE checks. Make this checks more generally available while unlikely to be triggered, extend the memory range check and add an explanation including why the ToCToU should not be a security concern. Signed-off-by: Mickaël Salaün Acked-by: Daniel Borkmann Cc: Alexei Starovoitov Cc: David S. Miller Cc: Kees Cook Cc: Martin KaFai Lau Link: https://lkml.kernel.org/r/CAGXu5j+vRGFvJZmjtAcT8Hi8B+Wz0e1b6VKYZHfQP_=DXzC4CQ@mail.gmail.com Signed-off-by: David S. Miller --- kernel/bpf/syscall.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index c653ee0bd162..fbe09a0cccf4 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -48,6 +48,15 @@ static const struct bpf_map_ops * const bpf_map_types[] = { #undef BPF_MAP_TYPE }; +/* + * If we're handed a bigger struct than we know of, ensure all the unknown bits + * are 0 - i.e. new user-space does not rely on any kernel feature extensions + * we don't know about yet. + * + * There is a ToCToU between this function call and the following + * copy_from_user() call. However, this is not a concern since this function is + * meant to be a future-proofing of bits. + */ static int check_uarg_tail_zero(void __user *uaddr, size_t expected_size, size_t actual_size) @@ -57,6 +66,12 @@ static int check_uarg_tail_zero(void __user *uaddr, unsigned char val; int err; + if (unlikely(actual_size > PAGE_SIZE)) /* silly large */ + return -E2BIG; + + if (unlikely(!access_ok(VERIFY_READ, uaddr, actual_size))) + return -EFAULT; + if (actual_size <= expected_size) return 0; @@ -1393,17 +1408,6 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz if (!capable(CAP_SYS_ADMIN) && sysctl_unprivileged_bpf_disabled) return -EPERM; - if (!access_ok(VERIFY_READ, uattr, 1)) - return -EFAULT; - - if (size > PAGE_SIZE) /* silly large */ - return -E2BIG; - - /* If we're handed a bigger struct than we know of, - * ensure all the unknown bits are 0 - i.e. new - * user-space does not rely on any kernel feature - * extensions we dont know about yet. - */ err = check_uarg_tail_zero(uattr, sizeof(attr), size); if (err) return err; -- cgit v1.2.3 From 48fb6f4db940e92cfb16cd878cddd59ea6120d06 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Wed, 9 Aug 2017 08:27:11 +0100 Subject: futex: Remove unnecessary warning from get_futex_key Commit 65d8fc777f6d ("futex: Remove requirement for lock_page() in get_futex_key()") removed an unnecessary lock_page() with the side-effect that page->mapping needed to be treated very carefully. Two defensive warnings were added in case any assumption was missed and the first warning assumed a correct application would not alter a mapping backing a futex key. Since merging, it has not triggered for any unexpected case but Mark Rutland reported the following bug triggering due to the first warning. kernel BUG at kernel/futex.c:679! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 3695 Comm: syz-executor1 Not tainted 4.13.0-rc3-00020-g307fec773ba3 #3 Hardware name: linux,dummy-virt (DT) task: ffff80001e271780 task.stack: ffff000010908000 PC is at get_futex_key+0x6a4/0xcf0 kernel/futex.c:679 LR is at get_futex_key+0x6a4/0xcf0 kernel/futex.c:679 pc : [] lr : [] pstate: 80000145 The fact that it's a bug instead of a warning was due to an unrelated arm64 problem, but the warning itself triggered because the underlying mapping changed. This is an application issue but from a kernel perspective it's a recoverable situation and the warning is unnecessary so this patch removes the warning. The warning may potentially be triggered with the following test program from Mark although it may be necessary to adjust NR_FUTEX_THREADS to be a value smaller than the number of CPUs in the system. #include #include #include #include #include #include #include #include #define NR_FUTEX_THREADS 16 pthread_t threads[NR_FUTEX_THREADS]; void *mem; #define MEM_PROT (PROT_READ | PROT_WRITE) #define MEM_SIZE 65536 static int futex_wrapper(int *uaddr, int op, int val, const struct timespec *timeout, int *uaddr2, int val3) { syscall(SYS_futex, uaddr, op, val, timeout, uaddr2, val3); } void *poll_futex(void *unused) { for (;;) { futex_wrapper(mem, FUTEX_CMP_REQUEUE_PI, 1, NULL, mem + 4, 1); } } int main(int argc, char *argv[]) { int i; mem = mmap(NULL, MEM_SIZE, MEM_PROT, MAP_SHARED | MAP_ANONYMOUS, -1, 0); printf("Mapping @ %p\n", mem); printf("Creating futex threads...\n"); for (i = 0; i < NR_FUTEX_THREADS; i++) pthread_create(&threads[i], NULL, poll_futex, NULL); printf("Flipping mapping...\n"); for (;;) { mmap(mem, MEM_SIZE, MEM_PROT, MAP_FIXED | MAP_SHARED | MAP_ANONYMOUS, -1, 0); } return 0; } Reported-and-tested-by: Mark Rutland Signed-off-by: Mel Gorman Acked-by: Peter Zijlstra (Intel) Cc: stable@vger.kernel.org # 4.7+ Signed-off-by: Linus Torvalds --- kernel/futex.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index 16dbe4c93895..f50b434756c1 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -670,13 +670,14 @@ again: * this reference was taken by ihold under the page lock * pinning the inode in place so i_lock was unnecessary. The * only way for this check to fail is if the inode was - * truncated in parallel so warn for now if this happens. + * truncated in parallel which is almost certainly an + * application bug. In such a case, just retry. * * We are not calling into get_futex_key_refs() in file-backed * cases, therefore a successful atomic_inc return below will * guarantee that get_futex_key() will still imply smp_mb(); (B). */ - if (WARN_ON_ONCE(!atomic_inc_not_zero(&inode->i_count))) { + if (!atomic_inc_not_zero(&inode->i_count)) { rcu_read_unlock(); put_page(page); -- cgit v1.2.3 From 209887e6b974c22328487b55d0f390522b014b03 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 9 Aug 2017 10:21:46 +0530 Subject: cpufreq: Return 0 from ->fast_switch() on errors CPUFREQ_ENTRY_INVALID is a special symbol which is used to specify that an entry in the cpufreq table is invalid. But using it outside of the scope of the cpufreq table looks a bit incorrect. We can represent an invalid frequency by writing it as 0 instead if we need. Note that it is already done that way for the return value of the ->get() callback. Lets do the same for ->fast_switch() and not use CPUFREQ_ENTRY_INVALID outside of the scope of cpufreq table. Also update the comment over cpufreq_driver_fast_switch() to clearly mention what this returns. None of the drivers return CPUFREQ_ENTRY_INVALID as of now from ->fast_switch() callback and so we don't need to update any of those. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- kernel/sched/cpufreq_schedutil.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 7dbc76801f86..2ba04bb3182a 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -123,7 +123,7 @@ static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time, if (policy->fast_switch_enabled) { next_freq = cpufreq_driver_fast_switch(policy, next_freq); - if (next_freq == CPUFREQ_ENTRY_INVALID) + if (!next_freq) return; policy->cur = next_freq; -- cgit v1.2.3 From 92b31a9af73b3a3fc801899335d6c47966351830 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 10 Aug 2017 01:39:55 +0200 Subject: bpf: add BPF_J{LT,LE,SLT,SLE} instructions Currently, eBPF only understands BPF_JGT (>), BPF_JGE (>=), BPF_JSGT (s>), BPF_JSGE (s>=) instructions, this means that particularly *JLT/*JLE counterparts involving immediates need to be rewritten from e.g. X < [IMM] by swapping arguments into [IMM] > X, meaning the immediate first is required to be loaded into a register Y := [IMM], such that then we can compare with Y > X. Note that the destination operand is always required to be a register. This has the downside of having unnecessarily increased register pressure, meaning complex program would need to spill other registers temporarily to stack in order to obtain an unused register for the [IMM]. Loading to registers will thus also affect state pruning since we need to account for that register use and potentially those registers that had to be spilled/filled again. As a consequence slightly more stack space might have been used due to spilling, and BPF programs are a bit longer due to extra code involving the register load and potentially required spill/fills. Thus, add BPF_JLT (<), BPF_JLE (<=), BPF_JSLT (s<), BPF_JSLE (s<=) counterparts to the eBPF instruction set. Modifying LLVM to remove the NegateCC() workaround in a PoC patch at [1] and allowing it to also emit the new instructions resulted in cilium's BPF programs that are injected into the fast-path to have a reduced program length in the range of 2-3% (e.g. accumulated main and tail call sections from one of the object file reduced from 4864 to 4729 insns), reduced complexity in the range of 10-30% (e.g. accumulated sections reduced in one of the cases from 116432 to 88428 insns), and reduced stack usage in the range of 1-5% (e.g. accumulated sections from one of the object files reduced from 824 to 784b). The modification for LLVM will be incorporated in a backwards compatible way. Plan is for LLVM to have i) a target specific option to offer a possibility to explicitly enable the extension by the user (as we have with -m target specific extensions today for various CPU insns), and ii) have the kernel checked for presence of the extensions and enable them transparently when the user is selecting more aggressive options such as -march=native in a bpf target context. (Other frontends generating BPF byte code, e.g. ply can probe the kernel directly for its code generation.) [1] https://github.com/borkmann/llvm/tree/bpf-insns Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/core.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index ad5f55922a13..c69e7f5bfde7 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -595,9 +595,13 @@ static int bpf_jit_blind_insn(const struct bpf_insn *from, case BPF_JMP | BPF_JEQ | BPF_K: case BPF_JMP | BPF_JNE | BPF_K: case BPF_JMP | BPF_JGT | BPF_K: + case BPF_JMP | BPF_JLT | BPF_K: case BPF_JMP | BPF_JGE | BPF_K: + case BPF_JMP | BPF_JLE | BPF_K: case BPF_JMP | BPF_JSGT | BPF_K: + case BPF_JMP | BPF_JSLT | BPF_K: case BPF_JMP | BPF_JSGE | BPF_K: + case BPF_JMP | BPF_JSLE | BPF_K: case BPF_JMP | BPF_JSET | BPF_K: /* Accommodate for extra offset in case of a backjump. */ off = from->off; @@ -833,12 +837,20 @@ static unsigned int ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K, [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X, [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K, + [BPF_JMP | BPF_JLT | BPF_X] = &&JMP_JLT_X, + [BPF_JMP | BPF_JLT | BPF_K] = &&JMP_JLT_K, [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X, [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K, + [BPF_JMP | BPF_JLE | BPF_X] = &&JMP_JLE_X, + [BPF_JMP | BPF_JLE | BPF_K] = &&JMP_JLE_K, [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X, [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K, + [BPF_JMP | BPF_JSLT | BPF_X] = &&JMP_JSLT_X, + [BPF_JMP | BPF_JSLT | BPF_K] = &&JMP_JSLT_K, [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X, [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K, + [BPF_JMP | BPF_JSLE | BPF_X] = &&JMP_JSLE_X, + [BPF_JMP | BPF_JSLE | BPF_K] = &&JMP_JSLE_K, [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X, [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K, /* Program return */ @@ -1073,6 +1085,18 @@ out: CONT_JMP; } CONT; + JMP_JLT_X: + if (DST < SRC) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JLT_K: + if (DST < IMM) { + insn += insn->off; + CONT_JMP; + } + CONT; JMP_JGE_X: if (DST >= SRC) { insn += insn->off; @@ -1085,6 +1109,18 @@ out: CONT_JMP; } CONT; + JMP_JLE_X: + if (DST <= SRC) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JLE_K: + if (DST <= IMM) { + insn += insn->off; + CONT_JMP; + } + CONT; JMP_JSGT_X: if (((s64) DST) > ((s64) SRC)) { insn += insn->off; @@ -1097,6 +1133,18 @@ out: CONT_JMP; } CONT; + JMP_JSLT_X: + if (((s64) DST) < ((s64) SRC)) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JSLT_K: + if (((s64) DST) < ((s64) IMM)) { + insn += insn->off; + CONT_JMP; + } + CONT; JMP_JSGE_X: if (((s64) DST) >= ((s64) SRC)) { insn += insn->off; @@ -1109,6 +1157,18 @@ out: CONT_JMP; } CONT; + JMP_JSLE_X: + if (((s64) DST) <= ((s64) SRC)) { + insn += insn->off; + CONT_JMP; + } + CONT; + JMP_JSLE_K: + if (((s64) DST) <= ((s64) IMM)) { + insn += insn->off; + CONT_JMP; + } + CONT; JMP_JSET_X: if (DST & SRC) { insn += insn->off; -- cgit v1.2.3 From b4e432f1000a171d901e42551459059831925770 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 10 Aug 2017 01:40:02 +0200 Subject: bpf: enable BPF_J{LT, LE, SLT, SLE} opcodes in verifier Enable the newly added jump opcodes, main parts are in two different areas, namely direct packet access and dynamic map value access. For the direct packet access, we now allow for the following two new patterns to match in order to trigger markings with find_good_pkt_pointers(): Variant 1 (access ok when taking the branch): 0: (61) r2 = *(u32 *)(r1 +76) 1: (61) r3 = *(u32 *)(r1 +80) 2: (bf) r0 = r2 3: (07) r0 += 8 4: (ad) if r0 < r3 goto pc+2 R0=pkt(id=0,off=8,r=0) R1=ctx R2=pkt(id=0,off=0,r=0) R3=pkt_end R10=fp 5: (b7) r0 = 0 6: (95) exit from 4 to 7: R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R10=fp 7: (71) r0 = *(u8 *)(r2 +0) 8: (05) goto pc-4 5: (b7) r0 = 0 6: (95) exit processed 11 insns, stack depth 0 Variant 2 (access ok on fall-through): 0: (61) r2 = *(u32 *)(r1 +76) 1: (61) r3 = *(u32 *)(r1 +80) 2: (bf) r0 = r2 3: (07) r0 += 8 4: (bd) if r3 <= r0 goto pc+1 R0=pkt(id=0,off=8,r=8) R1=ctx R2=pkt(id=0,off=0,r=8) R3=pkt_end R10=fp 5: (71) r0 = *(u8 *)(r2 +0) 6: (b7) r0 = 1 7: (95) exit from 4 to 6: R0=pkt(id=0,off=8,r=0) R1=ctx R2=pkt(id=0,off=0,r=0) R3=pkt_end R10=fp 6: (b7) r0 = 1 7: (95) exit processed 10 insns, stack depth 0 The above two basically just swap the branches where we need to handle an exception and allow packet access compared to the two already existing variants for find_good_pkt_pointers(). For the dynamic map value access, we add the new instructions to reg_set_min_max() and reg_set_min_max_inv() in order to learn bounds. Verifier test cases for both are added in a follow-up patch. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Acked-by: John Fastabend Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 58 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 8160a81a40bf..ecc590e01a1d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -312,11 +312,15 @@ static const char *const bpf_jmp_string[16] = { [BPF_JA >> 4] = "jmp", [BPF_JEQ >> 4] = "==", [BPF_JGT >> 4] = ">", + [BPF_JLT >> 4] = "<", [BPF_JGE >> 4] = ">=", + [BPF_JLE >> 4] = "<=", [BPF_JSET >> 4] = "&", [BPF_JNE >> 4] = "!=", [BPF_JSGT >> 4] = "s>", + [BPF_JSLT >> 4] = "s<", [BPF_JSGE >> 4] = "s>=", + [BPF_JSLE >> 4] = "s<=", [BPF_CALL >> 4] = "call", [BPF_EXIT >> 4] = "exit", }; @@ -2383,27 +2387,37 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *state, */ return; - /* LLVM can generate two kind of checks: + /* LLVM can generate four kind of checks: * - * Type 1: + * Type 1/2: * * r2 = r3; * r2 += 8; * if (r2 > pkt_end) goto * * + * r2 = r3; + * r2 += 8; + * if (r2 < pkt_end) goto + * + * * Where: * r2 == dst_reg, pkt_end == src_reg * r2=pkt(id=n,off=8,r=0) * r3=pkt(id=n,off=0,r=0) * - * Type 2: + * Type 3/4: * * r2 = r3; * r2 += 8; * if (pkt_end >= r2) goto * * + * r2 = r3; + * r2 += 8; + * if (pkt_end <= r2) goto + * + * * Where: * pkt_end == dst_reg, r2 == src_reg * r2=pkt(id=n,off=8,r=0) @@ -2471,6 +2485,14 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, false_reg->smax_value = min_t(s64, false_reg->smax_value, val); true_reg->smin_value = max_t(s64, true_reg->smin_value, val + 1); break; + case BPF_JLT: + false_reg->umin_value = max(false_reg->umin_value, val); + true_reg->umax_value = min(true_reg->umax_value, val - 1); + break; + case BPF_JSLT: + false_reg->smin_value = max_t(s64, false_reg->smin_value, val); + true_reg->smax_value = min_t(s64, true_reg->smax_value, val - 1); + break; case BPF_JGE: false_reg->umax_value = min(false_reg->umax_value, val - 1); true_reg->umin_value = max(true_reg->umin_value, val); @@ -2479,6 +2501,14 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, false_reg->smax_value = min_t(s64, false_reg->smax_value, val - 1); true_reg->smin_value = max_t(s64, true_reg->smin_value, val); break; + case BPF_JLE: + false_reg->umin_value = max(false_reg->umin_value, val + 1); + true_reg->umax_value = min(true_reg->umax_value, val); + break; + case BPF_JSLE: + false_reg->smin_value = max_t(s64, false_reg->smin_value, val + 1); + true_reg->smax_value = min_t(s64, true_reg->smax_value, val); + break; default: break; } @@ -2527,6 +2557,14 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, true_reg->smax_value = min_t(s64, true_reg->smax_value, val - 1); false_reg->smin_value = max_t(s64, false_reg->smin_value, val); break; + case BPF_JLT: + true_reg->umin_value = max(true_reg->umin_value, val + 1); + false_reg->umax_value = min(false_reg->umax_value, val); + break; + case BPF_JSLT: + true_reg->smin_value = max_t(s64, true_reg->smin_value, val + 1); + false_reg->smax_value = min_t(s64, false_reg->smax_value, val); + break; case BPF_JGE: true_reg->umax_value = min(true_reg->umax_value, val); false_reg->umin_value = max(false_reg->umin_value, val + 1); @@ -2535,6 +2573,14 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, true_reg->smax_value = min_t(s64, true_reg->smax_value, val); false_reg->smin_value = max_t(s64, false_reg->smin_value, val + 1); break; + case BPF_JLE: + true_reg->umin_value = max(true_reg->umin_value, val); + false_reg->umax_value = min(false_reg->umax_value, val - 1); + break; + case BPF_JSLE: + true_reg->smin_value = max_t(s64, true_reg->smin_value, val); + false_reg->smax_value = min_t(s64, false_reg->smax_value, val - 1); + break; default: break; } @@ -2659,7 +2705,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, u8 opcode = BPF_OP(insn->code); int err; - if (opcode > BPF_EXIT) { + if (opcode > BPF_JSLE) { verbose("invalid BPF_JMP opcode %x\n", opcode); return -EINVAL; } @@ -2761,10 +2807,18 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, dst_reg->type == PTR_TO_PACKET && regs[insn->src_reg].type == PTR_TO_PACKET_END) { find_good_pkt_pointers(this_branch, dst_reg); + } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JLT && + dst_reg->type == PTR_TO_PACKET && + regs[insn->src_reg].type == PTR_TO_PACKET_END) { + find_good_pkt_pointers(other_branch, dst_reg); } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGE && dst_reg->type == PTR_TO_PACKET_END && regs[insn->src_reg].type == PTR_TO_PACKET) { find_good_pkt_pointers(other_branch, ®s[insn->src_reg]); + } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JLE && + dst_reg->type == PTR_TO_PACKET_END && + regs[insn->src_reg].type == PTR_TO_PACKET) { + find_good_pkt_pointers(this_branch, ®s[insn->src_reg]); } else if (is_pointer_value(env, insn->dst_reg)) { verbose("R%d pointer comparison prohibited\n", insn->dst_reg); return -EACCES; -- cgit v1.2.3 From bfe334924ccd9f4a53f30240c03cf2f43f5b2df1 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 2 Aug 2017 19:39:30 +0200 Subject: perf/x86: Fix RDPMC vs. mm_struct tracking Vince reported the following rdpmc() testcase failure: > Failing test case: > > fd=perf_event_open(); > addr=mmap(fd); > exec() // without closing or unmapping the event > fd=perf_event_open(); > addr=mmap(fd); > rdpmc() // GPFs due to rdpmc being disabled The problem is of course that exec() plays tricks with what is current->mm, only destroying the old mappings after having installed the new mm. Fix this confusion by passing along vma->vm_mm instead of relying on current->mm. Reported-by: Vince Weaver Tested-by: Vince Weaver Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: stable@vger.kernel.org Fixes: 1e0fb9ec679c ("perf: Add pmu callbacks to track event mapping and unmapping") Link: http://lkml.kernel.org/r/20170802173930.cstykcqefmqt7jau@hirez.programming.kicks-ass.net [ Minor cleanups. ] Signed-off-by: Ingo Molnar --- kernel/events/core.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 426c2ffba16d..a654b8a3586f 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5090,7 +5090,7 @@ static void perf_mmap_open(struct vm_area_struct *vma) atomic_inc(&event->rb->aux_mmap_count); if (event->pmu->event_mapped) - event->pmu->event_mapped(event); + event->pmu->event_mapped(event, vma->vm_mm); } static void perf_pmu_output_stop(struct perf_event *event); @@ -5113,7 +5113,7 @@ static void perf_mmap_close(struct vm_area_struct *vma) unsigned long size = perf_data_size(rb); if (event->pmu->event_unmapped) - event->pmu->event_unmapped(event); + event->pmu->event_unmapped(event, vma->vm_mm); /* * rb->aux_mmap_count will always drop before rb->mmap_count and @@ -5411,7 +5411,7 @@ aux_unlock: vma->vm_ops = &perf_mmap_vmops; if (event->pmu->event_mapped) - event->pmu->event_mapped(event); + event->pmu->event_mapped(event, vma->vm_mm); return ret; } -- cgit v1.2.3 From 9b231d9f47c6114d317ce28cff92a74ad80547f5 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 3 Aug 2017 15:42:09 +0200 Subject: perf/core: Fix time on IOC_ENABLE Vince reported that when we do IOC_ENABLE/IOC_DISABLE while the task is SIGSTOP'ed state the timestamps go wobbly. It turns out we indeed fail to correctly account time while in 'OFF' state and doing IOC_ENABLE without getting scheduled in exposes the problem. Further thinking about this problem, it occurred to me that we can suffer a similar fate when we migrate an uncore event between CPUs. The perf_event_install() on the 'new' CPU will do add_event_to_ctx() which will reset all the time stamp, resulting in a subsequent update_event_times() to overwrite the total_time_* fields with smaller values. Reported-by: Vince Weaver Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/events/core.c | 41 ++++++++++++++++++++++++++++++++++++----- 1 file changed, 36 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index a654b8a3586f..ee20d4c546b5 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2217,6 +2217,33 @@ static int group_can_go_on(struct perf_event *event, return can_add_hw; } +/* + * Complement to update_event_times(). This computes the tstamp_* values to + * continue 'enabled' state from @now, and effectively discards the time + * between the prior tstamp_stopped and now (as we were in the OFF state, or + * just switched (context) time base). + * + * This further assumes '@event->state == INACTIVE' (we just came from OFF) and + * cannot have been scheduled in yet. And going into INACTIVE state means + * '@event->tstamp_stopped = @now'. + * + * Thus given the rules of update_event_times(): + * + * total_time_enabled = tstamp_stopped - tstamp_enabled + * total_time_running = tstamp_stopped - tstamp_running + * + * We can insert 'tstamp_stopped == now' and reverse them to compute new + * tstamp_* values. + */ +static void __perf_event_enable_time(struct perf_event *event, u64 now) +{ + WARN_ON_ONCE(event->state != PERF_EVENT_STATE_INACTIVE); + + event->tstamp_stopped = now; + event->tstamp_enabled = now - event->total_time_enabled; + event->tstamp_running = now - event->total_time_running; +} + static void add_event_to_ctx(struct perf_event *event, struct perf_event_context *ctx) { @@ -2224,9 +2251,12 @@ static void add_event_to_ctx(struct perf_event *event, list_add_event(event, ctx); perf_group_attach(event); - event->tstamp_enabled = tstamp; - event->tstamp_running = tstamp; - event->tstamp_stopped = tstamp; + /* + * We can be called with event->state == STATE_OFF when we create with + * .disabled = 1. In that case the IOC_ENABLE will call this function. + */ + if (event->state == PERF_EVENT_STATE_INACTIVE) + __perf_event_enable_time(event, tstamp); } static void ctx_sched_out(struct perf_event_context *ctx, @@ -2471,10 +2501,11 @@ static void __perf_event_mark_enabled(struct perf_event *event) u64 tstamp = perf_event_time(event); event->state = PERF_EVENT_STATE_INACTIVE; - event->tstamp_enabled = tstamp - event->total_time_enabled; + __perf_event_enable_time(event, tstamp); list_for_each_entry(sub, &event->sibling_list, group_entry) { + /* XXX should not be > INACTIVE if event isn't */ if (sub->state >= PERF_EVENT_STATE_INACTIVE) - sub->tstamp_enabled = tstamp - sub->total_time_enabled; + __perf_event_enable_time(sub, tstamp); } } -- cgit v1.2.3 From fdccc3fb7a42ea4e4cd77d2fb8fa3a45c66ec0bf Mon Sep 17 00:00:00 2001 From: "leilei.lin" Date: Wed, 9 Aug 2017 08:29:21 +0800 Subject: perf/core: Reduce context switch overhead Skip most of the PMU context switching overhead when ctx->nr_events is 0. 50% performance overhead was observed under an extreme testcase. Signed-off-by: leilei.lin Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: acme@kernel.org Cc: alexander.shishkin@linux.intel.com Cc: eranian@gmail.com Cc: jolsa@redhat.com Cc: linxiulei@gmail.com Cc: yang_oliver@hotmail.com Link: http://lkml.kernel.org/r/20170809002921.69813-1-leilei.lin@alibaba-inc.com [ Rewrote the changelog. ] Signed-off-by: Ingo Molnar --- kernel/events/core.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index ee20d4c546b5..d704e23914bf 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3211,6 +3211,13 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx, return; perf_ctx_lock(cpuctx, ctx); + /* + * We must check ctx->nr_events while holding ctx->lock, such + * that we serialize against perf_install_in_context(). + */ + if (!ctx->nr_events) + goto unlock; + perf_pmu_disable(ctx->pmu); /* * We want to keep the following priority order: @@ -3224,6 +3231,8 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx, cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); perf_event_sched_in(cpuctx, ctx, task); perf_pmu_enable(ctx->pmu); + +unlock: perf_ctx_unlock(cpuctx, ctx); } -- cgit v1.2.3 From a030d7381d8b3adabde724e3077bb6cb32d1b3ee Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 24 May 2017 10:59:52 +0530 Subject: sched/fair: Call cpufreq update util handlers less frequently on UP For SMP systems, update_load_avg() calls the cpufreq update util handlers only for the top level cfs_rq (i.e. rq->cfs). But that is not the case for UP systems. update_load_avg() calls util handler for any cfs_rq for which it is called. This would result in way too many calls from the scheduler to the cpufreq governors when CONFIG_FAIR_GROUP_SCHED is enabled. Reduce the frequency of these calls by copying the behavior from the SMP case, i.e. Only call util handlers for the top level cfs_rq. Signed-off-by: Viresh Kumar Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vincent Guittot Cc: linaro-kernel@lists.linaro.org Fixes: 536bd00cdbb7 ("sched/fair: Fix !CONFIG_SMP kernel cpufreq governor breakage") Link: http://lkml.kernel.org/r/6abf69a2107525885b616a2c1ec03d9c0946171c.1495603536.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 48 ++++++++++++++++++++++++------------------------ 1 file changed, 24 insertions(+), 24 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c95880e216f6..139abf2ae2a5 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2790,6 +2790,29 @@ static inline void update_cfs_shares(struct sched_entity *se) } #endif /* CONFIG_FAIR_GROUP_SCHED */ +static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq) +{ + if (&this_rq()->cfs == cfs_rq) { + /* + * There are a few boundary cases this might miss but it should + * get called often enough that that should (hopefully) not be + * a real problem -- added to that it only calls on the local + * CPU, so if we enqueue remotely we'll miss an update, but + * the next tick/schedule should update. + * + * It will not get called when we go idle, because the idle + * thread is a different class (!fair), nor will the utilization + * number include things like RT tasks. + * + * As is, the util number is not freq-invariant (we'd have to + * implement arch_scale_freq_capacity() for that). + * + * See cpu_util(). + */ + cpufreq_update_util(rq_of(cfs_rq), 0); + } +} + #ifdef CONFIG_SMP /* * Approximate: @@ -3276,29 +3299,6 @@ static inline void set_tg_cfs_propagate(struct cfs_rq *cfs_rq) {} #endif /* CONFIG_FAIR_GROUP_SCHED */ -static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq) -{ - if (&this_rq()->cfs == cfs_rq) { - /* - * There are a few boundary cases this might miss but it should - * get called often enough that that should (hopefully) not be - * a real problem -- added to that it only calls on the local - * CPU, so if we enqueue remotely we'll miss an update, but - * the next tick/schedule should update. - * - * It will not get called when we go idle, because the idle - * thread is a different class (!fair), nor will the utilization - * number include things like RT tasks. - * - * As is, the util number is not freq-invariant (we'd have to - * implement arch_scale_freq_capacity() for that). - * - * See cpu_util(). - */ - cpufreq_update_util(rq_of(cfs_rq), 0); - } -} - /* * Unsigned subtract and clamp on underflow. * @@ -3544,7 +3544,7 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq) static inline void update_load_avg(struct sched_entity *se, int not_used1) { - cpufreq_update_util(rq_of(cfs_rq_of(se)), 0); + cfs_rq_util_change(cfs_rq_of(se)); } static inline void -- cgit v1.2.3 From 5b713a3d949bd7f8c615a335a8c40297586bc1b1 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 24 May 2017 10:59:53 +0530 Subject: sched/core: Reuse put_prev_task() Reuse put_prev_task() instead of copying its implementation. Signed-off-by: Viresh Kumar Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vincent Guittot Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/e2e50578223d05c5e90a9feb964fe1ec5d09a052.1495603536.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0869b20fba81..835a234d35e8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5438,7 +5438,7 @@ static void migrate_tasks(struct rq *dead_rq, struct rq_flags *rf) */ next = pick_next_task(rq, &fake_task, rf); BUG_ON(!next); - next->sched_class->put_prev_task(rq, next); + put_prev_task(rq, next); /* * Rules for changing task_struct::cpus_allowed are holding -- cgit v1.2.3 From c7132dd6f0e3b07bd4541cda9040897cc460d855 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 24 May 2017 10:59:54 +0530 Subject: sched/fair: Pass 'rq' to weighted_cpuload() weighted_cpuload() uses the cpu number passed to it get pointer to the runqueue. Almost all callers of weighted_cpuload() already have the rq pointer with them and can send that directly to weighted_cpuload(). In some cases the callers actually get the CPU number by doing cpu_of(rq). It would be simpler to pass rq to weighted_cpuload(). Signed-off-by: Viresh Kumar Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vincent Guittot Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/b7720627e0576dc29b4ba3f9b6edbc913bb4f684.1495603536.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 139abf2ae2a5..27d425eccaad 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1378,7 +1378,7 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page, group_faults_cpu(ng, src_nid) * group_faults(p, dst_nid) * 4; } -static unsigned long weighted_cpuload(const int cpu); +static unsigned long weighted_cpuload(struct rq *rq); static unsigned long source_load(int cpu, int type); static unsigned long target_load(int cpu, int type); static unsigned long capacity_of(int cpu); @@ -1409,7 +1409,7 @@ static void update_numa_stats(struct numa_stats *ns, int nid) struct rq *rq = cpu_rq(cpu); ns->nr_running += rq->nr_running; - ns->load += weighted_cpuload(cpu); + ns->load += weighted_cpuload(rq); ns->compute_capacity += capacity_of(cpu); cpus++; @@ -5125,9 +5125,9 @@ static void cpu_load_update(struct rq *this_rq, unsigned long this_load, } /* Used instead of source_load when we know the type == 0 */ -static unsigned long weighted_cpuload(const int cpu) +static unsigned long weighted_cpuload(struct rq *rq) { - return cfs_rq_runnable_load_avg(&cpu_rq(cpu)->cfs); + return cfs_rq_runnable_load_avg(&rq->cfs); } #ifdef CONFIG_NO_HZ_COMMON @@ -5172,7 +5172,7 @@ static void cpu_load_update_idle(struct rq *this_rq) /* * bail if there's load or we're actually up-to-date. */ - if (weighted_cpuload(cpu_of(this_rq))) + if (weighted_cpuload(this_rq)) return; cpu_load_update_nohz(this_rq, READ_ONCE(jiffies), 0); @@ -5193,7 +5193,7 @@ void cpu_load_update_nohz_start(void) * concurrently we'll exit nohz. And cpu_load write can race with * cpu_load_update_idle() but both updater would be writing the same. */ - this_rq->cpu_load[0] = weighted_cpuload(cpu_of(this_rq)); + this_rq->cpu_load[0] = weighted_cpuload(this_rq); } /* @@ -5209,7 +5209,7 @@ void cpu_load_update_nohz_stop(void) if (curr_jiffies == this_rq->last_load_update_tick) return; - load = weighted_cpuload(cpu_of(this_rq)); + load = weighted_cpuload(this_rq); rq_lock(this_rq, &rf); update_rq_clock(this_rq); cpu_load_update_nohz(this_rq, curr_jiffies, load); @@ -5235,7 +5235,7 @@ static void cpu_load_update_periodic(struct rq *this_rq, unsigned long load) */ void cpu_load_update_active(struct rq *this_rq) { - unsigned long load = weighted_cpuload(cpu_of(this_rq)); + unsigned long load = weighted_cpuload(this_rq); if (tick_nohz_tick_stopped()) cpu_load_update_nohz(this_rq, READ_ONCE(jiffies), load); @@ -5253,7 +5253,7 @@ void cpu_load_update_active(struct rq *this_rq) static unsigned long source_load(int cpu, int type) { struct rq *rq = cpu_rq(cpu); - unsigned long total = weighted_cpuload(cpu); + unsigned long total = weighted_cpuload(rq); if (type == 0 || !sched_feat(LB_BIAS)) return total; @@ -5268,7 +5268,7 @@ static unsigned long source_load(int cpu, int type) static unsigned long target_load(int cpu, int type) { struct rq *rq = cpu_rq(cpu); - unsigned long total = weighted_cpuload(cpu); + unsigned long total = weighted_cpuload(rq); if (type == 0 || !sched_feat(LB_BIAS)) return total; @@ -5290,7 +5290,7 @@ static unsigned long cpu_avg_load_per_task(int cpu) { struct rq *rq = cpu_rq(cpu); unsigned long nr_running = READ_ONCE(rq->cfs.h_nr_running); - unsigned long load_avg = weighted_cpuload(cpu); + unsigned long load_avg = weighted_cpuload(rq); if (nr_running) return load_avg / nr_running; @@ -5550,7 +5550,7 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) shallowest_idle_cpu = i; } } else if (shallowest_idle_cpu == -1) { - load = weighted_cpuload(i); + load = weighted_cpuload(cpu_rq(i)); if (load < min_load || (load == min_load && i == this_cpu)) { min_load = load; least_loaded_cpu = i; @@ -7363,7 +7363,7 @@ static inline void update_sg_lb_stats(struct lb_env *env, sgs->nr_numa_running += rq->nr_numa_running; sgs->nr_preferred_running += rq->nr_preferred_running; #endif - sgs->sum_weighted_load += weighted_cpuload(i); + sgs->sum_weighted_load += weighted_cpuload(rq); /* * No need to call idle_cpu() if nr_running is not 0 */ @@ -7892,7 +7892,7 @@ static struct rq *find_busiest_queue(struct lb_env *env, capacity = capacity_of(i); - wl = weighted_cpuload(i); + wl = weighted_cpuload(rq); /* * When comparing with imbalance, use weighted_cpuload() -- cgit v1.2.3 From 9674f5cad22a590c865a330ce333026b9f9c078b Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 24 May 2017 10:59:55 +0530 Subject: sched/fair: Avoid checking cfs_rq->nr_running twice Rearrange pick_next_task_fair() a bit to avoid checking cfs_rq->nr_running twice for the case where FAIR_GROUP_SCHED is enabled and the previous task doesn't belong to the fair class. Signed-off-by: Viresh Kumar Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vincent Guittot Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/000903ab3df3350943d3271c53615893a230dc95.1495603536.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 27d425eccaad..30fd196c0cde 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6187,10 +6187,10 @@ pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf int new_tasks; again: -#ifdef CONFIG_FAIR_GROUP_SCHED if (!cfs_rq->nr_running) goto idle; +#ifdef CONFIG_FAIR_GROUP_SCHED if (prev->sched_class != &fair_sched_class) goto simple; @@ -6220,11 +6220,17 @@ again: /* * This call to check_cfs_rq_runtime() will do the * throttle and dequeue its entity in the parent(s). - * Therefore the 'simple' nr_running test will indeed + * Therefore the nr_running test will indeed * be correct. */ - if (unlikely(check_cfs_rq_runtime(cfs_rq))) + if (unlikely(check_cfs_rq_runtime(cfs_rq))) { + cfs_rq = &rq->cfs; + + if (!cfs_rq->nr_running) + goto idle; + goto simple; + } } se = pick_next_entity(cfs_rq, curr); @@ -6264,12 +6270,8 @@ again: return p; simple: - cfs_rq = &rq->cfs; #endif - if (!cfs_rq->nr_running) - goto idle; - put_prev_task(rq, prev); do { -- cgit v1.2.3 From 3a123bbbb10d54dbdde6ccbbd519c74c91ba2f52 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 24 May 2017 10:59:56 +0530 Subject: sched/fair: Drop always true parameter of update_cfs_rq_load_avg() update_freq is always true and there is no need to pass it to update_cfs_rq_load_avg(). Remove it. Signed-off-by: Viresh Kumar Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vincent Guittot Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/2d28d295f3f591ede7e931462bce1bda5aaa4896.1495603536.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 30fd196c0cde..75c58c77450a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -806,7 +806,7 @@ void post_init_entity_util_avg(struct sched_entity *se) /* * For !fair tasks do: * - update_cfs_rq_load_avg(now, cfs_rq, false); + update_cfs_rq_load_avg(now, cfs_rq); attach_entity_load_avg(cfs_rq, se); switched_from_fair(rq, p); * @@ -3320,7 +3320,6 @@ static inline void set_tg_cfs_propagate(struct cfs_rq *cfs_rq) {} * update_cfs_rq_load_avg - update the cfs_rq's load/util averages * @now: current time, as per cfs_rq_clock_task() * @cfs_rq: cfs_rq to update - * @update_freq: should we call cfs_rq_util_change() or will the call do so * * The cfs_rq avg is the direct sum of all its entities (blocked and runnable) * avg. The immediate corollary is that all (fair) tasks must be attached, see @@ -3334,7 +3333,7 @@ static inline void set_tg_cfs_propagate(struct cfs_rq *cfs_rq) {} * call update_tg_load_avg() when this function returns true. */ static inline int -update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq) +update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) { struct sched_avg *sa = &cfs_rq->avg; int decayed, removed_load = 0, removed_util = 0; @@ -3362,7 +3361,7 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq) cfs_rq->load_last_update_time_copy = sa->last_update_time; #endif - if (update_freq && (decayed || removed_util)) + if (decayed || removed_util) cfs_rq_util_change(cfs_rq); return decayed || removed_load; @@ -3390,7 +3389,7 @@ static inline void update_load_avg(struct sched_entity *se, int flags) if (se->avg.last_update_time && !(flags & SKIP_AGE_LOAD)) __update_load_avg_se(now, cpu, cfs_rq, se); - decayed = update_cfs_rq_load_avg(now, cfs_rq, true); + decayed = update_cfs_rq_load_avg(now, cfs_rq); decayed |= propagate_entity_load_avg(se); if (decayed && (flags & UPDATE_TG)) @@ -3534,7 +3533,7 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf); #else /* CONFIG_SMP */ static inline int -update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq) +update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) { return 0; } @@ -6919,7 +6918,7 @@ static void update_blocked_averages(int cpu) if (throttled_hierarchy(cfs_rq)) continue; - if (update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, true)) + if (update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq)) update_tg_load_avg(cfs_rq, 0); /* Propagate pending load changes to the parent, if any: */ @@ -6992,7 +6991,7 @@ static inline void update_blocked_averages(int cpu) rq_lock_irqsave(rq, &rf); update_rq_clock(rq); - update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, true); + update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq); rq_unlock_irqrestore(rq, &rf); } -- cgit v1.2.3 From 4d13a06d54c415238325b0fe2c14f1052da4512f Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 13 Apr 2017 14:45:48 +0530 Subject: sched/topology: Drop memset() from init_rootdomain() There are only two callers of init_rootdomain(). One of them passes a global to it and another one sends dynamically allocated root-domain. There is no need to memset the root-domain in the first case as the structure is already reset. Update alloc_rootdomain() to allocate the memory with kzalloc() and remove the memset() call from init_rootdomain(). Signed-off-by: Viresh Kumar Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vincent Guittot Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/fc2f6cc90b098040970c85a97046512572d765bc.1492065513.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/topology.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 79895aec281e..216fee014b32 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -261,8 +261,6 @@ void rq_attach_root(struct rq *rq, struct root_domain *rd) static int init_rootdomain(struct root_domain *rd) { - memset(rd, 0, sizeof(*rd)); - if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL)) goto out; if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL)) @@ -311,7 +309,7 @@ static struct root_domain *alloc_rootdomain(void) { struct root_domain *rd; - rd = kmalloc(sizeof(*rd), GFP_KERNEL); + rd = kzalloc(sizeof(*rd), GFP_KERNEL); if (!rd) return NULL; -- cgit v1.2.3 From 42d394d41ab90f4ed9d7a7403ed22e8f7590948a Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 13 Apr 2017 14:45:49 +0530 Subject: sched/deadline: Don't re-initialize 'struct cpudl' The 'struct cpudl' passed to cpudl_init() is already initialized to zero. Don't do that again. Signed-off-by: Viresh Kumar Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vincent Guittot Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/bd4c229806bc96694b15546207afcc221387d2f5.1492065513.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/cpudeadline.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c index fba235c7d026..bdf448b6556f 100644 --- a/kernel/sched/cpudeadline.c +++ b/kernel/sched/cpudeadline.c @@ -246,7 +246,6 @@ int cpudl_init(struct cpudl *cp) { int i; - memset(cp, 0, sizeof(*cp)); raw_spin_lock_init(&cp->lock); cp->size = 0; -- cgit v1.2.3 From 1c2a4861dbfca373fea1ff2cf9e9793933d024ce Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 13 Apr 2017 14:45:50 +0530 Subject: sched/cpupri: Don't re-initialize 'struct cpupri' The 'struct cpupri' passed to cpupri_init() is already initialized to zero. Don't do that again. Signed-off-by: Viresh Kumar Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vincent Guittot Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/8a71d48c5a077500b6ddc1a41484c0ac8d3aad94.1492065513.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/cpupri.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c index 981fcd7dc394..2511aba36b89 100644 --- a/kernel/sched/cpupri.c +++ b/kernel/sched/cpupri.c @@ -209,8 +209,6 @@ int cpupri_init(struct cpupri *cp) { int i; - memset(cp, 0, sizeof(*cp)); - for (i = 0; i < CPUPRI_NR_PRIORITIES; i++) { struct cpupri_vec *vec = &cp->pri_to_cpu[i]; -- cgit v1.2.3 From 181a80d1f7f453f58c4b47f89084d0849632858c Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 27 Apr 2017 13:58:59 +0530 Subject: sched: Mark pick_next_task_dl() and build_sched_domain() as static pick_next_task_dl() and build_sched_domain() aren't used outside deadline.c and topology.c. Make them static. Signed-off-by: Viresh Kumar Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vincent Guittot Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/36e4cbb6210002cadae89920ae97e19e7e513008.1493281605.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/deadline.c | 2 +- kernel/sched/topology.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 755bd3f1a1a9..a205ac7cf435 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1655,7 +1655,7 @@ static struct sched_dl_entity *pick_next_dl_entity(struct rq *rq, return rb_entry(left, struct sched_dl_entity, rb_node); } -struct task_struct * +static struct task_struct * pick_next_task_dl(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) { struct sched_dl_entity *dl_se; diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 216fee014b32..bd8b6d6f5387 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -1593,7 +1593,7 @@ static void __sdt_free(const struct cpumask *cpu_map) } } -struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, +static struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, const struct cpumask *cpu_map, struct sched_domain_attr *attr, struct sched_domain *child, int cpu) { -- cgit v1.2.3 From f235a54f00449c611f85173fe8a66c4d189c5ce1 Mon Sep 17 00:00:00 2001 From: Vincent Guittot Date: Sat, 1 Jul 2017 07:06:13 +0200 Subject: sched/pelt: Fix false running accounting The running state is a subset of runnable state which means that running can't be set if runnable (weight) is cleared. There are corner cases where the current sched_entity has been already dequeued but cfs_rq->curr has not been updated yet and still points to the dequeued sched_entity. If ___update_load_avg() is called at that time, weight will be 0 and running will be set which is not possible. This case happens during pick_next_task_fair() when a cfs_rq becomes idles. The current sched_entity has been dequeued so se->on_rq is cleared and cfs_rq->weight is null. But cfs_rq->curr still points to se (it will be cleared when picking the idle thread). Because the cfs_rq becomes idle, idle_balance() is called and ends up to call update_blocked_averages() with these wrong running and runnable states. Add a test in ___update_load_avg() to correct the running state in this case. Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: dietmar.eggemann@arm.com Link: http://lkml.kernel.org/r/1498885573-18984-1-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 75c58c77450a..ef5b66b110f8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2990,6 +2990,18 @@ ___update_load_avg(u64 now, int cpu, struct sched_avg *sa, sa->last_update_time += delta << 10; + /* + * running is a subset of runnable (weight) so running can't be set if + * runnable is clear. But there are some corner cases where the current + * se has been already dequeued but cfs_rq->curr still points to it. + * This means that weight will be 0 but not running for a sched_entity + * but also for a cfs_rq if the latter becomes idle. As an example, + * this happens during idle_balance() which calls + * update_blocked_averages() + */ + if (!weight) + running = 0; + /* * Now we know we crossed measurement unit boundaries. The *_avg * accrues by two steps: -- cgit v1.2.3 From 37ec97deb3a8c68a7adfab61beb261ffeab19d09 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Mon, 31 Jul 2017 15:28:46 -0400 Subject: sched/numa: Slow down scan rate if shared faults dominate The comment above update_task_scan_period() says the scan period should be increased (scanning slows down) if the majority of memory accesses are on the local node, or if the majority of the page accesses are shared with other tasks. However, with the current code, all a high ratio of shared accesses does is slow down the rate at which scanning is made faster. This patch changes things so either lots of shared accesses or lots of local accesses will slow down scanning, and numa scanning is sped up only when there are lots of private faults on remote memory pages. Signed-off-by: Rik van Riel Signed-off-by: Peter Zijlstra (Intel) Acked-by: Mel Gorman Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: jhladky@redhat.com Cc: lvenanci@redhat.com Link: http://lkml.kernel.org/r/20170731192847.23050-2-riel@redhat.com Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 39 +++++++++++++++++++++++++-------------- 1 file changed, 25 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ef5b66b110f8..cb6b7c83b74d 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1892,7 +1892,7 @@ static void update_task_scan_period(struct task_struct *p, unsigned long shared, unsigned long private) { unsigned int period_slot; - int ratio; + int lr_ratio, ps_ratio; int diff; unsigned long remote = p->numa_faults_locality[0]; @@ -1922,25 +1922,36 @@ static void update_task_scan_period(struct task_struct *p, * >= NUMA_PERIOD_THRESHOLD scan period increases (scan slower) */ period_slot = DIV_ROUND_UP(p->numa_scan_period, NUMA_PERIOD_SLOTS); - ratio = (local * NUMA_PERIOD_SLOTS) / (local + remote); - if (ratio >= NUMA_PERIOD_THRESHOLD) { - int slot = ratio - NUMA_PERIOD_THRESHOLD; + lr_ratio = (local * NUMA_PERIOD_SLOTS) / (local + remote); + ps_ratio = (private * NUMA_PERIOD_SLOTS) / (private + shared); + + if (ps_ratio >= NUMA_PERIOD_THRESHOLD) { + /* + * Most memory accesses are local. There is no need to + * do fast NUMA scanning, since memory is already local. + */ + int slot = ps_ratio - NUMA_PERIOD_THRESHOLD; + if (!slot) + slot = 1; + diff = slot * period_slot; + } else if (lr_ratio >= NUMA_PERIOD_THRESHOLD) { + /* + * Most memory accesses are shared with other tasks. + * There is no point in continuing fast NUMA scanning, + * since other tasks may just move the memory elsewhere. + */ + int slot = lr_ratio - NUMA_PERIOD_THRESHOLD; if (!slot) slot = 1; diff = slot * period_slot; } else { - diff = -(NUMA_PERIOD_THRESHOLD - ratio) * period_slot; - /* - * Scale scan rate increases based on sharing. There is an - * inverse relationship between the degree of sharing and - * the adjustment made to the scanning period. Broadly - * speaking the intent is that there is little point - * scanning faster if shared accesses dominate as it may - * simply bounce migrations uselessly + * Private memory faults exceed (SLOTS-THRESHOLD)/SLOTS, + * yet they are not on the local NUMA node. Speed up + * NUMA scanning to get the memory moved over. */ - ratio = DIV_ROUND_UP(private * NUMA_PERIOD_SLOTS, (private + shared + 1)); - diff = (diff * ratio) / NUMA_PERIOD_SLOTS; + int ratio = max(lr_ratio, ps_ratio); + diff = -(NUMA_PERIOD_THRESHOLD - ratio) * period_slot; } p->numa_scan_period = clamp(p->numa_scan_period + diff, -- cgit v1.2.3 From b5dd77c8bdada7b6262d0cba02a6ed525bf4e6e1 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Mon, 31 Jul 2017 15:28:47 -0400 Subject: sched/numa: Scale scan period with tasks in group and shared/private Running 80 tasks in the same group, or as threads of the same process, results in the memory getting scanned 80x as fast as it would be if a single task was using the memory. This really hurts some workloads. Scale the scan period by the number of tasks in the numa group, and the shared / private ratio, so the average rate at which memory in the group is scanned corresponds roughly to the rate at which a single task would scan its memory. Signed-off-by: Rik van Riel Signed-off-by: Peter Zijlstra (Intel) Acked-by: Mel Gorman Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: jhladky@redhat.com Cc: lvenanci@redhat.com Link: http://lkml.kernel.org/r/20170731192847.23050-3-riel@redhat.com Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 111 ++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 86 insertions(+), 25 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index cb6b7c83b74d..a7f1c3b797f8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1071,6 +1071,29 @@ unsigned int sysctl_numa_balancing_scan_size = 256; /* Scan @scan_size MB every @scan_period after an initial @scan_delay in ms */ unsigned int sysctl_numa_balancing_scan_delay = 1000; +struct numa_group { + atomic_t refcount; + + spinlock_t lock; /* nr_tasks, tasks */ + int nr_tasks; + pid_t gid; + int active_nodes; + + struct rcu_head rcu; + unsigned long total_faults; + unsigned long max_faults_cpu; + /* + * Faults_cpu is used to decide whether memory should move + * towards the CPU. As a consequence, these stats are weighted + * more by CPU use than by memory faults. + */ + unsigned long *faults_cpu; + unsigned long faults[0]; +}; + +static inline unsigned long group_faults_priv(struct numa_group *ng); +static inline unsigned long group_faults_shared(struct numa_group *ng); + static unsigned int task_nr_scan_windows(struct task_struct *p) { unsigned long rss = 0; @@ -1107,13 +1130,47 @@ static unsigned int task_scan_min(struct task_struct *p) return max_t(unsigned int, floor, scan); } +static unsigned int task_scan_start(struct task_struct *p) +{ + unsigned long smin = task_scan_min(p); + unsigned long period = smin; + + /* Scale the maximum scan period with the amount of shared memory. */ + if (p->numa_group) { + struct numa_group *ng = p->numa_group; + unsigned long shared = group_faults_shared(ng); + unsigned long private = group_faults_priv(ng); + + period *= atomic_read(&ng->refcount); + period *= shared + 1; + period /= private + shared + 1; + } + + return max(smin, period); +} + static unsigned int task_scan_max(struct task_struct *p) { - unsigned int smin = task_scan_min(p); - unsigned int smax; + unsigned long smin = task_scan_min(p); + unsigned long smax; /* Watch for min being lower than max due to floor calculations */ smax = sysctl_numa_balancing_scan_period_max / task_nr_scan_windows(p); + + /* Scale the maximum scan period with the amount of shared memory. */ + if (p->numa_group) { + struct numa_group *ng = p->numa_group; + unsigned long shared = group_faults_shared(ng); + unsigned long private = group_faults_priv(ng); + unsigned long period = smax; + + period *= atomic_read(&ng->refcount); + period *= shared + 1; + period /= private + shared + 1; + + smax = max(smax, period); + } + return max(smin, smax); } @@ -1129,26 +1186,6 @@ static void account_numa_dequeue(struct rq *rq, struct task_struct *p) rq->nr_preferred_running -= (p->numa_preferred_nid == task_node(p)); } -struct numa_group { - atomic_t refcount; - - spinlock_t lock; /* nr_tasks, tasks */ - int nr_tasks; - pid_t gid; - int active_nodes; - - struct rcu_head rcu; - unsigned long total_faults; - unsigned long max_faults_cpu; - /* - * Faults_cpu is used to decide whether memory should move - * towards the CPU. As a consequence, these stats are weighted - * more by CPU use than by memory faults. - */ - unsigned long *faults_cpu; - unsigned long faults[0]; -}; - /* Shared or private faults. */ #define NR_NUMA_HINT_FAULT_TYPES 2 @@ -1198,6 +1235,30 @@ static inline unsigned long group_faults_cpu(struct numa_group *group, int nid) group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 1)]; } +static inline unsigned long group_faults_priv(struct numa_group *ng) +{ + unsigned long faults = 0; + int node; + + for_each_online_node(node) { + faults += ng->faults[task_faults_idx(NUMA_MEM, node, 1)]; + } + + return faults; +} + +static inline unsigned long group_faults_shared(struct numa_group *ng) +{ + unsigned long faults = 0; + int node; + + for_each_online_node(node) { + faults += ng->faults[task_faults_idx(NUMA_MEM, node, 0)]; + } + + return faults; +} + /* * A node triggering more than 1/3 as many NUMA faults as the maximum is * considered part of a numa group's pseudo-interleaving set. Migrations @@ -1808,7 +1869,7 @@ static int task_numa_migrate(struct task_struct *p) * Reset the scan period if the task is being rescheduled on an * alternative node to recheck if the tasks is now properly placed. */ - p->numa_scan_period = task_scan_min(p); + p->numa_scan_period = task_scan_start(p); if (env.best_task == NULL) { ret = migrate_task_to(p, env.best_cpu); @@ -2459,7 +2520,7 @@ void task_numa_work(struct callback_head *work) if (p->numa_scan_period == 0) { p->numa_scan_period_max = task_scan_max(p); - p->numa_scan_period = task_scan_min(p); + p->numa_scan_period = task_scan_start(p); } next_scan = now + msecs_to_jiffies(p->numa_scan_period); @@ -2587,7 +2648,7 @@ void task_tick_numa(struct rq *rq, struct task_struct *curr) if (now > curr->node_stamp + period) { if (!curr->node_stamp) - curr->numa_scan_period = task_scan_min(curr); + curr->numa_scan_period = task_scan_start(curr); curr->node_stamp += period; if (!time_before(jiffies, curr->mm->numa_next_scan)) { -- cgit v1.2.3 From b18c3ca11c20caa4a397baa9b893ebc4aaa4fe9f Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Tue, 23 May 2017 11:00:56 +0900 Subject: sched/deadline: Make find_later_rq() choose a closer CPU in topology When cpudl_find() returns any among free_cpus, the CPU might not be closer than others, considering sched domain. For example: this_cpu: 15 free_cpus: 0, 1,..., 14 (== later_mask) best_cpu: 0 topology: 0 --+ +--+ 1 --+ | +-- ... --+ 2 --+ | | +--+ | 3 --+ | ... ... 12 --+ | +--+ | 13 --+ | | +-- ... -+ 14 --+ | +--+ 15 --+ In this case, it would be best to select 14 since it's a free CPU and closest to 15 (this_cpu). However, currently the code selects 0 (best_cpu) even though that's just any among free_cpus. Fix it. This (re)aligns the deadline behaviour with the rt behaviour. Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Cc: Cc: Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1495504859-10960-2-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- kernel/sched/deadline.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index a205ac7cf435..ac07d7c3a978 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1798,7 +1798,7 @@ static int find_later_rq(struct task_struct *task) struct sched_domain *sd; struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl); int this_cpu = smp_processor_id(); - int best_cpu, cpu = task_cpu(task); + int cpu = task_cpu(task); /* Make sure the mask is initialized first */ if (unlikely(!later_mask)) @@ -1811,17 +1811,14 @@ static int find_later_rq(struct task_struct *task) * We have to consider system topology and task affinity * first, then we can look for a suitable cpu. */ - best_cpu = cpudl_find(&task_rq(task)->rd->cpudl, - task, later_mask); - if (best_cpu == -1) + if (cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask) == -1) return -1; /* - * If we are here, some target has been found, - * the most suitable of which is cached in best_cpu. - * This is, among the runqueues where the current tasks - * have later deadlines than the task's one, the rq - * with the latest possible one. + * If we are here, some targets have been found, including + * the most suitable which is, among the runqueues where the + * current tasks have later deadlines than the task's one, the + * rq with the latest possible one. * * Now we check how well this matches with task's * affinity and system topology. @@ -1841,6 +1838,7 @@ static int find_later_rq(struct task_struct *task) rcu_read_lock(); for_each_domain(cpu, sd) { if (sd->flags & SD_WAKE_AFFINE) { + int best_cpu; /* * If possible, preempting this_cpu is @@ -1852,12 +1850,15 @@ static int find_later_rq(struct task_struct *task) return this_cpu; } + best_cpu = cpumask_first_and(later_mask, + sched_domain_span(sd)); /* - * Last chance: if best_cpu is valid and is - * in the mask, that becomes our choice. + * Last chance: if a cpu being in both later_mask + * and current sd span is valid, that becomes our + * choice. Of course, the latest possible cpu is + * already under consideration through later_mask. */ - if (best_cpu < nr_cpu_ids && - cpumask_test_cpu(best_cpu, sched_domain_span(sd))) { + if (best_cpu < nr_cpu_ids) { rcu_read_unlock(); return best_cpu; } -- cgit v1.2.3 From 3261ed0b25098f92d36d5ad14524254d8c7fba54 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Tue, 23 May 2017 11:00:57 +0900 Subject: sched/deadline: Change return value of cpudl_find() cpudl_find() users are only interested in knowing if suitable CPU(s) were found or not (and then they look at later_mask to know which). Change cpudl_find() return type accordingly. Aligns with rt code. Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Cc: Cc: Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1495504859-10960-3-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- kernel/sched/cpudeadline.c | 26 +++++++++++++------------- kernel/sched/deadline.c | 6 +++--- 2 files changed, 16 insertions(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c index bdf448b6556f..8d9562d890d3 100644 --- a/kernel/sched/cpudeadline.c +++ b/kernel/sched/cpudeadline.c @@ -119,29 +119,29 @@ static inline int cpudl_maximum(struct cpudl *cp) * @p: the task * @later_mask: a mask to fill in with the selected CPUs (or NULL) * - * Returns: int - best CPU (heap maximum if suitable) + * Returns: int - CPUs were found */ int cpudl_find(struct cpudl *cp, struct task_struct *p, struct cpumask *later_mask) { - int best_cpu = -1; const struct sched_dl_entity *dl_se = &p->dl; if (later_mask && cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) { - best_cpu = cpumask_any(later_mask); - goto out; - } else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) && - dl_time_before(dl_se->deadline, cp->elements[0].dl)) { - best_cpu = cpudl_maximum(cp); - if (later_mask) - cpumask_set_cpu(best_cpu, later_mask); - } + return 1; + } else { + int best_cpu = cpudl_maximum(cp); + WARN_ON(best_cpu != -1 && !cpu_present(best_cpu)); -out: - WARN_ON(best_cpu != -1 && !cpu_present(best_cpu)); + if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) && + dl_time_before(dl_se->deadline, cp->elements[0].dl)) { + if (later_mask) + cpumask_set_cpu(best_cpu, later_mask); - return best_cpu; + return 1; + } + } + return 0; } /* diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index ac07d7c3a978..d05bd9457a40 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1594,7 +1594,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p) * let's hope p can move out. */ if (rq->curr->nr_cpus_allowed == 1 || - cpudl_find(&rq->rd->cpudl, rq->curr, NULL) == -1) + !cpudl_find(&rq->rd->cpudl, rq->curr, NULL)) return; /* @@ -1602,7 +1602,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p) * see if it is pushed or pulled somewhere else. */ if (p->nr_cpus_allowed != 1 && - cpudl_find(&rq->rd->cpudl, p, NULL) != -1) + cpudl_find(&rq->rd->cpudl, p, NULL)) return; resched_curr(rq); @@ -1811,7 +1811,7 @@ static int find_later_rq(struct task_struct *task) * We have to consider system topology and task affinity * first, then we can look for a suitable cpu. */ - if (cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask) == -1) + if (!cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask)) return -1; /* -- cgit v1.2.3 From 18f08dae19990f5fffde92e3a63e0d90cda0f1a8 Mon Sep 17 00:00:00 2001 From: Cheng Jian Date: Fri, 4 Aug 2017 17:19:37 +0800 Subject: sched/core: Remove unnecessary initialization init_idle_bootup_task() init_idle_bootup_task( ) is called in rest_init( ) to switch the scheduling class of the boot thread to the idle class. the function only sets: idle->sched_class = &idle_sched_class; which has been set in init_idle() called by sched_init(): /* * The idle tasks have their own, simple scheduling class: */ idle->sched_class = &idle_sched_class; We've already set the boot thread to idle class in start_kernel()->sched_init()->init_idle() so it's unnecessary to set it again in start_kernel()->rest_init()->init_idle_bootup_task() Signed-off-by: Cheng Jian Signed-off-by: Xie XiuQi Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1501838377-109720-1-git-send-email-cj.chengjian@huawei.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 5 ----- 1 file changed, 5 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 835a234d35e8..6d91c10b1814 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5177,11 +5177,6 @@ void show_state_filter(unsigned long state_filter) debug_show_all_locks(); } -void init_idle_bootup_task(struct task_struct *idle) -{ - idle->sched_class = &idle_sched_class; -} - /** * init_idle - set up an idle thread for a given CPU * @idle: task in question -- cgit v1.2.3 From 74dc3384fc7983b78cc46ebb1824968a3db85eb1 Mon Sep 17 00:00:00 2001 From: Aleksa Sarai Date: Sun, 6 Aug 2017 14:41:41 +1000 Subject: sched/debug: Use task_pid_nr_ns in /proc/$pid/sched It appears as though the addition of the PID namespace did not update the output code for /proc/*/sched, which resulted in it providing PIDs that were not self-consistent with the /proc mount. This additionally made it trivial to detect whether a process was inside &init_pid_ns from userspace, making container detection trivial: https://github.com/jessfraz/amicontained This leads to situations such as: % unshare -pmf % mount -t proc proc /proc % head -n1 /proc/1/sched head (10047, #threads: 1) Fix this by just using task_pid_nr_ns for the output of /proc/*/sched. All of the other uses of task_pid_nr in kernel/sched/debug.c are from a sysctl context and thus don't need to be namespaced. Signed-off-by: Aleksa Sarai Signed-off-by: Peter Zijlstra (Intel) Acked-by: Eric W. Biederman Cc: Jess Frazelle Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: cyphar@cyphar.com Link: http://lkml.kernel.org/r/20170806044141.5093-1-asarai@suse.com Signed-off-by: Ingo Molnar --- kernel/sched/debug.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 4fa66de52bd6..ac345115877b 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -872,11 +872,12 @@ static void sched_show_numa(struct task_struct *p, struct seq_file *m) #endif } -void proc_sched_show_task(struct task_struct *p, struct seq_file *m) +void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns, + struct seq_file *m) { unsigned long nr_switches; - SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr(p), + SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr_ns(p, ns), get_nr_threads(p)); SEQ_printf(m, "---------------------------------------------------------" -- cgit v1.2.3 From e8c164954b926f06f109a42fb8595ed01275b141 Mon Sep 17 00:00:00 2001 From: Xie XiuQi Date: Mon, 7 Aug 2017 16:44:22 +0800 Subject: sched/debug: Show task state in /proc/sched_debug Currently we print the runnable task in /proc/sched_debug, but there is no task state information. We don't know which task is in the runqueue and which task is sleeping. Add task state in the runnable task list, like this: runnable tasks: S task PID tree-key switches prio wait-time sum-exec sum-sleep ----------------------------------------------------------------------------------------------------------- S watchdog/239 1452 -11.917445 2811 0 0.000000 8.949306 0.000000 7 0 / S migration/239 1453 20686.367740 8 0 0.000000 16215.720897 0.000000 7 0 / S ksoftirqd/239 1454 115383.841071 12 120 0.000000 0.200683 0.000000 7 0 / >R test 21287 4872.190970 407 120 0.000000 4874.911790 0.000000 7 0 /autogroup-150 R test 21288 4868.385454 401 120 0.000000 3672.341489 0.000000 7 0 /autogroup-150 R test 21289 4868.326776 384 120 0.000000 3424.934159 0.000000 7 0 /autogroup-150 Signed-off-by: Xie XiuQi Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1502095463-160172-2-git-send-email-xiexiuqi@huawei.com Signed-off-by: Ingo Molnar --- kernel/sched/debug.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index ac345115877b..d8d2ea215b85 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -421,13 +421,19 @@ static char *task_group_path(struct task_group *tg) } #endif +static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; + static void print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) { - if (rq->curr == p) - SEQ_printf(m, "R"); - else - SEQ_printf(m, " "); + unsigned long state; + + if (rq->curr == p) { + SEQ_printf(m, ">R"); + } else { + state = p->state ? __ffs(p->state) + 1 : 0; + SEQ_printf(m, " %c", state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); + } SEQ_printf(m, "%15s %5d %9Ld.%06ld %9Ld %5d ", p->comm, task_pid_nr(p), @@ -456,9 +462,9 @@ static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu) SEQ_printf(m, "\nrunnable tasks:\n" - " task PID tree-key switches prio" + " S task PID tree-key switches prio" " wait-time sum-exec sum-sleep\n" - "------------------------------------------------------" + "-------------------------------------------------------" "----------------------------------------------------\n"); rcu_read_lock(); -- cgit v1.2.3 From 20435d84e5f2041c64c792399ab6f2948a2c2252 Mon Sep 17 00:00:00 2001 From: Xie XiuQi Date: Mon, 7 Aug 2017 16:44:23 +0800 Subject: sched/debug: Intruduce task_state_to_char() helper function Now that we have more than one place to get the task state, intruduce the task_state_to_char() helper function to save some code. No functionality changed. Signed-off-by: Xie XiuQi Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1502095463-160172-3-git-send-email-xiexiuqi@huawei.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 15 ++++----------- kernel/sched/debug.c | 10 +++------- 2 files changed, 7 insertions(+), 18 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 6d91c10b1814..f9f9948e2470 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5103,24 +5103,17 @@ out_unlock: return retval; } -static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; - void sched_show_task(struct task_struct *p) { unsigned long free = 0; int ppid; - unsigned long state = p->state; - - /* Make sure the string lines up properly with the number of task states: */ - BUILD_BUG_ON(sizeof(TASK_STATE_TO_CHAR_STR)-1 != ilog2(TASK_STATE_MAX)+1); if (!try_get_task_stack(p)) return; - if (state) - state = __ffs(state) + 1; - printk(KERN_INFO "%-15.15s %c", p->comm, - state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); - if (state == TASK_RUNNING) + + printk(KERN_INFO "%-15.15s %c", p->comm, task_state_to_char(p)); + + if (p->state == TASK_RUNNING) printk(KERN_CONT " running task "); #ifdef CONFIG_DEBUG_STACK_USAGE free = stack_not_used(p); diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index d8d2ea215b85..cfd84f79e075 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -426,14 +426,10 @@ static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; static void print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) { - unsigned long state; - - if (rq->curr == p) { + if (rq->curr == p) SEQ_printf(m, ">R"); - } else { - state = p->state ? __ffs(p->state) + 1 : 0; - SEQ_printf(m, " %c", state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); - } + else + SEQ_printf(m, " %c", task_state_to_char(p)); SEQ_printf(m, "%15s %5d %9Ld.%06ld %9Ld %5d ", p->comm, task_pid_nr(p), -- cgit v1.2.3 From 35a2897c2a306cca344ca5c0b43416707018f434 Mon Sep 17 00:00:00 2001 From: Boqun Feng Date: Thu, 15 Jun 2017 12:18:28 +0800 Subject: sched/wait: Remove the lockless swait_active() check in swake_up*() Steven Rostedt reported a potential race in RCU core because of swake_up(): CPU0 CPU1 ---- ---- __call_rcu_core() { spin_lock(rnp_root) need_wake = __rcu_start_gp() { rcu_start_gp_advanced() { gp_flags = FLAG_INIT } } rcu_gp_kthread() { swait_event_interruptible(wq, gp_flags & FLAG_INIT) { spin_lock(q->lock) *fetch wq->task_list here! * list_add(wq->task_list, q->task_list) spin_unlock(q->lock); *fetch old value of gp_flags here * spin_unlock(rnp_root) rcu_gp_kthread_wake() { swake_up(wq) { swait_active(wq) { list_empty(wq->task_list) } * return false * if (condition) * false * schedule(); In this case, a wakeup is missed, which could cause the rcu_gp_kthread waits for a long time. The reason of this is that we do a lockless swait_active() check in swake_up(). To fix this, we can either 1) add a smp_mb() in swake_up() before swait_active() to provide the proper order or 2) simply remove the swait_active() in swake_up(). The solution 2 not only fixes this problem but also keeps the swait and wait API as close as possible, as wake_up() doesn't provide a full barrier and doesn't do a lockless check of the wait queue either. Moreover, there are users already using swait_active() to do their quick checks for the wait queues, so it make less sense that swake_up() and swake_up_all() do this on their own. This patch then removes the lockless swait_active() check in swake_up() and swake_up_all(). Reported-by: Steven Rostedt Signed-off-by: Boqun Feng Signed-off-by: Peter Zijlstra (Intel) Cc: Krister Johansen Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Paul Gortmaker Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170615041828.zk3a3sfyudm5p6nl@tardis Signed-off-by: Ingo Molnar --- kernel/sched/swait.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c index 3d5610dcce11..2227e183e202 100644 --- a/kernel/sched/swait.c +++ b/kernel/sched/swait.c @@ -33,9 +33,6 @@ void swake_up(struct swait_queue_head *q) { unsigned long flags; - if (!swait_active(q)) - return; - raw_spin_lock_irqsave(&q->lock, flags); swake_up_locked(q); raw_spin_unlock_irqrestore(&q->lock, flags); @@ -51,9 +48,6 @@ void swake_up_all(struct swait_queue_head *q) struct swait_queue *curr; LIST_HEAD(tmp); - if (!swait_active(q)) - return; - raw_spin_lock_irq(&q->lock); list_splice_init(&q->task_list, &tmp); while (!list_empty(&tmp)) { -- cgit v1.2.3 From 50972fe78f24f1cd0b9d7bbf1f87d2be9e4f412e Mon Sep 17 00:00:00 2001 From: Prateek Sood Date: Fri, 14 Jul 2017 19:17:56 +0530 Subject: locking/osq_lock: Fix osq_lock queue corruption Fix ordering of link creation between node->prev and prev->next in osq_lock(). A case in which the status of optimistic spin queue is CPU6->CPU2 in which CPU6 has acquired the lock. tail v ,-. <- ,-. |6| |2| `-' -> `-' At this point if CPU0 comes in to acquire osq_lock, it will update the tail count. CPU2 CPU0 ---------------------------------- tail v ,-. <- ,-. ,-. |6| |2| |0| `-' -> `-' `-' After tail count update if CPU2 starts to unqueue itself from optimistic spin queue, it will find an updated tail count with CPU0 and update CPU2 node->next to NULL in osq_wait_next(). unqueue-A tail v ,-. <- ,-. ,-. |6| |2| |0| `-' `-' `-' unqueue-B ->tail != curr && !node->next If reordering of following stores happen then prev->next where prev being CPU2 would be updated to point to CPU0 node: tail v ,-. <- ,-. ,-. |6| |2| |0| `-' `-' -> `-' osq_wait_next() node->next <- 0 xchg(node->next, NULL) tail v ,-. <- ,-. ,-. |6| |2| |0| `-' `-' `-' unqueue-C At this point if next instruction WRITE_ONCE(next->prev, prev); in CPU2 path is committed before the update of CPU0 node->prev = prev then CPU0 node->prev will point to CPU6 node. tail v----------. v ,-. <- ,-. ,-. |6| |2| |0| `-' `-' `-' `----------^ At this point if CPU0 path's node->prev = prev is committed resulting in change of CPU0 prev back to CPU2 node. CPU2 node->next is NULL currently, tail v ,-. <- ,-. <- ,-. |6| |2| |0| `-' `-' `-' `----------^ so if CPU0 gets into unqueue path of osq_lock it will keep spinning in infinite loop as condition prev->next == node will never be true. Signed-off-by: Prateek Sood [ Added pictures, rewrote comments. ] Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: sramana@codeaurora.org Link: http://lkml.kernel.org/r/1500040076-27626-1-git-send-email-prsood@codeaurora.org Signed-off-by: Ingo Molnar --- kernel/locking/osq_lock.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'kernel') diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c index a3167941093b..a74ee6abd039 100644 --- a/kernel/locking/osq_lock.c +++ b/kernel/locking/osq_lock.c @@ -109,6 +109,19 @@ bool osq_lock(struct optimistic_spin_queue *lock) prev = decode_cpu(old); node->prev = prev; + + /* + * osq_lock() unqueue + * + * node->prev = prev osq_wait_next() + * WMB MB + * prev->next = node next->prev = prev // unqueue-C + * + * Here 'node->prev' and 'next->prev' are the same variable and we need + * to ensure these stores happen in-order to avoid corrupting the list. + */ + smp_wmb(); + WRITE_ONCE(prev->next, node); /* -- cgit v1.2.3 From 0aa1125fa8bc5e5f98317156728fa4d0293561a5 Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Mon, 19 Jun 2017 21:02:12 +0300 Subject: locking/rwsem-spinlock: Add killable versions of __down_read() Rename __down_read() in __down_read_common() and teach it to abort waiting in case of pending signals and killable state argument passed. Note, that we shouldn't wake anybody up in EINTR path, as: We check for signal_pending_state() after (!waiter.task) test and under spinlock. So, current task wasn't able to be woken up. It may be in two cases: a writer is owner of the sem, or a writer is a first waiter of the sem. If a writer is owner of the sem, no one else may work with it in parallel. It will wake somebody, when it call up_write() or downgrade_write(). If a writer is the first waiter, it will be woken up, when the last active reader releases the sem, and sem->count became 0. Also note, that set_current_state() may be moved down to schedule() (after !waiter.task check), as all assignments in this type of semaphore (including wake_up), occur under spinlock, so we can't miss anything. Signed-off-by: Kirill Tkhai Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: arnd@arndb.de Cc: avagin@virtuozzo.com Cc: davem@davemloft.net Cc: fenghua.yu@intel.com Cc: gorcunov@virtuozzo.com Cc: heiko.carstens@de.ibm.com Cc: hpa@zytor.com Cc: ink@jurassic.park.msu.ru Cc: mattst88@gmail.com Cc: rth@twiddle.net Cc: schwidefsky@de.ibm.com Cc: tony.luck@intel.com Link: http://lkml.kernel.org/r/149789533283.9059.9829416940494747182.stgit@localhost.localdomain Signed-off-by: Ingo Molnar --- kernel/locking/rwsem-spinlock.c | 37 ++++++++++++++++++++++++++++--------- 1 file changed, 28 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/rwsem-spinlock.c b/kernel/locking/rwsem-spinlock.c index 20819df98125..0848634c5512 100644 --- a/kernel/locking/rwsem-spinlock.c +++ b/kernel/locking/rwsem-spinlock.c @@ -126,7 +126,7 @@ __rwsem_wake_one_writer(struct rw_semaphore *sem) /* * get a read lock on the semaphore */ -void __sched __down_read(struct rw_semaphore *sem) +int __sched __down_read_common(struct rw_semaphore *sem, int state) { struct rwsem_waiter waiter; unsigned long flags; @@ -140,8 +140,6 @@ void __sched __down_read(struct rw_semaphore *sem) goto out; } - set_current_state(TASK_UNINTERRUPTIBLE); - /* set up my own style of waitqueue */ waiter.task = current; waiter.type = RWSEM_WAITING_FOR_READ; @@ -149,20 +147,41 @@ void __sched __down_read(struct rw_semaphore *sem) list_add_tail(&waiter.list, &sem->wait_list); - /* we don't need to touch the semaphore struct anymore */ - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - /* wait to be given the lock */ for (;;) { if (!waiter.task) break; + if (signal_pending_state(state, current)) + goto out_nolock; + set_current_state(state); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); schedule(); - set_current_state(TASK_UNINTERRUPTIBLE); + raw_spin_lock_irqsave(&sem->wait_lock, flags); } - __set_current_state(TASK_RUNNING); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); out: - ; + return 0; + +out_nolock: + /* + * We didn't take the lock, so that there is a writer, which + * is owner or the first waiter of the sem. If it's a waiter, + * it will be woken by current owner. Not need to wake anybody. + */ + list_del(&waiter.list); + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); + return -EINTR; +} + +void __sched __down_read(struct rw_semaphore *sem) +{ + __down_read_common(sem, TASK_UNINTERRUPTIBLE); +} + +int __sched __down_read_killable(struct rw_semaphore *sem) +{ + return __down_read_common(sem, TASK_KILLABLE); } /* -- cgit v1.2.3 From 83ced169d9a01f22eb39f1fcc1f89ad9d223238f Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Mon, 19 Jun 2017 21:02:26 +0300 Subject: locking/rwsem-xadd: Add killable versions of rwsem_down_read_failed() Rename rwsem_down_read_failed() in __rwsem_down_read_failed_common() and teach it to abort waiting in case of pending signals and killable state argument passed. Note, that we shouldn't wake anybody up in EINTR path, as: We check for (waiter.task) under spinlock before we go to out_nolock path. Current task wasn't able to be woken up, so there are a writer, owning the sem, or a writer, which is the first waiter. In the both cases we shouldn't wake anybody. If there is a writer, owning the sem, and we were the only waiter, remove RWSEM_WAITING_BIAS, as there are no waiters anymore. Signed-off-by: Kirill Tkhai Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: arnd@arndb.de Cc: avagin@virtuozzo.com Cc: davem@davemloft.net Cc: fenghua.yu@intel.com Cc: gorcunov@virtuozzo.com Cc: heiko.carstens@de.ibm.com Cc: hpa@zytor.com Cc: ink@jurassic.park.msu.ru Cc: mattst88@gmail.com Cc: rth@twiddle.net Cc: schwidefsky@de.ibm.com Cc: tony.luck@intel.com Link: http://lkml.kernel.org/r/149789534632.9059.2901382369609922565.stgit@localhost.localdomain Signed-off-by: Ingo Molnar --- kernel/locking/rwsem-xadd.c | 33 ++++++++++++++++++++++++++++++--- 1 file changed, 30 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 34e727f18e49..02f660666ab8 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -221,8 +221,8 @@ static void __rwsem_mark_wake(struct rw_semaphore *sem, /* * Wait for the read lock to be granted */ -__visible -struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem) +static inline struct rw_semaphore __sched * +__rwsem_down_read_failed_common(struct rw_semaphore *sem, int state) { long count, adjustment = -RWSEM_ACTIVE_READ_BIAS; struct rwsem_waiter waiter; @@ -255,17 +255,44 @@ struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem) /* wait to be given the lock */ while (true) { - set_current_state(TASK_UNINTERRUPTIBLE); + set_current_state(state); if (!waiter.task) break; + if (signal_pending_state(state, current)) { + raw_spin_lock_irq(&sem->wait_lock); + if (waiter.task) + goto out_nolock; + raw_spin_unlock_irq(&sem->wait_lock); + break; + } schedule(); } __set_current_state(TASK_RUNNING); return sem; +out_nolock: + list_del(&waiter.list); + if (list_empty(&sem->wait_list)) + atomic_long_add(-RWSEM_WAITING_BIAS, &sem->count); + raw_spin_unlock_irq(&sem->wait_lock); + __set_current_state(TASK_RUNNING); + return ERR_PTR(-EINTR); +} + +__visible struct rw_semaphore * __sched +rwsem_down_read_failed(struct rw_semaphore *sem) +{ + return __rwsem_down_read_failed_common(sem, TASK_UNINTERRUPTIBLE); } EXPORT_SYMBOL(rwsem_down_read_failed); +__visible struct rw_semaphore * __sched +rwsem_down_read_failed_killable(struct rw_semaphore *sem) +{ + return __rwsem_down_read_failed_common(sem, TASK_KILLABLE); +} +EXPORT_SYMBOL(rwsem_down_read_failed_killable); + /* * This function must be called with the sem->wait_lock held to prevent * race conditions between checking the rwsem wait list and setting the -- cgit v1.2.3 From 1dbb6704de91b169a58d0c8221624afd6a95cfc7 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 1 Aug 2017 17:24:04 +0200 Subject: jump_label: Fix concurrent static_key_enable/disable() static_key_enable/disable are trying to cap the static key count to 0/1. However, their use of key->enabled is outside jump_label_lock so they do not really ensure that. Rewrite them to do a quick check for an already enabled (respectively, already disabled), and then recheck under the jump label lock. Unlike static_key_slow_inc/dec, a failed check under the jump label lock does not modify key->enabled. Signed-off-by: Paolo Bonzini Signed-off-by: Peter Zijlstra (Intel) Cc: Eric Dumazet Cc: Jason Baron Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1501601046-35683-2-git-send-email-pbonzini@redhat.com Signed-off-by: Ingo Molnar --- kernel/jump_label.c | 59 +++++++++++++++++++++++++++++++++-------------------- 1 file changed, 37 insertions(+), 22 deletions(-) (limited to 'kernel') diff --git a/kernel/jump_label.c b/kernel/jump_label.c index d11c506a6ac3..833eecae825e 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -79,28 +79,6 @@ int static_key_count(struct static_key *key) } EXPORT_SYMBOL_GPL(static_key_count); -void static_key_enable(struct static_key *key) -{ - int count = static_key_count(key); - - WARN_ON_ONCE(count < 0 || count > 1); - - if (!count) - static_key_slow_inc(key); -} -EXPORT_SYMBOL_GPL(static_key_enable); - -void static_key_disable(struct static_key *key) -{ - int count = static_key_count(key); - - WARN_ON_ONCE(count < 0 || count > 1); - - if (count) - static_key_slow_dec(key); -} -EXPORT_SYMBOL_GPL(static_key_disable); - void static_key_slow_inc(struct static_key *key) { int v, v1; @@ -139,6 +117,43 @@ void static_key_slow_inc(struct static_key *key) } EXPORT_SYMBOL_GPL(static_key_slow_inc); +void static_key_enable(struct static_key *key) +{ + STATIC_KEY_CHECK_USE(); + if (atomic_read(&key->enabled) > 0) { + WARN_ON_ONCE(atomic_read(&key->enabled) != 1); + return; + } + + cpus_read_lock(); + jump_label_lock(); + if (atomic_read(&key->enabled) == 0) { + atomic_set(&key->enabled, -1); + jump_label_update(key); + atomic_set(&key->enabled, 1); + } + jump_label_unlock(); + cpus_read_unlock(); +} +EXPORT_SYMBOL_GPL(static_key_enable); + +void static_key_disable(struct static_key *key) +{ + STATIC_KEY_CHECK_USE(); + if (atomic_read(&key->enabled) != 1) { + WARN_ON_ONCE(atomic_read(&key->enabled) != 0); + return; + } + + cpus_read_lock(); + jump_label_lock(); + if (atomic_cmpxchg(&key->enabled, 1, 0)) + jump_label_update(key); + jump_label_unlock(); + cpus_read_unlock(); +} +EXPORT_SYMBOL_GPL(static_key_disable); + static void __static_key_slow_dec(struct static_key *key, unsigned long rate_limit, struct delayed_work *work) { -- cgit v1.2.3 From be040bea9085a9c2b1700c9e60888777baeb96d5 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 1 Aug 2017 17:24:06 +0200 Subject: cpuset: Make nr_cpusets private Any use of key->enabled (that is static_key_enabled and static_key_count) outside jump_label_lock should handle its own serialization. In the case of cpusets_enabled_key, the key is always incremented/decremented under cpuset_mutex, and hence the same rule applies to nr_cpusets. The rule *is* respected currently, but the mutex is static so nr_cpusets should be static too. Signed-off-by: Paolo Bonzini Signed-off-by: Peter Zijlstra (Intel) Acked-by: Zefan Li Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1501601046-35683-4-git-send-email-pbonzini@redhat.com Signed-off-by: Ingo Molnar --- kernel/cgroup/cpuset.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 8d5151688504..9ed6a051a1b9 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -577,6 +577,13 @@ static void update_domain_attr_tree(struct sched_domain_attr *dattr, rcu_read_unlock(); } +/* Must be called with cpuset_mutex held. */ +static inline int nr_cpusets(void) +{ + /* jump label reference count + the top-level cpuset */ + return static_key_count(&cpusets_enabled_key.key) + 1; +} + /* * generate_sched_domains() * -- cgit v1.2.3 From d0646a6f5533226ceb7620c20717286d3a372794 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 1 Aug 2017 23:58:50 +0200 Subject: jump_label: Add RELEASE barrier after text changes In the unlikely case text modification does not fully order things, add some extra ordering of our own to ensure we only enabled the fast path after all text is visible. Signed-off-by: Peter Zijlstra (Intel) Cc: Jason Baron Cc: Linus Torvalds Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/jump_label.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 833eecae825e..f2ea678c269f 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -108,7 +108,11 @@ void static_key_slow_inc(struct static_key *key) if (atomic_read(&key->enabled) == 0) { atomic_set(&key->enabled, -1); jump_label_update(key); - atomic_set(&key->enabled, 1); + /* + * Ensure that if the above cmpxchg loop observes our positive + * value, it must also observe all the text changes. + */ + atomic_set_release(&key->enabled, 1); } else { atomic_inc(&key->enabled); } @@ -130,7 +134,10 @@ void static_key_enable(struct static_key *key) if (atomic_read(&key->enabled) == 0) { atomic_set(&key->enabled, -1); jump_label_update(key); - atomic_set(&key->enabled, 1); + /* + * See static_key_slow_inc(). + */ + atomic_set_release(&key->enabled, 1); } jump_label_unlock(); cpus_read_unlock(); -- cgit v1.2.3 From b70cecf4b6b72a9977576ab32cca0e24f286f517 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 1 Aug 2017 09:02:54 +0100 Subject: jump_label: Move CPU hotplug locking As we're about to rework the locking, let's move the taking and release of the CPU hotplug lock to locations that will make its reworking completely obvious. Signed-off-by: Marc Zyngier Signed-off-by: Peter Zijlstra (Intel) Cc: Leo Yan Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20170801080257.5056-2-marc.zyngier@arm.com Signed-off-by: Ingo Molnar --- kernel/jump_label.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/jump_label.c b/kernel/jump_label.c index f2ea678c269f..161301fff97d 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -83,6 +83,7 @@ void static_key_slow_inc(struct static_key *key) { int v, v1; + cpus_read_lock(); STATIC_KEY_CHECK_USE(); /* @@ -99,11 +100,12 @@ void static_key_slow_inc(struct static_key *key) */ for (v = atomic_read(&key->enabled); v > 0; v = v1) { v1 = atomic_cmpxchg(&key->enabled, v, v + 1); - if (likely(v1 == v)) + if (likely(v1 == v)) { + cpus_read_unlock(); return; + } } - cpus_read_lock(); jump_label_lock(); if (atomic_read(&key->enabled) == 0) { atomic_set(&key->enabled, -1); -- cgit v1.2.3 From 8b7b412807053ab5f059ffae426a280e769a5bda Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 1 Aug 2017 09:02:55 +0100 Subject: jump_label: Split out code under the hotplug lock In order to later introduce an "already locked" version of some of the static key funcions, let's split the code into the core stuff (the *_cpuslocked functions) and the usual helpers, which now take/release the hotplug lock and call into the _cpuslocked versions. Signed-off-by: Marc Zyngier Signed-off-by: Peter Zijlstra (Intel) Cc: Leo Yan Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20170801080257.5056-3-marc.zyngier@arm.com Signed-off-by: Ingo Molnar --- kernel/jump_label.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 161301fff97d..cc6d815c75ed 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -79,11 +79,10 @@ int static_key_count(struct static_key *key) } EXPORT_SYMBOL_GPL(static_key_count); -void static_key_slow_inc(struct static_key *key) +static void static_key_slow_inc_cpuslocked(struct static_key *key) { int v, v1; - cpus_read_lock(); STATIC_KEY_CHECK_USE(); /* @@ -100,10 +99,8 @@ void static_key_slow_inc(struct static_key *key) */ for (v = atomic_read(&key->enabled); v > 0; v = v1) { v1 = atomic_cmpxchg(&key->enabled, v, v + 1); - if (likely(v1 == v)) { - cpus_read_unlock(); + if (likely(v1 == v)) return; - } } jump_label_lock(); @@ -119,6 +116,12 @@ void static_key_slow_inc(struct static_key *key) atomic_inc(&key->enabled); } jump_label_unlock(); +} + +void static_key_slow_inc(struct static_key *key) +{ + cpus_read_lock(); + static_key_slow_inc_cpuslocked(key); cpus_read_unlock(); } EXPORT_SYMBOL_GPL(static_key_slow_inc); @@ -163,10 +166,10 @@ void static_key_disable(struct static_key *key) } EXPORT_SYMBOL_GPL(static_key_disable); -static void __static_key_slow_dec(struct static_key *key, - unsigned long rate_limit, struct delayed_work *work) +static void static_key_slow_dec_cpuslocked(struct static_key *key, + unsigned long rate_limit, + struct delayed_work *work) { - cpus_read_lock(); /* * The negative count check is valid even when a negative * key->enabled is in use by static_key_slow_inc(); a @@ -177,7 +180,6 @@ static void __static_key_slow_dec(struct static_key *key, if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) { WARN(atomic_read(&key->enabled) < 0, "jump label: negative count!\n"); - cpus_read_unlock(); return; } @@ -188,6 +190,14 @@ static void __static_key_slow_dec(struct static_key *key, jump_label_update(key); } jump_label_unlock(); +} + +static void __static_key_slow_dec(struct static_key *key, + unsigned long rate_limit, + struct delayed_work *work) +{ + cpus_read_lock(); + static_key_slow_dec_cpuslocked(key, rate_limit, work); cpus_read_unlock(); } -- cgit v1.2.3 From 5a40527f8f0798553764fc8db4111d7d9c33ea51 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 1 Aug 2017 09:02:56 +0100 Subject: jump_label: Provide hotplug context variants As using the normal static key API under the hotplug lock is pretty much impossible, let's provide a variant of some of them that require the hotplug lock to have already been taken. These function are only meant to be used in CPU hotplug callbacks. Signed-off-by: Marc Zyngier Signed-off-by: Peter Zijlstra (Intel) Cc: Leo Yan Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20170801080257.5056-4-marc.zyngier@arm.com Signed-off-by: Ingo Molnar --- kernel/jump_label.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/jump_label.c b/kernel/jump_label.c index cc6d815c75ed..0bf2e8f5244a 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -126,15 +126,15 @@ void static_key_slow_inc(struct static_key *key) } EXPORT_SYMBOL_GPL(static_key_slow_inc); -void static_key_enable(struct static_key *key) +void static_key_enable_cpuslocked(struct static_key *key) { STATIC_KEY_CHECK_USE(); + if (atomic_read(&key->enabled) > 0) { WARN_ON_ONCE(atomic_read(&key->enabled) != 1); return; } - cpus_read_lock(); jump_label_lock(); if (atomic_read(&key->enabled) == 0) { atomic_set(&key->enabled, -1); @@ -145,23 +145,37 @@ void static_key_enable(struct static_key *key) atomic_set_release(&key->enabled, 1); } jump_label_unlock(); +} +EXPORT_SYMBOL_GPL(static_key_enable_cpuslocked); + +void static_key_enable(struct static_key *key) +{ + cpus_read_lock(); + static_key_enable_cpuslocked(key); cpus_read_unlock(); } EXPORT_SYMBOL_GPL(static_key_enable); -void static_key_disable(struct static_key *key) +void static_key_disable_cpuslocked(struct static_key *key) { STATIC_KEY_CHECK_USE(); + if (atomic_read(&key->enabled) != 1) { WARN_ON_ONCE(atomic_read(&key->enabled) != 0); return; } - cpus_read_lock(); jump_label_lock(); if (atomic_cmpxchg(&key->enabled, 1, 0)) jump_label_update(key); jump_label_unlock(); +} +EXPORT_SYMBOL_GPL(static_key_disable_cpuslocked); + +void static_key_disable(struct static_key *key) +{ + cpus_read_lock(); + static_key_disable_cpuslocked(key); cpus_read_unlock(); } EXPORT_SYMBOL_GPL(static_key_disable); -- cgit v1.2.3 From d89e588ca4081615216cc25f2489b0281ac0bfe9 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 5 Sep 2016 11:37:53 +0200 Subject: locking: Introduce smp_mb__after_spinlock() Since its inception, our understanding of ACQUIRE, esp. as applied to spinlocks, has changed somewhat. Also, I wonder if, with a simple change, we cannot make it provide more. The problem with the comment is that the STORE done by spin_lock isn't itself ordered by the ACQUIRE, and therefore a later LOAD can pass over it and cross with any prior STORE, rendering the default WMB insufficient (pointed out by Alan). Now, this is only really a problem on PowerPC and ARM64, both of which already defined smp_mb__before_spinlock() as a smp_mb(). At the same time, we can get a much stronger construct if we place that same barrier _inside_ the spin_lock(). In that case we upgrade the RCpc spinlock to an RCsc. That would make all schedule() calls fully transitive against one another. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Cc: Alan Stern Cc: Benjamin Herrenschmidt Cc: Linus Torvalds Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Oleg Nesterov Cc: Paul McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0869b20fba81..9fece583a1f0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1967,8 +1967,8 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) * reordered with p->state check below. This pairs with mb() in * set_current_state() the waiting thread does. */ - smp_mb__before_spinlock(); raw_spin_lock_irqsave(&p->pi_lock, flags); + smp_mb__after_spinlock(); if (!(p->state & state)) goto out; @@ -3281,8 +3281,8 @@ static void __sched notrace __schedule(bool preempt) * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) * done by the caller to avoid the race with signal_wake_up(). */ - smp_mb__before_spinlock(); rq_lock(rq, &rf); + smp_mb__after_spinlock(); /* Promote REQ to ACT */ rq->clock_update_flags <<= 1; -- cgit v1.2.3 From d92a8cfcb37ecd1315269dab741f073b63b3a8b6 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 3 Mar 2017 10:13:38 +0100 Subject: locking/lockdep: Rework FS_RECLAIM annotation A while ago someone, and I cannot find the email just now, asked if we could not implement the RECLAIM_FS inversion stuff with a 'fake' lock like we use for other things like workqueues etc. I think this should be possible which allows reducing the 'irq' states and will reduce the amount of __bfs() lookups we do. Removing the 1 IRQ state results in 4 less __bfs() walks per dependency, improving lockdep performance. And by moving this annotation out of the lockdep code it becomes easier for the mm people to extend. Signed-off-by: Peter Zijlstra (Intel) Cc: Byungchul Park Cc: Linus Torvalds Cc: Mel Gorman Cc: Michal Hocko Cc: Nikolay Borisov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: iamjoonsoo.kim@lge.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 95 +---------------------------------------- kernel/locking/lockdep_states.h | 1 - 2 files changed, 1 insertion(+), 95 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 7d2499bec5fe..986f2fa79dbb 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -344,14 +344,12 @@ EXPORT_SYMBOL(lockdep_on); #if VERBOSE # define HARDIRQ_VERBOSE 1 # define SOFTIRQ_VERBOSE 1 -# define RECLAIM_VERBOSE 1 #else # define HARDIRQ_VERBOSE 0 # define SOFTIRQ_VERBOSE 0 -# define RECLAIM_VERBOSE 0 #endif -#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE +#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE /* * Quick filtering for interesting events: */ @@ -2567,14 +2565,6 @@ static int SOFTIRQ_verbose(struct lock_class *class) return 0; } -static int RECLAIM_FS_verbose(struct lock_class *class) -{ -#if RECLAIM_VERBOSE - return class_filter(class); -#endif - return 0; -} - #define STRICT_READ_CHECKS 1 static int (*state_verbose_f[])(struct lock_class *class) = { @@ -2870,57 +2860,6 @@ void trace_softirqs_off(unsigned long ip) debug_atomic_inc(redundant_softirqs_off); } -static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) -{ - struct task_struct *curr = current; - - if (unlikely(!debug_locks)) - return; - - gfp_mask = current_gfp_context(gfp_mask); - - /* no reclaim without waiting on it */ - if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) - return; - - /* this guy won't enter reclaim */ - if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) - return; - - /* We're only interested __GFP_FS allocations for now */ - if (!(gfp_mask & __GFP_FS) || (curr->flags & PF_MEMALLOC_NOFS)) - return; - - /* - * Oi! Can't be having __GFP_FS allocations with IRQs disabled. - */ - if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) - return; - - /* Disable lockdep if explicitly requested */ - if (gfp_mask & __GFP_NOLOCKDEP) - return; - - mark_held_locks(curr, RECLAIM_FS); -} - -static void check_flags(unsigned long flags); - -void lockdep_trace_alloc(gfp_t gfp_mask) -{ - unsigned long flags; - - if (unlikely(current->lockdep_recursion)) - return; - - raw_local_irq_save(flags); - check_flags(flags); - current->lockdep_recursion = 1; - __lockdep_trace_alloc(gfp_mask, flags); - current->lockdep_recursion = 0; - raw_local_irq_restore(flags); -} - static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) { /* @@ -2966,22 +2905,6 @@ static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) } } - /* - * We reuse the irq context infrastructure more broadly as a general - * context checking code. This tests GFP_FS recursion (a lock taken - * during reclaim for a GFP_FS allocation is held over a GFP_FS - * allocation). - */ - if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { - if (hlock->read) { - if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) - return 0; - } else { - if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) - return 0; - } - } - return 1; } @@ -3040,10 +2963,6 @@ static inline int separate_irq_context(struct task_struct *curr, return 0; } -void lockdep_trace_alloc(gfp_t gfp_mask) -{ -} - #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ /* @@ -3952,18 +3871,6 @@ void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) } EXPORT_SYMBOL_GPL(lock_unpin_lock); -void lockdep_set_current_reclaim_state(gfp_t gfp_mask) -{ - current->lockdep_reclaim_gfp = current_gfp_context(gfp_mask); -} -EXPORT_SYMBOL_GPL(lockdep_set_current_reclaim_state); - -void lockdep_clear_current_reclaim_state(void) -{ - current->lockdep_reclaim_gfp = 0; -} -EXPORT_SYMBOL_GPL(lockdep_clear_current_reclaim_state); - #ifdef CONFIG_LOCK_STAT static int print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, diff --git a/kernel/locking/lockdep_states.h b/kernel/locking/lockdep_states.h index 995b0cc2b84c..35ca09f2ed0b 100644 --- a/kernel/locking/lockdep_states.h +++ b/kernel/locking/lockdep_states.h @@ -6,4 +6,3 @@ */ LOCKDEP_STATE(HARDIRQ) LOCKDEP_STATE(SOFTIRQ) -LOCKDEP_STATE(RECLAIM_FS) -- cgit v1.2.3 From ae813308f4630642d2c1c87553929ce95f29f9ef Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 3 Mar 2017 10:13:38 +0100 Subject: locking/lockdep: Avoid creating redundant links Two boots + a make defconfig, the first didn't have the redundant bit in, the second did: lock-classes: 1168 1169 [max: 8191] direct dependencies: 7688 5812 [max: 32768] indirect dependencies: 25492 25937 all direct dependencies: 220113 217512 dependency chains: 9005 9008 [max: 65536] dependency chain hlocks: 34450 34366 [max: 327680] in-hardirq chains: 55 51 in-softirq chains: 371 378 in-process chains: 8579 8579 stack-trace entries: 108073 88474 [max: 524288] combined max dependencies: 178738560 169094640 max locking depth: 15 15 max bfs queue depth: 320 329 cyclic checks: 9123 9190 redundant checks: 5046 redundant links: 1828 find-mask forwards checks: 2564 2599 find-mask backwards checks: 39521 39789 So it saves nearly 2k links and a fair chunk of stack-trace entries, but as expected, makes no real difference on the indirect dependencies. At the same time, you see the max BFS depth increase, which is also expected, although it could easily be boot variance -- these numbers are not entirely stable between boots. The down side is that the cycles in the graph become larger and thus the reports harder to read. XXX: do we want this as a CONFIG variable, implied by LOCKDEP_SMALL? Signed-off-by: Peter Zijlstra (Intel) Cc: Byungchul Park Cc: Linus Torvalds Cc: Mel Gorman Cc: Michal Hocko Cc: Nikolay Borisov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: iamjoonsoo.kim@lge.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Link: http://lkml.kernel.org/r/20170303091338.GH6536@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 27 +++++++++++++++++++++++++++ kernel/locking/lockdep_internals.h | 2 ++ kernel/locking/lockdep_proc.c | 4 ++++ 3 files changed, 33 insertions(+) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 986f2fa79dbb..b2dd313951ce 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1307,6 +1307,19 @@ check_noncircular(struct lock_list *root, struct lock_class *target, return result; } +static noinline int +check_redundant(struct lock_list *root, struct lock_class *target, + struct lock_list **target_entry) +{ + int result; + + debug_atomic_inc(nr_redundant_checks); + + result = __bfs_forwards(root, target, class_equal, target_entry); + + return result; +} + #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) /* * Forwards and backwards subgraph searching, for the purposes of @@ -1872,6 +1885,20 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, } } + /* + * Is the -> link redundant? + */ + this.class = hlock_class(prev); + this.parent = NULL; + ret = check_redundant(&this, hlock_class(next), &target_entry); + if (!ret) { + debug_atomic_inc(nr_redundant); + return 2; + } + if (ret < 0) + return print_bfs_bug(ret); + + if (!*stack_saved) { if (!save_trace(&trace)) return 0; diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h index c08fbd2f5ba9..1da4669d57a7 100644 --- a/kernel/locking/lockdep_internals.h +++ b/kernel/locking/lockdep_internals.h @@ -143,6 +143,8 @@ struct lockdep_stats { int redundant_softirqs_on; int redundant_softirqs_off; int nr_unused_locks; + int nr_redundant_checks; + int nr_redundant; int nr_cyclic_checks; int nr_cyclic_check_recursions; int nr_find_usage_forwards_checks; diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c index 6d1fcc786081..68d9e267ccd4 100644 --- a/kernel/locking/lockdep_proc.c +++ b/kernel/locking/lockdep_proc.c @@ -201,6 +201,10 @@ static void lockdep_stats_debug_show(struct seq_file *m) debug_atomic_read(chain_lookup_hits)); seq_printf(m, " cyclic checks: %11llu\n", debug_atomic_read(nr_cyclic_checks)); + seq_printf(m, " redundant checks: %11llu\n", + debug_atomic_read(nr_redundant_checks)); + seq_printf(m, " redundant links: %11llu\n", + debug_atomic_read(nr_redundant)); seq_printf(m, " find-mask forwards checks: %11llu\n", debug_atomic_read(nr_find_usage_forwards_checks)); seq_printf(m, " find-mask backwards checks: %11llu\n", -- cgit v1.2.3 From 545c23f2e954eb3365629b20ceeef4eadb1ff97f Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 7 Aug 2017 16:12:48 +0900 Subject: locking/lockdep: Refactor lookup_chain_cache() Currently, lookup_chain_cache() provides both 'lookup' and 'add' functionalities in a function. However, each is useful. So this patch makes lookup_chain_cache() only do 'lookup' functionality and makes add_chain_cahce() only do 'add' functionality. And it's more readable than before. Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502089981-21272-2-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 141 +++++++++++++++++++++++++++++++---------------- 1 file changed, 93 insertions(+), 48 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index b2dd313951ce..e029f2f3b8dc 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -2151,20 +2151,26 @@ static int check_no_collision(struct task_struct *curr, } /* - * Look up a dependency chain. If the key is not present yet then - * add it and return 1 - in this case the new dependency chain is - * validated. If the key is already hashed, return 0. - * (On return with 1 graph_lock is held.) + * Adds a dependency chain into chain hashtable. And must be called with + * graph_lock held. + * + * Return 0 if fail, and graph_lock is released. + * Return 1 if succeed, with graph_lock held. */ -static inline int lookup_chain_cache(struct task_struct *curr, - struct held_lock *hlock, - u64 chain_key) +static inline int add_chain_cache(struct task_struct *curr, + struct held_lock *hlock, + u64 chain_key) { struct lock_class *class = hlock_class(hlock); struct hlist_head *hash_head = chainhashentry(chain_key); struct lock_chain *chain; int i, j; + /* + * Allocate a new chain entry from the static array, and add + * it to the hash: + */ + /* * We might need to take the graph lock, ensure we've got IRQs * disabled to make this an IRQ-safe lock.. for recursion reasons @@ -2172,43 +2178,7 @@ static inline int lookup_chain_cache(struct task_struct *curr, */ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) return 0; - /* - * We can walk it lock-free, because entries only get added - * to the hash: - */ - hlist_for_each_entry_rcu(chain, hash_head, entry) { - if (chain->chain_key == chain_key) { -cache_hit: - debug_atomic_inc(chain_lookup_hits); - if (!check_no_collision(curr, hlock, chain)) - return 0; - if (very_verbose(class)) - printk("\nhash chain already cached, key: " - "%016Lx tail class: [%p] %s\n", - (unsigned long long)chain_key, - class->key, class->name); - return 0; - } - } - if (very_verbose(class)) - printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", - (unsigned long long)chain_key, class->key, class->name); - /* - * Allocate a new chain entry from the static array, and add - * it to the hash: - */ - if (!graph_lock()) - return 0; - /* - * We have to walk the chain again locked - to avoid duplicates: - */ - hlist_for_each_entry(chain, hash_head, entry) { - if (chain->chain_key == chain_key) { - graph_unlock(); - goto cache_hit; - } - } if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { if (!debug_locks_off_graph_unlock()) return 0; @@ -2260,6 +2230,78 @@ cache_hit: return 1; } +/* + * Look up a dependency chain. + */ +static inline struct lock_chain *lookup_chain_cache(u64 chain_key) +{ + struct hlist_head *hash_head = chainhashentry(chain_key); + struct lock_chain *chain; + + /* + * We can walk it lock-free, because entries only get added + * to the hash: + */ + hlist_for_each_entry_rcu(chain, hash_head, entry) { + if (chain->chain_key == chain_key) { + debug_atomic_inc(chain_lookup_hits); + return chain; + } + } + return NULL; +} + +/* + * If the key is not present yet in dependency chain cache then + * add it and return 1 - in this case the new dependency chain is + * validated. If the key is already hashed, return 0. + * (On return with 1 graph_lock is held.) + */ +static inline int lookup_chain_cache_add(struct task_struct *curr, + struct held_lock *hlock, + u64 chain_key) +{ + struct lock_class *class = hlock_class(hlock); + struct lock_chain *chain = lookup_chain_cache(chain_key); + + if (chain) { +cache_hit: + if (!check_no_collision(curr, hlock, chain)) + return 0; + + if (very_verbose(class)) { + printk("\nhash chain already cached, key: " + "%016Lx tail class: [%p] %s\n", + (unsigned long long)chain_key, + class->key, class->name); + } + + return 0; + } + + if (very_verbose(class)) { + printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", + (unsigned long long)chain_key, class->key, class->name); + } + + if (!graph_lock()) + return 0; + + /* + * We have to walk the chain again locked - to avoid duplicates: + */ + chain = lookup_chain_cache(chain_key); + if (chain) { + graph_unlock(); + goto cache_hit; + } + + if (!add_chain_cache(curr, hlock, chain_key)) + return 0; + + return 1; +} + static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, struct held_lock *hlock, int chain_head, u64 chain_key) { @@ -2270,11 +2312,11 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, * * We look up the chain_key and do the O(N^2) check and update of * the dependencies only if this is a new dependency chain. - * (If lookup_chain_cache() returns with 1 it acquires + * (If lookup_chain_cache_add() return with 1 it acquires * graph_lock for us) */ if (!hlock->trylock && hlock->check && - lookup_chain_cache(curr, hlock, chain_key)) { + lookup_chain_cache_add(curr, hlock, chain_key)) { /* * Check whether last held lock: * @@ -2302,14 +2344,17 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, * Add dependency only if this lock is not the head * of the chain, and if it's not a secondary read-lock: */ - if (!chain_head && ret != 2) + if (!chain_head && ret != 2) { if (!check_prevs_add(curr, hlock)) return 0; + } + graph_unlock(); - } else - /* after lookup_chain_cache(): */ + } else { + /* after lookup_chain_cache_add(): */ if (unlikely(!debug_locks)) return 0; + } return 1; } -- cgit v1.2.3 From 49347a986ab45eb1dafbf25170647c890f8ff192 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 7 Aug 2017 16:12:49 +0900 Subject: locking/lockdep: Add a function building a chain between two classes Crossrelease needs to build a chain between two classes regardless of their contexts. However, add_chain_cache() cannot be used for that purpose since it assumes that it's called in the acquisition context of the hlock. So this patch introduces a new function doing it. Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502089981-21272-3-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index e029f2f3b8dc..bdf6b31f702b 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -2150,6 +2150,76 @@ static int check_no_collision(struct task_struct *curr, return 1; } +/* + * This is for building a chain between just two different classes, + * instead of adding a new hlock upon current, which is done by + * add_chain_cache(). + * + * This can be called in any context with two classes, while + * add_chain_cache() must be done within the lock owener's context + * since it uses hlock which might be racy in another context. + */ +static inline int add_chain_cache_classes(unsigned int prev, + unsigned int next, + unsigned int irq_context, + u64 chain_key) +{ + struct hlist_head *hash_head = chainhashentry(chain_key); + struct lock_chain *chain; + + /* + * Allocate a new chain entry from the static array, and add + * it to the hash: + */ + + /* + * We might need to take the graph lock, ensure we've got IRQs + * disabled to make this an IRQ-safe lock.. for recursion reasons + * lockdep won't complain about its own locking errors. + */ + if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) + return 0; + + if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { + if (!debug_locks_off_graph_unlock()) + return 0; + + print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!"); + dump_stack(); + return 0; + } + + chain = lock_chains + nr_lock_chains++; + chain->chain_key = chain_key; + chain->irq_context = irq_context; + chain->depth = 2; + if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { + chain->base = nr_chain_hlocks; + nr_chain_hlocks += chain->depth; + chain_hlocks[chain->base] = prev - 1; + chain_hlocks[chain->base + 1] = next -1; + } +#ifdef CONFIG_DEBUG_LOCKDEP + /* + * Important for check_no_collision(). + */ + else { + if (!debug_locks_off_graph_unlock()) + return 0; + + print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!"); + dump_stack(); + return 0; + } +#endif + + hlist_add_head_rcu(&chain->entry, hash_head); + debug_atomic_inc(chain_lookup_misses); + inc_chains(); + + return 1; +} + /* * Adds a dependency chain into chain hashtable. And must be called with * graph_lock held. -- cgit v1.2.3 From 70911fdc9576f4eeb3986689a1c9a778a4a4aacb Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 7 Aug 2017 16:12:50 +0900 Subject: locking/lockdep: Change the meaning of check_prev_add()'s return value Firstly, return 1 instead of 2 when 'prev -> next' dependency already exists. Since the value 2 is not referenced anywhere, just return 1 indicating success in this case. Secondly, return 2 instead of 1 when successfully added a lock_list entry with saving stack_trace. With that, a caller can decide whether to avoid redundant save_trace() on the caller site. Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502089981-21272-4-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index bdf6b31f702b..7cf02fab1725 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1881,7 +1881,7 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, if (entry->class == hlock_class(next)) { if (distance == 1) entry->distance = 1; - return 2; + return 1; } } @@ -1935,9 +1935,10 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, print_lock_name(hlock_class(next)); printk(KERN_CONT "\n"); dump_stack(); - return graph_lock(); + if (!graph_lock()) + return 0; } - return 1; + return 2; } /* -- cgit v1.2.3 From ce07a9415f266e181a0a33033a5f7138760240a4 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 7 Aug 2017 16:12:51 +0900 Subject: locking/lockdep: Make check_prev_add() able to handle external stack_trace Currently, a space for stack_trace is pinned in check_prev_add(), that makes us not able to use external stack_trace. The simplest way to achieve it is to pass an external stack_trace as an argument. A more suitable solution is to pass a callback additionally along with a stack_trace so that callers can decide the way to save or whether to save. Actually crossrelease needs to do other than saving a stack_trace. So pass a stack_trace and callback to handle it, to check_prev_add(). Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502089981-21272-5-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 40 +++++++++++++++++++--------------------- 1 file changed, 19 insertions(+), 21 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 7cf02fab1725..841828ba35b9 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1824,20 +1824,13 @@ check_deadlock(struct task_struct *curr, struct held_lock *next, */ static int check_prev_add(struct task_struct *curr, struct held_lock *prev, - struct held_lock *next, int distance, int *stack_saved) + struct held_lock *next, int distance, struct stack_trace *trace, + int (*save)(struct stack_trace *trace)) { struct lock_list *entry; int ret; struct lock_list this; struct lock_list *uninitialized_var(target_entry); - /* - * Static variable, serialized by the graph_lock(). - * - * We use this static variable to save the stack trace in case - * we call into this function multiple times due to encountering - * trylocks in the held lock stack. - */ - static struct stack_trace trace; /* * Prove that the new -> dependency would not @@ -1899,11 +1892,8 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, return print_bfs_bug(ret); - if (!*stack_saved) { - if (!save_trace(&trace)) - return 0; - *stack_saved = 1; - } + if (save && !save(trace)) + return 0; /* * Ok, all validations passed, add the new lock @@ -1911,14 +1901,14 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, */ ret = add_lock_to_list(hlock_class(next), &hlock_class(prev)->locks_after, - next->acquire_ip, distance, &trace); + next->acquire_ip, distance, trace); if (!ret) return 0; ret = add_lock_to_list(hlock_class(prev), &hlock_class(next)->locks_before, - next->acquire_ip, distance, &trace); + next->acquire_ip, distance, trace); if (!ret) return 0; @@ -1926,8 +1916,6 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, * Debugging printouts: */ if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { - /* We drop graph lock, so another thread can overwrite trace. */ - *stack_saved = 0; graph_unlock(); printk("\n new dependency: "); print_lock_name(hlock_class(prev)); @@ -1951,8 +1939,9 @@ static int check_prevs_add(struct task_struct *curr, struct held_lock *next) { int depth = curr->lockdep_depth; - int stack_saved = 0; struct held_lock *hlock; + struct stack_trace trace; + int (*save)(struct stack_trace *trace) = save_trace; /* * Debugging checks. @@ -1977,9 +1966,18 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) * added: */ if (hlock->read != 2 && hlock->check) { - if (!check_prev_add(curr, hlock, next, - distance, &stack_saved)) + int ret = check_prev_add(curr, hlock, next, + distance, &trace, save); + if (!ret) return 0; + + /* + * Stop saving stack_trace if save_trace() was + * called at least once: + */ + if (save && ret == 2) + save = NULL; + /* * Stop after the first non-trylock entry, * as non-trylock entries have added their -- cgit v1.2.3 From b09be676e0ff25bd6d2e7637e26d349f9109ad75 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 7 Aug 2017 16:12:52 +0900 Subject: locking/lockdep: Implement the 'crossrelease' feature Lockdep is a runtime locking correctness validator that detects and reports a deadlock or its possibility by checking dependencies between locks. It's useful since it does not report just an actual deadlock but also the possibility of a deadlock that has not actually happened yet. That enables problems to be fixed before they affect real systems. However, this facility is only applicable to typical locks, such as spinlocks and mutexes, which are normally released within the context in which they were acquired. However, synchronization primitives like page locks or completions, which are allowed to be released in any context, also create dependencies and can cause a deadlock. So lockdep should track these locks to do a better job. The 'crossrelease' implementation makes these primitives also be tracked. Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502089981-21272-6-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- kernel/exit.c | 1 + kernel/fork.c | 4 + kernel/locking/lockdep.c | 508 ++++++++++++++++++++++++++++++++++++++++++++--- kernel/workqueue.c | 2 + 4 files changed, 492 insertions(+), 23 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index c5548faa9f37..fa72d57db747 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -920,6 +920,7 @@ void __noreturn do_exit(long code) exit_rcu(); TASKS_RCU(__srcu_read_unlock(&tasks_rcu_exit_srcu, tasks_rcu_i)); + lockdep_free_task(tsk); do_task_dead(); } EXPORT_SYMBOL_GPL(do_exit); diff --git a/kernel/fork.c b/kernel/fork.c index 17921b0390b4..cbf2221ee81a 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -484,6 +484,8 @@ void __init fork_init(void) cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache", NULL, free_vm_stack_cache); #endif + + lockdep_init_task(&init_task); } int __weak arch_dup_task_struct(struct task_struct *dst, @@ -1691,6 +1693,7 @@ static __latent_entropy struct task_struct *copy_process( p->lockdep_depth = 0; /* no locks held yet */ p->curr_chain_key = 0; p->lockdep_recursion = 0; + lockdep_init_task(p); #endif #ifdef CONFIG_DEBUG_MUTEXES @@ -1949,6 +1952,7 @@ bad_fork_cleanup_audit: bad_fork_cleanup_perf: perf_event_free_task(p); bad_fork_cleanup_policy: + lockdep_free_task(p); #ifdef CONFIG_NUMA mpol_put(p->mempolicy); bad_fork_cleanup_threadgroup_lock: diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 841828ba35b9..56f69cc53ddc 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -58,6 +58,10 @@ #define CREATE_TRACE_POINTS #include +#ifdef CONFIG_LOCKDEP_CROSSRELEASE +#include +#endif + #ifdef CONFIG_PROVE_LOCKING int prove_locking = 1; module_param(prove_locking, int, 0644); @@ -724,6 +728,18 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) return is_static || static_obj(lock->key) ? NULL : ERR_PTR(-EINVAL); } +#ifdef CONFIG_LOCKDEP_CROSSRELEASE +static void cross_init(struct lockdep_map *lock, int cross); +static int cross_lock(struct lockdep_map *lock); +static int lock_acquire_crosslock(struct held_lock *hlock); +static int lock_release_crosslock(struct lockdep_map *lock); +#else +static inline void cross_init(struct lockdep_map *lock, int cross) {} +static inline int cross_lock(struct lockdep_map *lock) { return 0; } +static inline int lock_acquire_crosslock(struct held_lock *hlock) { return 2; } +static inline int lock_release_crosslock(struct lockdep_map *lock) { return 2; } +#endif + /* * Register a lock's class in the hash-table, if the class is not present * yet. Otherwise we look it up. We cache the result in the lock object @@ -1795,6 +1811,9 @@ check_deadlock(struct task_struct *curr, struct held_lock *next, if (nest) return 2; + if (cross_lock(prev->instance)) + continue; + return print_deadlock_bug(curr, prev, next); } return 1; @@ -1962,30 +1981,36 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) int distance = curr->lockdep_depth - depth + 1; hlock = curr->held_locks + depth - 1; /* - * Only non-recursive-read entries get new dependencies - * added: + * Only non-crosslock entries get new dependencies added. + * Crosslock entries will be added by commit later: */ - if (hlock->read != 2 && hlock->check) { - int ret = check_prev_add(curr, hlock, next, - distance, &trace, save); - if (!ret) - return 0; - + if (!cross_lock(hlock->instance)) { /* - * Stop saving stack_trace if save_trace() was - * called at least once: + * Only non-recursive-read entries get new dependencies + * added: */ - if (save && ret == 2) - save = NULL; + if (hlock->read != 2 && hlock->check) { + int ret = check_prev_add(curr, hlock, next, + distance, &trace, save); + if (!ret) + return 0; - /* - * Stop after the first non-trylock entry, - * as non-trylock entries have added their - * own direct dependencies already, so this - * lock is connected to them indirectly: - */ - if (!hlock->trylock) - break; + /* + * Stop saving stack_trace if save_trace() was + * called at least once: + */ + if (save && ret == 2) + save = NULL; + + /* + * Stop after the first non-trylock entry, + * as non-trylock entries have added their + * own direct dependencies already, so this + * lock is connected to them indirectly: + */ + if (!hlock->trylock) + break; + } } depth--; /* @@ -3176,7 +3201,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, /* * Initialize a lock instance's lock-class mapping info: */ -void lockdep_init_map(struct lockdep_map *lock, const char *name, +static void __lockdep_init_map(struct lockdep_map *lock, const char *name, struct lock_class_key *key, int subclass) { int i; @@ -3234,8 +3259,25 @@ void lockdep_init_map(struct lockdep_map *lock, const char *name, raw_local_irq_restore(flags); } } + +void lockdep_init_map(struct lockdep_map *lock, const char *name, + struct lock_class_key *key, int subclass) +{ + cross_init(lock, 0); + __lockdep_init_map(lock, name, key, subclass); +} EXPORT_SYMBOL_GPL(lockdep_init_map); +#ifdef CONFIG_LOCKDEP_CROSSRELEASE +void lockdep_init_map_crosslock(struct lockdep_map *lock, const char *name, + struct lock_class_key *key, int subclass) +{ + cross_init(lock, 1); + __lockdep_init_map(lock, name, key, subclass); +} +EXPORT_SYMBOL_GPL(lockdep_init_map_crosslock); +#endif + struct lock_class_key __lockdep_no_validate__; EXPORT_SYMBOL_GPL(__lockdep_no_validate__); @@ -3291,6 +3333,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, int chain_head = 0; int class_idx; u64 chain_key; + int ret; if (unlikely(!debug_locks)) return 0; @@ -3339,7 +3382,8 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, class_idx = class - lock_classes + 1; - if (depth) { + /* TODO: nest_lock is not implemented for crosslock yet. */ + if (depth && !cross_lock(lock)) { hlock = curr->held_locks + depth - 1; if (hlock->class_idx == class_idx && nest_lock) { if (hlock->references) { @@ -3427,6 +3471,14 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) return 0; + ret = lock_acquire_crosslock(hlock); + /* + * 2 means normal acquire operations are needed. Otherwise, it's + * ok just to return with '0:fail, 1:success'. + */ + if (ret != 2) + return ret; + curr->curr_chain_key = chain_key; curr->lockdep_depth++; check_chain_key(curr); @@ -3664,11 +3716,19 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) struct task_struct *curr = current; struct held_lock *hlock; unsigned int depth; - int i; + int ret, i; if (unlikely(!debug_locks)) return 0; + ret = lock_release_crosslock(lock); + /* + * 2 means normal release operations are needed. Otherwise, it's + * ok just to return with '0:fail, 1:success'. + */ + if (ret != 2) + return ret; + depth = curr->lockdep_depth; /* * So we're all set to release this lock.. wait what lock? We don't @@ -4532,6 +4592,13 @@ asmlinkage __visible void lockdep_sys_exit(void) curr->comm, curr->pid); lockdep_print_held_locks(curr); } + + /* + * The lock history for each syscall should be independent. So wipe the + * slate clean on return to userspace. + */ + crossrelease_hist_end(XHLOCK_PROC); + crossrelease_hist_start(XHLOCK_PROC); } void lockdep_rcu_suspicious(const char *file, const int line, const char *s) @@ -4580,3 +4647,398 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s) dump_stack(); } EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); + +#ifdef CONFIG_LOCKDEP_CROSSRELEASE + +/* + * Crossrelease works by recording a lock history for each thread and + * connecting those historic locks that were taken after the + * wait_for_completion() in the complete() context. + * + * Task-A Task-B + * + * mutex_lock(&A); + * mutex_unlock(&A); + * + * wait_for_completion(&C); + * lock_acquire_crosslock(); + * atomic_inc_return(&cross_gen_id); + * | + * | mutex_lock(&B); + * | mutex_unlock(&B); + * | + * | complete(&C); + * `-- lock_commit_crosslock(); + * + * Which will then add a dependency between B and C. + */ + +#define xhlock(i) (current->xhlocks[(i) % MAX_XHLOCKS_NR]) + +/* + * Whenever a crosslock is held, cross_gen_id will be increased. + */ +static atomic_t cross_gen_id; /* Can be wrapped */ + +/* + * Lock history stacks; we have 3 nested lock history stacks: + * + * Hard IRQ + * Soft IRQ + * History / Task + * + * The thing is that once we complete a (Hard/Soft) IRQ the future task locks + * should not depend on any of the locks observed while running the IRQ. + * + * So what we do is rewind the history buffer and erase all our knowledge of + * that temporal event. + */ + +/* + * We need this to annotate lock history boundaries. Take for instance + * workqueues; each work is independent of the last. The completion of a future + * work does not depend on the completion of a past work (in general). + * Therefore we must not carry that (lock) dependency across works. + * + * This is true for many things; pretty much all kthreads fall into this + * pattern, where they have an 'idle' state and future completions do not + * depend on past completions. Its just that since they all have the 'same' + * form -- the kthread does the same over and over -- it doesn't typically + * matter. + * + * The same is true for system-calls, once a system call is completed (we've + * returned to userspace) the next system call does not depend on the lock + * history of the previous system call. + */ +void crossrelease_hist_start(enum xhlock_context_t c) +{ + if (current->xhlocks) + current->xhlock_idx_hist[c] = current->xhlock_idx; +} + +void crossrelease_hist_end(enum xhlock_context_t c) +{ + if (current->xhlocks) + current->xhlock_idx = current->xhlock_idx_hist[c]; +} + +static int cross_lock(struct lockdep_map *lock) +{ + return lock ? lock->cross : 0; +} + +/* + * This is needed to decide the relationship between wrapable variables. + */ +static inline int before(unsigned int a, unsigned int b) +{ + return (int)(a - b) < 0; +} + +static inline struct lock_class *xhlock_class(struct hist_lock *xhlock) +{ + return hlock_class(&xhlock->hlock); +} + +static inline struct lock_class *xlock_class(struct cross_lock *xlock) +{ + return hlock_class(&xlock->hlock); +} + +/* + * Should we check a dependency with previous one? + */ +static inline int depend_before(struct held_lock *hlock) +{ + return hlock->read != 2 && hlock->check && !hlock->trylock; +} + +/* + * Should we check a dependency with next one? + */ +static inline int depend_after(struct held_lock *hlock) +{ + return hlock->read != 2 && hlock->check; +} + +/* + * Check if the xhlock is valid, which would be false if, + * + * 1. Has not used after initializaion yet. + * + * Remind hist_lock is implemented as a ring buffer. + */ +static inline int xhlock_valid(struct hist_lock *xhlock) +{ + /* + * xhlock->hlock.instance must be !NULL. + */ + return !!xhlock->hlock.instance; +} + +/* + * Record a hist_lock entry. + * + * Irq disable is only required. + */ +static void add_xhlock(struct held_lock *hlock) +{ + unsigned int idx = ++current->xhlock_idx; + struct hist_lock *xhlock = &xhlock(idx); + +#ifdef CONFIG_DEBUG_LOCKDEP + /* + * This can be done locklessly because they are all task-local + * state, we must however ensure IRQs are disabled. + */ + WARN_ON_ONCE(!irqs_disabled()); +#endif + + /* Initialize hist_lock's members */ + xhlock->hlock = *hlock; + + xhlock->trace.nr_entries = 0; + xhlock->trace.max_entries = MAX_XHLOCK_TRACE_ENTRIES; + xhlock->trace.entries = xhlock->trace_entries; + xhlock->trace.skip = 3; + save_stack_trace(&xhlock->trace); +} + +static inline int same_context_xhlock(struct hist_lock *xhlock) +{ + return xhlock->hlock.irq_context == task_irq_context(current); +} + +/* + * This should be lockless as far as possible because this would be + * called very frequently. + */ +static void check_add_xhlock(struct held_lock *hlock) +{ + /* + * Record a hist_lock, only in case that acquisitions ahead + * could depend on the held_lock. For example, if the held_lock + * is trylock then acquisitions ahead never depends on that. + * In that case, we don't need to record it. Just return. + */ + if (!current->xhlocks || !depend_before(hlock)) + return; + + add_xhlock(hlock); +} + +/* + * For crosslock. + */ +static int add_xlock(struct held_lock *hlock) +{ + struct cross_lock *xlock; + unsigned int gen_id; + + if (!graph_lock()) + return 0; + + xlock = &((struct lockdep_map_cross *)hlock->instance)->xlock; + + gen_id = (unsigned int)atomic_inc_return(&cross_gen_id); + xlock->hlock = *hlock; + xlock->hlock.gen_id = gen_id; + graph_unlock(); + + return 1; +} + +/* + * Called for both normal and crosslock acquires. Normal locks will be + * pushed on the hist_lock queue. Cross locks will record state and + * stop regular lock_acquire() to avoid being placed on the held_lock + * stack. + * + * Return: 0 - failure; + * 1 - crosslock, done; + * 2 - normal lock, continue to held_lock[] ops. + */ +static int lock_acquire_crosslock(struct held_lock *hlock) +{ + /* + * CONTEXT 1 CONTEXT 2 + * --------- --------- + * lock A (cross) + * X = atomic_inc_return(&cross_gen_id) + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * Y = atomic_read_acquire(&cross_gen_id) + * lock B + * + * atomic_read_acquire() is for ordering between A and B, + * IOW, A happens before B, when CONTEXT 2 see Y >= X. + * + * Pairs with atomic_inc_return() in add_xlock(). + */ + hlock->gen_id = (unsigned int)atomic_read_acquire(&cross_gen_id); + + if (cross_lock(hlock->instance)) + return add_xlock(hlock); + + check_add_xhlock(hlock); + return 2; +} + +static int copy_trace(struct stack_trace *trace) +{ + unsigned long *buf = stack_trace + nr_stack_trace_entries; + unsigned int max_nr = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; + unsigned int nr = min(max_nr, trace->nr_entries); + + trace->nr_entries = nr; + memcpy(buf, trace->entries, nr * sizeof(trace->entries[0])); + trace->entries = buf; + nr_stack_trace_entries += nr; + + if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { + if (!debug_locks_off_graph_unlock()) + return 0; + + print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); + dump_stack(); + + return 0; + } + + return 1; +} + +static int commit_xhlock(struct cross_lock *xlock, struct hist_lock *xhlock) +{ + unsigned int xid, pid; + u64 chain_key; + + xid = xlock_class(xlock) - lock_classes; + chain_key = iterate_chain_key((u64)0, xid); + pid = xhlock_class(xhlock) - lock_classes; + chain_key = iterate_chain_key(chain_key, pid); + + if (lookup_chain_cache(chain_key)) + return 1; + + if (!add_chain_cache_classes(xid, pid, xhlock->hlock.irq_context, + chain_key)) + return 0; + + if (!check_prev_add(current, &xlock->hlock, &xhlock->hlock, 1, + &xhlock->trace, copy_trace)) + return 0; + + return 1; +} + +static void commit_xhlocks(struct cross_lock *xlock) +{ + unsigned int cur = current->xhlock_idx; + unsigned int i; + + if (!graph_lock()) + return; + + for (i = 0; i < MAX_XHLOCKS_NR; i++) { + struct hist_lock *xhlock = &xhlock(cur - i); + + if (!xhlock_valid(xhlock)) + break; + + if (before(xhlock->hlock.gen_id, xlock->hlock.gen_id)) + break; + + if (!same_context_xhlock(xhlock)) + break; + + /* + * commit_xhlock() returns 0 with graph_lock already + * released if fail. + */ + if (!commit_xhlock(xlock, xhlock)) + return; + } + + graph_unlock(); +} + +void lock_commit_crosslock(struct lockdep_map *lock) +{ + struct cross_lock *xlock; + unsigned long flags; + + if (unlikely(!debug_locks || current->lockdep_recursion)) + return; + + if (!current->xhlocks) + return; + + /* + * Do commit hist_locks with the cross_lock, only in case that + * the cross_lock could depend on acquisitions after that. + * + * For example, if the cross_lock does not have the 'check' flag + * then we don't need to check dependencies and commit for that. + * Just skip it. In that case, of course, the cross_lock does + * not depend on acquisitions ahead, either. + * + * WARNING: Don't do that in add_xlock() in advance. When an + * acquisition context is different from the commit context, + * invalid(skipped) cross_lock might be accessed. + */ + if (!depend_after(&((struct lockdep_map_cross *)lock)->xlock.hlock)) + return; + + raw_local_irq_save(flags); + check_flags(flags); + current->lockdep_recursion = 1; + xlock = &((struct lockdep_map_cross *)lock)->xlock; + commit_xhlocks(xlock); + current->lockdep_recursion = 0; + raw_local_irq_restore(flags); +} +EXPORT_SYMBOL_GPL(lock_commit_crosslock); + +/* + * Return: 1 - crosslock, done; + * 2 - normal lock, continue to held_lock[] ops. + */ +static int lock_release_crosslock(struct lockdep_map *lock) +{ + return cross_lock(lock) ? 1 : 2; +} + +static void cross_init(struct lockdep_map *lock, int cross) +{ + lock->cross = cross; + + /* + * Crossrelease assumes that the ring buffer size of xhlocks + * is aligned with power of 2. So force it on build. + */ + BUILD_BUG_ON(MAX_XHLOCKS_NR & (MAX_XHLOCKS_NR - 1)); +} + +void lockdep_init_task(struct task_struct *task) +{ + int i; + + task->xhlock_idx = UINT_MAX; + + for (i = 0; i < XHLOCK_CTX_NR; i++) + task->xhlock_idx_hist[i] = UINT_MAX; + + task->xhlocks = kzalloc(sizeof(struct hist_lock) * MAX_XHLOCKS_NR, + GFP_KERNEL); +} + +void lockdep_free_task(struct task_struct *task) +{ + if (task->xhlocks) { + void *tmp = task->xhlocks; + /* Diable crossrelease for current */ + task->xhlocks = NULL; + kfree(tmp); + } +} +#endif diff --git a/kernel/workqueue.c b/kernel/workqueue.c index ca937b0c3a96..e86733a8b344 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2093,6 +2093,7 @@ __acquires(&pool->lock) lock_map_acquire_read(&pwq->wq->lockdep_map); lock_map_acquire(&lockdep_map); + crossrelease_hist_start(XHLOCK_PROC); trace_workqueue_execute_start(work); worker->current_func(work); /* @@ -2100,6 +2101,7 @@ __acquires(&pool->lock) * point will only record its address. */ trace_workqueue_execute_end(work); + crossrelease_hist_end(XHLOCK_PROC); lock_map_release(&lockdep_map); lock_map_release(&pwq->wq->lockdep_map); -- cgit v1.2.3 From 23f873d8f9526ed7e49a1a02a45f8afb9ae5fb84 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 7 Aug 2017 16:12:53 +0900 Subject: locking/lockdep: Detect and handle hist_lock ring buffer overwrite The ring buffer can be overwritten by hardirq/softirq/work contexts. That cases must be considered on rollback or commit. For example, |<------ hist_lock ring buffer size ----->| ppppppppppppiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii wrapped > iiiiiiiiiiiiiiiiiiiiiii.................... where 'p' represents an acquisition in process context, 'i' represents an acquisition in irq context. On irq exit, crossrelease tries to rollback idx to original position, but it should not because the entry already has been invalid by overwriting 'i'. Avoid rollback or commit for entries overwritten. Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502089981-21272-7-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 52 +++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 47 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 56f69cc53ddc..eda8114ef793 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4680,6 +4680,17 @@ EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); */ static atomic_t cross_gen_id; /* Can be wrapped */ +/* + * Make an entry of the ring buffer invalid. + */ +static inline void invalidate_xhlock(struct hist_lock *xhlock) +{ + /* + * Normally, xhlock->hlock.instance must be !NULL. + */ + xhlock->hlock.instance = NULL; +} + /* * Lock history stacks; we have 3 nested lock history stacks: * @@ -4712,14 +4723,28 @@ static atomic_t cross_gen_id; /* Can be wrapped */ */ void crossrelease_hist_start(enum xhlock_context_t c) { - if (current->xhlocks) - current->xhlock_idx_hist[c] = current->xhlock_idx; + struct task_struct *cur = current; + + if (cur->xhlocks) { + cur->xhlock_idx_hist[c] = cur->xhlock_idx; + cur->hist_id_save[c] = cur->hist_id; + } } void crossrelease_hist_end(enum xhlock_context_t c) { - if (current->xhlocks) - current->xhlock_idx = current->xhlock_idx_hist[c]; + struct task_struct *cur = current; + + if (cur->xhlocks) { + unsigned int idx = cur->xhlock_idx_hist[c]; + struct hist_lock *h = &xhlock(idx); + + cur->xhlock_idx = idx; + + /* Check if the ring was overwritten. */ + if (h->hist_id != cur->hist_id_save[c]) + invalidate_xhlock(h); + } } static int cross_lock(struct lockdep_map *lock) @@ -4765,6 +4790,7 @@ static inline int depend_after(struct held_lock *hlock) * Check if the xhlock is valid, which would be false if, * * 1. Has not used after initializaion yet. + * 2. Got invalidated. * * Remind hist_lock is implemented as a ring buffer. */ @@ -4796,6 +4822,7 @@ static void add_xhlock(struct held_lock *hlock) /* Initialize hist_lock's members */ xhlock->hlock = *hlock; + xhlock->hist_id = current->hist_id++; xhlock->trace.nr_entries = 0; xhlock->trace.max_entries = MAX_XHLOCK_TRACE_ENTRIES; @@ -4934,6 +4961,7 @@ static int commit_xhlock(struct cross_lock *xlock, struct hist_lock *xhlock) static void commit_xhlocks(struct cross_lock *xlock) { unsigned int cur = current->xhlock_idx; + unsigned int prev_hist_id = xhlock(cur).hist_id; unsigned int i; if (!graph_lock()) @@ -4951,6 +4979,17 @@ static void commit_xhlocks(struct cross_lock *xlock) if (!same_context_xhlock(xhlock)) break; + /* + * Filter out the cases that the ring buffer was + * overwritten and the previous entry has a bigger + * hist_id than the following one, which is impossible + * otherwise. + */ + if (unlikely(before(xhlock->hist_id, prev_hist_id))) + break; + + prev_hist_id = xhlock->hist_id; + /* * commit_xhlock() returns 0 with graph_lock already * released if fail. @@ -5024,9 +5063,12 @@ void lockdep_init_task(struct task_struct *task) int i; task->xhlock_idx = UINT_MAX; + task->hist_id = 0; - for (i = 0; i < XHLOCK_CTX_NR; i++) + for (i = 0; i < XHLOCK_CTX_NR; i++) { task->xhlock_idx_hist[i] = UINT_MAX; + task->hist_id_save[i] = 0; + } task->xhlocks = kzalloc(sizeof(struct hist_lock) * MAX_XHLOCKS_NR, GFP_KERNEL); -- cgit v1.2.3 From 28a903f63ec0811ead70ad0f8665e838d207a25e Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 7 Aug 2017 16:12:54 +0900 Subject: locking/lockdep: Handle non(or multi)-acquisition of a crosslock No acquisition might be in progress on commit of a crosslock. Completion operations enabling crossrelease are the case like: CONTEXT X CONTEXT Y --------- --------- trigger completion context complete AX commit AX wait_for_complete AX acquire AX wait where AX is a crosslock. When no acquisition is in progress, we should not perform commit because the lock does not exist, which might cause incorrect memory access. So we have to track the number of acquisitions of a crosslock to handle it. Moreover, in case that more than one acquisition of a crosslock are overlapped like: CONTEXT W CONTEXT X CONTEXT Y CONTEXT Z --------- --------- --------- --------- acquire AX (gen_id: 1) acquire A acquire AX (gen_id: 10) acquire B commit AX acquire C commit AX where A, B and C are typical locks and AX is a crosslock. Current crossrelease code performs commits in Y and Z with gen_id = 10. However, we can use gen_id = 1 to do it, since not only 'acquire AX in X' but 'acquire AX in W' also depends on each acquisition in Y and Z until their commits. So make it use gen_id = 1 instead of 10 on their commits, which adds an additional dependency 'AX -> A' in the example above. Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502089981-21272-8-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 82 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 56 insertions(+), 26 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index eda8114ef793..7f97871d48d5 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4867,11 +4867,28 @@ static int add_xlock(struct held_lock *hlock) xlock = &((struct lockdep_map_cross *)hlock->instance)->xlock; + /* + * When acquisitions for a crosslock are overlapped, we use + * nr_acquire to perform commit for them, based on cross_gen_id + * of the first acquisition, which allows to add additional + * dependencies. + * + * Moreover, when no acquisition of a crosslock is in progress, + * we should not perform commit because the lock might not exist + * any more, which might cause incorrect memory access. So we + * have to track the number of acquisitions of a crosslock. + * + * depend_after() is necessary to initialize only the first + * valid xlock so that the xlock can be used on its commit. + */ + if (xlock->nr_acquire++ && depend_after(&xlock->hlock)) + goto unlock; + gen_id = (unsigned int)atomic_inc_return(&cross_gen_id); xlock->hlock = *hlock; xlock->hlock.gen_id = gen_id; +unlock: graph_unlock(); - return 1; } @@ -4967,35 +4984,37 @@ static void commit_xhlocks(struct cross_lock *xlock) if (!graph_lock()) return; - for (i = 0; i < MAX_XHLOCKS_NR; i++) { - struct hist_lock *xhlock = &xhlock(cur - i); + if (xlock->nr_acquire) { + for (i = 0; i < MAX_XHLOCKS_NR; i++) { + struct hist_lock *xhlock = &xhlock(cur - i); - if (!xhlock_valid(xhlock)) - break; + if (!xhlock_valid(xhlock)) + break; - if (before(xhlock->hlock.gen_id, xlock->hlock.gen_id)) - break; + if (before(xhlock->hlock.gen_id, xlock->hlock.gen_id)) + break; - if (!same_context_xhlock(xhlock)) - break; + if (!same_context_xhlock(xhlock)) + break; - /* - * Filter out the cases that the ring buffer was - * overwritten and the previous entry has a bigger - * hist_id than the following one, which is impossible - * otherwise. - */ - if (unlikely(before(xhlock->hist_id, prev_hist_id))) - break; + /* + * Filter out the cases that the ring buffer was + * overwritten and the previous entry has a bigger + * hist_id than the following one, which is impossible + * otherwise. + */ + if (unlikely(before(xhlock->hist_id, prev_hist_id))) + break; - prev_hist_id = xhlock->hist_id; + prev_hist_id = xhlock->hist_id; - /* - * commit_xhlock() returns 0 with graph_lock already - * released if fail. - */ - if (!commit_xhlock(xlock, xhlock)) - return; + /* + * commit_xhlock() returns 0 with graph_lock already + * released if fail. + */ + if (!commit_xhlock(xlock, xhlock)) + return; + } } graph_unlock(); @@ -5039,16 +5058,27 @@ void lock_commit_crosslock(struct lockdep_map *lock) EXPORT_SYMBOL_GPL(lock_commit_crosslock); /* - * Return: 1 - crosslock, done; + * Return: 0 - failure; + * 1 - crosslock, done; * 2 - normal lock, continue to held_lock[] ops. */ static int lock_release_crosslock(struct lockdep_map *lock) { - return cross_lock(lock) ? 1 : 2; + if (cross_lock(lock)) { + if (!graph_lock()) + return 0; + ((struct lockdep_map_cross *)lock)->xlock.nr_acquire--; + graph_unlock(); + return 1; + } + return 2; } static void cross_init(struct lockdep_map *lock, int cross) { + if (cross) + ((struct lockdep_map_cross *)lock)->xlock.nr_acquire = 0; + lock->cross = cross; /* -- cgit v1.2.3 From 383a4bc88849b804385162e81bf704f8f9690a87 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 7 Aug 2017 16:12:55 +0900 Subject: locking/lockdep: Make print_circular_bug() aware of crossrelease print_circular_bug() reporting circular bug assumes that target hlock is owned by the current. However, in crossrelease, target hlock can be owned by other than the current. So the report format needs to be changed to reflect the change. Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502089981-21272-9-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 67 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 47 insertions(+), 20 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 7f97871d48d5..1114dc42c27f 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1139,22 +1139,41 @@ print_circular_lock_scenario(struct held_lock *src, printk(KERN_CONT "\n\n"); } - printk(" Possible unsafe locking scenario:\n\n"); - printk(" CPU0 CPU1\n"); - printk(" ---- ----\n"); - printk(" lock("); - __print_lock_name(target); - printk(KERN_CONT ");\n"); - printk(" lock("); - __print_lock_name(parent); - printk(KERN_CONT ");\n"); - printk(" lock("); - __print_lock_name(target); - printk(KERN_CONT ");\n"); - printk(" lock("); - __print_lock_name(source); - printk(KERN_CONT ");\n"); - printk("\n *** DEADLOCK ***\n\n"); + if (cross_lock(tgt->instance)) { + printk(" Possible unsafe locking scenario by crosslock:\n\n"); + printk(" CPU0 CPU1\n"); + printk(" ---- ----\n"); + printk(" lock("); + __print_lock_name(parent); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(target); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(source); + printk(KERN_CONT ");\n"); + printk(" unlock("); + __print_lock_name(target); + printk(KERN_CONT ");\n"); + printk("\n *** DEADLOCK ***\n\n"); + } else { + printk(" Possible unsafe locking scenario:\n\n"); + printk(" CPU0 CPU1\n"); + printk(" ---- ----\n"); + printk(" lock("); + __print_lock_name(target); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(parent); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(target); + printk(KERN_CONT ");\n"); + printk(" lock("); + __print_lock_name(source); + printk(KERN_CONT ");\n"); + printk("\n *** DEADLOCK ***\n\n"); + } } /* @@ -1179,7 +1198,12 @@ print_circular_bug_header(struct lock_list *entry, unsigned int depth, pr_warn("%s/%d is trying to acquire lock:\n", curr->comm, task_pid_nr(curr)); print_lock(check_src); - pr_warn("\nbut task is already holding lock:\n"); + + if (cross_lock(check_tgt->instance)) + pr_warn("\nbut now in release context of a crosslock acquired at the following:\n"); + else + pr_warn("\nbut task is already holding lock:\n"); + print_lock(check_tgt); pr_warn("\nwhich lock already depends on the new lock.\n\n"); pr_warn("\nthe existing dependency chain (in reverse order) is:\n"); @@ -1197,7 +1221,8 @@ static inline int class_equal(struct lock_list *entry, void *data) static noinline int print_circular_bug(struct lock_list *this, struct lock_list *target, struct held_lock *check_src, - struct held_lock *check_tgt) + struct held_lock *check_tgt, + struct stack_trace *trace) { struct task_struct *curr = current; struct lock_list *parent; @@ -1207,7 +1232,9 @@ static noinline int print_circular_bug(struct lock_list *this, if (!debug_locks_off_graph_unlock() || debug_locks_silent) return 0; - if (!save_trace(&this->trace)) + if (cross_lock(check_tgt->instance)) + this->trace = *trace; + else if (!save_trace(&this->trace)) return 0; depth = get_lock_depth(target); @@ -1864,7 +1891,7 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, this.parent = NULL; ret = check_noncircular(&this, hlock_class(prev), &target_entry); if (unlikely(!ret)) - return print_circular_bug(&this, target_entry, next, prev); + return print_circular_bug(&this, target_entry, next, prev, trace); else if (unlikely(ret < 0)) return print_bfs_bug(ret); -- cgit v1.2.3 From cd8084f91c02c1afd256a39aa833bff737631304 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 7 Aug 2017 16:12:56 +0900 Subject: locking/lockdep: Apply crossrelease to completions Although wait_for_completion() and its family can cause deadlock, the lock correctness validator could not be applied to them until now, because things like complete() are usually called in a different context from the waiting context, which violates lockdep's assumption. Thanks to CONFIG_LOCKDEP_CROSSRELEASE, we can now apply the lockdep detector to those completion operations. Applied it. Signed-off-by: Byungchul Park Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502089981-21272-10-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- kernel/sched/completion.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'kernel') diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c index 13fc5ae9bf2f..566b6ec7b6fe 100644 --- a/kernel/sched/completion.c +++ b/kernel/sched/completion.c @@ -32,6 +32,12 @@ void complete(struct completion *x) unsigned long flags; spin_lock_irqsave(&x->wait.lock, flags); + + /* + * Perform commit of crossrelease here. + */ + complete_release_commit(x); + if (x->done != UINT_MAX) x->done++; __wake_up_locked(&x->wait, TASK_NORMAL, 1); @@ -92,9 +98,14 @@ __wait_for_common(struct completion *x, { might_sleep(); + complete_acquire(x); + spin_lock_irq(&x->wait.lock); timeout = do_wait_for_common(x, action, timeout, state); spin_unlock_irq(&x->wait.lock); + + complete_release(x); + return timeout; } -- cgit v1.2.3 From 90001d67be2fa2acbe3510d1f64fa6533efa30ef Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 31 Jul 2017 17:50:05 +0200 Subject: sched/fair: Fix wake_affine() for !NUMA_BALANCING In commit: 3fed382b46ba ("sched/numa: Implement NUMA node level wake_affine()") Rik changed wake_affine to consider NUMA information when balancing between LLC domains. There are a number of problems here which this patch tries to address: - LLC < NODE; in this case we'd use the wrong information to balance - !NUMA_BALANCING: in this case, the new code doesn't do any balancing at all - re-computes the NUMA data for every wakeup, this can mean iterating up to 64 CPUs for every wakeup. - default affine wakeups inside a cache We address these by saving the load/capacity values for each sched_domain during regular load-balance and using these values in wake_affine_llc(). The obvious down-side to using cached values is that they can be too old and poorly reflect reality. But this way we can use LLC wide information and thus not rely on assuming LLC matches NODE. We also don't rely on NUMA_BALANCING nor do we have to aggegate two nodes (or even cache domains) worth of CPUs for each wakeup. Signed-off-by: Peter Zijlstra (Intel) Cc: Josef Bacik Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Fixes: 3fed382b46ba ("sched/numa: Implement NUMA node level wake_affine()") [ Minor readability improvements. ] Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 190 +++++++++++++++++++++++++++++++++------------------- 1 file changed, 122 insertions(+), 68 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a7f1c3b797f8..8d5868771cb3 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2658,59 +2658,6 @@ void task_tick_numa(struct rq *rq, struct task_struct *curr) } } -/* - * Can a task be moved from prev_cpu to this_cpu without causing a load - * imbalance that would trigger the load balancer? - */ -static inline bool numa_wake_affine(struct sched_domain *sd, - struct task_struct *p, int this_cpu, - int prev_cpu, int sync) -{ - struct numa_stats prev_load, this_load; - s64 this_eff_load, prev_eff_load; - - update_numa_stats(&prev_load, cpu_to_node(prev_cpu)); - update_numa_stats(&this_load, cpu_to_node(this_cpu)); - - /* - * If sync wakeup then subtract the (maximum possible) - * effect of the currently running task from the load - * of the current CPU: - */ - if (sync) { - unsigned long current_load = task_h_load(current); - - if (this_load.load > current_load) - this_load.load -= current_load; - else - this_load.load = 0; - } - - /* - * In low-load situations, where this_cpu's node is idle due to the - * sync cause above having dropped this_load.load to 0, move the task. - * Moving to an idle socket will not create a bad imbalance. - * - * Otherwise check if the nodes are near enough in load to allow this - * task to be woken on this_cpu's node. - */ - if (this_load.load > 0) { - unsigned long task_load = task_h_load(p); - - this_eff_load = 100; - this_eff_load *= prev_load.compute_capacity; - - prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2; - prev_eff_load *= this_load.compute_capacity; - - this_eff_load *= this_load.load + task_load; - prev_eff_load *= prev_load.load - task_load; - - return this_eff_load <= prev_eff_load; - } - - return true; -} #else static void task_tick_numa(struct rq *rq, struct task_struct *curr) { @@ -2724,14 +2671,6 @@ static inline void account_numa_dequeue(struct rq *rq, struct task_struct *p) { } -#ifdef CONFIG_SMP -static inline bool numa_wake_affine(struct sched_domain *sd, - struct task_struct *p, int this_cpu, - int prev_cpu, int sync) -{ - return true; -} -#endif /* !SMP */ #endif /* CONFIG_NUMA_BALANCING */ static void @@ -5428,20 +5367,115 @@ static int wake_wide(struct task_struct *p) return 1; } +struct llc_stats { + unsigned long nr_running; + unsigned long load; + unsigned long capacity; + int has_capacity; +}; + +static bool get_llc_stats(struct llc_stats *stats, int cpu) +{ + struct sched_domain_shared *sds = rcu_dereference(per_cpu(sd_llc_shared, cpu)); + + if (!sds) + return false; + + stats->nr_running = READ_ONCE(sds->nr_running); + stats->load = READ_ONCE(sds->load); + stats->capacity = READ_ONCE(sds->capacity); + stats->has_capacity = stats->nr_running < per_cpu(sd_llc_size, cpu); + + return true; +} + +/* + * Can a task be moved from prev_cpu to this_cpu without causing a load + * imbalance that would trigger the load balancer? + * + * Since we're running on 'stale' values, we might in fact create an imbalance + * but recomputing these values is expensive, as that'd mean iteration 2 cache + * domains worth of CPUs. + */ +static bool +wake_affine_llc(struct sched_domain *sd, struct task_struct *p, + int this_cpu, int prev_cpu, int sync) +{ + struct llc_stats prev_stats, this_stats; + s64 this_eff_load, prev_eff_load; + unsigned long task_load; + + if (!get_llc_stats(&prev_stats, prev_cpu) || + !get_llc_stats(&this_stats, this_cpu)) + return false; + + /* + * If sync wakeup then subtract the (maximum possible) + * effect of the currently running task from the load + * of the current LLC. + */ + if (sync) { + unsigned long current_load = task_h_load(current); + + /* in this case load hits 0 and this LLC is considered 'idle' */ + if (current_load > this_stats.load) + return true; + + this_stats.load -= current_load; + } + + /* + * The has_capacity stuff is not SMT aware, but by trying to balance + * the nr_running on both ends we try and fill the domain at equal + * rates, thereby first consuming cores before siblings. + */ + + /* if the old cache has capacity, stay there */ + if (prev_stats.has_capacity && prev_stats.nr_running < this_stats.nr_running+1) + return false; + + /* if this cache has capacity, come here */ + if (this_stats.has_capacity && this_stats.nr_running < prev_stats.nr_running+1) + return true; + + /* + * Check to see if we can move the load without causing too much + * imbalance. + */ + task_load = task_h_load(p); + + this_eff_load = 100; + this_eff_load *= prev_stats.capacity; + + prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2; + prev_eff_load *= this_stats.capacity; + + this_eff_load *= this_stats.load + task_load; + prev_eff_load *= prev_stats.load - task_load; + + return this_eff_load <= prev_eff_load; +} + static int wake_affine(struct sched_domain *sd, struct task_struct *p, int prev_cpu, int sync) { int this_cpu = smp_processor_id(); - bool affine = false; + bool affine; /* - * Common case: CPUs are in the same socket, and select_idle_sibling() - * will do its thing regardless of what we return: + * Default to no affine wakeups; wake_affine() should not effect a task + * placement the load-balancer feels inclined to undo. The conservative + * option is therefore to not move tasks when they wake up. */ - if (cpus_share_cache(prev_cpu, this_cpu)) - affine = true; - else - affine = numa_wake_affine(sd, p, this_cpu, prev_cpu, sync); + affine = false; + + /* + * If the wakeup is across cache domains, try to evaluate if movement + * makes sense, otherwise rely on select_idle_siblings() to do + * placement inside the cache domain. + */ + if (!cpus_share_cache(prev_cpu, this_cpu)) + affine = wake_affine_llc(sd, p, this_cpu, prev_cpu, sync); schedstat_inc(p->se.statistics.nr_wakeups_affine_attempts); if (affine) { @@ -7121,6 +7155,7 @@ struct sg_lb_stats { struct sd_lb_stats { struct sched_group *busiest; /* Busiest group in this sd */ struct sched_group *local; /* Local group in this sd */ + unsigned long total_running; unsigned long total_load; /* Total load of all groups in sd */ unsigned long total_capacity; /* Total capacity of all groups in sd */ unsigned long avg_load; /* Average load across all groups in sd */ @@ -7140,6 +7175,7 @@ static inline void init_sd_lb_stats(struct sd_lb_stats *sds) *sds = (struct sd_lb_stats){ .busiest = NULL, .local = NULL, + .total_running = 0UL, .total_load = 0UL, .total_capacity = 0UL, .busiest_stat = { @@ -7575,6 +7611,7 @@ static inline enum fbq_type fbq_classify_rq(struct rq *rq) */ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sds) { + struct sched_domain_shared *shared = env->sd->shared; struct sched_domain *child = env->sd->child; struct sched_group *sg = env->sd->groups; struct sg_lb_stats *local = &sds->local_stat; @@ -7631,6 +7668,7 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd next_group: /* Now, start updating sd_lb_stats */ + sds->total_running += sgs->sum_nr_running; sds->total_load += sgs->group_load; sds->total_capacity += sgs->group_capacity; @@ -7646,6 +7684,21 @@ next_group: env->dst_rq->rd->overload = overload; } + if (!shared) + return; + + /* + * Since these are sums over groups they can contain some CPUs + * multiple times for the NUMA domains. + * + * Currently only wake_affine_llc() and find_busiest_group() + * uses these numbers, only the last is affected by this problem. + * + * XXX fix that. + */ + WRITE_ONCE(shared->nr_running, sds->total_running); + WRITE_ONCE(shared->load, sds->total_load); + WRITE_ONCE(shared->capacity, sds->total_capacity); } /** @@ -7875,6 +7928,7 @@ static struct sched_group *find_busiest_group(struct lb_env *env) if (!sds.busiest || busiest->sum_nr_running == 0) goto out_balanced; + /* XXX broken for overlapping NUMA groups */ sds.avg_load = (SCHED_CAPACITY_SCALE * sds.total_load) / sds.total_capacity; -- cgit v1.2.3 From 1e58565e6d147751d85ee9e692d1226059b3318f Mon Sep 17 00:00:00 2001 From: Anshuman Khandual Date: Wed, 2 Aug 2017 14:13:00 +0530 Subject: sched/autogroup: Fix error reporting printk text in autogroup_create() Its kzalloc() not kmalloc() which has failed earlier. While here remove a redundant empty line. Signed-off-by: Anshuman Khandual Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170802084300.29487-1-khandual@linux.vnet.ibm.com Signed-off-by: Ingo Molnar --- kernel/sched/autogroup.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/autogroup.c b/kernel/sched/autogroup.c index da39489d2d80..de6d7f4dfcb5 100644 --- a/kernel/sched/autogroup.c +++ b/kernel/sched/autogroup.c @@ -71,7 +71,6 @@ static inline struct autogroup *autogroup_create(void) goto out_fail; tg = sched_create_group(&root_task_group); - if (IS_ERR(tg)) goto out_free; @@ -101,7 +100,7 @@ out_free: out_fail: if (printk_ratelimit()) { printk(KERN_WARNING "autogroup_create: %s failure.\n", - ag ? "sched_create_group()" : "kmalloc()"); + ag ? "sched_create_group()" : "kzalloc()"); } return autogroup_kref_get(&autogroup_default); -- cgit v1.2.3 From d507e2ebd2c7be9138e5cf5c0cb1931c90c42ab1 Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Thu, 10 Aug 2017 15:23:31 -0700 Subject: mm: fix global NR_SLAB_.*CLAIMABLE counter reads As Tetsuo points out: "Commit 385386cff4c6 ("mm: vmstat: move slab statistics from zone to node counters") broke "Slab:" field of /proc/meminfo . It shows nearly 0kB" In addition to /proc/meminfo, this problem also affects the slab counters OOM/allocation failure info dumps, can cause early -ENOMEM from overcommit protection, and miscalculate image size requirements during suspend-to-disk. This is because the patch in question switched the slab counters from the zone level to the node level, but forgot to update the global accessor functions to read the aggregate node data instead of the aggregate zone data. Use global_node_page_state() to access the global slab counters. Fixes: 385386cff4c6 ("mm: vmstat: move slab statistics from zone to node counters") Link: http://lkml.kernel.org/r/20170801134256.5400-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Reported-by: Tetsuo Handa Acked-by: Michal Hocko Cc: Josef Bacik Cc: Vladimir Davydov Cc: Stefan Agner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/power/snapshot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 222317721c5a..0972a8e09d08 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1650,7 +1650,7 @@ static unsigned long minimum_image_size(unsigned long saveable) { unsigned long size; - size = global_page_state(NR_SLAB_RECLAIMABLE) + size = global_node_page_state(NR_SLAB_RECLAIMABLE) + global_node_page_state(NR_ACTIVE_ANON) + global_node_page_state(NR_INACTIVE_ANON) + global_node_page_state(NR_ACTIVE_FILE) -- cgit v1.2.3 From 16af97dc5a8975371a83d9e30a64038b48f40a2d Mon Sep 17 00:00:00 2001 From: Nadav Amit Date: Thu, 10 Aug 2017 15:23:56 -0700 Subject: mm: migrate: prevent racy access to tlb_flush_pending Patch series "fixes of TLB batching races", v6. It turns out that Linux TLB batching mechanism suffers from various races. Races that are caused due to batching during reclamation were recently handled by Mel and this patch-set deals with others. The more fundamental issue is that concurrent updates of the page-tables allow for TLB flushes to be batched on one core, while another core changes the page-tables. This other core may assume a PTE change does not require a flush based on the updated PTE value, while it is unaware that TLB flushes are still pending. This behavior affects KSM (which may result in memory corruption) and MADV_FREE and MADV_DONTNEED (which may result in incorrect behavior). A proof-of-concept can easily produce the wrong behavior of MADV_DONTNEED. Memory corruption in KSM is harder to produce in practice, but was observed by hacking the kernel and adding a delay before flushing and replacing the KSM page. Finally, there is also one memory barrier missing, which may affect architectures with weak memory model. This patch (of 7): Setting and clearing mm->tlb_flush_pending can be performed by multiple threads, since mmap_sem may only be acquired for read in task_numa_work(). If this happens, tlb_flush_pending might be cleared while one of the threads still changes PTEs and batches TLB flushes. This can lead to the same race between migration and change_protection_range() that led to the introduction of tlb_flush_pending. The result of this race was data corruption, which means that this patch also addresses a theoretically possible data corruption. An actual data corruption was not observed, yet the race was was confirmed by adding assertion to check tlb_flush_pending is not set by two threads, adding artificial latency in change_protection_range() and using sysctl to reduce kernel.numa_balancing_scan_delay_ms. Link: http://lkml.kernel.org/r/20170802000818.4760-2-namit@vmware.com Fixes: 20841405940e ("mm: fix TLB flush race between migration, and change_protection_range") Signed-off-by: Nadav Amit Acked-by: Mel Gorman Acked-by: Rik van Riel Acked-by: Minchan Kim Cc: Andy Lutomirski Cc: Hugh Dickins Cc: "David S. Miller" Cc: Andrea Arcangeli Cc: Heiko Carstens Cc: Ingo Molnar Cc: Jeff Dike Cc: Martin Schwidefsky Cc: Mel Gorman Cc: Russell King Cc: Sergey Senozhatsky Cc: Tony Luck Cc: Yoshinori Sato Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index 17921b0390b4..e075b7780421 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -807,7 +807,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, mm_init_aio(mm); mm_init_owner(mm, p); mmu_notifier_mm_init(mm); - clear_tlb_flush_pending(mm); + init_tlb_flush_pending(mm); #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS mm->pmd_huge_pte = NULL; #endif -- cgit v1.2.3 From 690cbb90a709c1b9389c6cb8e1978e77553ce0fb Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 10 Aug 2017 00:13:07 +0200 Subject: PM / s2idle: Rename PM_SUSPEND_FREEZE to PM_SUSPEND_TO_IDLE To make it clear that the symbol in question refers to suspend-to-idle, rename it from PM_SUSPEND_FREEZE to PM_SUSPEND_TO_IDLE. Signed-off-by: Rafael J. Wysocki --- kernel/power/suspend.c | 44 ++++++++++++++++++++++---------------------- kernel/power/suspend_test.c | 4 ++-- 2 files changed, 24 insertions(+), 24 deletions(-) (limited to 'kernel') diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 0639d3a79852..6333078a438b 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -35,19 +35,19 @@ #include "power.h" const char * const pm_labels[] = { - [PM_SUSPEND_FREEZE] = "freeze", + [PM_SUSPEND_TO_IDLE] = "freeze", [PM_SUSPEND_STANDBY] = "standby", [PM_SUSPEND_MEM] = "mem", }; const char *pm_states[PM_SUSPEND_MAX]; static const char * const mem_sleep_labels[] = { - [PM_SUSPEND_FREEZE] = "s2idle", + [PM_SUSPEND_TO_IDLE] = "s2idle", [PM_SUSPEND_STANDBY] = "shallow", [PM_SUSPEND_MEM] = "deep", }; const char *mem_sleep_states[PM_SUSPEND_MAX]; -suspend_state_t mem_sleep_current = PM_SUSPEND_FREEZE; +suspend_state_t mem_sleep_current = PM_SUSPEND_TO_IDLE; suspend_state_t mem_sleep_default = PM_SUSPEND_MAX; suspend_state_t pm_suspend_target_state; EXPORT_SYMBOL_GPL(pm_suspend_target_state); @@ -76,7 +76,7 @@ static void freeze_begin(void) static void freeze_enter(void) { - trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_FREEZE, true); + trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true); spin_lock_irq(&suspend_freeze_lock); if (pm_wakeup_pending()) @@ -103,7 +103,7 @@ static void freeze_enter(void) suspend_freeze_state = FREEZE_STATE_NONE; spin_unlock_irq(&suspend_freeze_lock); - trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_FREEZE, false); + trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false); } static void s2idle_loop(void) @@ -175,19 +175,19 @@ void __init pm_states_init(void) { /* "mem" and "freeze" are always present in /sys/power/state. */ pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM]; - pm_states[PM_SUSPEND_FREEZE] = pm_labels[PM_SUSPEND_FREEZE]; + pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE]; /* * Suspend-to-idle should be supported even without any suspend_ops, * initialize mem_sleep_states[] accordingly here. */ - mem_sleep_states[PM_SUSPEND_FREEZE] = mem_sleep_labels[PM_SUSPEND_FREEZE]; + mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE]; } static int __init mem_sleep_default_setup(char *str) { suspend_state_t state; - for (state = PM_SUSPEND_FREEZE; state <= PM_SUSPEND_MEM; state++) + for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++) if (mem_sleep_labels[state] && !strcmp(str, mem_sleep_labels[state])) { mem_sleep_default = state; @@ -239,48 +239,48 @@ EXPORT_SYMBOL_GPL(suspend_valid_only_mem); static bool sleep_state_supported(suspend_state_t state) { - return state == PM_SUSPEND_FREEZE || (suspend_ops && suspend_ops->enter); + return state == PM_SUSPEND_TO_IDLE || (suspend_ops && suspend_ops->enter); } static int platform_suspend_prepare(suspend_state_t state) { - return state != PM_SUSPEND_FREEZE && suspend_ops->prepare ? + return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ? suspend_ops->prepare() : 0; } static int platform_suspend_prepare_late(suspend_state_t state) { - return state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->prepare ? + return state == PM_SUSPEND_TO_IDLE && freeze_ops && freeze_ops->prepare ? freeze_ops->prepare() : 0; } static int platform_suspend_prepare_noirq(suspend_state_t state) { - return state != PM_SUSPEND_FREEZE && suspend_ops->prepare_late ? + return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0; } static void platform_resume_noirq(suspend_state_t state) { - if (state != PM_SUSPEND_FREEZE && suspend_ops->wake) + if (state != PM_SUSPEND_TO_IDLE && suspend_ops->wake) suspend_ops->wake(); } static void platform_resume_early(suspend_state_t state) { - if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->restore) + if (state == PM_SUSPEND_TO_IDLE && freeze_ops && freeze_ops->restore) freeze_ops->restore(); } static void platform_resume_finish(suspend_state_t state) { - if (state != PM_SUSPEND_FREEZE && suspend_ops->finish) + if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish) suspend_ops->finish(); } static int platform_suspend_begin(suspend_state_t state) { - if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->begin) + if (state == PM_SUSPEND_TO_IDLE && freeze_ops && freeze_ops->begin) return freeze_ops->begin(); else if (suspend_ops && suspend_ops->begin) return suspend_ops->begin(state); @@ -290,7 +290,7 @@ static int platform_suspend_begin(suspend_state_t state) static void platform_resume_end(suspend_state_t state) { - if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->end) + if (state == PM_SUSPEND_TO_IDLE && freeze_ops && freeze_ops->end) freeze_ops->end(); else if (suspend_ops && suspend_ops->end) suspend_ops->end(); @@ -298,13 +298,13 @@ static void platform_resume_end(suspend_state_t state) static void platform_recover(suspend_state_t state) { - if (state != PM_SUSPEND_FREEZE && suspend_ops->recover) + if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover) suspend_ops->recover(); } static bool platform_suspend_again(suspend_state_t state) { - return state != PM_SUSPEND_FREEZE && suspend_ops->suspend_again ? + return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ? suspend_ops->suspend_again() : false; } @@ -400,7 +400,7 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) if (error) goto Devices_early_resume; - if (state == PM_SUSPEND_FREEZE && pm_test_level != TEST_PLATFORM) { + if (state == PM_SUSPEND_TO_IDLE && pm_test_level != TEST_PLATFORM) { s2idle_loop(); goto Platform_early_resume; } @@ -538,7 +538,7 @@ static int enter_state(suspend_state_t state) int error; trace_suspend_resume(TPS("suspend_enter"), state, true); - if (state == PM_SUSPEND_FREEZE) { + if (state == PM_SUSPEND_TO_IDLE) { #ifdef CONFIG_PM_DEBUG if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) { pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n"); @@ -551,7 +551,7 @@ static int enter_state(suspend_state_t state) if (!mutex_trylock(&pm_mutex)) return -EBUSY; - if (state == PM_SUSPEND_FREEZE) + if (state == PM_SUSPEND_TO_IDLE) freeze_begin(); #ifndef CONFIG_SUSPEND_SKIP_SYNC diff --git a/kernel/power/suspend_test.c b/kernel/power/suspend_test.c index 5db217051232..6a897e8b2a88 100644 --- a/kernel/power/suspend_test.c +++ b/kernel/power/suspend_test.c @@ -104,9 +104,9 @@ repeat: printk(info_test, pm_states[state]); status = pm_suspend(state); if (status < 0) - state = PM_SUSPEND_FREEZE; + state = PM_SUSPEND_TO_IDLE; } - if (state == PM_SUSPEND_FREEZE) { + if (state == PM_SUSPEND_TO_IDLE) { printk(info_test, pm_states[state]); status = pm_suspend(state); } -- cgit v1.2.3 From f02f4f9d826590f1ef1b087374d3e3cfb7949eac Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 10 Aug 2017 00:13:56 +0200 Subject: PM / s2idle: Rename freeze_state enum and related items Rename the freeze_state enum representing the suspend-to-idle state machine states to s2idle_states and rename the related variables and functions accordingly. Signed-off-by: Rafael J. Wysocki --- kernel/power/suspend.c | 48 ++++++++++++++++++++++++------------------------ kernel/sched/idle.c | 6 +++--- 2 files changed, 27 insertions(+), 27 deletions(-) (limited to 'kernel') diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 6333078a438b..ae9b579c2533 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -57,10 +57,10 @@ EXPORT_SYMBOL_GPL(pm_suspend_global_flags); static const struct platform_suspend_ops *suspend_ops; static const struct platform_freeze_ops *freeze_ops; -static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head); +static DECLARE_WAIT_QUEUE_HEAD(s2idle_wait_head); -enum freeze_state __read_mostly suspend_freeze_state; -static DEFINE_SPINLOCK(suspend_freeze_lock); +enum s2idle_states __read_mostly s2idle_state; +static DEFINE_SPINLOCK(s2idle_lock); void freeze_set_ops(const struct platform_freeze_ops *ops) { @@ -69,21 +69,21 @@ void freeze_set_ops(const struct platform_freeze_ops *ops) unlock_system_sleep(); } -static void freeze_begin(void) +static void s2idle_begin(void) { - suspend_freeze_state = FREEZE_STATE_NONE; + s2idle_state = S2IDLE_STATE_NONE; } -static void freeze_enter(void) +static void s2idle_enter(void) { trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true); - spin_lock_irq(&suspend_freeze_lock); + spin_lock_irq(&s2idle_lock); if (pm_wakeup_pending()) goto out; - suspend_freeze_state = FREEZE_STATE_ENTER; - spin_unlock_irq(&suspend_freeze_lock); + s2idle_state = S2IDLE_STATE_ENTER; + spin_unlock_irq(&s2idle_lock); get_online_cpus(); cpuidle_resume(); @@ -91,17 +91,17 @@ static void freeze_enter(void) /* Push all the CPUs into the idle loop. */ wake_up_all_idle_cpus(); /* Make the current CPU wait so it can enter the idle loop too. */ - wait_event(suspend_freeze_wait_head, - suspend_freeze_state == FREEZE_STATE_WAKE); + wait_event(s2idle_wait_head, + s2idle_state == S2IDLE_STATE_WAKE); cpuidle_pause(); put_online_cpus(); - spin_lock_irq(&suspend_freeze_lock); + spin_lock_irq(&s2idle_lock); out: - suspend_freeze_state = FREEZE_STATE_NONE; - spin_unlock_irq(&suspend_freeze_lock); + s2idle_state = S2IDLE_STATE_NONE; + spin_unlock_irq(&s2idle_lock); trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false); } @@ -118,12 +118,12 @@ static void s2idle_loop(void) /* * Suspend-to-idle equals * frozen processes + suspended devices + idle processors. - * Thus freeze_enter() should be called right after + * Thus s2idle_enter() should be called right after * all devices have been suspended. */ error = dpm_noirq_suspend_devices(PMSG_SUSPEND); if (!error) - freeze_enter(); + s2idle_enter(); dpm_noirq_resume_devices(PMSG_RESUME); if (error && (error != -EBUSY || !pm_wakeup_pending())) { @@ -148,18 +148,18 @@ static void s2idle_loop(void) pm_pr_dbg("resume from suspend-to-idle\n"); } -void freeze_wake(void) +void s2idle_wake(void) { unsigned long flags; - spin_lock_irqsave(&suspend_freeze_lock, flags); - if (suspend_freeze_state > FREEZE_STATE_NONE) { - suspend_freeze_state = FREEZE_STATE_WAKE; - wake_up(&suspend_freeze_wait_head); + spin_lock_irqsave(&s2idle_lock, flags); + if (s2idle_state > S2IDLE_STATE_NONE) { + s2idle_state = S2IDLE_STATE_WAKE; + wake_up(&s2idle_wait_head); } - spin_unlock_irqrestore(&suspend_freeze_lock, flags); + spin_unlock_irqrestore(&s2idle_lock, flags); } -EXPORT_SYMBOL_GPL(freeze_wake); +EXPORT_SYMBOL_GPL(s2idle_wake); static bool valid_state(suspend_state_t state) { @@ -552,7 +552,7 @@ static int enter_state(suspend_state_t state) return -EBUSY; if (state == PM_SUSPEND_TO_IDLE) - freeze_begin(); + s2idle_begin(); #ifndef CONFIG_SUSPEND_SKIP_SYNC trace_suspend_resume(TPS("sync_filesystems"), 0, true); diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 6c23e30c0e5c..2ea4b7b23044 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -158,7 +158,7 @@ static void cpuidle_idle_call(void) } /* - * Suspend-to-idle ("freeze") is a system state in which all user space + * Suspend-to-idle ("s2idle") is a system state in which all user space * has been frozen, all I/O devices have been suspended and the only * activity happens here and in iterrupts (if any). In that case bypass * the cpuidle governor and go stratight for the deepest idle state @@ -167,8 +167,8 @@ static void cpuidle_idle_call(void) * until a proper wakeup interrupt happens. */ - if (idle_should_freeze() || dev->use_deepest_state) { - if (idle_should_freeze()) { + if (idle_should_enter_s2idle() || dev->use_deepest_state) { + if (idle_should_enter_s2idle()) { entered_state = cpuidle_enter_freeze(drv, dev); if (entered_state > 0) { local_irq_enable(); -- cgit v1.2.3 From 28ba086ed30fb3fb714598aa029b894c3754fa7b Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 10 Aug 2017 00:14:45 +0200 Subject: PM / s2idle: Rename ->enter_freeze to ->enter_s2idle Rename the ->enter_freeze cpuidle driver callback to ->enter_s2idle to make it clear that it is used for entering suspend-to-idle and rename the related functions, variables and so on accordingly. Signed-off-by: Rafael J. Wysocki --- kernel/sched/idle.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 2ea4b7b23044..257f4f0b4532 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -169,7 +169,7 @@ static void cpuidle_idle_call(void) if (idle_should_enter_s2idle() || dev->use_deepest_state) { if (idle_should_enter_s2idle()) { - entered_state = cpuidle_enter_freeze(drv, dev); + entered_state = cpuidle_enter_s2idle(drv, dev); if (entered_state > 0) { local_irq_enable(); goto exit_idle; -- cgit v1.2.3 From 23d5855f4774f4f7c246a67057ecacc904696d8a Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 10 Aug 2017 00:15:30 +0200 Subject: PM / s2idle: Rename platform operations structure Rename struct platform_freeze_ops to platform_s2idle_ops to make it clear that the callbacks in it are used during suspend-to-idle suspend/resume transitions and rename the related functions, variables and so on accordingly. Signed-off-by: Rafael J. Wysocki --- kernel/power/suspend.c | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) (limited to 'kernel') diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index ae9b579c2533..3e2b4f519009 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -56,16 +56,16 @@ unsigned int pm_suspend_global_flags; EXPORT_SYMBOL_GPL(pm_suspend_global_flags); static const struct platform_suspend_ops *suspend_ops; -static const struct platform_freeze_ops *freeze_ops; +static const struct platform_s2idle_ops *s2idle_ops; static DECLARE_WAIT_QUEUE_HEAD(s2idle_wait_head); enum s2idle_states __read_mostly s2idle_state; static DEFINE_SPINLOCK(s2idle_lock); -void freeze_set_ops(const struct platform_freeze_ops *ops) +void s2idle_set_ops(const struct platform_s2idle_ops *ops) { lock_system_sleep(); - freeze_ops = ops; + s2idle_ops = ops; unlock_system_sleep(); } @@ -131,13 +131,13 @@ static void s2idle_loop(void) break; } - if (freeze_ops && freeze_ops->wake) - freeze_ops->wake(); + if (s2idle_ops && s2idle_ops->wake) + s2idle_ops->wake(); dpm_noirq_end(); - if (freeze_ops && freeze_ops->sync) - freeze_ops->sync(); + if (s2idle_ops && s2idle_ops->sync) + s2idle_ops->sync(); if (pm_wakeup_pending()) break; @@ -250,8 +250,8 @@ static int platform_suspend_prepare(suspend_state_t state) static int platform_suspend_prepare_late(suspend_state_t state) { - return state == PM_SUSPEND_TO_IDLE && freeze_ops && freeze_ops->prepare ? - freeze_ops->prepare() : 0; + return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ? + s2idle_ops->prepare() : 0; } static int platform_suspend_prepare_noirq(suspend_state_t state) @@ -268,8 +268,8 @@ static void platform_resume_noirq(suspend_state_t state) static void platform_resume_early(suspend_state_t state) { - if (state == PM_SUSPEND_TO_IDLE && freeze_ops && freeze_ops->restore) - freeze_ops->restore(); + if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore) + s2idle_ops->restore(); } static void platform_resume_finish(suspend_state_t state) @@ -280,8 +280,8 @@ static void platform_resume_finish(suspend_state_t state) static int platform_suspend_begin(suspend_state_t state) { - if (state == PM_SUSPEND_TO_IDLE && freeze_ops && freeze_ops->begin) - return freeze_ops->begin(); + if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin) + return s2idle_ops->begin(); else if (suspend_ops && suspend_ops->begin) return suspend_ops->begin(state); else @@ -290,8 +290,8 @@ static int platform_suspend_begin(suspend_state_t state) static void platform_resume_end(suspend_state_t state) { - if (state == PM_SUSPEND_TO_IDLE && freeze_ops && freeze_ops->end) - freeze_ops->end(); + if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end) + s2idle_ops->end(); else if (suspend_ops && suspend_ops->end) suspend_ops->end(); } -- cgit v1.2.3 From 3e48930cc74f0c212ee1838f89ad0ca7fcf2fea1 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 11 Aug 2017 05:49:01 -0700 Subject: cgroup: misc changes Misc trivial changes to prepare for future changes. No functional difference. * Expose cgroup_get(), cgroup_tryget() and cgroup_parent(). * Implement task_dfl_cgroup() which dereferences css_set->dfl_cgrp. * Rename cgroup_stats_show() to cgroup_stat_show() for consistency with the file name. Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 23 ++--------------------- 1 file changed, 2 insertions(+), 21 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index f5ca55db1fe1..c038ccf95b5d 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -319,15 +319,6 @@ static void cgroup_idr_remove(struct idr *idr, int id) spin_unlock_bh(&cgroup_idr_lock); } -static struct cgroup *cgroup_parent(struct cgroup *cgrp) -{ - struct cgroup_subsys_state *parent_css = cgrp->self.parent; - - if (parent_css) - return container_of(parent_css, struct cgroup, self); - return NULL; -} - static bool cgroup_has_tasks(struct cgroup *cgrp) { return cgrp->nr_populated_csets; @@ -534,22 +525,12 @@ out_unlock: return css; } -static void __maybe_unused cgroup_get(struct cgroup *cgrp) -{ - css_get(&cgrp->self); -} - static void cgroup_get_live(struct cgroup *cgrp) { WARN_ON_ONCE(cgroup_is_dead(cgrp)); css_get(&cgrp->self); } -static bool cgroup_tryget(struct cgroup *cgrp) -{ - return css_tryget(&cgrp->self); -} - struct cgroup_subsys_state *of_css(struct kernfs_open_file *of) { struct cgroup *cgrp = of->kn->parent->priv; @@ -3306,7 +3287,7 @@ static int cgroup_events_show(struct seq_file *seq, void *v) return 0; } -static int cgroup_stats_show(struct seq_file *seq, void *v) +static int cgroup_stat_show(struct seq_file *seq, void *v) { struct cgroup *cgroup = seq_css(seq)->cgroup; @@ -4423,7 +4404,7 @@ static struct cftype cgroup_base_files[] = { }, { .name = "cgroup.stat", - .seq_show = cgroup_stats_show, + .seq_show = cgroup_stat_show, }, { } /* terminate */ }; -- cgit v1.2.3 From 696b98f244f77a79840bf420861c996d61c82637 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 9 Aug 2017 13:25:21 +0300 Subject: cgroup: remove unneeded checks "descendants" and "depth" are declared as int, so they can't be larger than INT_MAX. Static checkers complain and it's slightly confusing for humans as well so let's just remove these conditions. Signed-off-by: Dan Carpenter Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index c038ccf95b5d..1591e9b20122 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3223,7 +3223,7 @@ static ssize_t cgroup_max_descendants_write(struct kernfs_open_file *of, return ret; } - if (descendants < 0 || descendants > INT_MAX) + if (descendants < 0) return -ERANGE; cgrp = cgroup_kn_lock_live(of->kn, false); @@ -3266,7 +3266,7 @@ static ssize_t cgroup_max_depth_write(struct kernfs_open_file *of, return ret; } - if (depth < 0 || depth > INT_MAX) + if (depth < 0) return -ERANGE; cgrp = cgroup_kn_lock_live(of->kn, false); -- cgit v1.2.3 From 23a9b748a3d27f67cdb078fcb891a920285e75d9 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 29 Jun 2017 12:08:26 -0700 Subject: sched: Replace spin_unlock_wait() with lock/unlock pair There is no agreed-upon definition of spin_unlock_wait()'s semantics, and it appears that all callers could do just as well with a lock/unlock pair. This commit therefore replaces the spin_unlock_wait() call in do_task_dead() with spin_lock() followed immediately by spin_unlock(). This should be safe from a performance perspective because the lock is this tasks ->pi_lock, and this is called only after the task exits. Signed-off-by: Paul E. McKenney Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Will Deacon Cc: Alan Stern Cc: Andrea Parri Cc: Linus Torvalds [ paulmck: Drop smp_mb() based on Peter Zijlstra's analysis: http://lkml.kernel.org/r/20170811144150.26gowhxte7ri5fpk@hirez.programming.kicks-ass.net ] --- kernel/sched/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 17c667b427b4..5d22323ae099 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3352,8 +3352,8 @@ void __noreturn do_task_dead(void) * To avoid it, we have to wait for releasing tsk->pi_lock which * is held by try_to_wake_up() */ - smp_mb(); - raw_spin_unlock_wait(¤t->pi_lock); + raw_spin_lock_irq(¤t->pi_lock); + raw_spin_unlock_irq(¤t->pi_lock); /* Causes final put_task_struct in finish_task_switch(): */ __set_current_state(TASK_DEAD); -- cgit v1.2.3 From 163616cf2f6ab7a8e37452ec00320039ab65bd45 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Wed, 9 Aug 2017 15:32:21 +0900 Subject: genirq: Fix for_each_action_of_desc() macro struct irq_desc does not have a member named "act". The correct name is "action". Currently, all users of this macro use an iterator named "action". If a different name is used, it will cause a build error. Fixes: f944b5a7aff0 ("genirq: Use a common macro to go through the actions list") Signed-off-by: Masahiro Yamada Signed-off-by: Thomas Gleixner Cc: Marc Zyngier Cc: Daniel Lezcano Cc: Jason Cooper Link: http://lkml.kernel.org/r/1502260341-28184-1-git-send-email-yamada.masahiro@socionext.com --- kernel/irq/internals.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index a2c48058354c..a4aa39009f0d 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -151,7 +151,7 @@ static inline void chip_bus_sync_unlock(struct irq_desc *desc) #define IRQ_GET_DESC_CHECK_PERCPU (_IRQ_DESC_CHECK | _IRQ_DESC_PERCPU) #define for_each_action_of_desc(desc, act) \ - for (act = desc->act; act; act = act->next) + for (act = desc->action; act; act = act->next) struct irq_desc * __irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus, -- cgit v1.2.3 From a10b5c564741cd3b6708f085a1fa892b63c2063d Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 14 Aug 2017 16:00:51 +0900 Subject: locking/lockdep: Add a comment about crossrelease_hist_end() in lockdep_sys_exit() In lockdep_sys_exit(), crossrelease_hist_end() is called unconditionally even when getting here without having started e.g. just after forking. But it's no problem since it would roll back to an invalid entry anyway. Add a comment to explain this. Signed-off-by: Byungchul Park Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: boqun.feng@gmail.com Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: linux-mm@kvack.org Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502694052-16085-2-git-send-email-byungchul.park@lge.com [ Improved the description and the comments. ] Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 1114dc42c27f..257931e2fbbe 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4623,6 +4623,10 @@ asmlinkage __visible void lockdep_sys_exit(void) /* * The lock history for each syscall should be independent. So wipe the * slate clean on return to userspace. + * + * crossrelease_hist_end() works well here even when getting here + * without starting (i.e. just after forking), because it rolls back + * the index to point to the last entry, which is already invalid. */ crossrelease_hist_end(XHLOCK_PROC); crossrelease_hist_start(XHLOCK_PROC); -- cgit v1.2.3 From 907dc16d7e23ec81a126c9585435494fa1b3a4b7 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 14 Aug 2017 16:00:52 +0900 Subject: locking/lockdep: Fix the rollback and overwrite detection logic in crossrelease As Boqun Feng pointed out, current->hist_id should be aligned with the latest valid xhlock->hist_id so that hist_id_save[] storing current->hist_id can be comparable with xhlock->hist_id. Fix it. Additionally, the condition for overwrite-detection should be the opposite. Fix the code and the comments as well. <- direction to visit hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh (h: history) ^^ ^ || start from here |previous entry current entry Reported-by: Boqun Feng Signed-off-by: Byungchul Park Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: kernel-team@lge.com Cc: kirill@shutemov.name Cc: linux-mm@kvack.org Cc: npiggin@gmail.com Cc: walken@google.com Cc: willy@infradead.org Link: http://lkml.kernel.org/r/1502694052-16085-3-git-send-email-byungchul.park@lge.com [ Improve the comments some more. ] Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 257931e2fbbe..66011c9f5df3 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4853,7 +4853,7 @@ static void add_xhlock(struct held_lock *hlock) /* Initialize hist_lock's members */ xhlock->hlock = *hlock; - xhlock->hist_id = current->hist_id++; + xhlock->hist_id = ++current->hist_id; xhlock->trace.nr_entries = 0; xhlock->trace.max_entries = MAX_XHLOCK_TRACE_ENTRIES; @@ -5029,12 +5029,12 @@ static void commit_xhlocks(struct cross_lock *xlock) break; /* - * Filter out the cases that the ring buffer was - * overwritten and the previous entry has a bigger - * hist_id than the following one, which is impossible - * otherwise. + * Filter out the cases where the ring buffer was + * overwritten and the current entry has a bigger + * hist_id than the previous one, which is impossible + * otherwise: */ - if (unlikely(before(xhlock->hist_id, prev_hist_id))) + if (unlikely(before(prev_hist_id, xhlock->hist_id))) break; prev_hist_id = xhlock->hist_id; -- cgit v1.2.3 From 077a1cc06f72f95efd077d433993c16191008e47 Mon Sep 17 00:00:00 2001 From: Nikitas Angelinas Date: Sat, 29 Jul 2017 20:36:36 -0700 Subject: printk: Clean up do_syslog() error handling The error variable in do_syslog() is preemptively set to the error code before the error condition is checked, and then set to 0 if the error condition is not encountered. This is not necessary, as it is likely simpler to return immediately upon encountering the error condition. A redundant set of the error variable to 0 is also removed. This patch has been build-tested on x86_64, but not tested for functionality. Link: http://lkml.kernel.org/r/20170730033636.GA935@vostro Cc: Steven Rostedt Cc: linux-kernel@vger.kernel.org Signed-off-by: Nikitas Angelinas Reviewed-by: Sergey Senozhatsky Signed-off-by: Petr Mladek --- kernel/printk/printk.c | 35 ++++++++++++----------------------- 1 file changed, 12 insertions(+), 23 deletions(-) (limited to 'kernel') diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 87f1a8f4e0f9..cfd9ab1b80c5 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1435,7 +1435,7 @@ int do_syslog(int type, char __user *buf, int len, int source) error = check_syslog_permissions(type, source); if (error) - goto out; + return error; switch (type) { case SYSLOG_ACTION_CLOSE: /* Close log */ @@ -1443,20 +1443,16 @@ int do_syslog(int type, char __user *buf, int len, int source) case SYSLOG_ACTION_OPEN: /* Open log */ break; case SYSLOG_ACTION_READ: /* Read from log */ - error = -EINVAL; if (!buf || len < 0) - goto out; - error = 0; + return -EINVAL; if (!len) - goto out; - if (!access_ok(VERIFY_WRITE, buf, len)) { - error = -EFAULT; - goto out; - } + return 0; + if (!access_ok(VERIFY_WRITE, buf, len)) + return -EFAULT; error = wait_event_interruptible(log_wait, syslog_seq != log_next_seq); if (error) - goto out; + return error; error = syslog_print(buf, len); break; /* Read/clear last kernel messages */ @@ -1465,16 +1461,12 @@ int do_syslog(int type, char __user *buf, int len, int source) /* FALL THRU */ /* Read last kernel messages */ case SYSLOG_ACTION_READ_ALL: - error = -EINVAL; if (!buf || len < 0) - goto out; - error = 0; + return -EINVAL; if (!len) - goto out; - if (!access_ok(VERIFY_WRITE, buf, len)) { - error = -EFAULT; - goto out; - } + return 0; + if (!access_ok(VERIFY_WRITE, buf, len)) + return -EFAULT; error = syslog_print_all(buf, len, clear); break; /* Clear ring buffer */ @@ -1496,15 +1488,13 @@ int do_syslog(int type, char __user *buf, int len, int source) break; /* Set level of messages printed to console */ case SYSLOG_ACTION_CONSOLE_LEVEL: - error = -EINVAL; if (len < 1 || len > 8) - goto out; + return -EINVAL; if (len < minimum_console_loglevel) len = minimum_console_loglevel; console_loglevel = len; /* Implicitly re-enable logging to console */ saved_console_loglevel = LOGLEVEL_DEFAULT; - error = 0; break; /* Number of chars in the log buffer */ case SYSLOG_ACTION_SIZE_UNREAD: @@ -1526,7 +1516,6 @@ int do_syslog(int type, char __user *buf, int len, int source) u64 seq = syslog_seq; u32 idx = syslog_idx; - error = 0; while (seq < log_next_seq) { struct printk_log *msg = log_from_idx(idx); @@ -1546,7 +1535,7 @@ int do_syslog(int type, char __user *buf, int len, int source) error = -EINVAL; break; } -out: + return error; } -- cgit v1.2.3 From 48ac3c18cc62d4a23d5dc5c59f8720589d0de14b Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Fri, 14 Jul 2017 12:23:09 +0100 Subject: fork: allow arch-override of VMAP stack alignment In some cases, an architecture might wish its stacks to be aligned to a boundary larger than THREAD_SIZE. For example, using an alignment of double THREAD_SIZE can allow for stack overflows smaller than THREAD_SIZE to be detected by checking a single bit of the stack pointer. This patch allows architectures to override the alignment of VMAP'd stacks, by defining THREAD_ALIGN. Where not defined, this defaults to THREAD_SIZE, as is the case today. Signed-off-by: Mark Rutland Reviewed-by: Will Deacon Tested-by: Laura Abbott Cc: Andy Lutomirski Cc: Ard Biesheuvel Cc: Catalin Marinas Cc: James Morse Cc: linux-kernel@vger.kernel.org --- kernel/fork.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index 17921b0390b4..f12882a2323b 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -88,6 +88,7 @@ #include #include #include +#include #include #include @@ -217,7 +218,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node) return s->addr; } - stack = __vmalloc_node_range(THREAD_SIZE, THREAD_SIZE, + stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN, VMALLOC_START, VMALLOC_END, THREADINFO_GFP, PAGE_KERNEL, -- cgit v1.2.3 From d76036ab47eafa6ce52b69482e91ca3ba337d6d6 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 15 Aug 2017 13:00:36 +0200 Subject: audit: Fix use after free in audit_remove_watch_rule() audit_remove_watch_rule() drops watch's reference to parent but then continues to work with it. That is not safe as parent can get freed once we drop our reference. The following is a trivial reproducer: mount -o loop image /mnt touch /mnt/file auditctl -w /mnt/file -p wax umount /mnt auditctl -D Grab our own reference in audit_remove_watch_rule() earlier to make sure mark does not get freed under us. CC: stable@vger.kernel.org Reported-by: Tony Jones Signed-off-by: Jan Kara Tested-by: Tony Jones Signed-off-by: Paul Moore --- kernel/audit_watch.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c index e0656bd63036..1c7ded42f82f 100644 --- a/kernel/audit_watch.c +++ b/kernel/audit_watch.c @@ -457,13 +457,15 @@ void audit_remove_watch_rule(struct audit_krule *krule) list_del(&krule->rlist); if (list_empty(&watch->rules)) { + /* + * audit_remove_watch() drops our reference to 'parent' which + * can get freed. Grab our own reference to be safe. + */ + audit_get_parent(parent); audit_remove_watch(watch); - - if (list_empty(&parent->watches)) { - audit_get_parent(parent); + if (list_empty(&parent->watches)) fsnotify_destroy_mark(&parent->mark, audit_watch_group); - audit_put_parent(parent); - } + audit_put_parent(parent); } } -- cgit v1.2.3 From b5fed474b98332559f2590c6bc90388a0899e793 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 15 Aug 2017 13:00:37 +0200 Subject: audit: Receive unmount event Although audit_watch_handle_event() can handle FS_UNMOUNT event, it is not part of AUDIT_FS_WATCH mask and thus such event never gets to audit_watch_handle_event(). Thus fsnotify marks are deleted by fsnotify subsystem on unmount without audit being notified about that which leads to a strange state of existing audit rules with dead fsnotify marks. Add FS_UNMOUNT to the mask of events to be received so that audit can clean up its state accordingly. Signed-off-by: Jan Kara Signed-off-by: Paul Moore --- kernel/audit_watch.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c index 1c7ded42f82f..d1b5857b7e33 100644 --- a/kernel/audit_watch.c +++ b/kernel/audit_watch.c @@ -66,7 +66,7 @@ static struct fsnotify_group *audit_watch_group; /* fsnotify events we care about. */ #define AUDIT_FS_WATCH (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\ - FS_MOVE_SELF | FS_EVENT_ON_CHILD) + FS_MOVE_SELF | FS_EVENT_ON_CHILD | FS_UNMOUNT) static void audit_free_parent(struct audit_parent *parent) { -- cgit v1.2.3 From dc503a8ad98474ea0073a1c5c4d9f18cb8dd0dbf Mon Sep 17 00:00:00 2001 From: Edward Cree Date: Tue, 15 Aug 2017 20:34:35 +0100 Subject: bpf/verifier: track liveness for pruning State of a register doesn't matter if it wasn't read in reaching an exit; a write screens off all reads downstream of it from all explored_states upstream of it. This allows us to prune many more branches; here are some processed insn counts for some Cilium programs: Program before after bpf_lb_opt_-DLB_L3.o 6515 3361 bpf_lb_opt_-DLB_L4.o 8976 5176 bpf_lb_opt_-DUNKNOWN.o 2960 1137 bpf_lxc_opt_-DDROP_ALL.o 95412 48537 bpf_lxc_opt_-DUNKNOWN.o 141706 78718 bpf_netdev.o 24251 17995 bpf_overlay.o 10999 9385 The runtime is also improved; here are 'time' results in ms: Program before after bpf_lb_opt_-DLB_L3.o 24 6 bpf_lb_opt_-DLB_L4.o 26 11 bpf_lb_opt_-DUNKNOWN.o 11 2 bpf_lxc_opt_-DDROP_ALL.o 1288 139 bpf_lxc_opt_-DUNKNOWN.o 1768 234 bpf_netdev.o 62 31 bpf_overlay.o 15 13 Signed-off-by: Edward Cree Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 189 ++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 146 insertions(+), 43 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index ecc590e01a1d..7dd96d064be1 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -629,8 +629,10 @@ static void init_reg_state(struct bpf_reg_state *regs) { int i; - for (i = 0; i < MAX_BPF_REG; i++) + for (i = 0; i < MAX_BPF_REG; i++) { mark_reg_not_init(regs, i); + regs[i].live = REG_LIVE_NONE; + } /* frame pointer */ regs[BPF_REG_FP].type = PTR_TO_STACK; @@ -647,9 +649,26 @@ enum reg_arg_type { DST_OP_NO_MARK /* same as above, check only, don't mark */ }; -static int check_reg_arg(struct bpf_reg_state *regs, u32 regno, +static void mark_reg_read(const struct bpf_verifier_state *state, u32 regno) +{ + struct bpf_verifier_state *parent = state->parent; + + while (parent) { + /* if read wasn't screened by an earlier write ... */ + if (state->regs[regno].live & REG_LIVE_WRITTEN) + break; + /* ... then we depend on parent's value */ + parent->regs[regno].live |= REG_LIVE_READ; + state = parent; + parent = state->parent; + } +} + +static int check_reg_arg(struct bpf_verifier_env *env, u32 regno, enum reg_arg_type t) { + struct bpf_reg_state *regs = env->cur_state.regs; + if (regno >= MAX_BPF_REG) { verbose("R%d is invalid\n", regno); return -EINVAL; @@ -661,12 +680,14 @@ static int check_reg_arg(struct bpf_reg_state *regs, u32 regno, verbose("R%d !read_ok\n", regno); return -EACCES; } + mark_reg_read(&env->cur_state, regno); } else { /* check whether register used as dest operand can be written to */ if (regno == BPF_REG_FP) { verbose("frame pointer is read only\n"); return -EACCES; } + regs[regno].live |= REG_LIVE_WRITTEN; if (t == DST_OP) mark_reg_unknown(regs, regno); } @@ -695,7 +716,7 @@ static bool is_spillable_regtype(enum bpf_reg_type type) static int check_stack_write(struct bpf_verifier_state *state, int off, int size, int value_regno) { - int i; + int i, spi = (MAX_BPF_STACK + off) / BPF_REG_SIZE; /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0, * so it's aligned access and [off, off + size) are within stack limits */ @@ -710,15 +731,14 @@ static int check_stack_write(struct bpf_verifier_state *state, int off, } /* save register state */ - state->spilled_regs[(MAX_BPF_STACK + off) / BPF_REG_SIZE] = - state->regs[value_regno]; + state->spilled_regs[spi] = state->regs[value_regno]; + state->spilled_regs[spi].live |= REG_LIVE_WRITTEN; for (i = 0; i < BPF_REG_SIZE; i++) state->stack_slot_type[MAX_BPF_STACK + off + i] = STACK_SPILL; } else { /* regular write of data into stack */ - state->spilled_regs[(MAX_BPF_STACK + off) / BPF_REG_SIZE] = - (struct bpf_reg_state) {}; + state->spilled_regs[spi] = (struct bpf_reg_state) {}; for (i = 0; i < size; i++) state->stack_slot_type[MAX_BPF_STACK + off + i] = STACK_MISC; @@ -726,11 +746,26 @@ static int check_stack_write(struct bpf_verifier_state *state, int off, return 0; } +static void mark_stack_slot_read(const struct bpf_verifier_state *state, int slot) +{ + struct bpf_verifier_state *parent = state->parent; + + while (parent) { + /* if read wasn't screened by an earlier write ... */ + if (state->spilled_regs[slot].live & REG_LIVE_WRITTEN) + break; + /* ... then we depend on parent's value */ + parent->spilled_regs[slot].live |= REG_LIVE_READ; + state = parent; + parent = state->parent; + } +} + static int check_stack_read(struct bpf_verifier_state *state, int off, int size, int value_regno) { u8 *slot_type; - int i; + int i, spi; slot_type = &state->stack_slot_type[MAX_BPF_STACK + off]; @@ -746,10 +781,13 @@ static int check_stack_read(struct bpf_verifier_state *state, int off, int size, } } - if (value_regno >= 0) + spi = (MAX_BPF_STACK + off) / BPF_REG_SIZE; + + if (value_regno >= 0) { /* restore register state from stack */ - state->regs[value_regno] = - state->spilled_regs[(MAX_BPF_STACK + off) / BPF_REG_SIZE]; + state->regs[value_regno] = state->spilled_regs[spi]; + mark_stack_slot_read(state, spi); + } return 0; } else { for (i = 0; i < size; i++) { @@ -1167,7 +1205,6 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_insn *insn) { - struct bpf_reg_state *regs = env->cur_state.regs; int err; if ((BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) || @@ -1177,12 +1214,12 @@ static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_ins } /* check src1 operand */ - err = check_reg_arg(regs, insn->src_reg, SRC_OP); + err = check_reg_arg(env, insn->src_reg, SRC_OP); if (err) return err; /* check src2 operand */ - err = check_reg_arg(regs, insn->dst_reg, SRC_OP); + err = check_reg_arg(env, insn->dst_reg, SRC_OP); if (err) return err; @@ -1297,10 +1334,9 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, if (arg_type == ARG_DONTCARE) return 0; - if (type == NOT_INIT) { - verbose("R%d !read_ok\n", regno); - return -EACCES; - } + err = check_reg_arg(env, regno, SRC_OP); + if (err) + return err; if (arg_type == ARG_ANYTHING) { if (is_pointer_value(env, regno)) { @@ -1639,10 +1675,12 @@ static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx) } /* reset caller saved regs */ - for (i = 0; i < CALLER_SAVED_REGS; i++) + for (i = 0; i < CALLER_SAVED_REGS; i++) { mark_reg_not_init(regs, caller_saved[i]); + check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK); + } - /* update return register */ + /* update return register (already marked as written above) */ if (fn->ret_type == RET_INTEGER) { /* sets type to SCALAR_VALUE */ mark_reg_unknown(regs, BPF_REG_0); @@ -2250,7 +2288,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) } /* check src operand */ - err = check_reg_arg(regs, insn->dst_reg, SRC_OP); + err = check_reg_arg(env, insn->dst_reg, SRC_OP); if (err) return err; @@ -2261,7 +2299,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) } /* check dest operand */ - err = check_reg_arg(regs, insn->dst_reg, DST_OP); + err = check_reg_arg(env, insn->dst_reg, DST_OP); if (err) return err; @@ -2274,7 +2312,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) } /* check src operand */ - err = check_reg_arg(regs, insn->src_reg, SRC_OP); + err = check_reg_arg(env, insn->src_reg, SRC_OP); if (err) return err; } else { @@ -2285,7 +2323,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) } /* check dest operand */ - err = check_reg_arg(regs, insn->dst_reg, DST_OP); + err = check_reg_arg(env, insn->dst_reg, DST_OP); if (err) return err; @@ -2328,7 +2366,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) return -EINVAL; } /* check src1 operand */ - err = check_reg_arg(regs, insn->src_reg, SRC_OP); + err = check_reg_arg(env, insn->src_reg, SRC_OP); if (err) return err; } else { @@ -2339,7 +2377,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) } /* check src2 operand */ - err = check_reg_arg(regs, insn->dst_reg, SRC_OP); + err = check_reg_arg(env, insn->dst_reg, SRC_OP); if (err) return err; @@ -2360,7 +2398,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) } /* check dest operand */ - err = check_reg_arg(regs, insn->dst_reg, DST_OP_NO_MARK); + err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); if (err) return err; @@ -2717,7 +2755,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, } /* check src1 operand */ - err = check_reg_arg(regs, insn->src_reg, SRC_OP); + err = check_reg_arg(env, insn->src_reg, SRC_OP); if (err) return err; @@ -2734,7 +2772,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, } /* check src2 operand */ - err = check_reg_arg(regs, insn->dst_reg, SRC_OP); + err = check_reg_arg(env, insn->dst_reg, SRC_OP); if (err) return err; @@ -2851,7 +2889,7 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) return -EINVAL; } - err = check_reg_arg(regs, insn->dst_reg, DST_OP); + err = check_reg_arg(env, insn->dst_reg, DST_OP); if (err) return err; @@ -2917,7 +2955,7 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) } /* check whether implicit source operand (register R6) is readable */ - err = check_reg_arg(regs, BPF_REG_6, SRC_OP); + err = check_reg_arg(env, BPF_REG_6, SRC_OP); if (err) return err; @@ -2928,17 +2966,20 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) if (mode == BPF_IND) { /* check explicit source operand */ - err = check_reg_arg(regs, insn->src_reg, SRC_OP); + err = check_reg_arg(env, insn->src_reg, SRC_OP); if (err) return err; } /* reset caller saved regs to unreadable */ - for (i = 0; i < CALLER_SAVED_REGS; i++) + for (i = 0; i < CALLER_SAVED_REGS; i++) { mark_reg_not_init(regs, caller_saved[i]); + check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK); + } /* mark destination R0 register as readable, since it contains - * the value fetched from the packet + * the value fetched from the packet. + * Already marked as written above. */ mark_reg_unknown(regs, BPF_REG_0); return 0; @@ -3194,7 +3235,11 @@ static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur, bool varlen_map_access, struct idpair *idmap) { - if (memcmp(rold, rcur, sizeof(*rold)) == 0) + if (!(rold->live & REG_LIVE_READ)) + /* explored state didn't use this */ + return true; + + if (memcmp(rold, rcur, offsetof(struct bpf_reg_state, live)) == 0) return true; if (rold->type == NOT_INIT) @@ -3372,10 +3417,56 @@ out_free: return ret; } +static bool do_propagate_liveness(const struct bpf_verifier_state *state, + struct bpf_verifier_state *parent) +{ + bool touched = false; /* any changes made? */ + int i; + + if (!parent) + return touched; + /* Propagate read liveness of registers... */ + BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG); + /* We don't need to worry about FP liveness because it's read-only */ + for (i = 0; i < BPF_REG_FP; i++) { + if (parent->regs[i].live & REG_LIVE_READ) + continue; + if (state->regs[i].live == REG_LIVE_READ) { + parent->regs[i].live |= REG_LIVE_READ; + touched = true; + } + } + /* ... and stack slots */ + for (i = 0; i < MAX_BPF_STACK / BPF_REG_SIZE; i++) { + if (parent->stack_slot_type[i * BPF_REG_SIZE] != STACK_SPILL) + continue; + if (state->stack_slot_type[i * BPF_REG_SIZE] != STACK_SPILL) + continue; + if (parent->spilled_regs[i].live & REG_LIVE_READ) + continue; + if (state->spilled_regs[i].live == REG_LIVE_READ) { + parent->regs[i].live |= REG_LIVE_READ; + touched = true; + } + } + return touched; +} + +static void propagate_liveness(const struct bpf_verifier_state *state, + struct bpf_verifier_state *parent) +{ + while (do_propagate_liveness(state, parent)) { + /* Something changed, so we need to feed those changes onward */ + state = parent; + parent = state->parent; + } +} + static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) { struct bpf_verifier_state_list *new_sl; struct bpf_verifier_state_list *sl; + int i; sl = env->explored_states[insn_idx]; if (!sl) @@ -3385,11 +3476,14 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) return 0; while (sl != STATE_LIST_MARK) { - if (states_equal(env, &sl->state, &env->cur_state)) + if (states_equal(env, &sl->state, &env->cur_state)) { /* reached equivalent register/stack state, - * prune the search + * prune the search. + * Registers read by the continuation are read by us. */ + propagate_liveness(&sl->state, &env->cur_state); return 1; + } sl = sl->next; } @@ -3407,6 +3501,14 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) memcpy(&new_sl->state, &env->cur_state, sizeof(env->cur_state)); new_sl->next = env->explored_states[insn_idx]; env->explored_states[insn_idx] = new_sl; + /* connect new state to parentage chain */ + env->cur_state.parent = &new_sl->state; + /* clear liveness marks in current state */ + for (i = 0; i < BPF_REG_FP; i++) + env->cur_state.regs[i].live = REG_LIVE_NONE; + for (i = 0; i < MAX_BPF_STACK / BPF_REG_SIZE; i++) + if (env->cur_state.stack_slot_type[i * BPF_REG_SIZE] == STACK_SPILL) + env->cur_state.spilled_regs[i].live = REG_LIVE_NONE; return 0; } @@ -3430,6 +3532,7 @@ static int do_check(struct bpf_verifier_env *env) bool do_print_state = false; init_reg_state(regs); + state->parent = NULL; insn_idx = 0; env->varlen_map_value_access = false; for (;;) { @@ -3500,11 +3603,11 @@ static int do_check(struct bpf_verifier_env *env) /* check for reserved fields is already done */ /* check src operand */ - err = check_reg_arg(regs, insn->src_reg, SRC_OP); + err = check_reg_arg(env, insn->src_reg, SRC_OP); if (err) return err; - err = check_reg_arg(regs, insn->dst_reg, DST_OP_NO_MARK); + err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); if (err) return err; @@ -3554,11 +3657,11 @@ static int do_check(struct bpf_verifier_env *env) } /* check src1 operand */ - err = check_reg_arg(regs, insn->src_reg, SRC_OP); + err = check_reg_arg(env, insn->src_reg, SRC_OP); if (err) return err; /* check src2 operand */ - err = check_reg_arg(regs, insn->dst_reg, SRC_OP); + err = check_reg_arg(env, insn->dst_reg, SRC_OP); if (err) return err; @@ -3589,7 +3692,7 @@ static int do_check(struct bpf_verifier_env *env) return -EINVAL; } /* check src operand */ - err = check_reg_arg(regs, insn->dst_reg, SRC_OP); + err = check_reg_arg(env, insn->dst_reg, SRC_OP); if (err) return err; @@ -3643,7 +3746,7 @@ static int do_check(struct bpf_verifier_env *env) * of bpf_exit, which means that program wrote * something into it earlier */ - err = check_reg_arg(regs, BPF_REG_0, SRC_OP); + err = check_reg_arg(env, BPF_REG_0, SRC_OP); if (err) return err; -- cgit v1.2.3 From 88a5c690b66110ad255380d8f629c629cf6ca559 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 16 Aug 2017 01:45:33 +0200 Subject: bpf: fix bpf_trace_printk on 32 bit archs James reported that on MIPS32 bpf_trace_printk() is currently broken while MIPS64 works fine: bpf_trace_printk() uses conditional operators to attempt to pass different types to __trace_printk() depending on the format operators. This doesn't work as intended on 32-bit architectures where u32 and long are passed differently to u64, since the result of C conditional operators follows the "usual arithmetic conversions" rules, such that the values passed to __trace_printk() will always be u64 [causing issues later in the va_list handling for vscnprintf()]. For example the samples/bpf/tracex5 test printed lines like below on MIPS32, where the fd and buf have come from the u64 fd argument, and the size from the buf argument: [...] 1180.941542: 0x00000001: write(fd=1, buf= (null), size=6258688) Instead of this: [...] 1625.616026: 0x00000001: write(fd=1, buf=009e4000, size=512) One way to get it working is to expand various combinations of argument types into 8 different combinations for 32 bit and 64 bit kernels. Fix tested by James on MIPS32 and MIPS64 as well that it resolves the issue. Fixes: 9c959c863f82 ("tracing: Allow BPF programs to call bpf_trace_printk()") Reported-by: James Hogan Tested-by: James Hogan Signed-off-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/trace/bpf_trace.c | 34 ++++++++++++++++++++++++++++++---- 1 file changed, 30 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 37385193a608..dc498b605d5d 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -204,10 +204,36 @@ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, fmt_cnt++; } - return __trace_printk(1/* fake ip will not be printed */, fmt, - mod[0] == 2 ? arg1 : mod[0] == 1 ? (long) arg1 : (u32) arg1, - mod[1] == 2 ? arg2 : mod[1] == 1 ? (long) arg2 : (u32) arg2, - mod[2] == 2 ? arg3 : mod[2] == 1 ? (long) arg3 : (u32) arg3); +/* Horrid workaround for getting va_list handling working with different + * argument type combinations generically for 32 and 64 bit archs. + */ +#define __BPF_TP_EMIT() __BPF_ARG3_TP() +#define __BPF_TP(...) \ + __trace_printk(1 /* Fake ip will not be printed. */, \ + fmt, ##__VA_ARGS__) + +#define __BPF_ARG1_TP(...) \ + ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \ + ? __BPF_TP(arg1, ##__VA_ARGS__) \ + : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32)) \ + ? __BPF_TP((long)arg1, ##__VA_ARGS__) \ + : __BPF_TP((u32)arg1, ##__VA_ARGS__))) + +#define __BPF_ARG2_TP(...) \ + ((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64)) \ + ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__) \ + : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32)) \ + ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__) \ + : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__))) + +#define __BPF_ARG3_TP(...) \ + ((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64)) \ + ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__) \ + : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32)) \ + ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__) \ + : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__))) + + return __BPF_TP_EMIT(); } static const struct bpf_func_proto bpf_trace_printk_proto = { -- cgit v1.2.3 From b19af510e67e6ca696b8721f45c148119437307c Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Mon, 14 Aug 2017 16:53:16 +0200 Subject: genirq/irq_sim: Add a simple interrupt simulator framework Implement a simple, irq_work-based framework for simulating interrupts. Currently the API exposes routines for initializing and deinitializing the simulator object, enqueueing the interrupts and retrieving the allocated interrupt numbers based on the offset of the dummy interrupt in the simulator struct. Signed-off-by: Bartosz Golaszewski Reviewed-by: Jonathan Cameron Cc: Lars-Peter Clausen Cc: Jonathan Corbet Cc: Marc Zyngier Cc: Linus Walleij Cc: linux-doc@vger.kernel.org Cc: linux-gpio@vger.kernel.org Cc: Bamvor Jian Zhang Cc: Jonathan Cameron Link: http://lkml.kernel.org/r/20170814145318.6495-2-brgl@bgdev.pl Signed-off-by: Thomas Gleixner --- kernel/irq/Kconfig | 5 +++ kernel/irq/Makefile | 1 + kernel/irq/irq_sim.c | 121 +++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 127 insertions(+) create mode 100644 kernel/irq/irq_sim.c (limited to 'kernel') diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig index 27c4e774071c..1d06af787932 100644 --- a/kernel/irq/Kconfig +++ b/kernel/irq/Kconfig @@ -63,6 +63,11 @@ config GENERIC_IRQ_CHIP config IRQ_DOMAIN bool +# Support for simulated interrupts +config IRQ_SIM + bool + select IRQ_WORK + # Support for hierarchical irq domains config IRQ_DOMAIN_HIERARCHY bool diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile index e4aef7351f2b..1970cafe8f2a 100644 --- a/kernel/irq/Makefile +++ b/kernel/irq/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_IRQ_TIMINGS) += timings.o obj-$(CONFIG_GENERIC_IRQ_CHIP) += generic-chip.o obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o obj-$(CONFIG_IRQ_DOMAIN) += irqdomain.o +obj-$(CONFIG_IRQ_SIM) += irq_sim.o obj-$(CONFIG_PROC_FS) += proc.o obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o obj-$(CONFIG_GENERIC_IRQ_MIGRATION) += cpuhotplug.o diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c new file mode 100644 index 000000000000..31a2c12a79ae --- /dev/null +++ b/kernel/irq/irq_sim.c @@ -0,0 +1,121 @@ +/* + * Copyright (C) 2017 Bartosz Golaszewski + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + */ + +#include +#include + +static void irq_sim_irqmask(struct irq_data *data) +{ + struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data); + + irq_ctx->enabled = false; +} + +static void irq_sim_irqunmask(struct irq_data *data) +{ + struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data); + + irq_ctx->enabled = true; +} + +static struct irq_chip irq_sim_irqchip = { + .name = "irq_sim", + .irq_mask = irq_sim_irqmask, + .irq_unmask = irq_sim_irqunmask, +}; + +static void irq_sim_handle_irq(struct irq_work *work) +{ + struct irq_sim_work_ctx *work_ctx; + + work_ctx = container_of(work, struct irq_sim_work_ctx, work); + handle_simple_irq(irq_to_desc(work_ctx->irq)); +} + +/** + * irq_sim_init - Initialize the interrupt simulator: allocate a range of + * dummy interrupts. + * + * @sim: The interrupt simulator object to initialize. + * @num_irqs: Number of interrupts to allocate + * + * Returns 0 on success and a negative error number on failure. + */ +int irq_sim_init(struct irq_sim *sim, unsigned int num_irqs) +{ + int i; + + sim->irqs = kmalloc_array(num_irqs, sizeof(*sim->irqs), GFP_KERNEL); + if (!sim->irqs) + return -ENOMEM; + + sim->irq_base = irq_alloc_descs(-1, 0, num_irqs, 0); + if (sim->irq_base < 0) { + kfree(sim->irqs); + return sim->irq_base; + } + + for (i = 0; i < num_irqs; i++) { + sim->irqs[i].irqnum = sim->irq_base + i; + sim->irqs[i].enabled = false; + irq_set_chip(sim->irq_base + i, &irq_sim_irqchip); + irq_set_chip_data(sim->irq_base + i, &sim->irqs[i]); + irq_set_handler(sim->irq_base + i, &handle_simple_irq); + irq_modify_status(sim->irq_base + i, + IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE); + } + + init_irq_work(&sim->work_ctx.work, irq_sim_handle_irq); + sim->irq_count = num_irqs; + + return 0; +} +EXPORT_SYMBOL_GPL(irq_sim_init); + +/** + * irq_sim_fini - Deinitialize the interrupt simulator: free the interrupt + * descriptors and allocated memory. + * + * @sim: The interrupt simulator to tear down. + */ +void irq_sim_fini(struct irq_sim *sim) +{ + irq_work_sync(&sim->work_ctx.work); + irq_free_descs(sim->irq_base, sim->irq_count); + kfree(sim->irqs); +} +EXPORT_SYMBOL_GPL(irq_sim_fini); + +/** + * irq_sim_fire - Enqueue an interrupt. + * + * @sim: The interrupt simulator object. + * @offset: Offset of the simulated interrupt which should be fired. + */ +void irq_sim_fire(struct irq_sim *sim, unsigned int offset) +{ + if (sim->irqs[offset].enabled) { + sim->work_ctx.irq = irq_sim_irqnum(sim, offset); + irq_work_queue(&sim->work_ctx.work); + } +} +EXPORT_SYMBOL_GPL(irq_sim_fire); + +/** + * irq_sim_irqnum - Get the allocated number of a dummy interrupt. + * + * @sim: The interrupt simulator object. + * @offset: Offset of the simulated interrupt for which to retrieve + * the number. + */ +int irq_sim_irqnum(struct irq_sim *sim, unsigned int offset) +{ + return sim->irqs[offset].irqnum; +} +EXPORT_SYMBOL_GPL(irq_sim_irqnum); -- cgit v1.2.3 From 44e72c7ebf294043cfe276f7328b8c0e6a3e50e9 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Mon, 14 Aug 2017 16:53:17 +0200 Subject: genirq/irq_sim: Add a devres variant of irq_sim_init() Add a resource managed version of irq_sim_init(). This can be conveniently used in device drivers. Signed-off-by: Bartosz Golaszewski Acked-by: Jonathan Cameron Cc: Lars-Peter Clausen Cc: Jonathan Corbet Cc: Marc Zyngier Cc: Linus Walleij Cc: linux-doc@vger.kernel.org Cc: linux-gpio@vger.kernel.org Cc: Bamvor Jian Zhang Cc: Jonathan Cameron Link: http://lkml.kernel.org/r/20170814145318.6495-3-brgl@bgdev.pl Signed-off-by: Thomas Gleixner --- kernel/irq/irq_sim.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) (limited to 'kernel') diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c index 31a2c12a79ae..24caabf1a0f7 100644 --- a/kernel/irq/irq_sim.c +++ b/kernel/irq/irq_sim.c @@ -10,6 +10,10 @@ #include #include +struct irq_sim_devres { + struct irq_sim *sim; +}; + static void irq_sim_irqmask(struct irq_data *data) { struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data); @@ -92,6 +96,45 @@ void irq_sim_fini(struct irq_sim *sim) } EXPORT_SYMBOL_GPL(irq_sim_fini); +static void devm_irq_sim_release(struct device *dev, void *res) +{ + struct irq_sim_devres *this = res; + + irq_sim_fini(this->sim); +} + +/** + * irq_sim_init - Initialize the interrupt simulator for a managed device. + * + * @dev: Device to initialize the simulator object for. + * @sim: The interrupt simulator object to initialize. + * @num_irqs: Number of interrupts to allocate + * + * Returns 0 on success and a negative error number on failure. + */ +int devm_irq_sim_init(struct device *dev, struct irq_sim *sim, + unsigned int num_irqs) +{ + struct irq_sim_devres *dr; + int rv; + + dr = devres_alloc(devm_irq_sim_release, sizeof(*dr), GFP_KERNEL); + if (!dr) + return -ENOMEM; + + rv = irq_sim_init(sim, num_irqs); + if (rv) { + devres_free(dr); + return rv; + } + + dr->sim = sim; + devres_add(dev, dr); + + return 0; +} +EXPORT_SYMBOL_GPL(devm_irq_sim_init); + /** * irq_sim_fire - Enqueue an interrupt. * -- cgit v1.2.3 From 9c8783201cb58e9af8ddeb0cc68f37b0a44ca16c Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 16 Aug 2017 13:12:02 -0400 Subject: sched/completion: Document that reinit_completion() must be called after complete_all() The complete_all() function modifies the completion's "done" variable to UINT_MAX, and no other caller (wait_for_completion(), etc) will modify it back to zero. That means that any call to complete_all() must have a reinit_completion() before that completion can be used again. Document this fact by the complete_all() function. Also document that completion_done() will always return true if complete_all() is called. Signed-off-by: Steven Rostedt (VMware) Acked-by: Linus Torvalds Cc: Andrew Morton Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170816131202.195c2f4b@gandalf.local.home Signed-off-by: Ingo Molnar --- kernel/sched/completion.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'kernel') diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c index 13fc5ae9bf2f..2950f446820d 100644 --- a/kernel/sched/completion.c +++ b/kernel/sched/completion.c @@ -47,6 +47,13 @@ EXPORT_SYMBOL(complete); * * It may be assumed that this function implies a write memory barrier before * changing the task state if and only if any tasks are woken up. + * + * Since complete_all() sets the completion of @x permanently to done + * to allow multiple waiters to finish, a call to reinit_completion() + * must be used on @x if @x is to be used again. The code must make + * sure that all waiters have woken and finished before reinitializing + * @x. Also note that the function completion_done() can not be used + * to know if there are still waiters after complete_all() has been called. */ void complete_all(struct completion *x) { @@ -297,6 +304,7 @@ EXPORT_SYMBOL(try_wait_for_completion); * Return: 0 if there are waiters (wait_for_completion() in progress) * 1 if there are no waiters. * + * Note, this will always return true if complete_all() was called on @X. */ bool completion_done(struct completion *x) { -- cgit v1.2.3 From a6f6df69c48b86cd84f36c70593eb4968fceb34a Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Tue, 15 Aug 2017 22:32:22 -0700 Subject: bpf: export bpf_prog_inc_not_zero bpf_prog_inc_not_zero will be used by upcoming sockmap patches this patch simply exports it so we can pull it in. Signed-off-by: John Fastabend Signed-off-by: David S. Miller --- kernel/bpf/syscall.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index fbe09a0cccf4..17e29f596de1 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -911,7 +911,7 @@ struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) EXPORT_SYMBOL_GPL(bpf_prog_inc); /* prog_idr_lock should have been held */ -static struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog) +struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog) { int refold; @@ -927,6 +927,7 @@ static struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog) return prog; } +EXPORT_SYMBOL_GPL(bpf_prog_inc_not_zero); static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *type) { -- cgit v1.2.3 From 174a79ff9515f400b9a6115643dafd62a635b7e6 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Tue, 15 Aug 2017 22:32:47 -0700 Subject: bpf: sockmap with sk redirect support Recently we added a new map type called dev map used to forward XDP packets between ports (6093ec2dc313). This patches introduces a similar notion for sockets. A sockmap allows users to add participating sockets to a map. When sockets are added to the map enough context is stored with the map entry to use the entry with a new helper bpf_sk_redirect_map(map, key, flags) This helper (analogous to bpf_redirect_map in XDP) is given the map and an entry in the map. When called from a sockmap program, discussed below, the skb will be sent on the socket using skb_send_sock(). With the above we need a bpf program to call the helper from that will then implement the send logic. The initial site implemented in this series is the recv_sock hook. For this to work we implemented a map attach command to add attributes to a map. In sockmap we add two programs a parse program and a verdict program. The parse program uses strparser to build messages and pass them to the verdict program. The parse programs use the normal strparser semantics. The verdict program is of type SK_SKB. The verdict program returns a verdict SK_DROP, or SK_REDIRECT for now. Additional actions may be added later. When SK_REDIRECT is returned, expected when bpf program uses bpf_sk_redirect_map(), the sockmap logic will consult per cpu variables set by the helper routine and pull the sock entry out of the sock map. This pattern follows the existing redirect logic in cls and xdp programs. This gives the flow, recv_sock -> str_parser (parse_prog) -> verdict_prog -> skb_send_sock \ -> kfree_skb As an example use case a message based load balancer may use specific logic in the verdict program to select the sock to send on. Sample programs are provided in future patches that hopefully illustrate the user interfaces. Also selftests are in follow-on patches. Signed-off-by: John Fastabend Signed-off-by: David S. Miller --- kernel/bpf/Makefile | 2 +- kernel/bpf/sockmap.c | 792 ++++++++++++++++++++++++++++++++++++++++++++++++++ kernel/bpf/syscall.c | 51 +++- kernel/bpf/verifier.c | 14 + 4 files changed, 857 insertions(+), 2 deletions(-) create mode 100644 kernel/bpf/sockmap.c (limited to 'kernel') diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 2f0bcda40e90..aa24287db888 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -3,7 +3,7 @@ obj-y := core.o obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o ifeq ($(CONFIG_NET),y) -obj-$(CONFIG_BPF_SYSCALL) += devmap.o +obj-$(CONFIG_BPF_SYSCALL) += devmap.o sockmap.o endif ifeq ($(CONFIG_PERF_EVENTS),y) obj-$(CONFIG_BPF_SYSCALL) += stackmap.o diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c new file mode 100644 index 000000000000..792f0addfafa --- /dev/null +++ b/kernel/bpf/sockmap.c @@ -0,0 +1,792 @@ +/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ + +/* A BPF sock_map is used to store sock objects. This is primarly used + * for doing socket redirect with BPF helper routines. + * + * A sock map may have two BPF programs attached to it, a program used + * to parse packets and a program to provide a verdict and redirect + * decision on the packet. If no BPF parse program is provided it is + * assumed that every skb is a "message" (skb->len). Otherwise the + * parse program is attached to strparser and used to build messages + * that may span multiple skbs. The verdict program will either select + * a socket to send/receive the skb on or provide the drop code indicating + * the skb should be dropped. More actions may be added later as needed. + * The default program will drop packets. + * + * For reference this program is similar to devmap used in XDP context + * reviewing these together may be useful. For an example please review + * ./samples/bpf/sockmap/. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct bpf_stab { + struct bpf_map map; + struct sock **sock_map; + struct bpf_prog *bpf_parse; + struct bpf_prog *bpf_verdict; + refcount_t refcnt; +}; + +enum smap_psock_state { + SMAP_TX_RUNNING, +}; + +struct smap_psock { + struct rcu_head rcu; + + /* datapath variables */ + struct sk_buff_head rxqueue; + bool strp_enabled; + + /* datapath error path cache across tx work invocations */ + int save_rem; + int save_off; + struct sk_buff *save_skb; + + struct strparser strp; + struct bpf_prog *bpf_parse; + struct bpf_prog *bpf_verdict; + struct bpf_stab *stab; + + /* Back reference used when sock callback trigger sockmap operations */ + int key; + struct sock *sock; + unsigned long state; + + struct work_struct tx_work; + struct work_struct gc_work; + + void (*save_data_ready)(struct sock *sk); + void (*save_write_space)(struct sock *sk); + void (*save_state_change)(struct sock *sk); +}; + +static inline struct smap_psock *smap_psock_sk(const struct sock *sk) +{ + return (struct smap_psock *)rcu_dereference_sk_user_data(sk); +} + +static int smap_verdict_func(struct smap_psock *psock, struct sk_buff *skb) +{ + struct bpf_prog *prog = READ_ONCE(psock->bpf_verdict); + int rc; + + if (unlikely(!prog)) + return SK_DROP; + + skb_orphan(skb); + skb->sk = psock->sock; + bpf_compute_data_end(skb); + rc = (*prog->bpf_func)(skb, prog->insnsi); + skb->sk = NULL; + + return rc; +} + +static void smap_do_verdict(struct smap_psock *psock, struct sk_buff *skb) +{ + struct sock *sock; + int rc; + + /* Because we use per cpu values to feed input from sock redirect + * in BPF program to do_sk_redirect_map() call we need to ensure we + * are not preempted. RCU read lock is not sufficient in this case + * with CONFIG_PREEMPT_RCU enabled so we must be explicit here. + */ + preempt_disable(); + rc = smap_verdict_func(psock, skb); + switch (rc) { + case SK_REDIRECT: + sock = do_sk_redirect_map(); + preempt_enable(); + if (likely(sock)) { + struct smap_psock *peer = smap_psock_sk(sock); + + if (likely(peer && + test_bit(SMAP_TX_RUNNING, &peer->state) && + sk_stream_memory_free(peer->sock))) { + peer->sock->sk_wmem_queued += skb->truesize; + sk_mem_charge(peer->sock, skb->truesize); + skb_queue_tail(&peer->rxqueue, skb); + schedule_work(&peer->tx_work); + break; + } + } + /* Fall through and free skb otherwise */ + case SK_DROP: + default: + preempt_enable(); + kfree_skb(skb); + } +} + +static void smap_report_sk_error(struct smap_psock *psock, int err) +{ + struct sock *sk = psock->sock; + + sk->sk_err = err; + sk->sk_error_report(sk); +} + +static void smap_release_sock(struct sock *sock); + +/* Called with lock_sock(sk) held */ +static void smap_state_change(struct sock *sk) +{ + struct smap_psock *psock; + struct sock *osk; + + rcu_read_lock(); + + /* Allowing transitions into an established syn_recv states allows + * for early binding sockets to a smap object before the connection + * is established. + */ + switch (sk->sk_state) { + case TCP_SYN_RECV: + case TCP_ESTABLISHED: + break; + case TCP_CLOSE_WAIT: + case TCP_CLOSING: + case TCP_LAST_ACK: + case TCP_FIN_WAIT1: + case TCP_FIN_WAIT2: + case TCP_LISTEN: + break; + case TCP_CLOSE: + /* Only release if the map entry is in fact the sock in + * question. There is a case where the operator deletes + * the sock from the map, but the TCP sock is closed before + * the psock is detached. Use cmpxchg to verify correct + * sock is removed. + */ + psock = smap_psock_sk(sk); + if (unlikely(!psock)) + break; + osk = cmpxchg(&psock->stab->sock_map[psock->key], sk, NULL); + if (osk == sk) + smap_release_sock(sk); + break; + default: + smap_report_sk_error(psock, EPIPE); + break; + } + rcu_read_unlock(); +} + +static void smap_read_sock_strparser(struct strparser *strp, + struct sk_buff *skb) +{ + struct smap_psock *psock; + + rcu_read_lock(); + psock = container_of(strp, struct smap_psock, strp); + smap_do_verdict(psock, skb); + rcu_read_unlock(); +} + +/* Called with lock held on socket */ +static void smap_data_ready(struct sock *sk) +{ + struct smap_psock *psock; + + write_lock_bh(&sk->sk_callback_lock); + psock = smap_psock_sk(sk); + if (likely(psock)) + strp_data_ready(&psock->strp); + write_unlock_bh(&sk->sk_callback_lock); +} + +static void smap_tx_work(struct work_struct *w) +{ + struct smap_psock *psock; + struct sk_buff *skb; + int rem, off, n; + + psock = container_of(w, struct smap_psock, tx_work); + + /* lock sock to avoid losing sk_socket at some point during loop */ + lock_sock(psock->sock); + if (psock->save_skb) { + skb = psock->save_skb; + rem = psock->save_rem; + off = psock->save_off; + psock->save_skb = NULL; + goto start; + } + + while ((skb = skb_dequeue(&psock->rxqueue))) { + rem = skb->len; + off = 0; +start: + do { + if (likely(psock->sock->sk_socket)) + n = skb_send_sock_locked(psock->sock, + skb, off, rem); + else + n = -EINVAL; + if (n <= 0) { + if (n == -EAGAIN) { + /* Retry when space is available */ + psock->save_skb = skb; + psock->save_rem = rem; + psock->save_off = off; + goto out; + } + /* Hard errors break pipe and stop xmit */ + smap_report_sk_error(psock, n ? -n : EPIPE); + clear_bit(SMAP_TX_RUNNING, &psock->state); + sk_mem_uncharge(psock->sock, skb->truesize); + psock->sock->sk_wmem_queued -= skb->truesize; + kfree_skb(skb); + goto out; + } + rem -= n; + off += n; + } while (rem); + sk_mem_uncharge(psock->sock, skb->truesize); + psock->sock->sk_wmem_queued -= skb->truesize; + kfree_skb(skb); + } +out: + release_sock(psock->sock); +} + +static void smap_write_space(struct sock *sk) +{ + struct smap_psock *psock; + + rcu_read_lock(); + psock = smap_psock_sk(sk); + if (likely(psock && test_bit(SMAP_TX_RUNNING, &psock->state))) + schedule_work(&psock->tx_work); + rcu_read_unlock(); +} + +static void smap_stop_sock(struct smap_psock *psock, struct sock *sk) +{ + write_lock_bh(&sk->sk_callback_lock); + if (!psock->strp_enabled) + goto out; + sk->sk_data_ready = psock->save_data_ready; + sk->sk_write_space = psock->save_write_space; + sk->sk_state_change = psock->save_state_change; + psock->save_data_ready = NULL; + psock->save_write_space = NULL; + psock->save_state_change = NULL; + strp_stop(&psock->strp); + psock->strp_enabled = false; +out: + write_unlock_bh(&sk->sk_callback_lock); +} + +static void smap_destroy_psock(struct rcu_head *rcu) +{ + struct smap_psock *psock = container_of(rcu, + struct smap_psock, rcu); + + /* Now that a grace period has passed there is no longer + * any reference to this sock in the sockmap so we can + * destroy the psock, strparser, and bpf programs. But, + * because we use workqueue sync operations we can not + * do it in rcu context + */ + schedule_work(&psock->gc_work); +} + +static void smap_release_sock(struct sock *sock) +{ + struct smap_psock *psock = smap_psock_sk(sock); + + smap_stop_sock(psock, sock); + clear_bit(SMAP_TX_RUNNING, &psock->state); + rcu_assign_sk_user_data(sock, NULL); + call_rcu_sched(&psock->rcu, smap_destroy_psock); +} + +static int smap_parse_func_strparser(struct strparser *strp, + struct sk_buff *skb) +{ + struct smap_psock *psock; + struct bpf_prog *prog; + int rc; + + rcu_read_lock(); + psock = container_of(strp, struct smap_psock, strp); + prog = READ_ONCE(psock->bpf_parse); + + if (unlikely(!prog)) { + rcu_read_unlock(); + return skb->len; + } + + /* Attach socket for bpf program to use if needed we can do this + * because strparser clones the skb before handing it to a upper + * layer, meaning skb_orphan has been called. We NULL sk on the + * way out to ensure we don't trigger a BUG_ON in skb/sk operations + * later and because we are not charging the memory of this skb to + * any socket yet. + */ + skb->sk = psock->sock; + bpf_compute_data_end(skb); + rc = (*prog->bpf_func)(skb, prog->insnsi); + skb->sk = NULL; + rcu_read_unlock(); + return rc; +} + + +static int smap_read_sock_done(struct strparser *strp, int err) +{ + return err; +} + +static int smap_init_sock(struct smap_psock *psock, + struct sock *sk) +{ + struct strp_callbacks cb; + + memset(&cb, 0, sizeof(cb)); + cb.rcv_msg = smap_read_sock_strparser; + cb.parse_msg = smap_parse_func_strparser; + cb.read_sock_done = smap_read_sock_done; + return strp_init(&psock->strp, sk, &cb); +} + +static void smap_init_progs(struct smap_psock *psock, + struct bpf_stab *stab, + struct bpf_prog *verdict, + struct bpf_prog *parse) +{ + struct bpf_prog *orig_parse, *orig_verdict; + + orig_parse = xchg(&psock->bpf_parse, parse); + orig_verdict = xchg(&psock->bpf_verdict, verdict); + + if (orig_verdict) + bpf_prog_put(orig_verdict); + if (orig_parse) + bpf_prog_put(orig_parse); +} + +static void smap_start_sock(struct smap_psock *psock, struct sock *sk) +{ + if (sk->sk_data_ready == smap_data_ready) + return; + psock->save_data_ready = sk->sk_data_ready; + psock->save_write_space = sk->sk_write_space; + psock->save_state_change = sk->sk_state_change; + sk->sk_data_ready = smap_data_ready; + sk->sk_write_space = smap_write_space; + sk->sk_state_change = smap_state_change; + psock->strp_enabled = true; +} + +static void sock_map_remove_complete(struct bpf_stab *stab) +{ + bpf_map_area_free(stab->sock_map); + kfree(stab); +} + +static void smap_gc_work(struct work_struct *w) +{ + struct smap_psock *psock; + + psock = container_of(w, struct smap_psock, gc_work); + + /* no callback lock needed because we already detached sockmap ops */ + if (psock->strp_enabled) + strp_done(&psock->strp); + + cancel_work_sync(&psock->tx_work); + __skb_queue_purge(&psock->rxqueue); + + /* At this point all strparser and xmit work must be complete */ + if (psock->bpf_parse) + bpf_prog_put(psock->bpf_parse); + if (psock->bpf_verdict) + bpf_prog_put(psock->bpf_verdict); + + if (refcount_dec_and_test(&psock->stab->refcnt)) + sock_map_remove_complete(psock->stab); + + sock_put(psock->sock); + kfree(psock); +} + +static struct smap_psock *smap_init_psock(struct sock *sock, + struct bpf_stab *stab) +{ + struct smap_psock *psock; + + psock = kzalloc(sizeof(struct smap_psock), GFP_ATOMIC | __GFP_NOWARN); + if (!psock) + return ERR_PTR(-ENOMEM); + + psock->sock = sock; + skb_queue_head_init(&psock->rxqueue); + INIT_WORK(&psock->tx_work, smap_tx_work); + INIT_WORK(&psock->gc_work, smap_gc_work); + + rcu_assign_sk_user_data(sock, psock); + sock_hold(sock); + return psock; +} + +static struct bpf_map *sock_map_alloc(union bpf_attr *attr) +{ + struct bpf_stab *stab; + int err = -EINVAL; + u64 cost; + + /* check sanity of attributes */ + if (attr->max_entries == 0 || attr->key_size != 4 || + attr->value_size != 4 || attr->map_flags) + return ERR_PTR(-EINVAL); + + if (attr->value_size > KMALLOC_MAX_SIZE) + return ERR_PTR(-E2BIG); + + stab = kzalloc(sizeof(*stab), GFP_USER); + if (!stab) + return ERR_PTR(-ENOMEM); + + /* mandatory map attributes */ + stab->map.map_type = attr->map_type; + stab->map.key_size = attr->key_size; + stab->map.value_size = attr->value_size; + stab->map.max_entries = attr->max_entries; + stab->map.map_flags = attr->map_flags; + + /* make sure page count doesn't overflow */ + cost = (u64) stab->map.max_entries * sizeof(struct sock *); + if (cost >= U32_MAX - PAGE_SIZE) + goto free_stab; + + stab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; + + /* if map size is larger than memlock limit, reject it early */ + err = bpf_map_precharge_memlock(stab->map.pages); + if (err) + goto free_stab; + + stab->sock_map = bpf_map_area_alloc(stab->map.max_entries * + sizeof(struct sock *)); + if (!stab->sock_map) + goto free_stab; + + refcount_set(&stab->refcnt, 1); + return &stab->map; +free_stab: + kfree(stab); + return ERR_PTR(err); +} + +static void sock_map_free(struct bpf_map *map) +{ + struct bpf_stab *stab = container_of(map, struct bpf_stab, map); + int i; + + synchronize_rcu(); + + /* At this point no update, lookup or delete operations can happen. + * However, be aware we can still get a socket state event updates, + * and data ready callabacks that reference the psock from sk_user_data + * Also psock worker threads are still in-flight. So smap_release_sock + * will only free the psock after cancel_sync on the worker threads + * and a grace period expire to ensure psock is really safe to remove. + */ + rcu_read_lock(); + for (i = 0; i < stab->map.max_entries; i++) { + struct sock *sock; + + sock = xchg(&stab->sock_map[i], NULL); + if (!sock) + continue; + + smap_release_sock(sock); + } + rcu_read_unlock(); + + if (stab->bpf_verdict) + bpf_prog_put(stab->bpf_verdict); + if (stab->bpf_parse) + bpf_prog_put(stab->bpf_parse); + + if (refcount_dec_and_test(&stab->refcnt)) + sock_map_remove_complete(stab); +} + +static int sock_map_get_next_key(struct bpf_map *map, void *key, void *next_key) +{ + struct bpf_stab *stab = container_of(map, struct bpf_stab, map); + u32 i = key ? *(u32 *)key : U32_MAX; + u32 *next = (u32 *)next_key; + + if (i >= stab->map.max_entries) { + *next = 0; + return 0; + } + + if (i == stab->map.max_entries - 1) + return -ENOENT; + + *next = i + 1; + return 0; +} + +struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key) +{ + struct bpf_stab *stab = container_of(map, struct bpf_stab, map); + + if (key >= map->max_entries) + return NULL; + + return READ_ONCE(stab->sock_map[key]); +} + +static int sock_map_delete_elem(struct bpf_map *map, void *key) +{ + struct bpf_stab *stab = container_of(map, struct bpf_stab, map); + int k = *(u32 *)key; + struct sock *sock; + + if (k >= map->max_entries) + return -EINVAL; + + sock = xchg(&stab->sock_map[k], NULL); + if (!sock) + return -EINVAL; + + smap_release_sock(sock); + return 0; +} + +/* Locking notes: Concurrent updates, deletes, and lookups are allowed and are + * done inside rcu critical sections. This ensures on updates that the psock + * will not be released via smap_release_sock() until concurrent updates/deletes + * complete. All operations operate on sock_map using cmpxchg and xchg + * operations to ensure we do not get stale references. Any reads into the + * map must be done with READ_ONCE() because of this. + * + * A psock is destroyed via call_rcu and after any worker threads are cancelled + * and syncd so we are certain all references from the update/lookup/delete + * operations as well as references in the data path are no longer in use. + * + * A psock object holds a refcnt on the sockmap it is attached to and this is + * not decremented until after a RCU grace period and garbage collection occurs. + * This ensures the map is not free'd until psocks linked to it are removed. The + * map link is used when the independent sock events trigger map deletion. + * + * Psocks may only participate in one sockmap at a time. Users that try to + * join a single sock to multiple maps will get an error. + * + * Last, but not least, it is possible the socket is closed while running + * an update on an existing psock. This will release the psock, but again + * not until the update has completed due to rcu grace period rules. + */ +static int sock_map_ctx_update_elem(struct bpf_sock_ops_kern *skops, + struct bpf_map *map, + void *key, u64 flags, u64 map_flags) +{ + struct bpf_stab *stab = container_of(map, struct bpf_stab, map); + struct bpf_prog *verdict, *parse; + struct smap_psock *psock = NULL; + struct sock *old_sock, *sock; + u32 i = *(u32 *)key; + bool update = false; + int err = 0; + + if (unlikely(flags > BPF_EXIST)) + return -EINVAL; + + if (unlikely(i >= stab->map.max_entries)) + return -E2BIG; + + if (unlikely(map_flags > BPF_SOCKMAP_STRPARSER)) + return -EINVAL; + + verdict = parse = NULL; + sock = READ_ONCE(stab->sock_map[i]); + + if (flags == BPF_EXIST || flags == BPF_ANY) { + if (!sock && flags == BPF_EXIST) { + return -ENOENT; + } else if (sock && sock != skops->sk) { + return -EINVAL; + } else if (sock) { + psock = smap_psock_sk(sock); + if (unlikely(!psock)) + return -EBUSY; + update = true; + } + } else if (sock && BPF_NOEXIST) { + return -EEXIST; + } + + /* reserve BPF programs early so can abort easily on failures */ + if (map_flags & BPF_SOCKMAP_STRPARSER) { + verdict = READ_ONCE(stab->bpf_verdict); + parse = READ_ONCE(stab->bpf_parse); + + if (!verdict || !parse) + return -ENOENT; + + /* bpf prog refcnt may be zero if a concurrent attach operation + * removes the program after the above READ_ONCE() but before + * we increment the refcnt. If this is the case abort with an + * error. + */ + verdict = bpf_prog_inc_not_zero(stab->bpf_verdict); + if (IS_ERR(verdict)) + return PTR_ERR(verdict); + + parse = bpf_prog_inc_not_zero(stab->bpf_parse); + if (IS_ERR(parse)) { + bpf_prog_put(verdict); + return PTR_ERR(parse); + } + } + + if (!psock) { + sock = skops->sk; + if (rcu_dereference_sk_user_data(sock)) + return -EEXIST; + psock = smap_init_psock(sock, stab); + if (IS_ERR(psock)) { + if (verdict) + bpf_prog_put(verdict); + if (parse) + bpf_prog_put(parse); + return PTR_ERR(psock); + } + psock->key = i; + psock->stab = stab; + refcount_inc(&stab->refcnt); + set_bit(SMAP_TX_RUNNING, &psock->state); + } + + if (map_flags & BPF_SOCKMAP_STRPARSER) { + write_lock_bh(&sock->sk_callback_lock); + if (psock->strp_enabled) + goto start_done; + err = smap_init_sock(psock, sock); + if (err) + goto out; + smap_init_progs(psock, stab, verdict, parse); + smap_start_sock(psock, sock); +start_done: + write_unlock_bh(&sock->sk_callback_lock); + } else if (update) { + smap_stop_sock(psock, sock); + } + + if (!update) { + old_sock = xchg(&stab->sock_map[i], skops->sk); + if (old_sock) + smap_release_sock(old_sock); + } + + return 0; +out: + write_unlock_bh(&sock->sk_callback_lock); + if (!update) + smap_release_sock(sock); + return err; +} + +static int sock_map_attach_prog(struct bpf_map *map, + struct bpf_prog *parse, + struct bpf_prog *verdict) +{ + struct bpf_stab *stab = container_of(map, struct bpf_stab, map); + struct bpf_prog *_parse, *_verdict; + + _parse = xchg(&stab->bpf_parse, parse); + _verdict = xchg(&stab->bpf_verdict, verdict); + + if (_parse) + bpf_prog_put(_parse); + if (_verdict) + bpf_prog_put(_verdict); + + return 0; +} + +static void *sock_map_lookup(struct bpf_map *map, void *key) +{ + return NULL; +} + +static int sock_map_update_elem(struct bpf_map *map, + void *key, void *value, u64 flags) +{ + struct bpf_sock_ops_kern skops; + u32 fd = *(u32 *)value; + struct socket *socket; + int err; + + socket = sockfd_lookup(fd, &err); + if (!socket) + return err; + + skops.sk = socket->sk; + if (!skops.sk) { + fput(socket->file); + return -EINVAL; + } + + err = sock_map_ctx_update_elem(&skops, map, key, + flags, BPF_SOCKMAP_STRPARSER); + fput(socket->file); + return err; +} + +const struct bpf_map_ops sock_map_ops = { + .map_alloc = sock_map_alloc, + .map_free = sock_map_free, + .map_lookup_elem = sock_map_lookup, + .map_get_next_key = sock_map_get_next_key, + .map_update_elem = sock_map_update_elem, + .map_delete_elem = sock_map_delete_elem, + .map_attach = sock_map_attach_prog, +}; + +BPF_CALL_5(bpf_sock_map_update, struct bpf_sock_ops_kern *, bpf_sock, + struct bpf_map *, map, void *, key, u64, flags, u64, map_flags) +{ + WARN_ON_ONCE(!rcu_read_lock_held()); + return sock_map_ctx_update_elem(bpf_sock, map, key, flags, map_flags); +} + +const struct bpf_func_proto bpf_sock_map_update_proto = { + .func = bpf_sock_map_update, + .gpl_only = false, + .pkt_access = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_CONST_MAP_PTR, + .arg3_type = ARG_PTR_TO_MAP_KEY, + .arg4_type = ARG_ANYTHING, + .arg5_type = ARG_ANYTHING, +}; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 17e29f596de1..d2f2bdf71ffa 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1087,7 +1087,50 @@ static int bpf_obj_get(const union bpf_attr *attr) #ifdef CONFIG_CGROUP_BPF -#define BPF_PROG_ATTACH_LAST_FIELD attach_flags +#define BPF_PROG_ATTACH_LAST_FIELD attach_bpf_fd2 + +static int sockmap_get_from_fd(const union bpf_attr *attr, int ptype) +{ + struct bpf_prog *prog1, *prog2; + int ufd = attr->target_fd; + struct bpf_map *map; + struct fd f; + int err; + + f = fdget(ufd); + map = __bpf_map_get(f); + if (IS_ERR(map)) + return PTR_ERR(map); + + if (!map->ops->map_attach) { + fdput(f); + return -EOPNOTSUPP; + } + + prog1 = bpf_prog_get_type(attr->attach_bpf_fd, ptype); + if (IS_ERR(prog1)) { + fdput(f); + return PTR_ERR(prog1); + } + + prog2 = bpf_prog_get_type(attr->attach_bpf_fd2, ptype); + if (IS_ERR(prog2)) { + fdput(f); + bpf_prog_put(prog1); + return PTR_ERR(prog2); + } + + err = map->ops->map_attach(map, prog1, prog2); + if (err) { + fdput(f); + bpf_prog_put(prog1); + bpf_prog_put(prog2); + return PTR_ERR(map); + } + + fdput(f); + return err; +} static int bpf_prog_attach(const union bpf_attr *attr) { @@ -1116,10 +1159,16 @@ static int bpf_prog_attach(const union bpf_attr *attr) case BPF_CGROUP_SOCK_OPS: ptype = BPF_PROG_TYPE_SOCK_OPS; break; + case BPF_CGROUP_SMAP_INGRESS: + ptype = BPF_PROG_TYPE_SK_SKB; + break; default: return -EINVAL; } + if (attr->attach_type == BPF_CGROUP_SMAP_INGRESS) + return sockmap_get_from_fd(attr, ptype); + prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype); if (IS_ERR(prog)) return PTR_ERR(prog); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 7dd96d064be1..a71bc0996572 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1522,6 +1522,12 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id) case BPF_MAP_TYPE_HASH_OF_MAPS: if (func_id != BPF_FUNC_map_lookup_elem) goto error; + case BPF_MAP_TYPE_SOCKMAP: + if (func_id != BPF_FUNC_sk_redirect_map && + func_id != BPF_FUNC_sock_map_update && + func_id != BPF_FUNC_map_delete_elem) + goto error; + break; default: break; } @@ -1550,6 +1556,14 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id) if (map->map_type != BPF_MAP_TYPE_DEVMAP) goto error; break; + case BPF_FUNC_sk_redirect_map: + if (map->map_type != BPF_MAP_TYPE_SOCKMAP) + goto error; + break; + case BPF_FUNC_sock_map_update: + if (map->map_type != BPF_MAP_TYPE_SOCKMAP) + goto error; + break; default: break; } -- cgit v1.2.3 From 8a31db5615667956c513d205cfb06885c3ec6d0b Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Tue, 15 Aug 2017 22:33:09 -0700 Subject: bpf: add access to sock fields and pkt data from sk_skb programs Signed-off-by: John Fastabend Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a71bc0996572..958ba84a9995 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -886,6 +886,7 @@ static bool may_access_direct_pkt_data(struct bpf_verifier_env *env, case BPF_PROG_TYPE_SCHED_ACT: case BPF_PROG_TYPE_XDP: case BPF_PROG_TYPE_LWT_XMIT: + case BPF_PROG_TYPE_SK_SKB: if (meta) return meta->pkt_access; -- cgit v1.2.3 From cf9d01405925e3f8144c99d7bf7b184449794066 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Tue, 15 Aug 2017 23:35:12 -0700 Subject: bpf: devmap: remove unnecessary value size check In the devmap alloc map logic we check to ensure that the sizeof the values are not greater than KMALLOC_MAX_SIZE. But, in the dev map case we ensure the value size is 4bytes earlier in the function because all values should be netdev ifindex values. The second check is harmless but is not needed so remove it. Signed-off-by: John Fastabend Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/devmap.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 7192fb67d4de..18a72a8add43 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -83,12 +83,6 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) attr->value_size != 4 || attr->map_flags) return ERR_PTR(-EINVAL); - /* if value_size is bigger, the user space won't be able to - * access the elements. - */ - if (attr->value_size > KMALLOC_MAX_SIZE) - return ERR_PTR(-E2BIG); - dtab = kzalloc(sizeof(*dtab), GFP_USER); if (!dtab) return ERR_PTR(-ENOMEM); -- cgit v1.2.3 From cf56e3b98c5358883c8df5ed8e04661481225a8f Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Wed, 16 Aug 2017 15:02:12 -0700 Subject: bpf: sockmap state change warning fix MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit psock will uninitialized in default case we need to do the same psock lookup and check as in other branch. Fixes compile warning below. kernel/bpf/sockmap.c: In function ‘smap_state_change’: kernel/bpf/sockmap.c:156:21: warning: ‘psock’ may be used uninitialized in this function [-Wmaybe-uninitialized] struct smap_psock *psock; Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support") Reported-by: David Miller Signed-off-by: John Fastabend Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/sockmap.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 792f0addfafa..f7e5e6cf124a 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -188,6 +188,9 @@ static void smap_state_change(struct sock *sk) smap_release_sock(sk); break; default: + psock = smap_psock_sk(sk); + if (unlikely(!psock)) + break; smap_report_sk_error(psock, EPIPE); break; } -- cgit v1.2.3 From 6bdc9c4c31c81688e19cb186d49be01bbb6a1618 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Wed, 16 Aug 2017 15:02:32 -0700 Subject: bpf: sock_map fixes for !CONFIG_BPF_SYSCALL and !STREAM_PARSER MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Resolve issues with !CONFIG_BPF_SYSCALL and !STREAM_PARSER net/core/filter.c: In function ‘do_sk_redirect_map’: net/core/filter.c:1881:3: error: implicit declaration of function ‘__sock_map_lookup_elem’ [-Werror=implicit-function-declaration] sk = __sock_map_lookup_elem(ri->map, ri->ifindex); ^ net/core/filter.c:1881:6: warning: assignment makes pointer from integer without a cast [enabled by default] sk = __sock_map_lookup_elem(ri->map, ri->ifindex); Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support") Reported-by: Eric Dumazet Signed-off-by: John Fastabend Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/Makefile | 5 ++++- kernel/bpf/core.c | 1 + 2 files changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index aa24287db888..897daa005b23 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -3,7 +3,10 @@ obj-y := core.o obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o ifeq ($(CONFIG_NET),y) -obj-$(CONFIG_BPF_SYSCALL) += devmap.o sockmap.o +obj-$(CONFIG_BPF_SYSCALL) += devmap.o +ifeq ($(CONFIG_STREAM_PARSER),y) +obj-$(CONFIG_BPF_SYSCALL) += sockmap.o +endif endif ifeq ($(CONFIG_PERF_EVENTS),y) obj-$(CONFIG_BPF_SYSCALL) += stackmap.o diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index c69e7f5bfde7..917cc04a0a94 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1438,6 +1438,7 @@ const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; const struct bpf_func_proto bpf_get_current_comm_proto __weak; +const struct bpf_func_proto bpf_sock_map_update_proto __weak; const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) { -- cgit v1.2.3 From 7a46ec0e2f4850407de5e1d19a44edee6efa58ec Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 15 Aug 2017 09:19:24 -0700 Subject: locking/refcounts, x86/asm: Implement fast refcount overflow protection This implements refcount_t overflow protection on x86 without a noticeable performance impact, though without the fuller checking of REFCOUNT_FULL. This is done by duplicating the existing atomic_t refcount implementation but with normally a single instruction added to detect if the refcount has gone negative (e.g. wrapped past INT_MAX or below zero). When detected, the handler saturates the refcount_t to INT_MIN / 2. With this overflow protection, the erroneous reference release that would follow a wrap back to zero is blocked from happening, avoiding the class of refcount-overflow use-after-free vulnerabilities entirely. Only the overflow case of refcounting can be perfectly protected, since it can be detected and stopped before the reference is freed and left to be abused by an attacker. There isn't a way to block early decrements, and while REFCOUNT_FULL stops increment-from-zero cases (which would be the state _after_ an early decrement and stops potential double-free conditions), this fast implementation does not, since it would require the more expensive cmpxchg loops. Since the overflow case is much more common (e.g. missing a "put" during an error path), this protection provides real-world protection. For example, the two public refcount overflow use-after-free exploits published in 2016 would have been rendered unexploitable: http://perception-point.io/2016/01/14/analysis-and-exploitation-of-a-linux-kernel-vulnerability-cve-2016-0728/ http://cyseclabs.com/page?n=02012016 This implementation does, however, notice an unchecked decrement to zero (i.e. caller used refcount_dec() instead of refcount_dec_and_test() and it resulted in a zero). Decrements under zero are noticed (since they will have resulted in a negative value), though this only indicates that a use-after-free may have already happened. Such notifications are likely avoidable by an attacker that has already exploited a use-after-free vulnerability, but it's better to have them reported than allow such conditions to remain universally silent. On first overflow detection, the refcount value is reset to INT_MIN / 2 (which serves as a saturation value) and a report and stack trace are produced. When operations detect only negative value results (such as changing an already saturated value), saturation still happens but no notification is performed (since the value was already saturated). On the matter of races, since the entire range beyond INT_MAX but before 0 is negative, every operation at INT_MIN / 2 will trap, leaving no overflow-only race condition. As for performance, this implementation adds a single "js" instruction to the regular execution flow of a copy of the standard atomic_t refcount operations. (The non-"and_test" refcount_dec() function, which is uncommon in regular refcount design patterns, has an additional "jz" instruction to detect reaching exactly zero.) Since this is a forward jump, it is by default the non-predicted path, which will be reinforced by dynamic branch prediction. The result is this protection having virtually no measurable change in performance over standard atomic_t operations. The error path, located in .text.unlikely, saves the refcount location and then uses UD0 to fire a refcount exception handler, which resets the refcount, handles reporting, and returns to regular execution. This keeps the changes to .text size minimal, avoiding return jumps and open-coded calls to the error reporting routine. Example assembly comparison: refcount_inc() before: .text: ffffffff81546149: f0 ff 45 f4 lock incl -0xc(%rbp) refcount_inc() after: .text: ffffffff81546149: f0 ff 45 f4 lock incl -0xc(%rbp) ffffffff8154614d: 0f 88 80 d5 17 00 js ffffffff816c36d3 ... .text.unlikely: ffffffff816c36d3: 48 8d 4d f4 lea -0xc(%rbp),%rcx ffffffff816c36d7: 0f ff (bad) These are the cycle counts comparing a loop of refcount_inc() from 1 to INT_MAX and back down to 0 (via refcount_dec_and_test()), between unprotected refcount_t (atomic_t), fully protected REFCOUNT_FULL (refcount_t-full), and this overflow-protected refcount (refcount_t-fast): 2147483646 refcount_inc()s and 2147483647 refcount_dec_and_test()s: cycles protections atomic_t 82249267387 none refcount_t-fast 82211446892 overflow, untested dec-to-zero refcount_t-full 144814735193 overflow, untested dec-to-zero, inc-from-zero This code is a modified version of the x86 PAX_REFCOUNT atomic_t overflow defense from the last public patch of PaX/grsecurity, based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Thanks to PaX Team for various suggestions for improvement for repurposing this code to be a refcount-only protection. Signed-off-by: Kees Cook Reviewed-by: Josh Poimboeuf Cc: Alexey Dobriyan Cc: Andrew Morton Cc: Arnd Bergmann Cc: Christoph Hellwig Cc: David S. Miller Cc: Davidlohr Bueso Cc: Elena Reshetova Cc: Eric Biggers Cc: Eric W. Biederman Cc: Greg KH Cc: Hans Liljestrand Cc: James Bottomley Cc: Jann Horn Cc: Linus Torvalds Cc: Manfred Spraul Cc: Peter Zijlstra Cc: Rik van Riel Cc: Serge E. Hallyn Cc: Thomas Gleixner Cc: arozansk@redhat.com Cc: axboe@kernel.dk Cc: kernel-hardening@lists.openwall.com Cc: linux-arch Link: http://lkml.kernel.org/r/20170815161924.GA133115@beast Signed-off-by: Ingo Molnar --- kernel/panic.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'kernel') diff --git a/kernel/panic.c b/kernel/panic.c index a58932b41700..bdd18afa19a4 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -26,6 +26,7 @@ #include #include #include +#include #define PANIC_TIMER_STEP 100 #define PANIC_BLINK_SPD 18 @@ -601,6 +602,17 @@ EXPORT_SYMBOL(__stack_chk_fail); #endif +#ifdef CONFIG_ARCH_HAS_REFCOUNT +void refcount_error_report(struct pt_regs *regs, const char *err) +{ + WARN_RATELIMIT(1, "refcount_t %s at %pB in %s[%d], uid/euid: %u/%u\n", + err, (void *)instruction_pointer(regs), + current->comm, task_pid_nr(current), + from_kuid_munged(&init_user_ns, current_uid()), + from_kuid_munged(&init_user_ns, current_euid())); +} +#endif + core_param(panic, panic_timeout, int, 0644); core_param(pause_on_oops, pause_on_oops, int, 0644); core_param(panic_on_warn, panic_on_warn, int, 0644); -- cgit v1.2.3 From 52fa5bc5cbba089f09bc2c372e3432f3f3e48051 Mon Sep 17 00:00:00 2001 From: Boqun Feng Date: Thu, 17 Aug 2017 17:46:12 +0800 Subject: locking/lockdep: Explicitly initialize wq_barrier::done::map With the new lockdep crossrelease feature, which checks completions usage, a false positive is reported in the workqueue code: > Worker A : acquired of wfc.work -> wait for cpu_hotplug_lock to be released > Task B : acquired of cpu_hotplug_lock -> wait for lock#3 to be released > Task C : acquired of lock#3 -> wait for completion of barr->done > (Task C is in lru_add_drain_all_cpuslocked()) > Worker D : wait for wfc.work to be released -> will complete barr->done Such a dead lock can not happen because Task C's barr->done and Worker D's barr->done can not be the same instance. The reason of this false positive is we initialize all wq_barrier::done at insert_wq_barrier() via init_completion(), which makes them belong to the same lock class, therefore, impossible circles are reported. To fix this, explicitly initialize the lockdep map for wq_barrier::done in insert_wq_barrier(), so that the lock class key of wq_barrier::done is a subkey of the corresponding work_struct, as a result we won't build a dependency between a wq_barrier with a unrelated work, and we can differ wq barriers based on the related works, so the false positive above is avoided. Also define the empty lockdep_init_map_crosslock() for !CROSSRELEASE to make the code simple and away from unnecessary #ifdefs. Reported-by: Ingo Molnar Signed-off-by: Boqun Feng Cc: Byungchul Park Cc: Lai Jiangshan Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Tejun Heo Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170817094622.12915-1-boqun.feng@gmail.com Signed-off-by: Ingo Molnar --- kernel/workqueue.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index e86733a8b344..f128b3becfe1 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2476,7 +2476,16 @@ static void insert_wq_barrier(struct pool_workqueue *pwq, */ INIT_WORK_ONSTACK(&barr->work, wq_barrier_func); __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); - init_completion(&barr->done); + + /* + * Explicitly init the crosslock for wq_barrier::done, make its lock + * key a subkey of the corresponding work. As a result we won't + * build a dependency between wq_barrier::done and unrelated work. + */ + lockdep_init_map_crosslock((struct lockdep_map *)&barr->done.map, + "(complete)wq_barr::done", + target->lockdep_map.key, 1); + __init_completion(&barr->done); barr->task = current; /* -- cgit v1.2.3 From 7e42776d5ed1fe9a941ed8876c5d15cd7cf5d89f Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 25 May 2017 08:05:00 -0700 Subject: rcu: Drive TASKS_RCU directly off of PREEMPT The actual use of TASKS_RCU is only when PREEMPT, otherwise RCU-sched is used instead. This commit therefore makes synchronize_rcu_tasks() and call_rcu_tasks() available always, but mapped to synchronize_sched() and call_rcu_sched(), respectively, when !PREEMPT. This approach also allows some #ifdefs to be removed from rcutorture. Reported-by: Ingo Molnar Signed-off-by: Paul E. McKenney Reviewed-by: Masami Hiramatsu Acked-by: Ingo Molnar --- kernel/rcu/Kconfig | 3 +-- kernel/rcu/rcutorture.c | 17 +---------------- 2 files changed, 2 insertions(+), 18 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig index be90c945063f..9210379c0353 100644 --- a/kernel/rcu/Kconfig +++ b/kernel/rcu/Kconfig @@ -69,8 +69,7 @@ config TREE_SRCU This option selects the full-fledged version of SRCU. config TASKS_RCU - bool - default n + def_bool PREEMPT select SRCU help This option enables a task-based RCU implementation that uses diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index b8f7f8ce8575..b284c861a511 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -696,8 +696,6 @@ static struct rcu_torture_ops sched_ops = { .name = "sched" }; -#ifdef CONFIG_TASKS_RCU - /* * Definitions for RCU-tasks torture testing. */ @@ -735,24 +733,11 @@ static struct rcu_torture_ops tasks_ops = { .name = "tasks" }; -#define RCUTORTURE_TASKS_OPS &tasks_ops, - static bool __maybe_unused torturing_tasks(void) { return cur_ops == &tasks_ops; } -#else /* #ifdef CONFIG_TASKS_RCU */ - -#define RCUTORTURE_TASKS_OPS - -static bool __maybe_unused torturing_tasks(void) -{ - return false; -} - -#endif /* #else #ifdef CONFIG_TASKS_RCU */ - /* * RCU torture priority-boost testing. Runs one real-time thread per * CPU for moderate bursts, repeatedly registering RCU callbacks and @@ -1749,7 +1734,7 @@ rcu_torture_init(void) int firsterr = 0; static struct rcu_torture_ops *torture_ops[] = { &rcu_ops, &rcu_bh_ops, &rcu_busted_ops, &srcu_ops, &srcud_ops, - &sched_ops, RCUTORTURE_TASKS_OPS + &sched_ops, &tasks_ops, }; if (!torture_init_begin(torture_type, verbose, &torture_runnable)) -- cgit v1.2.3 From ccdd29ffffa7246cb359b9408772858a15fc4ea5 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 25 May 2017 08:51:48 -0700 Subject: rcu: Create reasonable API for do_exit() TASKS_RCU processing Currently, the exit-time support for TASKS_RCU is open-coded in do_exit(). This commit creates exit_tasks_rcu_start() and exit_tasks_rcu_finish() APIs for do_exit() use. This has the benefit of confining the use of the tasks_rcu_exit_srcu variable to one file, allowing it to become static. Signed-off-by: Paul E. McKenney --- kernel/exit.c | 7 ++----- kernel/rcu/update.c | 18 +++++++++++++++++- 2 files changed, 19 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index c5548faa9f37..d297c525f188 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -764,7 +764,6 @@ void __noreturn do_exit(long code) { struct task_struct *tsk = current; int group_dead; - TASKS_RCU(int tasks_rcu_i); profile_task_exit(tsk); kcov_task_exit(tsk); @@ -881,9 +880,7 @@ void __noreturn do_exit(long code) */ flush_ptrace_hw_breakpoint(tsk); - TASKS_RCU(preempt_disable()); - TASKS_RCU(tasks_rcu_i = __srcu_read_lock(&tasks_rcu_exit_srcu)); - TASKS_RCU(preempt_enable()); + exit_tasks_rcu_start(); exit_notify(tsk, group_dead); proc_exit_connector(tsk); mpol_put_task_policy(tsk); @@ -918,7 +915,7 @@ void __noreturn do_exit(long code) if (tsk->nr_dirtied) __this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied); exit_rcu(); - TASKS_RCU(__srcu_read_unlock(&tasks_rcu_exit_srcu, tasks_rcu_i)); + exit_tasks_rcu_finish(); do_task_dead(); } diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 00e77c470017..5033b66d2753 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -568,7 +568,7 @@ static DECLARE_WAIT_QUEUE_HEAD(rcu_tasks_cbs_wq); static DEFINE_RAW_SPINLOCK(rcu_tasks_cbs_lock); /* Track exiting tasks in order to allow them to be waited for. */ -DEFINE_SRCU(tasks_rcu_exit_srcu); +DEFINE_STATIC_SRCU(tasks_rcu_exit_srcu); /* Control stall timeouts. Disable with <= 0, otherwise jiffies till stall. */ #define RCU_TASK_STALL_TIMEOUT (HZ * 60 * 10) @@ -875,6 +875,22 @@ static void rcu_spawn_tasks_kthread(void) mutex_unlock(&rcu_tasks_kthread_mutex); } +/* Do the srcu_read_lock() for the above synchronize_srcu(). */ +void exit_tasks_rcu_start(void) +{ + preempt_disable(); + current->rcu_tasks_idx = __srcu_read_lock(&tasks_rcu_exit_srcu); + preempt_enable(); +} + +/* Do the srcu_read_unlock() for the above synchronize_srcu(). */ +void exit_tasks_rcu_finish(void) +{ + preempt_disable(); + __srcu_read_unlock(&tasks_rcu_exit_srcu, current->rcu_tasks_idx); + preempt_enable(); +} + #endif /* #ifdef CONFIG_TASKS_RCU */ #ifndef CONFIG_TINY_RCU -- cgit v1.2.3 From bedbb648efe178c8e4708ada272536744d0f8118 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 6 Jun 2017 15:49:39 -0700 Subject: rcu: Add TPS() to event-traced strings Strings used in event tracing need to be specially handled, for example, using the TPS() macro. Without the TPS() macro, although output looks fine from within a running kernel, extracting traces from a crash dump produces garbage instead of strings. This commit therefore adds the TPS() macro to some unadorned strings that were passed to event-tracing macros. Signed-off-by: Paul E. McKenney Acked-by: Steven Rostedt (VMware) --- kernel/rcu/tree_plugin.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index bb9e6e43130f..14ba496a13cd 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2073,7 +2073,7 @@ wait_again: /* Wait for callbacks to appear. */ if (!rcu_nocb_poll) { - trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "Sleep"); + trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, TPS("Sleep")); swait_event_interruptible(my_rdp->nocb_wq, !READ_ONCE(my_rdp->nocb_leader_sleep)); raw_spin_lock_irqsave(&my_rdp->nocb_lock, flags); @@ -2083,7 +2083,7 @@ wait_again: raw_spin_unlock_irqrestore(&my_rdp->nocb_lock, flags); } else if (firsttime) { firsttime = false; /* Don't drown trace log with "Poll"! */ - trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "Poll"); + trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, TPS("Poll")); } /* @@ -2111,7 +2111,7 @@ wait_again: schedule_timeout_interruptible(1); } else { trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, - "WokeEmpty"); + TPS("WokeEmpty")); } goto wait_again; } @@ -2155,7 +2155,7 @@ wait_again: static void nocb_follower_wait(struct rcu_data *rdp) { for (;;) { - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "FollowerSleep"); + trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("FollowerSleep")); swait_event_interruptible(rdp->nocb_wq, READ_ONCE(rdp->nocb_follower_head)); if (smp_load_acquire(&rdp->nocb_follower_head)) { @@ -2163,7 +2163,7 @@ static void nocb_follower_wait(struct rcu_data *rdp) return; } WARN_ON(signal_pending(current)); - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "WokeEmpty"); + trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WokeEmpty")); } } @@ -2198,7 +2198,7 @@ static int rcu_nocb_kthread(void *arg) rdp->nocb_follower_tail = &rdp->nocb_follower_head; raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags); BUG_ON(!list); - trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, "WokeNonEmpty"); + trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WokeNonEmpty")); /* Each pass through the following loop invokes a callback. */ trace_rcu_batch_start(rdp->rsp->name, -- cgit v1.2.3 From 7414fac050d5e0b64554b902f3955eabbebb6cb2 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 12 Jun 2017 16:44:19 -0700 Subject: rcu: Move rcu.h to new trivial-function style This commit saves a few lines in kernel/rcu/rcu.h by moving to single-line definitions for trivial functions, instead of the old style where the two curly braces each get their own line. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcu.h | 128 +++++++++---------------------------------------------- 1 file changed, 20 insertions(+), 108 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 808b8c85f626..e4b43fef89f5 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -356,22 +356,10 @@ do { \ #ifdef CONFIG_TINY_RCU /* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */ -static inline bool rcu_gp_is_normal(void) /* Internal RCU use. */ -{ - return true; -} -static inline bool rcu_gp_is_expedited(void) /* Internal RCU use. */ -{ - return false; -} - -static inline void rcu_expedite_gp(void) -{ -} - -static inline void rcu_unexpedite_gp(void) -{ -} +static inline bool rcu_gp_is_normal(void) { return true; } +static inline bool rcu_gp_is_expedited(void) { return false; } +static inline void rcu_expedite_gp(void) { } +static inline void rcu_unexpedite_gp(void) { } #else /* #ifdef CONFIG_TINY_RCU */ bool rcu_gp_is_normal(void); /* Internal RCU use. */ bool rcu_gp_is_expedited(void); /* Internal RCU use. */ @@ -419,12 +407,8 @@ static inline void rcutorture_get_gp_data(enum rcutorture_type test_type, *gpnum = 0; *completed = 0; } -static inline void rcutorture_record_test_transition(void) -{ -} -static inline void rcutorture_record_progress(unsigned long vernum) -{ -} +static inline void rcutorture_record_test_transition(void) { } +static inline void rcutorture_record_progress(unsigned long vernum) { } #ifdef CONFIG_RCU_TRACE void do_trace_rcu_torture_read(const char *rcutorturename, struct rcu_head *rhp, @@ -460,92 +444,20 @@ void srcutorture_get_gp_data(enum rcutorture_type test_type, #endif #ifdef CONFIG_TINY_RCU - -/* - * Return the number of grace periods started. - */ -static inline unsigned long rcu_batches_started(void) -{ - return 0; -} - -/* - * Return the number of bottom-half grace periods started. - */ -static inline unsigned long rcu_batches_started_bh(void) -{ - return 0; -} - -/* - * Return the number of sched grace periods started. - */ -static inline unsigned long rcu_batches_started_sched(void) -{ - return 0; -} - -/* - * Return the number of grace periods completed. - */ -static inline unsigned long rcu_batches_completed(void) -{ - return 0; -} - -/* - * Return the number of bottom-half grace periods completed. - */ -static inline unsigned long rcu_batches_completed_bh(void) -{ - return 0; -} - -/* - * Return the number of sched grace periods completed. - */ -static inline unsigned long rcu_batches_completed_sched(void) -{ - return 0; -} - -/* - * Return the number of expedited grace periods completed. - */ -static inline unsigned long rcu_exp_batches_completed(void) -{ - return 0; -} - -/* - * Return the number of expedited sched grace periods completed. - */ -static inline unsigned long rcu_exp_batches_completed_sched(void) -{ - return 0; -} - -static inline unsigned long srcu_batches_completed(struct srcu_struct *sp) -{ - return 0; -} - -static inline void rcu_force_quiescent_state(void) -{ -} - -static inline void rcu_bh_force_quiescent_state(void) -{ -} - -static inline void rcu_sched_force_quiescent_state(void) -{ -} - -static inline void show_rcu_gp_kthreads(void) -{ -} - +static inline unsigned long rcu_batches_started(void) { return 0; } +static inline unsigned long rcu_batches_started_bh(void) { return 0; } +static inline unsigned long rcu_batches_started_sched(void) { return 0; } +static inline unsigned long rcu_batches_completed(void) { return 0; } +static inline unsigned long rcu_batches_completed_bh(void) { return 0; } +static inline unsigned long rcu_batches_completed_sched(void) { return 0; } +static inline unsigned long rcu_exp_batches_completed(void) { return 0; } +static inline unsigned long rcu_exp_batches_completed_sched(void) { return 0; } +static inline unsigned long +srcu_batches_completed(struct srcu_struct *sp) { return 0; } +static inline void rcu_force_quiescent_state(void) { } +static inline void rcu_bh_force_quiescent_state(void) { } +static inline void rcu_sched_force_quiescent_state(void) { } +static inline void show_rcu_gp_kthreads(void) { } #else /* #ifdef CONFIG_TINY_RCU */ extern unsigned long rcutorture_testseq; extern unsigned long rcutorture_vernum; -- cgit v1.2.3 From c5ebe66ce774126b888617cab658f6556d23365e Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 19 Jun 2017 10:32:23 -0700 Subject: rcu: Add event tracing to ->gp_tasks update at GP start There is currently event tracing to track when a task is preempted within a preemptible RCU read-side critical section, and also when that task subsequently reaches its outermost rcu_read_unlock(), but none indicating when a new grace period starts when that grace period must wait on pre-existing readers that have been been preempted at least once since the beginning of their current RCU read-side critical sections. This commit therefore adds an event trace at grace-period start in the case where there are such readers. Note that only the first reader in the list is traced. Signed-off-by: Paul E. McKenney Acked-by: Steven Rostedt (VMware) --- kernel/rcu/tree_plugin.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 14ba496a13cd..3e3f92e981a1 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -636,10 +636,17 @@ static int rcu_print_task_exp_stall(struct rcu_node *rnp) */ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp) { + struct task_struct *t; + RCU_LOCKDEP_WARN(preemptible(), "rcu_preempt_check_blocked_tasks() invoked with preemption enabled!!!\n"); WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)); - if (rcu_preempt_has_tasks(rnp)) + if (rcu_preempt_has_tasks(rnp)) { rnp->gp_tasks = rnp->blkd_tasks.next; + t = container_of(rnp->gp_tasks, struct task_struct, + rcu_node_entry); + trace_rcu_unlock_preempted_task(TPS("rcu_preempt-GPS"), + rnp->gpnum, t->pid); + } WARN_ON_ONCE(rnp->qsmask); } -- cgit v1.2.3 From d5374226c3e444239e063f005dfb59cae4390db4 Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Tue, 20 Jun 2017 14:45:47 -0700 Subject: rcu: Use idle versions of swait to make idle-hack clear These RCU waits were set to use interruptible waits to avoid the kthreads contributing to system load average, even though they are not interruptible as they are spawned from a kthread. Use the new TASK_IDLE swaits which makes our goal clear, and removes confusion about these paths possibly being interruptible -- they are not. When the system is idle the RCU grace-period kthread will spend all its time blocked inside the swait_event_interruptible(). If the interruptible() was not used, then this kthread would contribute to the load average. This means that an idle system would have a load average of 2 (or 3 if PREEMPT=y), rather than the load average of 0 that almost fifty years of UNIX has conditioned sysadmins to expect. The same argument applies to swait_event_interruptible_timeout() use. The RCU grace-period kthread spends its time blocked inside this call while waiting for grace periods to complete. In particular, if there was only one busy CPU, but that CPU was frequently invoking call_rcu(), then the RCU grace-period kthread would spend almost all its time blocked inside the swait_event_interruptible_timeout(). This would mean that the load average would be 2 rather than the expected 1 for the single busy CPU. Acked-by: "Eric W. Biederman" Tested-by: Paul E. McKenney Signed-off-by: Luis R. Rodriguez Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 51d4c3acf32d..2b13d9679f57 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2067,8 +2067,8 @@ static bool rcu_gp_init(struct rcu_state *rsp) } /* - * Helper function for wait_event_interruptible_timeout() wakeup - * at force-quiescent-state time. + * Helper function for swait_event_idle() wakeup at force-quiescent-state + * time. */ static bool rcu_gp_fqs_check_wake(struct rcu_state *rsp, int *gfp) { @@ -2206,9 +2206,8 @@ static int __noreturn rcu_gp_kthread(void *arg) READ_ONCE(rsp->gpnum), TPS("reqwait")); rsp->gp_state = RCU_GP_WAIT_GPS; - swait_event_interruptible(rsp->gp_wq, - READ_ONCE(rsp->gp_flags) & - RCU_GP_FLAG_INIT); + swait_event_idle(rsp->gp_wq, READ_ONCE(rsp->gp_flags) & + RCU_GP_FLAG_INIT); rsp->gp_state = RCU_GP_DONE_GPS; /* Locking provides needed memory barrier. */ if (rcu_gp_init(rsp)) @@ -2239,7 +2238,7 @@ static int __noreturn rcu_gp_kthread(void *arg) READ_ONCE(rsp->gpnum), TPS("fqswait")); rsp->gp_state = RCU_GP_WAIT_FQS; - ret = swait_event_interruptible_timeout(rsp->gp_wq, + ret = swait_event_idle_timeout(rsp->gp_wq, rcu_gp_fqs_check_wake(rsp, &gf), j); rsp->gp_state = RCU_GP_DOING_FQS; /* Locking provides needed memory barriers. */ -- cgit v1.2.3 From d8db2e86d8ba20ef7eb8ba8627129ade40192838 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 27 Jun 2017 13:22:17 -0700 Subject: rcu: Add TPS() protection for _rcu_barrier_trace strings The _rcu_barrier_trace() function is a wrapper for trace_rcu_barrier(), which needs TPS() protection for strings passed through the second argument. However, it has escaped prior TPS()-ification efforts because it _rcu_barrier_trace() does not start with "trace_". This commit therefore adds the needed TPS() protection Signed-off-by: Paul E. McKenney Acked-by: Steven Rostedt (VMware) --- kernel/rcu/tree.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 2b13d9679f57..c1442bea1b5c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3568,10 +3568,11 @@ static void rcu_barrier_callback(struct rcu_head *rhp) struct rcu_state *rsp = rdp->rsp; if (atomic_dec_and_test(&rsp->barrier_cpu_count)) { - _rcu_barrier_trace(rsp, "LastCB", -1, rsp->barrier_sequence); + _rcu_barrier_trace(rsp, TPS("LastCB"), -1, + rsp->barrier_sequence); complete(&rsp->barrier_completion); } else { - _rcu_barrier_trace(rsp, "CB", -1, rsp->barrier_sequence); + _rcu_barrier_trace(rsp, TPS("CB"), -1, rsp->barrier_sequence); } } @@ -3583,14 +3584,15 @@ static void rcu_barrier_func(void *type) struct rcu_state *rsp = type; struct rcu_data *rdp = raw_cpu_ptr(rsp->rda); - _rcu_barrier_trace(rsp, "IRQ", -1, rsp->barrier_sequence); + _rcu_barrier_trace(rsp, TPS("IRQ"), -1, rsp->barrier_sequence); rdp->barrier_head.func = rcu_barrier_callback; debug_rcu_head_queue(&rdp->barrier_head); if (rcu_segcblist_entrain(&rdp->cblist, &rdp->barrier_head, 0)) { atomic_inc(&rsp->barrier_cpu_count); } else { debug_rcu_head_unqueue(&rdp->barrier_head); - _rcu_barrier_trace(rsp, "IRQNQ", -1, rsp->barrier_sequence); + _rcu_barrier_trace(rsp, TPS("IRQNQ"), -1, + rsp->barrier_sequence); } } @@ -3604,14 +3606,15 @@ static void _rcu_barrier(struct rcu_state *rsp) struct rcu_data *rdp; unsigned long s = rcu_seq_snap(&rsp->barrier_sequence); - _rcu_barrier_trace(rsp, "Begin", -1, s); + _rcu_barrier_trace(rsp, TPS("Begin"), -1, s); /* Take mutex to serialize concurrent rcu_barrier() requests. */ mutex_lock(&rsp->barrier_mutex); /* Did someone else do our work for us? */ if (rcu_seq_done(&rsp->barrier_sequence, s)) { - _rcu_barrier_trace(rsp, "EarlyExit", -1, rsp->barrier_sequence); + _rcu_barrier_trace(rsp, TPS("EarlyExit"), -1, + rsp->barrier_sequence); smp_mb(); /* caller's subsequent code after above check. */ mutex_unlock(&rsp->barrier_mutex); return; @@ -3619,7 +3622,7 @@ static void _rcu_barrier(struct rcu_state *rsp) /* Mark the start of the barrier operation. */ rcu_seq_start(&rsp->barrier_sequence); - _rcu_barrier_trace(rsp, "Inc1", -1, rsp->barrier_sequence); + _rcu_barrier_trace(rsp, TPS("Inc1"), -1, rsp->barrier_sequence); /* * Initialize the count to one rather than to zero in order to @@ -3642,10 +3645,10 @@ static void _rcu_barrier(struct rcu_state *rsp) rdp = per_cpu_ptr(rsp->rda, cpu); if (rcu_is_nocb_cpu(cpu)) { if (!rcu_nocb_cpu_needs_barrier(rsp, cpu)) { - _rcu_barrier_trace(rsp, "OfflineNoCB", cpu, + _rcu_barrier_trace(rsp, TPS("OfflineNoCB"), cpu, rsp->barrier_sequence); } else { - _rcu_barrier_trace(rsp, "OnlineNoCB", cpu, + _rcu_barrier_trace(rsp, TPS("OnlineNoCB"), cpu, rsp->barrier_sequence); smp_mb__before_atomic(); atomic_inc(&rsp->barrier_cpu_count); @@ -3653,11 +3656,11 @@ static void _rcu_barrier(struct rcu_state *rsp) rcu_barrier_callback, rsp, cpu, 0); } } else if (rcu_segcblist_n_cbs(&rdp->cblist)) { - _rcu_barrier_trace(rsp, "OnlineQ", cpu, + _rcu_barrier_trace(rsp, TPS("OnlineQ"), cpu, rsp->barrier_sequence); smp_call_function_single(cpu, rcu_barrier_func, rsp, 1); } else { - _rcu_barrier_trace(rsp, "OnlineNQ", cpu, + _rcu_barrier_trace(rsp, TPS("OnlineNQ"), cpu, rsp->barrier_sequence); } } @@ -3674,7 +3677,7 @@ static void _rcu_barrier(struct rcu_state *rsp) wait_for_completion(&rsp->barrier_completion); /* Mark the end of the barrier operation. */ - _rcu_barrier_trace(rsp, "Inc2", -1, rsp->barrier_sequence); + _rcu_barrier_trace(rsp, TPS("Inc2"), -1, rsp->barrier_sequence); rcu_seq_end(&rsp->barrier_sequence); /* Other rcu_barrier() invocations can now safely proceed. */ -- cgit v1.2.3 From 35fe723bda12c25f4ac20a4fb91e345cacf568f7 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 27 Jun 2017 17:41:25 -0700 Subject: rcu/tracing: Set disable_rcu_irq_enter on rcu_eqs_exit() Set disable_rcu_irq_enter on not only rcu_eqs_enter_common() but also rcu_eqs_exit(), since rcu_eqs_exit() suffers from the same issue as was fixed for rcu_eqs_enter_common() by commit 03ecd3f48e57 ("rcu/tracing: Add rcu_disabled to denote when rcu_irq_enter() will not work"). Signed-off-by: Masami Hiramatsu Acked-by: Steven Rostedt (VMware) Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index c1442bea1b5c..2b37f1a8e235 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -955,8 +955,10 @@ static void rcu_eqs_exit(bool user) if (oldval & DYNTICK_TASK_NEST_MASK) { rdtp->dynticks_nesting += DYNTICK_TASK_NEST_VALUE; } else { + __this_cpu_inc(disable_rcu_irq_enter); rdtp->dynticks_nesting = DYNTICK_TASK_EXIT_IDLE; rcu_eqs_exit_common(oldval, user); + __this_cpu_dec(disable_rcu_irq_enter); } } -- cgit v1.2.3 From 2dee9404fa8c4384453a5f3a15ad74ab9480f2d6 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 11 Jul 2017 21:52:31 -0700 Subject: rcu: Add assertions verifying blocked-tasks list This commit adds assertions verifying the consistency of the rcu_node structure's ->blkd_tasks list and its ->gp_tasks, ->exp_tasks, and ->boost_tasks pointers. In particular, the ->blkd_tasks lists must be empty except for leaf rcu_node structures. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 2 ++ kernel/rcu/tree_plugin.h | 11 +++++++++-- 2 files changed, 11 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 2b37f1a8e235..ac2617d857a3 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2410,6 +2410,8 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp, return; } WARN_ON_ONCE(oldmask); /* Any child must be all zeroed! */ + WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1 && + rcu_preempt_blocked_readers_cgp(rnp)); rnp->qsmask &= ~mask; trace_rcu_quiescent_state_report(rsp->name, rnp->gpnum, mask, rnp->qsmask, rnp->level, diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 3e3f92e981a1..eadf8b95b5e9 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -180,6 +180,8 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp) struct task_struct *t = current; lockdep_assert_held(&rnp->lock); + WARN_ON_ONCE(rdp->mynode != rnp); + WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1); /* * Decide where to queue the newly blocked task. In theory, @@ -261,6 +263,10 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp) rnp->gp_tasks = &t->rcu_node_entry; if (!rnp->exp_tasks && (blkd_state & RCU_EXP_BLKD)) rnp->exp_tasks = &t->rcu_node_entry; + WARN_ON_ONCE(!(blkd_state & RCU_GP_BLKD) != + !(rnp->qsmask & rdp->grpmask)); + WARN_ON_ONCE(!(blkd_state & RCU_EXP_BLKD) != + !(rnp->expmask & rdp->grpmask)); raw_spin_unlock_rcu_node(rnp); /* interrupts remain disabled. */ /* @@ -482,6 +488,7 @@ void rcu_read_unlock_special(struct task_struct *t) rnp = t->rcu_blocked_node; raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */ WARN_ON_ONCE(rnp != t->rcu_blocked_node); + WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1); empty_norm = !rcu_preempt_blocked_readers_cgp(rnp); empty_exp = sync_rcu_preempt_exp_done(rnp); smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */ @@ -495,10 +502,10 @@ void rcu_read_unlock_special(struct task_struct *t) if (&t->rcu_node_entry == rnp->exp_tasks) rnp->exp_tasks = np; if (IS_ENABLED(CONFIG_RCU_BOOST)) { - if (&t->rcu_node_entry == rnp->boost_tasks) - rnp->boost_tasks = np; /* Snapshot ->boost_mtx ownership w/rnp->lock held. */ drop_boost_mutex = rt_mutex_owner(&rnp->boost_mtx) == t; + if (&t->rcu_node_entry == rnp->boost_tasks) + rnp->boost_tasks = np; } /* -- cgit v1.2.3 From 3a60799269daff5ed254a9b473a8db6f0f5c6bd9 Mon Sep 17 00:00:00 2001 From: "Peter Zijlstra (Intel)" Date: Wed, 12 Jul 2017 07:59:54 -0700 Subject: rcu: Make rcu_idle_enter() rely on callers disabling irqs All callers to rcu_idle_enter() have irqs disabled, so there is no point in rcu_idle_enter disabling them again. This commit therefore replaces the irq disabling with a RCU_LOCKDEP_WARN(). Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index ac2617d857a3..76f88b65961f 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -843,11 +843,8 @@ static void rcu_eqs_enter(bool user) */ void rcu_idle_enter(void) { - unsigned long flags; - - local_irq_save(flags); + RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_idle_enter() invoked with irqs enabled!!!"); rcu_eqs_enter(false); - local_irq_restore(flags); } EXPORT_SYMBOL_GPL(rcu_idle_enter); -- cgit v1.2.3 From d4db30af51eb94ccfd0037e114c1c12cc299a3f8 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 12 Jul 2017 09:03:35 -0700 Subject: rcu: Add warning to rcu_idle_enter() for irqs enabled All current callers of rcu_idle_enter() have irqs disabled, and rcu_idle_enter() relies on this, but doesn't check. This commit therefore adds a RCU_LOCKDEP_WARN() to add some verification to the trust. While we are there, pass "true" rather than "1" to rcu_eqs_enter(). Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 76f88b65961f..5f4eccac1701 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -859,7 +859,8 @@ EXPORT_SYMBOL_GPL(rcu_idle_enter); */ void rcu_user_enter(void) { - rcu_eqs_enter(1); + RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_user_enter() invoked with irqs enabled!!!"); + rcu_eqs_enter(true); } #endif /* CONFIG_NO_HZ_FULL */ -- cgit v1.2.3 From 16c0b106070f4760f7d1fffb0cd40393552b5294 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 12 Jul 2017 11:55:21 -0700 Subject: rcu: Remove exports from rcu_idle_exit() and rcu_idle_enter() The rcu_idle_exit() and rcu_idle_enter() functions are exported because they were originally used by RCU_NONIDLE(), which was intended to be usable from modules. However, RCU_NONIDLE() now instead uses rcu_irq_enter_irqson() and rcu_irq_exit_irqson(), which are not exported, and there have been no complaints. This commit therefore removes the exports from rcu_idle_exit() and rcu_idle_enter(). Reported-by: Peter Zijlstra Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 5f4eccac1701..7938754faca8 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -846,7 +846,6 @@ void rcu_idle_enter(void) RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_idle_enter() invoked with irqs enabled!!!"); rcu_eqs_enter(false); } -EXPORT_SYMBOL_GPL(rcu_idle_enter); #ifdef CONFIG_NO_HZ_FULL /** @@ -979,7 +978,6 @@ void rcu_idle_exit(void) rcu_eqs_exit(false); local_irq_restore(flags); } -EXPORT_SYMBOL_GPL(rcu_idle_exit); #ifdef CONFIG_NO_HZ_FULL /** -- cgit v1.2.3 From 22e4ebb975822833b083533035233d128b30e98f Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Fri, 28 Jul 2017 16:40:40 -0400 Subject: membarrier: Provide expedited private command Implement MEMBARRIER_CMD_PRIVATE_EXPEDITED with IPIs using cpumask built from all runqueues for which current thread's mm is the same as the thread calling sys_membarrier. It executes faster than the non-expedited variant (no blocking). It also works on NOHZ_FULL configurations. Scheduler-wise, it requires a memory barrier before and after context switching between processes (which have different mm). The memory barrier before context switch is already present. For the barrier after context switch: * Our TSO archs can do RELEASE without being a full barrier. Look at x86 spin_unlock() being a regular STORE for example. But for those archs, all atomics imply smp_mb and all of them have atomic ops in switch_mm() for mm_cpumask(), and on x86 the CR3 load acts as a full barrier. * From all weakly ordered machines, only ARM64 and PPC can do RELEASE, the rest does indeed do smp_mb(), so there the spin_unlock() is a full barrier and we're good. * ARM64 has a very heavy barrier in switch_to(), which suffices. * PPC just removed its barrier from switch_to(), but appears to be talking about adding something to switch_mm(). So add a smp_mb__after_unlock_lock() for now, until this is settled on the PPC side. Changes since v3: - Properly document the memory barriers provided by each architecture. Changes since v2: - Address comments from Peter Zijlstra, - Add smp_mb__after_unlock_lock() after finish_lock_switch() in finish_task_switch() to add the memory barrier we need after storing to rq->curr. This is much simpler than the previous approach relying on atomic_dec_and_test() in mmdrop(), which actually added a memory barrier in the common case of switching between userspace processes. - Return -EINVAL when MEMBARRIER_CMD_SHARED is used on a nohz_full kernel, rather than having the whole membarrier system call returning -ENOSYS. Indeed, CMD_PRIVATE_EXPEDITED is compatible with nohz_full. Adapt the CMD_QUERY mask accordingly. Changes since v1: - move membarrier code under kernel/sched/ because it uses the scheduler runqueue, - only add the barrier when we switch from a kernel thread. The case where we switch from a user-space thread is already handled by the atomic_dec_and_test() in mmdrop(). - add a comment to mmdrop() documenting the requirement on the implicit memory barrier. CC: Peter Zijlstra CC: Paul E. McKenney CC: Boqun Feng CC: Andrew Hunter CC: Maged Michael CC: gromer@google.com CC: Avi Kivity CC: Benjamin Herrenschmidt CC: Paul Mackerras CC: Michael Ellerman Signed-off-by: Mathieu Desnoyers Signed-off-by: Paul E. McKenney Tested-by: Dave Watson --- kernel/Makefile | 1 - kernel/membarrier.c | 70 --------------------- kernel/sched/Makefile | 1 + kernel/sched/core.c | 25 ++++++++ kernel/sched/membarrier.c | 152 ++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 178 insertions(+), 71 deletions(-) delete mode 100644 kernel/membarrier.c create mode 100644 kernel/sched/membarrier.c (limited to 'kernel') diff --git a/kernel/Makefile b/kernel/Makefile index 4cb8e8b23c6e..9c323a6daa46 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -108,7 +108,6 @@ obj-$(CONFIG_CRASH_DUMP) += crash_dump.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o obj-$(CONFIG_TORTURE_TEST) += torture.o -obj-$(CONFIG_MEMBARRIER) += membarrier.o obj-$(CONFIG_HAS_IOMEM) += memremap.o diff --git a/kernel/membarrier.c b/kernel/membarrier.c deleted file mode 100644 index 9f9284f37f8d..000000000000 --- a/kernel/membarrier.c +++ /dev/null @@ -1,70 +0,0 @@ -/* - * Copyright (C) 2010, 2015 Mathieu Desnoyers - * - * membarrier system call - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - */ - -#include -#include -#include - -/* - * Bitmask made from a "or" of all commands within enum membarrier_cmd, - * except MEMBARRIER_CMD_QUERY. - */ -#define MEMBARRIER_CMD_BITMASK (MEMBARRIER_CMD_SHARED) - -/** - * sys_membarrier - issue memory barriers on a set of threads - * @cmd: Takes command values defined in enum membarrier_cmd. - * @flags: Currently needs to be 0. For future extensions. - * - * If this system call is not implemented, -ENOSYS is returned. If the - * command specified does not exist, or if the command argument is invalid, - * this system call returns -EINVAL. For a given command, with flags argument - * set to 0, this system call is guaranteed to always return the same value - * until reboot. - * - * All memory accesses performed in program order from each targeted thread - * is guaranteed to be ordered with respect to sys_membarrier(). If we use - * the semantic "barrier()" to represent a compiler barrier forcing memory - * accesses to be performed in program order across the barrier, and - * smp_mb() to represent explicit memory barriers forcing full memory - * ordering across the barrier, we have the following ordering table for - * each pair of barrier(), sys_membarrier() and smp_mb(): - * - * The pair ordering is detailed as (O: ordered, X: not ordered): - * - * barrier() smp_mb() sys_membarrier() - * barrier() X X O - * smp_mb() X O O - * sys_membarrier() O O O - */ -SYSCALL_DEFINE2(membarrier, int, cmd, int, flags) -{ - /* MEMBARRIER_CMD_SHARED is not compatible with nohz_full. */ - if (tick_nohz_full_enabled()) - return -ENOSYS; - if (unlikely(flags)) - return -EINVAL; - switch (cmd) { - case MEMBARRIER_CMD_QUERY: - return MEMBARRIER_CMD_BITMASK; - case MEMBARRIER_CMD_SHARED: - if (num_online_cpus() > 1) - synchronize_sched(); - return 0; - default: - return -EINVAL; - } -} diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile index 53f0164ed362..78f54932ea1d 100644 --- a/kernel/sched/Makefile +++ b/kernel/sched/Makefile @@ -25,3 +25,4 @@ obj-$(CONFIG_SCHED_DEBUG) += debug.o obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o obj-$(CONFIG_CPU_FREQ) += cpufreq.o obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o +obj-$(CONFIG_MEMBARRIER) += membarrier.o diff --git a/kernel/sched/core.c b/kernel/sched/core.c index bfee6ea7db49..f77269c6c2f8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2640,6 +2640,16 @@ static struct rq *finish_task_switch(struct task_struct *prev) prev_state = prev->state; vtime_task_switch(prev); perf_event_task_sched_in(prev, current); + /* + * The membarrier system call requires a full memory barrier + * after storing to rq->curr, before going back to user-space. + * + * TODO: This smp_mb__after_unlock_lock can go away if PPC end + * up adding a full barrier to switch_mm(), or we should figure + * out if a smp_mb__after_unlock_lock is really the proper API + * to use. + */ + smp_mb__after_unlock_lock(); finish_lock_switch(rq, prev); finish_arch_post_lock_switch(); @@ -3329,6 +3339,21 @@ static void __sched notrace __schedule(bool preempt) if (likely(prev != next)) { rq->nr_switches++; rq->curr = next; + /* + * The membarrier system call requires each architecture + * to have a full memory barrier after updating + * rq->curr, before returning to user-space. For TSO + * (e.g. x86), the architecture must provide its own + * barrier in switch_mm(). For weakly ordered machines + * for which spin_unlock() acts as a full memory + * barrier, finish_lock_switch() in common code takes + * care of this barrier. For weakly ordered machines for + * which spin_unlock() acts as a RELEASE barrier (only + * arm64 and PowerPC), arm64 has a full barrier in + * switch_to(), and PowerPC has + * smp_mb__after_unlock_lock() before + * finish_lock_switch(). + */ ++*switch_count; trace_sched_switch(preempt, prev, next); diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c new file mode 100644 index 000000000000..a92fddc22747 --- /dev/null +++ b/kernel/sched/membarrier.c @@ -0,0 +1,152 @@ +/* + * Copyright (C) 2010-2017 Mathieu Desnoyers + * + * membarrier system call + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include +#include +#include +#include + +#include "sched.h" /* for cpu_rq(). */ + +/* + * Bitmask made from a "or" of all commands within enum membarrier_cmd, + * except MEMBARRIER_CMD_QUERY. + */ +#define MEMBARRIER_CMD_BITMASK \ + (MEMBARRIER_CMD_SHARED | MEMBARRIER_CMD_PRIVATE_EXPEDITED) + +static void ipi_mb(void *info) +{ + smp_mb(); /* IPIs should be serializing but paranoid. */ +} + +static void membarrier_private_expedited(void) +{ + int cpu; + bool fallback = false; + cpumask_var_t tmpmask; + + if (num_online_cpus() == 1) + return; + + /* + * Matches memory barriers around rq->curr modification in + * scheduler. + */ + smp_mb(); /* system call entry is not a mb. */ + + /* + * Expedited membarrier commands guarantee that they won't + * block, hence the GFP_NOWAIT allocation flag and fallback + * implementation. + */ + if (!zalloc_cpumask_var(&tmpmask, GFP_NOWAIT)) { + /* Fallback for OOM. */ + fallback = true; + } + + cpus_read_lock(); + for_each_online_cpu(cpu) { + struct task_struct *p; + + /* + * Skipping the current CPU is OK even through we can be + * migrated at any point. The current CPU, at the point + * where we read raw_smp_processor_id(), is ensured to + * be in program order with respect to the caller + * thread. Therefore, we can skip this CPU from the + * iteration. + */ + if (cpu == raw_smp_processor_id()) + continue; + rcu_read_lock(); + p = task_rcu_dereference(&cpu_rq(cpu)->curr); + if (p && p->mm == current->mm) { + if (!fallback) + __cpumask_set_cpu(cpu, tmpmask); + else + smp_call_function_single(cpu, ipi_mb, NULL, 1); + } + rcu_read_unlock(); + } + if (!fallback) { + smp_call_function_many(tmpmask, ipi_mb, NULL, 1); + free_cpumask_var(tmpmask); + } + cpus_read_unlock(); + + /* + * Memory barrier on the caller thread _after_ we finished + * waiting for the last IPI. Matches memory barriers around + * rq->curr modification in scheduler. + */ + smp_mb(); /* exit from system call is not a mb */ +} + +/** + * sys_membarrier - issue memory barriers on a set of threads + * @cmd: Takes command values defined in enum membarrier_cmd. + * @flags: Currently needs to be 0. For future extensions. + * + * If this system call is not implemented, -ENOSYS is returned. If the + * command specified does not exist, not available on the running + * kernel, or if the command argument is invalid, this system call + * returns -EINVAL. For a given command, with flags argument set to 0, + * this system call is guaranteed to always return the same value until + * reboot. + * + * All memory accesses performed in program order from each targeted thread + * is guaranteed to be ordered with respect to sys_membarrier(). If we use + * the semantic "barrier()" to represent a compiler barrier forcing memory + * accesses to be performed in program order across the barrier, and + * smp_mb() to represent explicit memory barriers forcing full memory + * ordering across the barrier, we have the following ordering table for + * each pair of barrier(), sys_membarrier() and smp_mb(): + * + * The pair ordering is detailed as (O: ordered, X: not ordered): + * + * barrier() smp_mb() sys_membarrier() + * barrier() X X O + * smp_mb() X O O + * sys_membarrier() O O O + */ +SYSCALL_DEFINE2(membarrier, int, cmd, int, flags) +{ + if (unlikely(flags)) + return -EINVAL; + switch (cmd) { + case MEMBARRIER_CMD_QUERY: + { + int cmd_mask = MEMBARRIER_CMD_BITMASK; + + if (tick_nohz_full_enabled()) + cmd_mask &= ~MEMBARRIER_CMD_SHARED; + return cmd_mask; + } + case MEMBARRIER_CMD_SHARED: + /* MEMBARRIER_CMD_SHARED is not compatible with nohz_full. */ + if (tick_nohz_full_enabled()) + return -EINVAL; + if (num_online_cpus() > 1) + synchronize_sched(); + return 0; + case MEMBARRIER_CMD_PRIVATE_EXPEDITED: + membarrier_private_expedited(); + return 0; + default: + return -EINVAL; + } +} -- cgit v1.2.3 From dec13c42d21a96adc5d0d25510d0b59775dfd2ec Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 29 Jun 2017 12:47:04 -0700 Subject: completion: Replace spin_unlock_wait() with lock/unlock pair There is no agreed-upon definition of spin_unlock_wait()'s semantics, and it appears that all callers could do just as well with a lock/unlock pair. This commit therefore replaces the spin_unlock_wait() call in completion_done() with spin_lock() followed immediately by spin_unlock(). This should be safe from a performance perspective because the lock will be held only the wakeup happens really quickly. Signed-off-by: Paul E. McKenney Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Will Deacon Cc: Alan Stern Cc: Andrea Parri Cc: Linus Torvalds Reviewed-by: Steven Rostedt (VMware) --- kernel/sched/completion.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c index 13fc5ae9bf2f..c9524d2d9316 100644 --- a/kernel/sched/completion.c +++ b/kernel/sched/completion.c @@ -300,6 +300,8 @@ EXPORT_SYMBOL(try_wait_for_completion); */ bool completion_done(struct completion *x) { + unsigned long flags; + if (!READ_ONCE(x->done)) return false; @@ -307,14 +309,9 @@ bool completion_done(struct completion *x) * If ->done, we need to wait for complete() to release ->wait.lock * otherwise we can end up freeing the completion before complete() * is done referencing it. - * - * The RMB pairs with complete()'s RELEASE of ->wait.lock and orders - * the loads of ->done and ->wait.lock such that we cannot observe - * the lock before complete() acquires it while observing the ->done - * after it's acquired the lock. */ - smp_rmb(); - spin_unlock_wait(&x->wait.lock); + spin_lock_irqsave(&x->wait.lock, flags); + spin_unlock_irqrestore(&x->wait.lock, flags); return true; } EXPORT_SYMBOL(completion_done); -- cgit v1.2.3 From 8083f29349372d5b949dc022ae9a981edc89ac41 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 29 Jun 2017 12:55:21 -0700 Subject: exit: Replace spin_unlock_wait() with lock/unlock pair There is no agreed-upon definition of spin_unlock_wait()'s semantics, and it appears that all callers could do just as well with a lock/unlock pair. This commit therefore replaces the spin_unlock_wait() call in do_exit() with spin_lock() followed immediately by spin_unlock(). This should be safe from a performance perspective because the lock is a per-task lock, and this is happening only at task-exit time. Signed-off-by: Paul E. McKenney Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Will Deacon Cc: Alan Stern Cc: Andrea Parri Cc: Linus Torvalds --- kernel/exit.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index c5548faa9f37..abfbcf66e5c0 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -819,7 +819,8 @@ void __noreturn do_exit(long code) * Ensure that we must observe the pi_state in exit_mm() -> * mm_release() -> exit_pi_state_list(). */ - raw_spin_unlock_wait(&tsk->pi_lock); + raw_spin_lock_irq(&tsk->pi_lock); + raw_spin_unlock_irq(&tsk->pi_lock); if (unlikely(in_atomic())) { pr_info("note: %s[%d] exited with preempt_count %d\n", -- cgit v1.2.3 From d3a024abbc438277851c510b51ec9b158821488b Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 29 Jun 2017 15:47:44 -0700 Subject: locking: Remove spin_unlock_wait() generic definitions There is no agreed-upon definition of spin_unlock_wait()'s semantics, and it appears that all callers could do just as well with a lock/unlock pair. This commit therefore removes spin_unlock_wait() and related definitions from core code. Signed-off-by: Paul E. McKenney Cc: Arnd Bergmann Cc: Ingo Molnar Cc: Will Deacon Cc: Peter Zijlstra Cc: Alan Stern Cc: Andrea Parri Cc: Linus Torvalds --- kernel/locking/qspinlock.c | 117 --------------------------------------------- 1 file changed, 117 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index fd24153e8a48..294294c71ba4 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -268,123 +268,6 @@ static __always_inline u32 __pv_wait_head_or_lock(struct qspinlock *lock, #define queued_spin_lock_slowpath native_queued_spin_lock_slowpath #endif -/* - * Various notes on spin_is_locked() and spin_unlock_wait(), which are - * 'interesting' functions: - * - * PROBLEM: some architectures have an interesting issue with atomic ACQUIRE - * operations in that the ACQUIRE applies to the LOAD _not_ the STORE (ARM64, - * PPC). Also qspinlock has a similar issue per construction, the setting of - * the locked byte can be unordered acquiring the lock proper. - * - * This gets to be 'interesting' in the following cases, where the /should/s - * end up false because of this issue. - * - * - * CASE 1: - * - * So the spin_is_locked() correctness issue comes from something like: - * - * CPU0 CPU1 - * - * global_lock(); local_lock(i) - * spin_lock(&G) spin_lock(&L[i]) - * for (i) if (!spin_is_locked(&G)) { - * spin_unlock_wait(&L[i]); smp_acquire__after_ctrl_dep(); - * return; - * } - * // deal with fail - * - * Where it is important CPU1 sees G locked or CPU0 sees L[i] locked such - * that there is exclusion between the two critical sections. - * - * The load from spin_is_locked(&G) /should/ be constrained by the ACQUIRE from - * spin_lock(&L[i]), and similarly the load(s) from spin_unlock_wait(&L[i]) - * /should/ be constrained by the ACQUIRE from spin_lock(&G). - * - * Similarly, later stuff is constrained by the ACQUIRE from CTRL+RMB. - * - * - * CASE 2: - * - * For spin_unlock_wait() there is a second correctness issue, namely: - * - * CPU0 CPU1 - * - * flag = set; - * smp_mb(); spin_lock(&l) - * spin_unlock_wait(&l); if (!flag) - * // add to lockless list - * spin_unlock(&l); - * // iterate lockless list - * - * Which wants to ensure that CPU1 will stop adding bits to the list and CPU0 - * will observe the last entry on the list (if spin_unlock_wait() had ACQUIRE - * semantics etc..) - * - * Where flag /should/ be ordered against the locked store of l. - */ - -/* - * queued_spin_lock_slowpath() can (load-)ACQUIRE the lock before - * issuing an _unordered_ store to set _Q_LOCKED_VAL. - * - * This means that the store can be delayed, but no later than the - * store-release from the unlock. This means that simply observing - * _Q_LOCKED_VAL is not sufficient to determine if the lock is acquired. - * - * There are two paths that can issue the unordered store: - * - * (1) clear_pending_set_locked(): *,1,0 -> *,0,1 - * - * (2) set_locked(): t,0,0 -> t,0,1 ; t != 0 - * atomic_cmpxchg_relaxed(): t,0,0 -> 0,0,1 - * - * However, in both cases we have other !0 state we've set before to queue - * ourseves: - * - * For (1) we have the atomic_cmpxchg_acquire() that set _Q_PENDING_VAL, our - * load is constrained by that ACQUIRE to not pass before that, and thus must - * observe the store. - * - * For (2) we have a more intersting scenario. We enqueue ourselves using - * xchg_tail(), which ends up being a RELEASE. This in itself is not - * sufficient, however that is followed by an smp_cond_acquire() on the same - * word, giving a RELEASE->ACQUIRE ordering. This again constrains our load and - * guarantees we must observe that store. - * - * Therefore both cases have other !0 state that is observable before the - * unordered locked byte store comes through. This means we can use that to - * wait for the lock store, and then wait for an unlock. - */ -#ifndef queued_spin_unlock_wait -void queued_spin_unlock_wait(struct qspinlock *lock) -{ - u32 val; - - for (;;) { - val = atomic_read(&lock->val); - - if (!val) /* not locked, we're done */ - goto done; - - if (val & _Q_LOCKED_MASK) /* locked, go wait for unlock */ - break; - - /* not locked, but pending, wait until we observe the lock */ - cpu_relax(); - } - - /* any unlock is good */ - while (atomic_read(&lock->val) & _Q_LOCKED_MASK) - cpu_relax(); - -done: - smp_acquire__after_ctrl_dep(); -} -EXPORT_SYMBOL(queued_spin_unlock_wait); -#endif - #endif /* _GEN_PV_LOCK_SLOWPATH */ /** -- cgit v1.2.3 From 1ab2de2bfed3ab2073ed1e7afa2b1134930d2b70 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 17 Aug 2017 14:59:40 +0200 Subject: bpf: fix liveness propagation to parent in spilled stack slots Using parent->regs[] when propagating REG_LIVE_READ for spilled regs doesn't work since parent->regs[] denote the set of normal registers but not spilled ones. Propagate to the correct regs. Fixes: dc503a8ad984 ("bpf/verifier: track liveness for pruning") Reported-by: Dan Carpenter Signed-off-by: Daniel Borkmann Acked-by: Edward Cree Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 958ba84a9995..40f669ddb571 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3460,7 +3460,7 @@ static bool do_propagate_liveness(const struct bpf_verifier_state *state, if (parent->spilled_regs[i].live & REG_LIVE_READ) continue; if (state->spilled_regs[i].live == REG_LIVE_READ) { - parent->regs[i].live |= REG_LIVE_READ; + parent->spilled_regs[i].live |= REG_LIVE_READ; touched = true; } } -- cgit v1.2.3 From 976d28bfd1f62a3f8e5370c5e7127ff5b3499359 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 17 Aug 2017 17:22:36 +0200 Subject: bpf: don't enable preemption twice in smap_do_verdict In smap_do_verdict(), the fall-through branch leads to call preempt_enable() twice for the SK_REDIRECT, which creates an imbalance. Only enable it for all remaining cases again. Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support") Reported-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/sockmap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index f7e5e6cf124a..39de541fbcdc 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -135,7 +135,8 @@ static void smap_do_verdict(struct smap_psock *psock, struct sk_buff *skb) /* Fall through and free skb otherwise */ case SK_DROP: default: - preempt_enable(); + if (rc != SK_REDIRECT) + preempt_enable(); kfree_skb(skb); } } -- cgit v1.2.3 From a529bea8fa6b6dded6179c72d3385e0f7d0a4fde Mon Sep 17 00:00:00 2001 From: Stafford Horne Date: Wed, 28 Jun 2017 22:21:35 +0900 Subject: timekeeping: Use proper timekeeper for debug code When CONFIG_DEBUG_TIMEKEEPING is enabled the timekeeping_check_update() function will update status like last_warning and underflow_seen on the timekeeper. If there are issues found this state is used to rate limit the warnings that get printed. This rate limiting doesn't really really work if stored in real_tk as the shadow timekeeper is overwritten onto real_tk at the end of every update_wall_time() call, resetting last_warning and other statuses. Fix rate limiting by using the shadow_timekeeper for timekeeping_check_update(). Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Miroslav Lichvar Cc: Richard Cochran Cc: Prarit Bhargava Cc: Stephen Boyd Fixes: commit 57d05a93ada7 ("time: Rework debugging variables so they aren't global") Signed-off-by: Stafford Horne Signed-off-by: John Stultz --- kernel/time/timekeeping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index cedafa008de5..8f5866981883 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -2066,7 +2066,7 @@ void update_wall_time(void) goto out; /* Do some additional sanity checking */ - timekeeping_check_update(real_tk, offset); + timekeeping_check_update(tk, offset); /* * With NO_HZ we may have to accumulate many cycle_intervals -- cgit v1.2.3 From 47b4a457e4cc816b3fdd2ee55c65fda8ea6de051 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 5 Jul 2017 14:08:35 +0200 Subject: alarmtimer: Fix unavailable wake-up source in sysfs Currently the alarmtimer registers a wake-up source unconditionally, regardless of the system having a (wake-up capable) RTC or not. Hence the alarmtimer will always show up in /sys/kernel/debug/wakeup_sources, even if it is not available, and thus cannot be a wake-up source. To fix this, postpone registration until a wake-up capable RTC device is added. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Miroslav Lichvar Cc: Richard Cochran Cc: Prarit Bhargava Cc: Stephen Boyd Signed-off-by: Geert Uytterhoeven Signed-off-by: John Stultz --- kernel/time/alarmtimer.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 0b8ff7d257ea..73a2b476e59f 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -56,9 +56,9 @@ static ktime_t freezer_delta; static DEFINE_SPINLOCK(freezer_delta_lock); #endif +#ifdef CONFIG_RTC_CLASS static struct wakeup_source *ws; -#ifdef CONFIG_RTC_CLASS /* rtc timer and device for setting alarm wakeups at suspend */ static struct rtc_timer rtctimer; static struct rtc_device *rtcdev; @@ -89,6 +89,7 @@ static int alarmtimer_rtc_add_device(struct device *dev, { unsigned long flags; struct rtc_device *rtc = to_rtc_device(dev); + struct wakeup_source *__ws; if (rtcdev) return -EBUSY; @@ -98,13 +99,20 @@ static int alarmtimer_rtc_add_device(struct device *dev, if (!device_may_wakeup(rtc->dev.parent)) return -1; + __ws = wakeup_source_register("alarmtimer"); + spin_lock_irqsave(&rtcdev_lock, flags); if (!rtcdev) { rtcdev = rtc; /* hold a reference so it doesn't go away */ get_device(dev); + ws = __ws; + __ws = NULL; } spin_unlock_irqrestore(&rtcdev_lock, flags); + + wakeup_source_unregister(__ws); + return 0; } @@ -860,7 +868,6 @@ static int __init alarmtimer_init(void) error = PTR_ERR(pdev); goto out_drv; } - ws = wakeup_source_register("alarmtimer"); return 0; out_drv: -- cgit v1.2.3 From c71b02e4d207cbcf097f9746d5f7967b22905e70 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 9 Aug 2017 21:11:00 -0700 Subject: Revert "pstore: Honor dmesg_restrict sysctl on dmesg dumps" This reverts commit 68c4a4f8abc60c9440ede9cd123d48b78325f7a3, with various conflict clean-ups. The capability check required too much privilege compared to simple DAC controls. A system builder was forced to have crash handler processes run with CAP_SYSLOG which would give it the ability to read (and wipe) the _current_ dmesg, which is much more access than being given access only to the historical log stored in pstorefs. With the prior commit to make the root directory 0750, the files are protected by default but a system builder can now opt to give access to a specific group (via chgrp on the pstorefs root directory) without being forced to also give away CAP_SYSLOG. Suggested-by: Nick Kralevich Signed-off-by: Kees Cook Reviewed-by: Petr Mladek Reviewed-by: Sergey Senozhatsky --- kernel/printk/printk.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index fc47863f629c..97bda7b0655b 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -649,7 +649,7 @@ static int syslog_action_restricted(int type) type != SYSLOG_ACTION_SIZE_BUFFER; } -int check_syslog_permissions(int type, int source) +static int check_syslog_permissions(int type, int source) { /* * If this is from /proc/kmsg and we've already opened it, then we've @@ -677,7 +677,6 @@ int check_syslog_permissions(int type, int source) ok: return security_syslog(type); } -EXPORT_SYMBOL_GPL(check_syslog_permissions); static void append_char(char **pp, char *e, char c) { -- cgit v1.2.3 From e2cabe48c20efb174ce0c01190f8b9c5f3ea1d13 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 10 Aug 2017 09:50:55 +0530 Subject: cpufreq: schedutil: Don't restrict kthread to related_cpus unnecessarily Utilization update callbacks are now processed remotely, even on the CPUs that don't share cpufreq policy with the target CPU (if dvfs_possible_from_any_cpu flag is set). But in non-fast switch paths, the frequency is changed only from one of policy->related_cpus. This happens because the kthread which does the actual update is bound to a subset of CPUs (i.e. related_cpus). Allow frequency to be remotely updated as well (i.e. call __cpufreq_driver_target()) if dvfs_possible_from_any_cpu flag is set. Reported-by: Pavan Kondeti Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- kernel/sched/cpufreq_schedutil.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 2ba04bb3182a..69571ee6a175 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -487,7 +487,11 @@ static int sugov_kthread_create(struct sugov_policy *sg_policy) } sg_policy->thread = thread; - kthread_bind_mask(thread, policy->related_cpus); + + /* Kthread is bound to all CPUs by default */ + if (!policy->dvfs_possible_from_any_cpu) + kthread_bind_mask(thread, policy->related_cpus); + init_irq_work(&sg_policy->irq_work, sugov_irq_work); mutex_init(&sg_policy->work_lock); -- cgit v1.2.3 From c49cbc19b31e069cb344921c7286d7549767d10e Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Mon, 14 Aug 2017 14:50:16 +0530 Subject: cpufreq: schedutil: Always process remote callback with slow switching The frequency update from the utilization update handlers can be divided into two parts: (A) Finding the next frequency (B) Updating the frequency While any CPU can do (A), (B) can be restricted to a group of CPUs only, depending on the current platform. For platforms where fast cpufreq switching is possible, both (A) and (B) are always done from the same CPU and that CPU should be capable of changing the frequency of the target CPU. But for platforms where fast cpufreq switching isn't possible, after doing (A) we wake up a kthread which will eventually do (B). This kthread is already bound to the right set of CPUs, i.e. only those which can change the frequency of CPUs of a cpufreq policy. And so any CPU can actually do (A) in this case, as the frequency is updated from the right set of CPUs only. Check cpufreq_can_do_remote_dvfs() only for the fast switching case. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- kernel/sched/cpufreq_schedutil.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 69571ee6a175..a07f17a5f38f 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -84,13 +84,18 @@ static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time) * * However, drivers cannot in general deal with cross-cpu * requests, so while get_next_freq() will work, our - * sugov_update_commit() call may not. + * sugov_update_commit() call may not for the fast switching platforms. * * Hence stop here for remote requests if they aren't supported * by the hardware, as calculating the frequency is pointless if * we cannot in fact act on it. + * + * For the slow switching platforms, the kthread is always scheduled on + * the right set of CPUs and any CPU can find the next frequency and + * schedule the kthread. */ - if (!cpufreq_can_do_remote_dvfs(sg_policy->policy)) + if (sg_policy->policy->fast_switch_enabled && + !cpufreq_can_do_remote_dvfs(sg_policy->policy)) return false; if (sg_policy->work_in_progress) -- cgit v1.2.3 From 726fb6b4f2a82a14a906f39bdabac4863b87c01a Mon Sep 17 00:00:00 2001 From: Srinivas Pandruvada Date: Tue, 15 Aug 2017 18:16:59 -0700 Subject: ACPI / PM: Check low power idle constraints for debug only For SoC to achieve its lowest power platform idle state a set of hardware preconditions must be met. These preconditions or constraints can be obtained by issuing a device specific method (_DSM) with function "1". Refer to the document provided in the link below. Here during initialization (from attach() callback of LPS0 device), invoke function 1 to get the device constraints. Each enabled constraint is stored in a table. The devices in this table are used to check whether they were in required minimum state, while entering suspend. This check is done from platform freeze wake() callback, only when /sys/power/pm_debug_messages attribute is non zero. If any constraint is not met and device is ACPI power managed then it prints the device information to kernel logs. Also if debug is enabled in acpi/sleep.c, the constraint table and state of each device on wake is dumped in kernel logs. Since pm_debug_messages_on setting is used as condition to check constraints outside kernel/power/main.c, pm_debug_messages_on is changed to a global variable. Link: http://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf Signed-off-by: Srinivas Pandruvada Signed-off-by: Rafael J. Wysocki --- kernel/power/main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/power/main.c b/kernel/power/main.c index 3074ea4cec0a..3a2ca9066583 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -361,7 +361,7 @@ static ssize_t pm_wakeup_irq_show(struct kobject *kobj, power_attr_ro(pm_wakeup_irq); -static bool pm_debug_messages_on __read_mostly; +bool pm_debug_messages_on __read_mostly; static ssize_t pm_debug_messages_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) -- cgit v1.2.3 From 536e2e34bd002267384b0668ffff3f023003a830 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 18 Aug 2017 09:11:56 +0100 Subject: genirq/debugfs: Triggering of interrupts from userspace When developing new (and therefore buggy) interrupt related code, it can sometimes be useful to inject interrupts without having to rely on a device to actually generate them. This functionnality relies either on the irqchip driver to expose a irq_set_irqchip_state(IRQCHIP_STATE_PENDING) callback, or on the core code to be able to retrigger a (edge-only) interrupt. To use this feature: echo -n trigger > /sys/kernel/debug/irq/irqs/IRQNUM WARNING: This is DANGEROUS, and strictly a debug feature. Do not use it on a production system. Your HW is likely to catch fire, your data to be corrupted, and reporting this will make you look an even bigger fool than the idiot who wrote this patch. Signed-off-by: Marc Zyngier Signed-off-by: Thomas Gleixner Link: http://lkml.kernel.org/r/20170818081156.9264-1-marc.zyngier@arm.com --- kernel/irq/debugfs.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 49 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c index 4d384edc0c64..c3fdb36dec30 100644 --- a/kernel/irq/debugfs.c +++ b/kernel/irq/debugfs.c @@ -5,6 +5,7 @@ */ #include #include +#include #include "internals.h" @@ -171,8 +172,55 @@ static int irq_debug_open(struct inode *inode, struct file *file) return single_open(file, irq_debug_show, inode->i_private); } +static ssize_t irq_debug_write(struct file *file, const char __user *user_buf, + size_t count, loff_t *ppos) +{ + struct irq_desc *desc = file_inode(file)->i_private; + char buf[8] = { 0, }; + size_t size; + + size = min(sizeof(buf) - 1, count); + if (copy_from_user(buf, user_buf, size)) + return -EFAULT; + + if (!strncmp(buf, "trigger", size)) { + unsigned long flags; + int err; + + /* Try the HW interface first */ + err = irq_set_irqchip_state(irq_desc_get_irq(desc), + IRQCHIP_STATE_PENDING, true); + if (!err) + return count; + + /* + * Otherwise, try to inject via the resend interface, + * which may or may not succeed. + */ + chip_bus_lock(desc); + raw_spin_lock_irqsave(&desc->lock, flags); + + if (irq_settings_is_level(desc)) { + /* Can't do level, sorry */ + err = -EINVAL; + } else { + desc->istate |= IRQS_PENDING; + check_irq_resend(desc); + err = 0; + } + + raw_spin_unlock_irqrestore(&desc->lock, flags); + chip_bus_sync_unlock(desc); + + return err ? err : count; + } + + return count; +} + static const struct file_operations dfs_irq_ops = { .open = irq_debug_open, + .write = irq_debug_write, .read = seq_read, .llseek = seq_lseek, .release = single_release, @@ -186,7 +234,7 @@ void irq_add_debugfs_entry(unsigned int irq, struct irq_desc *desc) return; sprintf(name, "%d", irq); - desc->debugfs_file = debugfs_create_file(name, 0444, irq_dir, desc, + desc->debugfs_file = debugfs_create_file(name, 0644, irq_dir, desc, &dfs_irq_ops); } -- cgit v1.2.3 From 6bc6d4abd22e890cf69a05554fa8f8f83f351515 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 18 Aug 2017 09:39:15 +0100 Subject: genirq/proc: Use the the accessor to report the effective affinity If CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK is defined, but that the interrupt is not single target, the effective affinity reported in /proc/irq/x/effective_affinity will be empty, which is not the truth. Instead, use the accessor to report the affinity, which will pick the right mask. Signed-off-by: Marc Zyngier Signed-off-by: Thomas Gleixner Cc: Andrew Lunn Cc: James Hogan Cc: Jason Cooper Cc: Paul Burton Cc: Chris Zankel Cc: Kevin Cernekee Cc: Wei Xu Cc: Max Filippov Cc: Florian Fainelli Cc: Gregory Clement Cc: Matt Redfearn Cc: Sebastian Hesselbarth Link: http://lkml.kernel.org/r/20170818083925.10108-3-marc.zyngier@arm.com --- kernel/irq/proc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 7f9642a1e267..0534781724d0 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -61,7 +61,7 @@ static int show_irq_affinity(int type, struct seq_file *m) case EFFECTIVE: case EFFECTIVE_LIST: #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK - mask = desc->irq_common_data.effective_affinity; + mask = irq_data_get_effective_affinity_mask(&desc->irq_data); break; #else return -EINVAL; -- cgit v1.2.3 From 65efd9a49af8174b2283fd5b27e9edf30e4483d0 Mon Sep 17 00:00:00 2001 From: David Daney Date: Thu, 17 Aug 2017 17:53:30 -0700 Subject: genirq: Export more irq_chip_*_parent() functions Many of the family of functions including irq_chip_mask_parent(), irq_chip_unmask_parent() are exported, but not all. Add EXPORT_SYMBOL_GPL to irq_chip_enable_parent, irq_chip_disable_parent and irq_chip_set_affinity_parent, so they likewise are usable from modules. Signed-off-by: David Daney Signed-off-by: Thomas Gleixner Cc: Mark Rutland Cc: Alexandre Courbot Cc: Marc Zyngier Cc: Linus Walleij Cc: linux-gpio@vger.kernel.org Link: http://lkml.kernel.org/r/1503017616-3252-2-git-send-email-david.daney@cavium.com --- kernel/irq/chip.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index a3cc37c0c85e..6514f07acaad 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -1105,6 +1105,7 @@ void irq_chip_enable_parent(struct irq_data *data) else data->chip->irq_unmask(data); } +EXPORT_SYMBOL_GPL(irq_chip_enable_parent); /** * irq_chip_disable_parent - Disable the parent interrupt (defaults to mask if @@ -1119,6 +1120,7 @@ void irq_chip_disable_parent(struct irq_data *data) else data->chip->irq_mask(data); } +EXPORT_SYMBOL_GPL(irq_chip_disable_parent); /** * irq_chip_ack_parent - Acknowledge the parent interrupt @@ -1181,6 +1183,7 @@ int irq_chip_set_affinity_parent(struct irq_data *data, return -ENOSYS; } +EXPORT_SYMBOL_GPL(irq_chip_set_affinity_parent); /** * irq_chip_set_type_parent - Set IRQ type on the parent interrupt -- cgit v1.2.3 From 7703b08cc93b3586f9eb733f3a2b10bed634a5cf Mon Sep 17 00:00:00 2001 From: David Daney Date: Thu, 17 Aug 2017 17:53:31 -0700 Subject: genirq: Add handle_fasteoi_{level,edge}_irq flow handlers Follow-on patch for gpio-thunderx uses a irqdomain hierarchy which requires slightly different flow handlers, add them to chip.c which contains most of the other flow handlers. Make these conditionally compiled based on CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS. Signed-off-by: David Daney Signed-off-by: Thomas Gleixner Cc: Mark Rutland Cc: Alexandre Courbot Cc: Marc Zyngier Cc: Linus Walleij Cc: linux-gpio@vger.kernel.org Link: http://lkml.kernel.org/r/1503017616-3252-3-git-send-email-david.daney@cavium.com --- kernel/irq/Kconfig | 4 ++ kernel/irq/chip.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 110 insertions(+) (limited to 'kernel') diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig index 1d06af787932..a117adf7084b 100644 --- a/kernel/irq/Kconfig +++ b/kernel/irq/Kconfig @@ -73,6 +73,10 @@ config IRQ_DOMAIN_HIERARCHY bool select IRQ_DOMAIN +# Support for hierarchical fasteoi+edge and fasteoi+level handlers +config IRQ_FASTEOI_HIERARCHY_HANDLERS + bool + # Generic IRQ IPI support config GENERIC_IRQ_IPI bool diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 6514f07acaad..23958980189d 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -1092,6 +1092,112 @@ void irq_cpu_offline(void) } #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY + +#ifdef CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS +/** + * handle_fasteoi_ack_irq - irq handler for edge hierarchy + * stacked on transparent controllers + * + * @desc: the interrupt description structure for this irq + * + * Like handle_fasteoi_irq(), but for use with hierarchy where + * the irq_chip also needs to have its ->irq_ack() function + * called. + */ +void handle_fasteoi_ack_irq(struct irq_desc *desc) +{ + struct irq_chip *chip = desc->irq_data.chip; + + raw_spin_lock(&desc->lock); + + if (!irq_may_run(desc)) + goto out; + + desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING); + + /* + * If its disabled or no action available + * then mask it and get out of here: + */ + if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) { + desc->istate |= IRQS_PENDING; + mask_irq(desc); + goto out; + } + + kstat_incr_irqs_this_cpu(desc); + if (desc->istate & IRQS_ONESHOT) + mask_irq(desc); + + /* Start handling the irq */ + desc->irq_data.chip->irq_ack(&desc->irq_data); + + preflow_handler(desc); + handle_irq_event(desc); + + cond_unmask_eoi_irq(desc, chip); + + raw_spin_unlock(&desc->lock); + return; +out: + if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED)) + chip->irq_eoi(&desc->irq_data); + raw_spin_unlock(&desc->lock); +} +EXPORT_SYMBOL_GPL(handle_fasteoi_ack_irq); + +/** + * handle_fasteoi_mask_irq - irq handler for level hierarchy + * stacked on transparent controllers + * + * @desc: the interrupt description structure for this irq + * + * Like handle_fasteoi_irq(), but for use with hierarchy where + * the irq_chip also needs to have its ->irq_mask_ack() function + * called. + */ +void handle_fasteoi_mask_irq(struct irq_desc *desc) +{ + struct irq_chip *chip = desc->irq_data.chip; + + raw_spin_lock(&desc->lock); + mask_ack_irq(desc); + + if (!irq_may_run(desc)) + goto out; + + desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING); + + /* + * If its disabled or no action available + * then mask it and get out of here: + */ + if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) { + desc->istate |= IRQS_PENDING; + mask_irq(desc); + goto out; + } + + kstat_incr_irqs_this_cpu(desc); + if (desc->istate & IRQS_ONESHOT) + mask_irq(desc); + + preflow_handler(desc); + handle_irq_event(desc); + + cond_unmask_eoi_irq(desc, chip); + + raw_spin_unlock(&desc->lock); + return; +out: + if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED)) + chip->irq_eoi(&desc->irq_data); + raw_spin_unlock(&desc->lock); +} +EXPORT_SYMBOL_GPL(handle_fasteoi_mask_irq); + +#endif /* CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS */ + /** * irq_chip_enable_parent - Enable the parent interrupt (defaults to unmask if * NULL) -- cgit v1.2.3 From b526adfe1b0531fceba44b18c156e4edf9c6205c Mon Sep 17 00:00:00 2001 From: David Daney Date: Thu, 17 Aug 2017 17:53:32 -0700 Subject: irqdomain: Factor out code to add and remove items to and from the revmap The code to add and remove items to and from the revmap occurs several times. In preparation for the follow on patches that add more uses of this code, factor this out in to separate static functions. Signed-off-by: David Daney Signed-off-by: Thomas Gleixner Reviewed-by: Marc Zyngier Cc: Mark Rutland Cc: Alexandre Courbot Cc: Linus Walleij Cc: linux-gpio@vger.kernel.org Link: http://lkml.kernel.org/r/1503017616-3252-4-git-send-email-david.daney@cavium.com --- kernel/irq/irqdomain.c | 58 +++++++++++++++++++++++++------------------------- 1 file changed, 29 insertions(+), 29 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index f1f251479aa6..2093b88ce9b7 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -455,6 +455,31 @@ void irq_set_default_host(struct irq_domain *domain) } EXPORT_SYMBOL_GPL(irq_set_default_host); +static void irq_domain_clear_mapping(struct irq_domain *domain, + irq_hw_number_t hwirq) +{ + if (hwirq < domain->revmap_size) { + domain->linear_revmap[hwirq] = 0; + } else { + mutex_lock(&revmap_trees_mutex); + radix_tree_delete(&domain->revmap_tree, hwirq); + mutex_unlock(&revmap_trees_mutex); + } +} + +static void irq_domain_set_mapping(struct irq_domain *domain, + irq_hw_number_t hwirq, + struct irq_data *irq_data) +{ + if (hwirq < domain->revmap_size) { + domain->linear_revmap[hwirq] = irq_data->irq; + } else { + mutex_lock(&revmap_trees_mutex); + radix_tree_insert(&domain->revmap_tree, hwirq, irq_data); + mutex_unlock(&revmap_trees_mutex); + } +} + void irq_domain_disassociate(struct irq_domain *domain, unsigned int irq) { struct irq_data *irq_data = irq_get_irq_data(irq); @@ -483,13 +508,7 @@ void irq_domain_disassociate(struct irq_domain *domain, unsigned int irq) domain->mapcount--; /* Clear reverse map for this hwirq */ - if (hwirq < domain->revmap_size) { - domain->linear_revmap[hwirq] = 0; - } else { - mutex_lock(&revmap_trees_mutex); - radix_tree_delete(&domain->revmap_tree, hwirq); - mutex_unlock(&revmap_trees_mutex); - } + irq_domain_clear_mapping(domain, hwirq); } int irq_domain_associate(struct irq_domain *domain, unsigned int virq, @@ -533,13 +552,7 @@ int irq_domain_associate(struct irq_domain *domain, unsigned int virq, } domain->mapcount++; - if (hwirq < domain->revmap_size) { - domain->linear_revmap[hwirq] = virq; - } else { - mutex_lock(&revmap_trees_mutex); - radix_tree_insert(&domain->revmap_tree, hwirq, irq_data); - mutex_unlock(&revmap_trees_mutex); - } + irq_domain_set_mapping(domain, hwirq, irq_data); mutex_unlock(&irq_domain_mutex); irq_clear_status_flags(virq, IRQ_NOREQUEST); @@ -1138,16 +1151,9 @@ static void irq_domain_insert_irq(int virq) for (data = irq_get_irq_data(virq); data; data = data->parent_data) { struct irq_domain *domain = data->domain; - irq_hw_number_t hwirq = data->hwirq; domain->mapcount++; - if (hwirq < domain->revmap_size) { - domain->linear_revmap[hwirq] = virq; - } else { - mutex_lock(&revmap_trees_mutex); - radix_tree_insert(&domain->revmap_tree, hwirq, data); - mutex_unlock(&revmap_trees_mutex); - } + irq_domain_set_mapping(domain, data->hwirq, data); /* If not already assigned, give the domain the chip's name */ if (!domain->name && data->chip) @@ -1171,13 +1177,7 @@ static void irq_domain_remove_irq(int virq) irq_hw_number_t hwirq = data->hwirq; domain->mapcount--; - if (hwirq < domain->revmap_size) { - domain->linear_revmap[hwirq] = 0; - } else { - mutex_lock(&revmap_trees_mutex); - radix_tree_delete(&domain->revmap_tree, hwirq); - mutex_unlock(&revmap_trees_mutex); - } + irq_domain_clear_mapping(domain, hwirq); } } -- cgit v1.2.3 From 0d12ec075a18f53e6f58ec95a4f534da2641bf9b Mon Sep 17 00:00:00 2001 From: David Daney Date: Thu, 17 Aug 2017 17:53:33 -0700 Subject: irqdomain: Check for NULL function pointer in irq_domain_free_irqs_hierarchy() A follow-on patch will call irq_domain_free_irqs_hierarchy() when the free() function pointer may be NULL. Add a NULL pointer check to handle this new use case. Signed-off-by: David Daney Signed-off-by: Thomas Gleixner Reviewed-by: Marc Zyngier Cc: Mark Rutland Cc: Alexandre Courbot Cc: Linus Walleij Cc: linux-gpio@vger.kernel.org Link: http://lkml.kernel.org/r/1503017616-3252-5-git-send-email-david.daney@cavium.com --- kernel/irq/irqdomain.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 2093b88ce9b7..24fda7557cef 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -1362,7 +1362,8 @@ static void irq_domain_free_irqs_hierarchy(struct irq_domain *domain, unsigned int irq_base, unsigned int nr_irqs) { - domain->ops->free(domain, irq_base, nr_irqs); + if (domain->ops->free) + domain->ops->free(domain, irq_base, nr_irqs); } int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain, -- cgit v1.2.3 From 495c38d3001fd226cf91df1d031320f349bcaf35 Mon Sep 17 00:00:00 2001 From: David Daney Date: Thu, 17 Aug 2017 17:53:34 -0700 Subject: irqdomain: Add irq_domain_{push,pop}_irq() functions For an already existing irqdomain hierarchy, as might be obtained via a call to pci_enable_msix_range(), a PCI driver wishing to add an additional irqdomain to the hierarchy needs to be able to insert the irqdomain to that already initialized hierarchy. Calling irq_domain_create_hierarchy() allows the new irqdomain to be created, but no existing code allows for initializing the associated irq_data. Add a couple of helper functions (irq_domain_push_irq() and irq_domain_pop_irq()) to initialize the irq_data for the new irqdomain added to an existing hierarchy. Signed-off-by: David Daney Signed-off-by: Thomas Gleixner Reviewed-by: Marc Zyngier Cc: Mark Rutland Cc: Alexandre Courbot Cc: Linus Walleij Cc: linux-gpio@vger.kernel.org Link: http://lkml.kernel.org/r/1503017616-3252-6-git-send-email-david.daney@cavium.com --- kernel/irq/irqdomain.c | 169 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 169 insertions(+) (limited to 'kernel') diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 24fda7557cef..1ff9912211e9 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -1449,6 +1449,175 @@ out_free_desc: return ret; } +/* The irq_data was moved, fix the revmap to refer to the new location */ +static void irq_domain_fix_revmap(struct irq_data *d) +{ + void **slot; + + if (d->hwirq < d->domain->revmap_size) + return; /* Not using radix tree. */ + + /* Fix up the revmap. */ + mutex_lock(&revmap_trees_mutex); + slot = radix_tree_lookup_slot(&d->domain->revmap_tree, d->hwirq); + if (slot) + radix_tree_replace_slot(&d->domain->revmap_tree, slot, d); + mutex_unlock(&revmap_trees_mutex); +} + +/** + * irq_domain_push_irq() - Push a domain in to the top of a hierarchy. + * @domain: Domain to push. + * @virq: Irq to push the domain in to. + * @arg: Passed to the irq_domain_ops alloc() function. + * + * For an already existing irqdomain hierarchy, as might be obtained + * via a call to pci_enable_msix(), add an additional domain to the + * head of the processing chain. Must be called before request_irq() + * has been called. + */ +int irq_domain_push_irq(struct irq_domain *domain, int virq, void *arg) +{ + struct irq_data *child_irq_data; + struct irq_data *root_irq_data = irq_get_irq_data(virq); + struct irq_desc *desc; + int rv = 0; + + /* + * Check that no action has been set, which indicates the virq + * is in a state where this function doesn't have to deal with + * races between interrupt handling and maintaining the + * hierarchy. This will catch gross misuse. Attempting to + * make the check race free would require holding locks across + * calls to struct irq_domain_ops->alloc(), which could lead + * to deadlock, so we just do a simple check before starting. + */ + desc = irq_to_desc(virq); + if (!desc) + return -EINVAL; + if (WARN_ON(desc->action)) + return -EBUSY; + + if (domain == NULL) + return -EINVAL; + + if (WARN_ON(!irq_domain_is_hierarchy(domain))) + return -EINVAL; + + if (domain->parent != root_irq_data->domain) + return -EINVAL; + + if (!root_irq_data) + return -EINVAL; + + child_irq_data = kzalloc_node(sizeof(*child_irq_data), GFP_KERNEL, + irq_data_get_node(root_irq_data)); + if (!child_irq_data) + return -ENOMEM; + + mutex_lock(&irq_domain_mutex); + + /* Copy the original irq_data. */ + *child_irq_data = *root_irq_data; + + /* + * Overwrite the root_irq_data, which is embedded in struct + * irq_desc, with values for this domain. + */ + root_irq_data->parent_data = child_irq_data; + root_irq_data->domain = domain; + root_irq_data->mask = 0; + root_irq_data->hwirq = 0; + root_irq_data->chip = NULL; + root_irq_data->chip_data = NULL; + + /* May (probably does) set hwirq, chip, etc. */ + rv = irq_domain_alloc_irqs_hierarchy(domain, virq, 1, arg); + if (rv) { + /* Restore the original irq_data. */ + *root_irq_data = *child_irq_data; + goto error; + } + + irq_domain_fix_revmap(child_irq_data); + irq_domain_set_mapping(domain, root_irq_data->hwirq, root_irq_data); + +error: + mutex_unlock(&irq_domain_mutex); + + return rv; +} +EXPORT_SYMBOL_GPL(irq_domain_push_irq); + +/** + * irq_domain_pop_irq() - Remove a domain from the top of a hierarchy. + * @domain: Domain to remove. + * @virq: Irq to remove the domain from. + * + * Undo the effects of a call to irq_domain_push_irq(). Must be + * called either before request_irq() or after free_irq(). + */ +int irq_domain_pop_irq(struct irq_domain *domain, int virq) +{ + struct irq_data *root_irq_data = irq_get_irq_data(virq); + struct irq_data *child_irq_data; + struct irq_data *tmp_irq_data; + struct irq_desc *desc; + + /* + * Check that no action is set, which indicates the virq is in + * a state where this function doesn't have to deal with races + * between interrupt handling and maintaining the hierarchy. + * This will catch gross misuse. Attempting to make the check + * race free would require holding locks across calls to + * struct irq_domain_ops->free(), which could lead to + * deadlock, so we just do a simple check before starting. + */ + desc = irq_to_desc(virq); + if (!desc) + return -EINVAL; + if (WARN_ON(desc->action)) + return -EBUSY; + + if (domain == NULL) + return -EINVAL; + + if (!root_irq_data) + return -EINVAL; + + tmp_irq_data = irq_domain_get_irq_data(domain, virq); + + /* We can only "pop" if this domain is at the top of the list */ + if (WARN_ON(root_irq_data != tmp_irq_data)) + return -EINVAL; + + if (WARN_ON(root_irq_data->domain != domain)) + return -EINVAL; + + child_irq_data = root_irq_data->parent_data; + if (WARN_ON(!child_irq_data)) + return -EINVAL; + + mutex_lock(&irq_domain_mutex); + + root_irq_data->parent_data = NULL; + + irq_domain_clear_mapping(domain, root_irq_data->hwirq); + irq_domain_free_irqs_hierarchy(domain, virq, 1); + + /* Restore the original irq_data. */ + *root_irq_data = *child_irq_data; + + irq_domain_fix_revmap(root_irq_data); + + mutex_unlock(&irq_domain_mutex); + + kfree(child_irq_data); + + return 0; +} +EXPORT_SYMBOL_GPL(irq_domain_pop_irq); + /** * irq_domain_free_irqs - Free IRQ number and associated data structures * @virq: base IRQ number -- cgit v1.2.3 From e8f241893dfbbebe2813c01eac54f263e6a5e59c Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 18 Aug 2017 10:53:45 +0100 Subject: genirq: Restore trigger settings in irq_modify_status() irq_modify_status starts by clearing the trigger settings from irq_data before applying the new settings, but doesn't restore them, leaving them to IRQ_TYPE_NONE. That's pretty confusing to the potential request_irq() that could follow. Instead, snapshot the settings before clearing them, and restore them if the irq_modify_status() invocation was not changing the trigger. Fixes: 1e2a7d78499e ("irqdomain: Don't set type when mapping an IRQ") Reported-and-tested-by: jeffy Signed-off-by: Marc Zyngier Signed-off-by: Thomas Gleixner Cc: Jon Hunter Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20170818095345.12378-1-marc.zyngier@arm.com --- kernel/irq/chip.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index a3cc37c0c85e..3675c6004f2a 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -1000,7 +1000,7 @@ EXPORT_SYMBOL_GPL(irq_set_chip_and_handler_name); void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set) { - unsigned long flags; + unsigned long flags, trigger, tmp; struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0); if (!desc) @@ -1014,6 +1014,8 @@ void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set) irq_settings_clr_and_set(desc, clr, set); + trigger = irqd_get_trigger_type(&desc->irq_data); + irqd_clear(&desc->irq_data, IRQD_NO_BALANCING | IRQD_PER_CPU | IRQD_TRIGGER_MASK | IRQD_LEVEL | IRQD_MOVE_PCNTXT); if (irq_settings_has_no_balance_set(desc)) @@ -1025,7 +1027,11 @@ void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set) if (irq_settings_is_level(desc)) irqd_set(&desc->irq_data, IRQD_LEVEL); - irqd_set(&desc->irq_data, irq_settings_get_trigger_mask(desc)); + tmp = irq_settings_get_trigger_mask(desc); + if (tmp != IRQ_TYPE_NONE) + trigger = tmp; + + irqd_set(&desc->irq_data, trigger); irq_put_desc_unlock(desc, flags); } -- cgit v1.2.3 From 7edaeb6841dfb27e362288ab8466ebdc4972e867 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 15 Aug 2017 09:50:13 +0200 Subject: kernel/watchdog: Prevent false positives with turbo modes The hardlockup detector on x86 uses a performance counter based on unhalted CPU cycles and a periodic hrtimer. The hrtimer period is about 2/5 of the performance counter period, so the hrtimer should fire 2-3 times before the performance counter NMI fires. The NMI code checks whether the hrtimer fired since the last invocation. If not, it assumess a hard lockup. The calculation of those periods is based on the nominal CPU frequency. Turbo modes increase the CPU clock frequency and therefore shorten the period of the perf/NMI watchdog. With extreme Turbo-modes (3x nominal frequency) the perf/NMI period is shorter than the hrtimer period which leads to false positives. A simple fix would be to shorten the hrtimer period, but that comes with the side effect of more frequent hrtimer and softlockup thread wakeups, which is not desired. Implement a low pass filter, which checks the perf/NMI period against kernel time. If the perf/NMI fires before 4/5 of the watchdog period has elapsed then the event is ignored and postponed to the next perf/NMI. That solves the problem and avoids the overhead of shorter hrtimer periods and more frequent softlockup thread wakeups. Fixes: 58687acba592 ("lockup_detector: Combine nmi_watchdog and softlockup detector") Reported-and-tested-by: Kan Liang Signed-off-by: Thomas Gleixner Cc: dzickus@redhat.com Cc: prarit@redhat.com Cc: ak@linux.intel.com Cc: babu.moger@oracle.com Cc: peterz@infradead.org Cc: eranian@google.com Cc: acme@redhat.com Cc: stable@vger.kernel.org Cc: atomlin@redhat.com Cc: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1708150931310.1886@nanos --- kernel/watchdog.c | 1 + kernel/watchdog_hld.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 60 insertions(+) (limited to 'kernel') diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 06d3389bca0d..f5d52024f6b7 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -240,6 +240,7 @@ static void set_sample_period(void) * hardlockup detector generates a warning */ sample_period = get_softlockup_thresh() * ((u64)NSEC_PER_SEC / 5); + watchdog_update_hrtimer_threshold(sample_period); } /* Commands for resetting the watchdog */ diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c index 295a0d84934c..3a09ea1b1d3d 100644 --- a/kernel/watchdog_hld.c +++ b/kernel/watchdog_hld.c @@ -37,6 +37,62 @@ void arch_touch_nmi_watchdog(void) } EXPORT_SYMBOL(arch_touch_nmi_watchdog); +#ifdef CONFIG_HARDLOCKUP_CHECK_TIMESTAMP +static DEFINE_PER_CPU(ktime_t, last_timestamp); +static DEFINE_PER_CPU(unsigned int, nmi_rearmed); +static ktime_t watchdog_hrtimer_sample_threshold __read_mostly; + +void watchdog_update_hrtimer_threshold(u64 period) +{ + /* + * The hrtimer runs with a period of (watchdog_threshold * 2) / 5 + * + * So it runs effectively with 2.5 times the rate of the NMI + * watchdog. That means the hrtimer should fire 2-3 times before + * the NMI watchdog expires. The NMI watchdog on x86 is based on + * unhalted CPU cycles, so if Turbo-Mode is enabled the CPU cycles + * might run way faster than expected and the NMI fires in a + * smaller period than the one deduced from the nominal CPU + * frequency. Depending on the Turbo-Mode factor this might be fast + * enough to get the NMI period smaller than the hrtimer watchdog + * period and trigger false positives. + * + * The sample threshold is used to check in the NMI handler whether + * the minimum time between two NMI samples has elapsed. That + * prevents false positives. + * + * Set this to 4/5 of the actual watchdog threshold period so the + * hrtimer is guaranteed to fire at least once within the real + * watchdog threshold. + */ + watchdog_hrtimer_sample_threshold = period * 2; +} + +static bool watchdog_check_timestamp(void) +{ + ktime_t delta, now = ktime_get_mono_fast_ns(); + + delta = now - __this_cpu_read(last_timestamp); + if (delta < watchdog_hrtimer_sample_threshold) { + /* + * If ktime is jiffies based, a stalled timer would prevent + * jiffies from being incremented and the filter would look + * at a stale timestamp and never trigger. + */ + if (__this_cpu_inc_return(nmi_rearmed) < 10) + return false; + } + __this_cpu_write(nmi_rearmed, 0); + __this_cpu_write(last_timestamp, now); + return true; +} +#else +static inline bool watchdog_check_timestamp(void) +{ + return true; +} +#endif + static struct perf_event_attr wd_hw_attr = { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES, @@ -61,6 +117,9 @@ static void watchdog_overflow_callback(struct perf_event *event, return; } + if (!watchdog_check_timestamp()) + return; + /* check for a hardlockup * This is done by making sure our timer interrupt * is incrementing. The timer interrupt should have -- cgit v1.2.3 From 3cf294962df8fcde710eb5e762e0929e2ba49947 Mon Sep 17 00:00:00 2001 From: Krzysztof Opasiak Date: Wed, 5 Jul 2017 19:25:48 +0200 Subject: posix-cpu-timers: Use dedicated helper to access rlimit values Use rlimit() and rlimit_max() helper instead of manually writing whole chain from task to rlimit value Signed-off-by: Krzysztof Opasiak Signed-off-by: Thomas Gleixner Link: http://lkml.kernel.org/r/20170705172548.7911-1-k.opasiak@samsung.com --- kernel/time/posix-cpu-timers.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index a3bd5dbe0dc4..8585ad6e472a 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -799,7 +799,6 @@ static void check_thread_timers(struct task_struct *tsk, struct list_head *firing) { struct list_head *timers = tsk->cpu_timers; - struct signal_struct *const sig = tsk->signal; struct task_cputime *tsk_expires = &tsk->cputime_expires; u64 expires; unsigned long soft; @@ -823,10 +822,9 @@ static void check_thread_timers(struct task_struct *tsk, /* * Check for the special case thread timers. */ - soft = READ_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_cur); + soft = task_rlimit(tsk, RLIMIT_RTTIME); if (soft != RLIM_INFINITY) { - unsigned long hard = - READ_ONCE(sig->rlim[RLIMIT_RTTIME].rlim_max); + unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME); if (hard != RLIM_INFINITY && tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) { @@ -847,7 +845,8 @@ static void check_thread_timers(struct task_struct *tsk, */ if (soft < hard) { soft += USEC_PER_SEC; - sig->rlim[RLIMIT_RTTIME].rlim_cur = soft; + tsk->signal->rlim[RLIMIT_RTTIME].rlim_cur = + soft; } if (print_fatal_signals) { pr_info("RT Watchdog Timeout (soft): %s[%d]\n", @@ -938,11 +937,10 @@ static void check_process_timers(struct task_struct *tsk, SIGPROF); check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime, SIGVTALRM); - soft = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); + soft = task_rlimit(tsk, RLIMIT_CPU); if (soft != RLIM_INFINITY) { unsigned long psecs = div_u64(ptime, NSEC_PER_SEC); - unsigned long hard = - READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_max); + unsigned long hard = task_rlimit_max(tsk, RLIMIT_CPU); u64 x; if (psecs >= hard) { /* -- cgit v1.2.3 From e1cba4b85daa71b710384d451ff6238d5e4d1ff6 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Thu, 17 Aug 2017 15:33:09 -0400 Subject: cgroup: Add mount flag to enable cpuset to use v2 behavior in v1 cgroup A new mount option "cpuset_v2_mode" is added to the v1 cgroupfs filesystem to enable cpuset controller to use v2 behavior in a v1 cgroup. This mount option applies only to cpuset controller and have no effect on other controllers. Signed-off-by: Waiman Long Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup-v1.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index f0e8601b13cb..024085daab1a 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -895,6 +895,8 @@ static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_roo seq_puts(seq, ",noprefix"); if (root->flags & CGRP_ROOT_XATTR) seq_puts(seq, ",xattr"); + if (root->flags & CGRP_ROOT_CPUSET_V2_MODE) + seq_puts(seq, ",cpuset_v2_mode"); spin_lock(&release_agent_path_lock); if (strlen(root->release_agent_path)) @@ -949,6 +951,10 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) opts->cpuset_clone_children = true; continue; } + if (!strcmp(token, "cpuset_v2_mode")) { + opts->flags |= CGRP_ROOT_CPUSET_V2_MODE; + continue; + } if (!strcmp(token, "xattr")) { opts->flags |= CGRP_ROOT_XATTR; continue; -- cgit v1.2.3 From b8d1b8ee93df8ffbabbeadd65d39853cfad6d698 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Thu, 17 Aug 2017 15:33:10 -0400 Subject: cpuset: Allow v2 behavior in v1 cgroup Cpuset v2 has some useful behaviors that are not present in v1 because of backward compatibility concern. One of that is the restoration of the original cpu and memory node mask after a hot removal and addition event sequence. This patch makes the cpuset controller to check the CGRP_ROOT_CPUSET_V2_MODE flag and use the v2 behavior if it is set. Signed-off-by: Waiman Long Signed-off-by: Tejun Heo --- kernel/cgroup/cpuset.c | 33 ++++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 252d70c9a49b..f3539a41c49d 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -298,6 +298,16 @@ static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn); static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq); +/* + * Cgroup v2 behavior is used when on default hierarchy or the + * cgroup_v2_mode flag is set. + */ +static inline bool is_in_v2_mode(void) +{ + return cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || + (cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE); +} + /* * This is ugly, but preserves the userspace API for existing cpuset * users. If someone tries to mount the "cpuset" filesystem, we @@ -488,8 +498,7 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial) /* On legacy hiearchy, we must be a subset of our parent cpuset. */ ret = -EACCES; - if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && - !is_cpuset_subset(trial, par)) + if (!is_in_v2_mode() && !is_cpuset_subset(trial, par)) goto out; /* @@ -895,8 +904,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus) * If it becomes empty, inherit the effective mask of the * parent, which is guaranteed to have some CPUs. */ - if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && - cpumask_empty(new_cpus)) + if (is_in_v2_mode() && cpumask_empty(new_cpus)) cpumask_copy(new_cpus, parent->effective_cpus); /* Skip the whole subtree if the cpumask remains the same. */ @@ -913,7 +921,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus) cpumask_copy(cp->effective_cpus, new_cpus); spin_unlock_irq(&callback_lock); - WARN_ON(!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && + WARN_ON(!is_in_v2_mode() && !cpumask_equal(cp->cpus_allowed, cp->effective_cpus)); update_tasks_cpumask(cp); @@ -1149,8 +1157,7 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems) * If it becomes empty, inherit the effective mask of the * parent, which is guaranteed to have some MEMs. */ - if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && - nodes_empty(*new_mems)) + if (is_in_v2_mode() && nodes_empty(*new_mems)) *new_mems = parent->effective_mems; /* Skip the whole subtree if the nodemask remains the same. */ @@ -1167,7 +1174,7 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems) cp->effective_mems = *new_mems; spin_unlock_irq(&callback_lock); - WARN_ON(!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && + WARN_ON(!is_in_v2_mode() && !nodes_equal(cp->mems_allowed, cp->effective_mems)); update_tasks_nodemask(cp); @@ -1459,7 +1466,7 @@ static int cpuset_can_attach(struct cgroup_taskset *tset) /* allow moving tasks into an empty cpuset if on default hierarchy */ ret = -ENOSPC; - if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && + if (!is_in_v2_mode() && (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))) goto out_unlock; @@ -1977,7 +1984,7 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) cpuset_inc(); spin_lock_irq(&callback_lock); - if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) { + if (is_in_v2_mode()) { cpumask_copy(cs->effective_cpus, parent->effective_cpus); cs->effective_mems = parent->effective_mems; } @@ -2054,7 +2061,7 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css) mutex_lock(&cpuset_mutex); spin_lock_irq(&callback_lock); - if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) { + if (is_in_v2_mode()) { cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask); top_cpuset.mems_allowed = node_possible_map; } else { @@ -2248,7 +2255,7 @@ retry: cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus); mems_updated = !nodes_equal(new_mems, cs->effective_mems); - if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) + if (is_in_v2_mode()) hotplug_update_tasks(cs, &new_cpus, &new_mems, cpus_updated, mems_updated); else @@ -2279,7 +2286,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work) static cpumask_t new_cpus; static nodemask_t new_mems; bool cpus_updated, mems_updated; - bool on_dfl = cgroup_subsys_on_dfl(cpuset_cgrp_subsys); + bool on_dfl = is_in_v2_mode(); mutex_lock(&cpuset_mutex); -- cgit v1.2.3 From ae2b27b859a144f503d382580320873c0beb09c7 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 18 Aug 2017 10:27:02 +0300 Subject: bpf: fix a return in sockmap_get_from_fd() "map" is a valid pointer. We wanted to return "err" instead. Also let's return a zero literal at the end. Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support") Signed-off-by: Dan Carpenter Acked-by: John Fastabend Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/syscall.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index d2f2bdf71ffa..b8cb1b3c9bfb 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1125,11 +1125,11 @@ static int sockmap_get_from_fd(const union bpf_attr *attr, int ptype) fdput(f); bpf_prog_put(prog1); bpf_prog_put(prog2); - return PTR_ERR(map); + return err; } fdput(f); - return err; + return 0; } static int bpf_prog_attach(const union bpf_attr *attr) -- cgit v1.2.3 From 2ba293c9e7db150943f06b12d3eb7213e7fae624 Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Fri, 18 Aug 2017 15:15:58 -0700 Subject: kmod: fix wait on recursive loop Recursive loops with module loading were previously handled in kmod by restricting the number of modprobe calls to 50 and if that limit was breached request_module() would return an error and a user would see the following on their kernel dmesg: request_module: runaway loop modprobe binfmt-464c Starting init:/sbin/init exists but couldn't execute it (error -8) This issue could happen for instance when a 64-bit kernel boots a 32-bit userspace on some architectures and has no 32-bit binary format hanlders. This is visible, for instance, when a CONFIG_MODULES enabled 64-bit MIPS kernel boots a into o32 root filesystem and the binfmt handler for o32 binaries is not built-in. After commit 6d7964a722af ("kmod: throttle kmod thread limit") we now don't have any visible signs of an error and the kernel just waits for the loop to end somehow. Although this *particular* recursive loop could also be addressed by doing a sanity check on search_binary_handler() and disallowing a modular binfmt to be required for modprobe, a generic solution for any recursive kernel kmod issues is still needed. This should catch these loops. We can investigate each loop and address each one separately as they come in, this however puts a stop gap for them as before. Link: http://lkml.kernel.org/r/20170809234635.13443-3-mcgrof@kernel.org Fixes: 6d7964a722af ("kmod: throttle kmod thread limit") Signed-off-by: Luis R. Rodriguez Reported-by: Matt Redfearn Tested-by: Matt Redfearn Cc: "Eric W. Biederman" Cc: Colin Ian King Cc: Dan Carpenter Cc: Daniel Mentz Cc: David Binderman Cc: Dmitry Torokhov Cc: Ingo Molnar Cc: Jessica Yu Cc: Josh Poimboeuf Cc: Kees Cook Cc: Michal Marek Cc: Miroslav Benes Cc: Peter Zijlstra (Intel) Cc: Petr Mladek Cc: Rusty Russell Cc: Shuah Khan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kmod.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/kmod.c b/kernel/kmod.c index 6d016c5d97c8..2f37acde640b 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -70,6 +70,18 @@ static DECLARE_RWSEM(umhelper_sem); static atomic_t kmod_concurrent_max = ATOMIC_INIT(MAX_KMOD_CONCURRENT); static DECLARE_WAIT_QUEUE_HEAD(kmod_wq); +/* + * This is a restriction on having *all* MAX_KMOD_CONCURRENT threads + * running at the same time without returning. When this happens we + * believe you've somehow ended up with a recursive module dependency + * creating a loop. + * + * We have no option but to fail. + * + * Userspace should proactively try to detect and prevent these. + */ +#define MAX_KMOD_ALL_BUSY_TIMEOUT 5 + /* modprobe_path is set via /proc/sys. */ @@ -167,8 +179,17 @@ int __request_module(bool wait, const char *fmt, ...) pr_warn_ratelimited("request_module: kmod_concurrent_max (%u) close to 0 (max_modprobes: %u), for module %s, throttling...", atomic_read(&kmod_concurrent_max), MAX_KMOD_CONCURRENT, module_name); - wait_event_interruptible(kmod_wq, - atomic_dec_if_positive(&kmod_concurrent_max) >= 0); + ret = wait_event_killable_timeout(kmod_wq, + atomic_dec_if_positive(&kmod_concurrent_max) >= 0, + MAX_KMOD_ALL_BUSY_TIMEOUT * HZ); + if (!ret) { + pr_warn_ratelimited("request_module: modprobe %s cannot be processed, kmod busy with %d threads for more than %d seconds now", + module_name, MAX_KMOD_CONCURRENT, MAX_KMOD_ALL_BUSY_TIMEOUT); + return -ETIME; + } else if (ret == -ERESTARTSYS) { + pr_warn_ratelimited("request_module: sigkill sent for modprobe %s, giving up", module_name); + return ret; + } } trace_module_request(module_name, wait, _RET_IP_); -- cgit v1.2.3 From eb61b5911bdc923875cde99eb25203a0e2b06d43 Mon Sep 17 00:00:00 2001 From: Jamie Iles Date: Fri, 18 Aug 2017 15:16:18 -0700 Subject: signal: don't remove SIGNAL_UNKILLABLE for traced tasks. When forcing a signal, SIGNAL_UNKILLABLE is removed to prevent recursive faults, but this is undesirable when tracing. For example, debugging an init process (whether global or namespace), hitting a breakpoint and SIGTRAP will force SIGTRAP and then remove SIGNAL_UNKILLABLE. Everything continues fine, but then once debugging has finished, the init process is left killable which is unlikely what the user expects, resulting in either an accidentally killed init or an init that stops reaping zombies. Link: http://lkml.kernel.org/r/20170815112806.10728-1-jamie.iles@oracle.com Signed-off-by: Jamie Iles Acked-by: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/signal.c b/kernel/signal.c index 7e33f8c583e6..ed804a470dcd 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1194,7 +1194,11 @@ force_sig_info(int sig, struct siginfo *info, struct task_struct *t) recalc_sigpending_and_wake(t); } } - if (action->sa.sa_handler == SIG_DFL) + /* + * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect + * debugging to leave init killable. + */ + if (action->sa.sa_handler == SIG_DFL && !t->ptrace) t->signal->flags &= ~SIGNAL_UNKILLABLE; ret = specific_send_sig_info(sig, info, t); spin_unlock_irqrestore(&t->sighand->siglock, flags); -- cgit v1.2.3 From 16a4362573782115096799aebd9862f8bb140169 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Thu, 17 Aug 2017 18:14:43 -0700 Subject: bpf: Fix map-in-map checking in the verifier In check_map_func_compatibility(), a 'break' has been accidentally removed for the BPF_MAP_TYPE_ARRAY_OF_MAPS and BPF_MAP_TYPE_HASH_OF_MAPS cases. This patch adds it back. Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support") Cc: John Fastabend Signed-off-by: Martin KaFai Lau Acked-by: Alexei Starovoitov Acked-by: John Fastabend Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 40f669ddb571..4f6e7eb42ba0 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1523,6 +1523,7 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id) case BPF_MAP_TYPE_HASH_OF_MAPS: if (func_id != BPF_FUNC_map_lookup_elem) goto error; + break; case BPF_MAP_TYPE_SOCKMAP: if (func_id != BPF_FUNC_sk_redirect_map && func_id != BPF_FUNC_sock_map_update && -- cgit v1.2.3 From 96eabe7a40aa17e613cf3db2c742ee8b1fc764d0 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Fri, 18 Aug 2017 11:28:00 -0700 Subject: bpf: Allow selecting numa node during map creation The current map creation API does not allow to provide the numa-node preference. The memory usually comes from where the map-creation-process is running. The performance is not ideal if the bpf_prog is known to always run in a numa node different from the map-creation-process. One of the use case is sharding on CPU to different LRU maps (i.e. an array of LRU maps). Here is the test result of map_perf_test on the INNER_LRU_HASH_PREALLOC test if we force the lru map used by CPU0 to be allocated from a remote numa node: [ The machine has 20 cores. CPU0-9 at node 0. CPU10-19 at node 1 ] ># taskset -c 10 ./map_perf_test 512 8 1260000 8000000 5:inner_lru_hash_map_perf pre-alloc 1628380 events per sec 4:inner_lru_hash_map_perf pre-alloc 1626396 events per sec 3:inner_lru_hash_map_perf pre-alloc 1626144 events per sec 6:inner_lru_hash_map_perf pre-alloc 1621657 events per sec 2:inner_lru_hash_map_perf pre-alloc 1621534 events per sec 1:inner_lru_hash_map_perf pre-alloc 1620292 events per sec 7:inner_lru_hash_map_perf pre-alloc 1613305 events per sec 0:inner_lru_hash_map_perf pre-alloc 1239150 events per sec #<<< After specifying numa node: ># taskset -c 10 ./map_perf_test 512 8 1260000 8000000 5:inner_lru_hash_map_perf pre-alloc 1629627 events per sec 3:inner_lru_hash_map_perf pre-alloc 1628057 events per sec 1:inner_lru_hash_map_perf pre-alloc 1623054 events per sec 6:inner_lru_hash_map_perf pre-alloc 1616033 events per sec 2:inner_lru_hash_map_perf pre-alloc 1614630 events per sec 4:inner_lru_hash_map_perf pre-alloc 1612651 events per sec 7:inner_lru_hash_map_perf pre-alloc 1609337 events per sec 0:inner_lru_hash_map_perf pre-alloc 1619340 events per sec #<<< This patch adds one field, numa_node, to the bpf_attr. Since numa node 0 is a valid node, a new flag BPF_F_NUMA_NODE is also added. The numa_node field is honored if and only if the BPF_F_NUMA_NODE flag is set. Numa node selection is not supported for percpu map. This patch does not change all the kmalloc. F.e. 'htab = kzalloc()' is not changed since the object is small enough to stay in the cache. Signed-off-by: Martin KaFai Lau Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/arraymap.c | 7 +++++-- kernel/bpf/devmap.c | 9 ++++++--- kernel/bpf/hashtab.c | 19 +++++++++++++++---- kernel/bpf/lpm_trie.c | 9 +++++++-- kernel/bpf/sockmap.c | 10 +++++++--- kernel/bpf/stackmap.c | 8 +++++--- kernel/bpf/syscall.c | 14 ++++++++++---- 7 files changed, 55 insertions(+), 21 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index d771a3872500..96e9c5c1dfc9 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -49,13 +49,15 @@ static int bpf_array_alloc_percpu(struct bpf_array *array) static struct bpf_map *array_map_alloc(union bpf_attr *attr) { bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY; + int numa_node = bpf_map_attr_numa_node(attr); struct bpf_array *array; u64 array_size; u32 elem_size; /* check sanity of attributes */ if (attr->max_entries == 0 || attr->key_size != 4 || - attr->value_size == 0 || attr->map_flags) + attr->value_size == 0 || attr->map_flags & ~BPF_F_NUMA_NODE || + (percpu && numa_node != NUMA_NO_NODE)) return ERR_PTR(-EINVAL); if (attr->value_size > KMALLOC_MAX_SIZE) @@ -77,7 +79,7 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr) return ERR_PTR(-ENOMEM); /* allocate all map elements and zero-initialize them */ - array = bpf_map_area_alloc(array_size); + array = bpf_map_area_alloc(array_size, numa_node); if (!array) return ERR_PTR(-ENOMEM); @@ -87,6 +89,7 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr) array->map.value_size = attr->value_size; array->map.max_entries = attr->max_entries; array->map.map_flags = attr->map_flags; + array->map.numa_node = numa_node; array->elem_size = elem_size; if (!percpu) diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 18a72a8add43..67f4f00ce33a 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -80,7 +80,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) /* check sanity of attributes */ if (attr->max_entries == 0 || attr->key_size != 4 || - attr->value_size != 4 || attr->map_flags) + attr->value_size != 4 || attr->map_flags & ~BPF_F_NUMA_NODE) return ERR_PTR(-EINVAL); dtab = kzalloc(sizeof(*dtab), GFP_USER); @@ -93,6 +93,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) dtab->map.value_size = attr->value_size; dtab->map.max_entries = attr->max_entries; dtab->map.map_flags = attr->map_flags; + dtab->map.numa_node = bpf_map_attr_numa_node(attr); err = -ENOMEM; @@ -119,7 +120,8 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) goto free_dtab; dtab->netdev_map = bpf_map_area_alloc(dtab->map.max_entries * - sizeof(struct bpf_dtab_netdev *)); + sizeof(struct bpf_dtab_netdev *), + dtab->map.numa_node); if (!dtab->netdev_map) goto free_dtab; @@ -344,7 +346,8 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value, if (!ifindex) { dev = NULL; } else { - dev = kmalloc(sizeof(*dev), GFP_ATOMIC | __GFP_NOWARN); + dev = kmalloc_node(sizeof(*dev), GFP_ATOMIC | __GFP_NOWARN, + map->numa_node); if (!dev) return -ENOMEM; diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 4fb463172aa8..47ae748c3a49 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -18,6 +18,9 @@ #include "bpf_lru_list.h" #include "map_in_map.h" +#define HTAB_CREATE_FLAG_MASK \ + (BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE) + struct bucket { struct hlist_nulls_head head; raw_spinlock_t lock; @@ -138,7 +141,8 @@ static int prealloc_init(struct bpf_htab *htab) if (!htab_is_percpu(htab) && !htab_is_lru(htab)) num_entries += num_possible_cpus(); - htab->elems = bpf_map_area_alloc(htab->elem_size * num_entries); + htab->elems = bpf_map_area_alloc(htab->elem_size * num_entries, + htab->map.numa_node); if (!htab->elems) return -ENOMEM; @@ -233,6 +237,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) */ bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU); bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC); + int numa_node = bpf_map_attr_numa_node(attr); struct bpf_htab *htab; int err, i; u64 cost; @@ -248,7 +253,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) */ return ERR_PTR(-EPERM); - if (attr->map_flags & ~(BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU)) + if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK) /* reserved bits should not be used */ return ERR_PTR(-EINVAL); @@ -258,6 +263,9 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) if (lru && !prealloc) return ERR_PTR(-ENOTSUPP); + if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru)) + return ERR_PTR(-EINVAL); + htab = kzalloc(sizeof(*htab), GFP_USER); if (!htab) return ERR_PTR(-ENOMEM); @@ -268,6 +276,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) htab->map.value_size = attr->value_size; htab->map.max_entries = attr->max_entries; htab->map.map_flags = attr->map_flags; + htab->map.numa_node = numa_node; /* check sanity of attributes. * value_size == 0 may be allowed in the future to use map as a set @@ -346,7 +355,8 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) err = -ENOMEM; htab->buckets = bpf_map_area_alloc(htab->n_buckets * - sizeof(struct bucket)); + sizeof(struct bucket), + htab->map.numa_node); if (!htab->buckets) goto free_htab; @@ -689,7 +699,8 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key, atomic_dec(&htab->count); return ERR_PTR(-E2BIG); } - l_new = kmalloc(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN); + l_new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN, + htab->map.numa_node); if (!l_new) return ERR_PTR(-ENOMEM); } diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c index b09185f0f17d..1b767844a76f 100644 --- a/kernel/bpf/lpm_trie.c +++ b/kernel/bpf/lpm_trie.c @@ -244,7 +244,8 @@ static struct lpm_trie_node *lpm_trie_node_alloc(const struct lpm_trie *trie, if (value) size += trie->map.value_size; - node = kmalloc(size, GFP_ATOMIC | __GFP_NOWARN); + node = kmalloc_node(size, GFP_ATOMIC | __GFP_NOWARN, + trie->map.numa_node); if (!node) return NULL; @@ -405,6 +406,8 @@ static int trie_delete_elem(struct bpf_map *map, void *key) #define LPM_KEY_SIZE_MAX LPM_KEY_SIZE(LPM_DATA_SIZE_MAX) #define LPM_KEY_SIZE_MIN LPM_KEY_SIZE(LPM_DATA_SIZE_MIN) +#define LPM_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_NUMA_NODE) + static struct bpf_map *trie_alloc(union bpf_attr *attr) { struct lpm_trie *trie; @@ -416,7 +419,8 @@ static struct bpf_map *trie_alloc(union bpf_attr *attr) /* check sanity of attributes */ if (attr->max_entries == 0 || - attr->map_flags != BPF_F_NO_PREALLOC || + !(attr->map_flags & BPF_F_NO_PREALLOC) || + attr->map_flags & ~LPM_CREATE_FLAG_MASK || attr->key_size < LPM_KEY_SIZE_MIN || attr->key_size > LPM_KEY_SIZE_MAX || attr->value_size < LPM_VAL_SIZE_MIN || @@ -433,6 +437,7 @@ static struct bpf_map *trie_alloc(union bpf_attr *attr) trie->map.value_size = attr->value_size; trie->map.max_entries = attr->max_entries; trie->map.map_flags = attr->map_flags; + trie->map.numa_node = bpf_map_attr_numa_node(attr); trie->data_size = attr->key_size - offsetof(struct bpf_lpm_trie_key, data); trie->max_prefixlen = trie->data_size * 8; diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 39de541fbcdc..78b2bb9370ac 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -443,7 +443,9 @@ static struct smap_psock *smap_init_psock(struct sock *sock, { struct smap_psock *psock; - psock = kzalloc(sizeof(struct smap_psock), GFP_ATOMIC | __GFP_NOWARN); + psock = kzalloc_node(sizeof(struct smap_psock), + GFP_ATOMIC | __GFP_NOWARN, + stab->map.numa_node); if (!psock) return ERR_PTR(-ENOMEM); @@ -465,7 +467,7 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr) /* check sanity of attributes */ if (attr->max_entries == 0 || attr->key_size != 4 || - attr->value_size != 4 || attr->map_flags) + attr->value_size != 4 || attr->map_flags & ~BPF_F_NUMA_NODE) return ERR_PTR(-EINVAL); if (attr->value_size > KMALLOC_MAX_SIZE) @@ -481,6 +483,7 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr) stab->map.value_size = attr->value_size; stab->map.max_entries = attr->max_entries; stab->map.map_flags = attr->map_flags; + stab->map.numa_node = bpf_map_attr_numa_node(attr); /* make sure page count doesn't overflow */ cost = (u64) stab->map.max_entries * sizeof(struct sock *); @@ -495,7 +498,8 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr) goto free_stab; stab->sock_map = bpf_map_area_alloc(stab->map.max_entries * - sizeof(struct sock *)); + sizeof(struct sock *), + stab->map.numa_node); if (!stab->sock_map) goto free_stab; diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 31147d730abf..135be433e9a0 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -31,7 +31,8 @@ static int prealloc_elems_and_freelist(struct bpf_stack_map *smap) u32 elem_size = sizeof(struct stack_map_bucket) + smap->map.value_size; int err; - smap->elems = bpf_map_area_alloc(elem_size * smap->map.max_entries); + smap->elems = bpf_map_area_alloc(elem_size * smap->map.max_entries, + smap->map.numa_node); if (!smap->elems) return -ENOMEM; @@ -59,7 +60,7 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr) if (!capable(CAP_SYS_ADMIN)) return ERR_PTR(-EPERM); - if (attr->map_flags) + if (attr->map_flags & ~BPF_F_NUMA_NODE) return ERR_PTR(-EINVAL); /* check sanity of attributes */ @@ -75,7 +76,7 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr) if (cost >= U32_MAX - PAGE_SIZE) return ERR_PTR(-E2BIG); - smap = bpf_map_area_alloc(cost); + smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr)); if (!smap) return ERR_PTR(-ENOMEM); @@ -91,6 +92,7 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr) smap->map.map_flags = attr->map_flags; smap->n_buckets = n_buckets; smap->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; + smap->map.numa_node = bpf_map_attr_numa_node(attr); err = bpf_map_precharge_memlock(smap->map.pages); if (err) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index b8cb1b3c9bfb..9378f3ba2cbf 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -105,7 +105,7 @@ static struct bpf_map *find_and_alloc_map(union bpf_attr *attr) return map; } -void *bpf_map_area_alloc(size_t size) +void *bpf_map_area_alloc(size_t size, int numa_node) { /* We definitely need __GFP_NORETRY, so OOM killer doesn't * trigger under memory pressure as we really just want to @@ -115,12 +115,13 @@ void *bpf_map_area_alloc(size_t size) void *area; if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) { - area = kmalloc(size, GFP_USER | flags); + area = kmalloc_node(size, GFP_USER | flags, numa_node); if (area != NULL) return area; } - return __vmalloc(size, GFP_KERNEL | flags, PAGE_KERNEL); + return __vmalloc_node_flags_caller(size, numa_node, GFP_KERNEL | flags, + __builtin_return_address(0)); } void bpf_map_area_free(void *area) @@ -309,10 +310,11 @@ int bpf_map_new_fd(struct bpf_map *map) offsetof(union bpf_attr, CMD##_LAST_FIELD) - \ sizeof(attr->CMD##_LAST_FIELD)) != NULL -#define BPF_MAP_CREATE_LAST_FIELD inner_map_fd +#define BPF_MAP_CREATE_LAST_FIELD numa_node /* called via syscall */ static int map_create(union bpf_attr *attr) { + int numa_node = bpf_map_attr_numa_node(attr); struct bpf_map *map; int err; @@ -320,6 +322,10 @@ static int map_create(union bpf_attr *attr) if (err) return -EINVAL; + if (numa_node != NUMA_NO_NODE && + (numa_node >= nr_node_ids || !node_online(numa_node))) + return -EINVAL; + /* find map type and init map: hashtable vs rbtree vs bloom vs ... */ map = find_and_alloc_map(attr); if (IS_ERR(map)) -- cgit v1.2.3 From 89c63074c2bc25874e4e72406ff15a9a8e3df750 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Sat, 19 Aug 2017 03:12:45 +0200 Subject: bpf: make htab inlining more robust wrt assumptions Commit 9015d2f59535 ("bpf: inline htab_map_lookup_elem()") was making the assumption that a direct call emission to the function __htab_map_lookup_elem() will always work out for JITs. This is currently true since all JITs we have are for 64 bit archs, but in case of 32 bit JITs like upcoming arm32, we get a NULL pointer dereference when executing the call to __htab_map_lookup_elem() since passed arguments are of a different size (due to pointer args) than what we do out of BPF. Guard and thus limit this for now for the current 64 bit JITs only. Reported-by: Shubham Bansal Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 4f6e7eb42ba0..e42c096ba20d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4160,7 +4160,11 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) continue; } - if (ebpf_jit_enabled() && insn->imm == BPF_FUNC_map_lookup_elem) { + /* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup + * handlers are currently limited to 64 bit only. + */ + if (ebpf_jit_enabled() && BITS_PER_LONG == 64 && + insn->imm == BPF_FUNC_map_lookup_elem) { map_ptr = env->insn_aux_data[i + delta].map_ptr; if (map_ptr == BPF_MAP_PTR_POISON || !map_ptr->ops->map_gen_lookup) -- cgit v1.2.3 From 7b0c2a0508b90fce79d3782b2e55d0e8bf6a283e Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Sat, 19 Aug 2017 03:12:46 +0200 Subject: bpf: inline map in map lookup functions for array and htab Avoid two successive functions calls for the map in map lookup, first is the bpf_map_lookup_elem() helper call, and second the callback via map->ops->map_lookup_elem() to get to the map in map implementation. Implementation inlines array and htab flavor for map in map lookups. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/arraymap.c | 26 ++++++++++++++++++++++++++ kernel/bpf/hashtab.c | 17 +++++++++++++++++ 2 files changed, 43 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 96e9c5c1dfc9..98c0f00c3f5e 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -606,6 +606,31 @@ static void *array_of_map_lookup_elem(struct bpf_map *map, void *key) return READ_ONCE(*inner_map); } +static u32 array_of_map_gen_lookup(struct bpf_map *map, + struct bpf_insn *insn_buf) +{ + u32 elem_size = round_up(map->value_size, 8); + struct bpf_insn *insn = insn_buf; + const int ret = BPF_REG_0; + const int map_ptr = BPF_REG_1; + const int index = BPF_REG_2; + + *insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value)); + *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0); + *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5); + if (is_power_of_2(elem_size)) + *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size)); + else + *insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size); + *insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr); + *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0); + *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1); + *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1); + *insn++ = BPF_MOV64_IMM(ret, 0); + + return insn - insn_buf; +} + const struct bpf_map_ops array_of_maps_map_ops = { .map_alloc = array_of_map_alloc, .map_free = array_of_map_free, @@ -615,4 +640,5 @@ const struct bpf_map_ops array_of_maps_map_ops = { .map_fd_get_ptr = bpf_map_fd_get_ptr, .map_fd_put_ptr = bpf_map_fd_put_ptr, .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem, + .map_gen_lookup = array_of_map_gen_lookup, }; diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 47ae748c3a49..ae822de4a90a 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -1322,6 +1322,22 @@ static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key) return READ_ONCE(*inner_map); } +static u32 htab_of_map_gen_lookup(struct bpf_map *map, + struct bpf_insn *insn_buf) +{ + struct bpf_insn *insn = insn_buf; + const int ret = BPF_REG_0; + + *insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__htab_map_lookup_elem); + *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2); + *insn++ = BPF_ALU64_IMM(BPF_ADD, ret, + offsetof(struct htab_elem, key) + + round_up(map->key_size, 8)); + *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0); + + return insn - insn_buf; +} + static void htab_of_map_free(struct bpf_map *map) { bpf_map_meta_free(map->inner_map_meta); @@ -1337,4 +1353,5 @@ const struct bpf_map_ops htab_of_maps_map_ops = { .map_fd_get_ptr = bpf_map_fd_get_ptr, .map_fd_put_ptr = bpf_map_fd_put_ptr, .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem, + .map_gen_lookup = htab_of_map_gen_lookup, }; -- cgit v1.2.3 From 8fbbe2d7cc478d1544f41f2271787c993c23a4f6 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Sat, 19 Aug 2017 12:57:51 +0300 Subject: genirq/ipi: Fixup checks against nr_cpu_ids Valid CPU ids are [0, nr_cpu_ids-1] inclusive. Fixes: 3b8e29a82dd1 ("genirq: Implement ipi_send_mask/single()") Fixes: f9bce791ae2a ("genirq: Add a new function to get IPI reverse mapping") Signed-off-by: Alexey Dobriyan Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20170819095751.GB27864@avx2 --- kernel/irq/ipi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/ipi.c b/kernel/irq/ipi.c index 1a9abc1c8ea0..259a22aa9934 100644 --- a/kernel/irq/ipi.c +++ b/kernel/irq/ipi.c @@ -165,7 +165,7 @@ irq_hw_number_t ipi_get_hwirq(unsigned int irq, unsigned int cpu) struct irq_data *data = irq_get_irq_data(irq); struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : NULL; - if (!data || !ipimask || cpu > nr_cpu_ids) + if (!data || !ipimask || cpu >= nr_cpu_ids) return INVALID_HWIRQ; if (!cpumask_test_cpu(cpu, ipimask)) @@ -195,7 +195,7 @@ static int ipi_send_verify(struct irq_chip *chip, struct irq_data *data, if (!chip->ipi_send_single && !chip->ipi_send_mask) return -EINVAL; - if (cpu > nr_cpu_ids) + if (cpu >= nr_cpu_ids) return -EINVAL; if (dest) { -- cgit v1.2.3 From 274043c6c95636e62f5b2514e78fdba82eb47601 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Mon, 21 Aug 2017 01:48:12 +0200 Subject: bpf: fix double free from dev_map_notification() In the current code, dev_map_free() can still race with dev_map_notification(). In dev_map_free(), we remove dtab from the list of dtabs after we purged all entries from it. However, we don't do xchg() with NULL or the like, so the entry at that point is still pointing to the device. If a unregister notification comes in at the same time, we therefore risk a double-free, since the pointer is still present in the map, and then pushed again to __dev_map_entry_free(). All this is completely unnecessary. Just remove the dtab from the list right before the synchronize_rcu(), so all outstanding readers from the notifier list have finished by then, thus we don't need to deal with this corner case anymore and also wouldn't need to nullify dev entires. This is fine because we iterate over the map releasing all entries and therefore dev references anyway. Fixes: 4cc7b9544b9a ("bpf: devmap fix mutex in rcu critical section") Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/devmap.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 67f4f00ce33a..fa08181d1c3d 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -148,6 +148,11 @@ static void dev_map_free(struct bpf_map *map) * no further reads against netdev_map. It does __not__ ensure pending * flush operations (if any) are complete. */ + + spin_lock(&dev_map_lock); + list_del_rcu(&dtab->list); + spin_unlock(&dev_map_lock); + synchronize_rcu(); /* To ensure all pending flush operations have completed wait for flush @@ -162,10 +167,6 @@ static void dev_map_free(struct bpf_map *map) cpu_relax(); } - /* Although we should no longer have datapath or bpf syscall operations - * at this point we we can still race with netdev notifier, hence the - * lock. - */ for (i = 0; i < dtab->map.max_entries; i++) { struct bpf_dtab_netdev *dev; @@ -180,9 +181,6 @@ static void dev_map_free(struct bpf_map *map) /* At this point bpf program is detached and all pending operations * _must_ be complete */ - spin_lock(&dev_map_lock); - list_del_rcu(&dtab->list); - spin_unlock(&dev_map_lock); free_percpu(dtab->flush_needed); bpf_map_area_free(dtab->netdev_map); kfree(dtab); -- cgit v1.2.3 From dd1c1f2f2028a7b851f701fc6a8ebe39dcb95e7c Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Mon, 21 Aug 2017 17:35:02 +0200 Subject: pids: make task_tgid_nr_ns() safe This was reported many times, and this was even mentioned in commit 52ee2dfdd4f5 ("pids: refactor vnr/nr_ns helpers to make them safe") but somehow nobody bothered to fix the obvious problem: task_tgid_nr_ns() is not safe because task->group_leader points to nowhere after the exiting task passes exit_notify(), rcu_read_lock() can not help. We really need to change __unhash_process() to nullify group_leader, parent, and real_parent, but this needs some cleanups. Until then we can turn task_tgid_nr_ns() into another user of __task_pid_nr_ns() and fix the problem. Reported-by: Troy Kensinger Signed-off-by: Oleg Nesterov Signed-off-by: Linus Torvalds --- kernel/pid.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/pid.c b/kernel/pid.c index c69c30d827e5..020dedbdf066 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -527,8 +527,11 @@ pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type, if (!ns) ns = task_active_pid_ns(current); if (likely(pid_alive(task))) { - if (type != PIDTYPE_PID) + if (type != PIDTYPE_PID) { + if (type == __PIDTYPE_TGID) + type = PIDTYPE_PID; task = task->group_leader; + } nr = pid_nr_ns(rcu_dereference(task->pids[type].pid), ns); } rcu_read_unlock(); @@ -537,12 +540,6 @@ pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type, } EXPORT_SYMBOL(__task_pid_nr_ns); -pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns) -{ - return pid_nr_ns(task_tgid(tsk), ns); -} -EXPORT_SYMBOL(task_tgid_nr_ns); - struct pid_namespace *task_active_pid_ns(struct task_struct *tsk) { return ns_of_pid(task_pid(tsk)); -- cgit v1.2.3 From cd36c3a21a400cac9c457394b9adf94e0027c136 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 23 Aug 2017 00:06:09 +0200 Subject: bpf: fix map value attribute for hash of maps Currently, iproute2's BPF ELF loader works fine with array of maps when retrieving the fd from a pinned node and doing a selfcheck against the provided map attributes from the object file, but we fail to do the same for hash of maps and thus refuse to get the map from pinned node. Reason is that when allocating hash of maps, fd_htab_map_alloc() will set the value size to sizeof(void *), and any user space map creation requests are forced to set 4 bytes as value size. Thus, selfcheck will complain about exposed 8 bytes on 64 bit archs vs. 4 bytes from object file as value size. Contract is that fdinfo or BPF_MAP_GET_FD_BY_ID returns the value size used to create the map. Fix it by handling it the same way as we do for array of maps, which means that we leave value size at 4 bytes and in the allocation phase round up value size to 8 bytes. alloc_htab_elem() needs an adjustment in order to copy rounded up 8 bytes due to bpf_fd_htab_map_update_elem() calling into htab_map_update_elem() with the pointer of the map pointer as value. Unlike array of maps where we just xchg(), we're using the generic htab_map_update_elem() callback also used from helper calls, which published the key/value already on return, so we need to ensure to memcpy() the right size. Fixes: bcc6b1b7ebf8 ("bpf: Add hash of maps support") Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller --- kernel/bpf/hashtab.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index ae822de4a90a..d246905f2bb1 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -662,12 +662,27 @@ static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr, } } +static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab) +{ + return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS && + BITS_PER_LONG == 64; +} + +static u32 htab_size_value(const struct bpf_htab *htab, bool percpu) +{ + u32 size = htab->map.value_size; + + if (percpu || fd_htab_map_needs_adjust(htab)) + size = round_up(size, 8); + return size; +} + static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key, void *value, u32 key_size, u32 hash, bool percpu, bool onallcpus, struct htab_elem *old_elem) { - u32 size = htab->map.value_size; + u32 size = htab_size_value(htab, percpu); bool prealloc = htab_is_prealloc(htab); struct htab_elem *l_new, **pl_new; void __percpu *pptr; @@ -707,9 +722,6 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key, memcpy(l_new->key, key, key_size); if (percpu) { - /* round up value_size to 8 bytes */ - size = round_up(size, 8); - if (prealloc) { pptr = htab_elem_get_ptr(l_new, key_size); } else { @@ -1220,17 +1232,9 @@ const struct bpf_map_ops htab_lru_percpu_map_ops = { static struct bpf_map *fd_htab_map_alloc(union bpf_attr *attr) { - struct bpf_map *map; - if (attr->value_size != sizeof(u32)) return ERR_PTR(-EINVAL); - - /* pointer is stored internally */ - attr->value_size = sizeof(void *); - map = htab_map_alloc(attr); - attr->value_size = sizeof(u32); - - return map; + return htab_map_alloc(attr); } static void fd_htab_map_free(struct bpf_map *map) -- cgit v1.2.3 From 33ba43ed0afc13a29b1314e3e45a9938d310ba13 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 23 Aug 2017 00:06:09 +0200 Subject: bpf: fix map value attribute for hash of maps Currently, iproute2's BPF ELF loader works fine with array of maps when retrieving the fd from a pinned node and doing a selfcheck against the provided map attributes from the object file, but we fail to do the same for hash of maps and thus refuse to get the map from pinned node. Reason is that when allocating hash of maps, fd_htab_map_alloc() will set the value size to sizeof(void *), and any user space map creation requests are forced to set 4 bytes as value size. Thus, selfcheck will complain about exposed 8 bytes on 64 bit archs vs. 4 bytes from object file as value size. Contract is that fdinfo or BPF_MAP_GET_FD_BY_ID returns the value size used to create the map. Fix it by handling it the same way as we do for array of maps, which means that we leave value size at 4 bytes and in the allocation phase round up value size to 8 bytes. alloc_htab_elem() needs an adjustment in order to copy rounded up 8 bytes due to bpf_fd_htab_map_update_elem() calling into htab_map_update_elem() with the pointer of the map pointer as value. Unlike array of maps where we just xchg(), we're using the generic htab_map_update_elem() callback also used from helper calls, which published the key/value already on return, so we need to ensure to memcpy() the right size. Fixes: bcc6b1b7ebf8 ("bpf: Add hash of maps support") Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller --- kernel/bpf/hashtab.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 4fb463172aa8..d11c8181f4c5 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -652,12 +652,27 @@ static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr, } } +static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab) +{ + return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS && + BITS_PER_LONG == 64; +} + +static u32 htab_size_value(const struct bpf_htab *htab, bool percpu) +{ + u32 size = htab->map.value_size; + + if (percpu || fd_htab_map_needs_adjust(htab)) + size = round_up(size, 8); + return size; +} + static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key, void *value, u32 key_size, u32 hash, bool percpu, bool onallcpus, struct htab_elem *old_elem) { - u32 size = htab->map.value_size; + u32 size = htab_size_value(htab, percpu); bool prealloc = htab_is_prealloc(htab); struct htab_elem *l_new, **pl_new; void __percpu *pptr; @@ -696,9 +711,6 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key, memcpy(l_new->key, key, key_size); if (percpu) { - /* round up value_size to 8 bytes */ - size = round_up(size, 8); - if (prealloc) { pptr = htab_elem_get_ptr(l_new, key_size); } else { @@ -1209,17 +1221,9 @@ const struct bpf_map_ops htab_lru_percpu_map_ops = { static struct bpf_map *fd_htab_map_alloc(union bpf_attr *attr) { - struct bpf_map *map; - if (attr->value_size != sizeof(u32)) return ERR_PTR(-EINVAL); - - /* pointer is stored internally */ - attr->value_size = sizeof(void *); - map = htab_map_alloc(attr); - attr->value_size = sizeof(u32); - - return map; + return htab_map_alloc(attr); } static void fd_htab_map_free(struct bpf_map *map) -- cgit v1.2.3 From 9e18d0c82f0c07f2a41898d4adbb698a953403ee Mon Sep 17 00:00:00 2001 From: Martijn Coenen Date: Fri, 28 Jul 2017 13:56:07 +0200 Subject: ANDROID: binder: add hwbinder,vndbinder to BINDER_DEVICES. These will be required going forward. Signed-off-by: Martijn Coenen Cc: stable # 4.11+ Signed-off-by: Greg Kroah-Hartman --- kernel/configs/android-base.config | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/configs/android-base.config b/kernel/configs/android-base.config index d70829033bb7..d3fd428f4b92 100644 --- a/kernel/configs/android-base.config +++ b/kernel/configs/android-base.config @@ -10,6 +10,7 @@ # CONFIG_USELIB is not set CONFIG_ANDROID=y CONFIG_ANDROID_BINDER_IPC=y +CONFIG_ANDROID_BINDER_DEVICES=binder,hwbinder,vndbinder CONFIG_ANDROID_LOW_MEMORY_KILLER=y CONFIG_ARMV8_DEPRECATED=y CONFIG_ASHMEM=y -- cgit v1.2.3 From af4d045ceeca04946d89453206269aea6c338a8e Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 23 Aug 2017 01:47:54 +0200 Subject: bpf: minor cleanups for dev_map Some minor code cleanups, while going over it I also noticed that we're accounting the bitmap only for one CPU currently, so fix that up as well. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/devmap.c | 100 +++++++++++++++++++++------------------------------- 1 file changed, 41 insertions(+), 59 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index fa08181d1c3d..bfecabfd4974 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -48,30 +48,30 @@ * calls will fail at this point. */ #include -#include #include -#include -#include "percpu_freelist.h" -#include "bpf_lru_list.h" -#include "map_in_map.h" struct bpf_dtab_netdev { struct net_device *dev; - int key; - struct rcu_head rcu; struct bpf_dtab *dtab; + unsigned int bit; + struct rcu_head rcu; }; struct bpf_dtab { struct bpf_map map; struct bpf_dtab_netdev **netdev_map; - unsigned long int __percpu *flush_needed; + unsigned long __percpu *flush_needed; struct list_head list; }; static DEFINE_SPINLOCK(dev_map_lock); static LIST_HEAD(dev_map_list); +static u64 dev_map_bitmap_size(const union bpf_attr *attr) +{ + return BITS_TO_LONGS(attr->max_entries) * sizeof(unsigned long); +} + static struct bpf_map *dev_map_alloc(union bpf_attr *attr) { struct bpf_dtab *dtab; @@ -95,11 +95,9 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) dtab->map.map_flags = attr->map_flags; dtab->map.numa_node = bpf_map_attr_numa_node(attr); - err = -ENOMEM; - /* make sure page count doesn't overflow */ cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *); - cost += BITS_TO_LONGS(attr->max_entries) * sizeof(unsigned long); + cost += dev_map_bitmap_size(attr) * num_possible_cpus(); if (cost >= U32_MAX - PAGE_SIZE) goto free_dtab; @@ -110,12 +108,9 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) if (err) goto free_dtab; - err = -ENOMEM; /* A per cpu bitfield with a bit per possible net device */ - dtab->flush_needed = __alloc_percpu( - BITS_TO_LONGS(attr->max_entries) * - sizeof(unsigned long), - __alignof__(unsigned long)); + dtab->flush_needed = __alloc_percpu(dev_map_bitmap_size(attr), + __alignof__(unsigned long)); if (!dtab->flush_needed) goto free_dtab; @@ -128,12 +123,12 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) spin_lock(&dev_map_lock); list_add_tail_rcu(&dtab->list, &dev_map_list); spin_unlock(&dev_map_lock); - return &dtab->map; + return &dtab->map; free_dtab: free_percpu(dtab->flush_needed); kfree(dtab); - return ERR_PTR(err); + return ERR_PTR(-ENOMEM); } static void dev_map_free(struct bpf_map *map) @@ -178,9 +173,6 @@ static void dev_map_free(struct bpf_map *map) kfree(dev); } - /* At this point bpf program is detached and all pending operations - * _must_ be complete - */ free_percpu(dtab->flush_needed); bpf_map_area_free(dtab->netdev_map); kfree(dtab); @@ -190,7 +182,7 @@ static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key) { struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); u32 index = key ? *(u32 *)key : U32_MAX; - u32 *next = (u32 *)next_key; + u32 *next = next_key; if (index >= dtab->map.max_entries) { *next = 0; @@ -199,29 +191,16 @@ static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key) if (index == dtab->map.max_entries - 1) return -ENOENT; - *next = index + 1; return 0; } -void __dev_map_insert_ctx(struct bpf_map *map, u32 key) +void __dev_map_insert_ctx(struct bpf_map *map, u32 bit) { struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); unsigned long *bitmap = this_cpu_ptr(dtab->flush_needed); - __set_bit(key, bitmap); -} - -struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key) -{ - struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); - struct bpf_dtab_netdev *dev; - - if (key >= map->max_entries) - return NULL; - - dev = READ_ONCE(dtab->netdev_map[key]); - return dev ? dev->dev : NULL; + __set_bit(bit, bitmap); } /* __dev_map_flush is called from xdp_do_flush_map() which _must_ be signaled @@ -248,7 +227,6 @@ void __dev_map_flush(struct bpf_map *map) continue; netdev = dev->dev; - __clear_bit(bit, bitmap); if (unlikely(!netdev || !netdev->netdev_ops->ndo_xdp_flush)) continue; @@ -261,43 +239,49 @@ void __dev_map_flush(struct bpf_map *map) * update happens in parallel here a dev_put wont happen until after reading the * ifindex. */ -static void *dev_map_lookup_elem(struct bpf_map *map, void *key) +struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key) { struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); struct bpf_dtab_netdev *dev; - u32 i = *(u32 *)key; - if (i >= map->max_entries) + if (key >= map->max_entries) return NULL; - dev = READ_ONCE(dtab->netdev_map[i]); - return dev ? &dev->dev->ifindex : NULL; + dev = READ_ONCE(dtab->netdev_map[key]); + return dev ? dev->dev : NULL; } -static void dev_map_flush_old(struct bpf_dtab_netdev *old_dev) +static void *dev_map_lookup_elem(struct bpf_map *map, void *key) +{ + struct net_device *dev = __dev_map_lookup_elem(map, *(u32 *)key); + + return dev ? &dev->ifindex : NULL; +} + +static void dev_map_flush_old(struct bpf_dtab_netdev *dev) { - if (old_dev->dev->netdev_ops->ndo_xdp_flush) { - struct net_device *fl = old_dev->dev; + if (dev->dev->netdev_ops->ndo_xdp_flush) { + struct net_device *fl = dev->dev; unsigned long *bitmap; int cpu; for_each_online_cpu(cpu) { - bitmap = per_cpu_ptr(old_dev->dtab->flush_needed, cpu); - __clear_bit(old_dev->key, bitmap); + bitmap = per_cpu_ptr(dev->dtab->flush_needed, cpu); + __clear_bit(dev->bit, bitmap); - fl->netdev_ops->ndo_xdp_flush(old_dev->dev); + fl->netdev_ops->ndo_xdp_flush(dev->dev); } } } static void __dev_map_entry_free(struct rcu_head *rcu) { - struct bpf_dtab_netdev *old_dev; + struct bpf_dtab_netdev *dev; - old_dev = container_of(rcu, struct bpf_dtab_netdev, rcu); - dev_map_flush_old(old_dev); - dev_put(old_dev->dev); - kfree(old_dev); + dev = container_of(rcu, struct bpf_dtab_netdev, rcu); + dev_map_flush_old(dev); + dev_put(dev->dev); + kfree(dev); } static int dev_map_delete_elem(struct bpf_map *map, void *key) @@ -309,8 +293,8 @@ static int dev_map_delete_elem(struct bpf_map *map, void *key) if (k >= map->max_entries) return -EINVAL; - /* Use synchronize_rcu() here to ensure any rcu critical sections - * have completed, but this does not guarantee a flush has happened + /* Use call_rcu() here to ensure any rcu critical sections have + * completed, but this does not guarantee a flush has happened * yet. Because driver side rcu_read_lock/unlock only protects the * running XDP program. However, for pending flush operations the * dev and ctx are stored in another per cpu map. And additionally, @@ -334,10 +318,8 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value, if (unlikely(map_flags > BPF_EXIST)) return -EINVAL; - if (unlikely(i >= dtab->map.max_entries)) return -E2BIG; - if (unlikely(map_flags == BPF_NOEXIST)) return -EEXIST; @@ -355,7 +337,7 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value, return -EINVAL; } - dev->key = i; + dev->bit = i; dev->dtab = dtab; } -- cgit v1.2.3 From 0abce64a55ae44d39b92f8e672736f4f324e610f Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 23 Jun 2017 21:42:57 +0100 Subject: genirq: Let irq_set_vcpu_affinity() iterate over hierarchy When assigning an interrupt to a vcpu, it is not unlikely that the level of the hierarchy implementing irq_set_vcpu_affinity is not the top level (think a generic MSI domain on top of a virtualization aware interrupt controller). In such a case, let's iterate over the hierarchy until we find an irqchip implementing it. Reviewed-by: Thomas Gleixner Signed-off-by: Marc Zyngier --- kernel/irq/manage.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 1d1a5b945ab4..573dc52b0806 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -400,8 +400,18 @@ int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info) return -EINVAL; data = irq_desc_get_irq_data(desc); - chip = irq_data_get_irq_chip(data); - if (chip && chip->irq_set_vcpu_affinity) + do { + chip = irq_data_get_irq_chip(data); + if (chip && chip->irq_set_vcpu_affinity) + break; +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY + data = data->parent_data; +#else + data = NULL; +#endif + } while (data); + + if (data) ret = chip->irq_set_vcpu_affinity(data, vcpu_info); irq_put_desc_unlock(desc, flags); -- cgit v1.2.3 From c5a94a618e7ac86b20f53d947f68d7cee6a4c6bc Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 23 Aug 2017 13:58:44 +0200 Subject: workqueue: Use TASK_IDLE Workqueues don't use signals, it (ab)uses TASK_INTERRUPTIBLE to avoid increasing the loadavg numbers. We've 'recently' introduced TASK_IDLE for this case: 80ed87c8a9ca ("sched/wait: Introduce TASK_NOLOAD and TASK_IDLE") use it. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Tejun Heo --- kernel/workqueue.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 4fa6c7650f09..2d278b9a5469 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2247,7 +2247,7 @@ sleep: * event. */ worker_enter_idle(worker); - __set_current_state(TASK_INTERRUPTIBLE); + __set_current_state(TASK_IDLE); spin_unlock_irq(&pool->lock); schedule(); goto woke_up; @@ -2289,7 +2289,7 @@ static int rescuer_thread(void *__rescuer) */ rescuer->task->flags |= PF_WQ_WORKER; repeat: - set_current_state(TASK_INTERRUPTIBLE); + set_current_state(TASK_IDLE); /* * By the time the rescuer is requested to stop, the workqueue -- cgit v1.2.3 From 74d46992e0d9dee7f1f376de0d56d31614c8a17a Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 23 Aug 2017 19:10:32 +0200 Subject: block: replace bi_bdev with a gendisk pointer and partitions index This way we don't need a block_device structure to submit I/O. The block_device has different life time rules from the gendisk and request_queue and is usually only available when the block device node is open. Other callers need to explicitly create one (e.g. the lightnvm passthrough code, or the new nvme multipathing code). For the actual I/O path all that we need is the gendisk, which exists once per block device. But given that the block layer also does partition remapping we additionally need a partition index, which is used for said remapping in generic_make_request. Note that all the block drivers generally want request_queue or sometimes the gendisk, so this removes a layer of indirection all over the stack. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- kernel/power/swap.c | 5 ++--- kernel/trace/blktrace.c | 2 +- 2 files changed, 3 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/power/swap.c b/kernel/power/swap.c index 57d22571f306..d7cdc426ee38 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -242,8 +242,7 @@ static void hib_end_io(struct bio *bio) if (bio->bi_status) { printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n", - imajor(bio->bi_bdev->bd_inode), - iminor(bio->bi_bdev->bd_inode), + MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)), (unsigned long long)bio->bi_iter.bi_sector); } @@ -270,7 +269,7 @@ static int hib_submit_io(int op, int op_flags, pgoff_t page_off, void *addr, bio = bio_alloc(__GFP_RECLAIM | __GFP_HIGH, 1); bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9); - bio->bi_bdev = hib_resume_bdev; + bio_set_dev(bio, hib_resume_bdev); bio_set_op_attrs(bio, op, op_flags); if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) { diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 7724de18d2fe..2a685b45b73b 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -963,7 +963,7 @@ static void blk_add_trace_bio_remap(void *ignore, return; r.device_from = cpu_to_be32(dev); - r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev); + r.device_to = cpu_to_be32(bio_dev(bio)); r.sector_from = cpu_to_be64(from); __blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size, -- cgit v1.2.3 From 63f45f840634ab5fd71bbc07acff915277764068 Mon Sep 17 00:00:00 2001 From: Edward Cree Date: Wed, 23 Aug 2017 15:10:03 +0100 Subject: bpf/verifier: when pruning a branch, ignore its write marks The fact that writes occurred in reaching the continuation state does not screen off its reads from us, because we're not really its parent. So detect 'not really the parent' in do_propagate_liveness, and ignore write marks in that case. Fixes: dc503a8ad984 ("bpf/verifier: track liveness for pruning") Signed-off-by: Edward Cree Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index e42c096ba20d..fdbaa6086559 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3436,6 +3436,7 @@ out_free: static bool do_propagate_liveness(const struct bpf_verifier_state *state, struct bpf_verifier_state *parent) { + bool writes = parent == state->parent; /* Observe write marks */ bool touched = false; /* any changes made? */ int i; @@ -3447,7 +3448,9 @@ static bool do_propagate_liveness(const struct bpf_verifier_state *state, for (i = 0; i < BPF_REG_FP; i++) { if (parent->regs[i].live & REG_LIVE_READ) continue; - if (state->regs[i].live == REG_LIVE_READ) { + if (writes && (state->regs[i].live & REG_LIVE_WRITTEN)) + continue; + if (state->regs[i].live & REG_LIVE_READ) { parent->regs[i].live |= REG_LIVE_READ; touched = true; } @@ -3460,7 +3463,9 @@ static bool do_propagate_liveness(const struct bpf_verifier_state *state, continue; if (parent->spilled_regs[i].live & REG_LIVE_READ) continue; - if (state->spilled_regs[i].live == REG_LIVE_READ) { + if (writes && (state->spilled_regs[i].live & REG_LIVE_WRITTEN)) + continue; + if (state->spilled_regs[i].live & REG_LIVE_READ) { parent->spilled_regs[i].live |= REG_LIVE_READ; touched = true; } -- cgit v1.2.3 From 1b688a19a92223cf2d1892c9d05d64dc397b33e3 Mon Sep 17 00:00:00 2001 From: Edward Cree Date: Wed, 23 Aug 2017 15:10:50 +0100 Subject: bpf/verifier: remove varlen_map_value_access flag The optimisation it does is broken when the 'new' register value has a variable offset and the 'old' was constant. I broke it with my pointer types unification (see Fixes tag below), before which the 'new' value would have type PTR_TO_MAP_VALUE_ADJ and would thus not compare equal; other changes in that patch mean that its original behaviour (ignore min/max values) cannot be restored. Tests on a sample set of cilium programs show no change in count of processed instructions. Fixes: f1174f77b50c ("bpf/verifier: rework value tracking") Signed-off-by: Edward Cree Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 41 ++++++++++++----------------------------- 1 file changed, 12 insertions(+), 29 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index fdbaa6086559..711bdbd22cea 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -832,11 +832,6 @@ static int check_map_access(struct bpf_verifier_env *env, u32 regno, */ if (log_level) print_verifier_state(state); - /* If the offset is variable, we will need to be stricter in state - * pruning from now on. - */ - if (!tnum_is_const(reg->var_off)) - env->varlen_map_value_access = true; /* The minimum value is only important with signed * comparisons where we can't assume the floor of a * value is 0. If we are using signed variables for our @@ -3247,9 +3242,8 @@ static bool check_ids(u32 old_id, u32 cur_id, struct idpair *idmap) } /* Returns true if (rold safe implies rcur safe) */ -static bool regsafe(struct bpf_reg_state *rold, - struct bpf_reg_state *rcur, - bool varlen_map_access, struct idpair *idmap) +static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur, + struct idpair *idmap) { if (!(rold->live & REG_LIVE_READ)) /* explored state didn't use this */ @@ -3281,22 +3275,14 @@ static bool regsafe(struct bpf_reg_state *rold, tnum_is_unknown(rold->var_off); } case PTR_TO_MAP_VALUE: - if (varlen_map_access) { - /* If the new min/max/var_off satisfy the old ones and - * everything else matches, we are OK. - * We don't care about the 'id' value, because nothing - * uses it for PTR_TO_MAP_VALUE (only for ..._OR_NULL) - */ - return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 && - range_within(rold, rcur) && - tnum_in(rold->var_off, rcur->var_off); - } else { - /* If the ranges/var_off were not the same, but - * everything else was and we didn't do a variable - * access into a map then we are a-ok. - */ - return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0; - } + /* If the new min/max/var_off satisfy the old ones and + * everything else matches, we are OK. + * We don't care about the 'id' value, because nothing + * uses it for PTR_TO_MAP_VALUE (only for ..._OR_NULL) + */ + return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 && + range_within(rold, rcur) && + tnum_in(rold->var_off, rcur->var_off); case PTR_TO_MAP_VALUE_OR_NULL: /* a PTR_TO_MAP_VALUE could be safe to use as a * PTR_TO_MAP_VALUE_OR_NULL into the same map. @@ -3380,7 +3366,6 @@ static bool states_equal(struct bpf_verifier_env *env, struct bpf_verifier_state *old, struct bpf_verifier_state *cur) { - bool varlen_map_access = env->varlen_map_value_access; struct idpair *idmap; bool ret = false; int i; @@ -3391,8 +3376,7 @@ static bool states_equal(struct bpf_verifier_env *env, return false; for (i = 0; i < MAX_BPF_REG; i++) { - if (!regsafe(&old->regs[i], &cur->regs[i], varlen_map_access, - idmap)) + if (!regsafe(&old->regs[i], &cur->regs[i], idmap)) goto out_free; } @@ -3412,7 +3396,7 @@ static bool states_equal(struct bpf_verifier_env *env, continue; if (!regsafe(&old->spilled_regs[i / BPF_REG_SIZE], &cur->spilled_regs[i / BPF_REG_SIZE], - varlen_map_access, idmap)) + idmap)) /* when explored and current stack slot are both storing * spilled registers, check that stored pointers types * are the same as well. @@ -3555,7 +3539,6 @@ static int do_check(struct bpf_verifier_env *env) init_reg_state(regs); state->parent = NULL; insn_idx = 0; - env->varlen_map_value_access = false; for (;;) { struct bpf_insn *insn; u8 class; -- cgit v1.2.3 From 8e9cd9ce90d48369b2c5ddd79fe3d4a4cb1ccb56 Mon Sep 17 00:00:00 2001 From: Edward Cree Date: Wed, 23 Aug 2017 15:11:21 +0100 Subject: bpf/verifier: document liveness analysis The liveness tracking algorithm is quite subtle; add comments to explain it. Signed-off-by: Edward Cree Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 711bdbd22cea..d690c7dd1f1a 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3417,6 +3417,12 @@ out_free: return ret; } +/* A write screens off any subsequent reads; but write marks come from the + * straight-line code between a state and its parent. When we arrive at a + * jump target (in the first iteration of the propagate_liveness() loop), + * we didn't arrive by the straight-line code, so read marks in state must + * propagate to parent regardless of state's write marks. + */ static bool do_propagate_liveness(const struct bpf_verifier_state *state, struct bpf_verifier_state *parent) { @@ -3457,6 +3463,15 @@ static bool do_propagate_liveness(const struct bpf_verifier_state *state, return touched; } +/* "parent" is "a state from which we reach the current state", but initially + * it is not the state->parent (i.e. "the state whose straight-line code leads + * to the current state"), instead it is the state that happened to arrive at + * a (prunable) equivalent of the current state. See comment above + * do_propagate_liveness() for consequences of this. + * This function is just a more efficient way of calling mark_reg_read() or + * mark_stack_slot_read() on each reg in "parent" that is read in "state", + * though it requires that parent != state->parent in the call arguments. + */ static void propagate_liveness(const struct bpf_verifier_state *state, struct bpf_verifier_state *parent) { @@ -3485,6 +3500,12 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) /* reached equivalent register/stack state, * prune the search. * Registers read by the continuation are read by us. + * If we have any write marks in env->cur_state, they + * will prevent corresponding reads in the continuation + * from reaching our parent (an explored_state). Our + * own state will get the read marks recorded, but + * they'll be immediately forgotten as we're pruning + * this state and will pop a new one. */ propagate_liveness(&sl->state, &env->cur_state); return 1; @@ -3508,7 +3529,12 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) env->explored_states[insn_idx] = new_sl; /* connect new state to parentage chain */ env->cur_state.parent = &new_sl->state; - /* clear liveness marks in current state */ + /* clear write marks in current state: the writes we did are not writes + * our child did, so they don't screen off its reads from us. + * (There are no read marks in current state, because reads always mark + * their parent and current state never has children yet. Only + * explored_states can get read marks.) + */ for (i = 0; i < BPF_REG_FP; i++) env->cur_state.regs[i].live = REG_LIVE_NONE; for (i = 0; i < MAX_BPF_STACK / BPF_REG_SIZE; i++) -- cgit v1.2.3 From a5e2da6e9787187ff104c34aa048419703c1f9cb Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 24 Aug 2017 03:20:11 +0200 Subject: bpf: netdev is never null in __dev_map_flush No need to test for it in fast-path, every dev in bpf_dtab_netdev is guaranteed to be non-NULL, otherwise dev_map_update_elem() will fail in the first place. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Acked-by: John Fastabend Signed-off-by: David S. Miller --- kernel/bpf/devmap.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index bfecabfd4974..ecf9f99ecc57 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -226,12 +226,10 @@ void __dev_map_flush(struct bpf_map *map) if (unlikely(!dev)) continue; - netdev = dev->dev; __clear_bit(bit, bitmap); - if (unlikely(!netdev || !netdev->netdev_ops->ndo_xdp_flush)) - continue; - - netdev->netdev_ops->ndo_xdp_flush(netdev); + netdev = dev->dev; + if (likely(netdev->netdev_ops->ndo_xdp_flush)) + netdev->netdev_ops->ndo_xdp_flush(netdev); } } -- cgit v1.2.3 From 2fe59f507a65dbd734b990a11ebc7488f6f87a24 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Tue, 22 Aug 2017 18:43:48 +1000 Subject: timers: Fix excessive granularity of new timers after a nohz idle When a timer base is idle, it is forwarded when a new timer is added to ensure that granularity does not become excessive. When not idle, the timer tick is expected to increment the base. However there are several problems: - If an existing timer is modified, the base is forwarded only after the index is calculated. - The base is not forwarded by add_timer_on. - There is a window after a timer is restarted from a nohz idle, after it is marked not-idle and before the timer tick on this CPU, where a timer may be added but the ancient base does not get forwarded. These result in excessive granularity (a 1 jiffy timeout can blow out to 100s of jiffies), which cause the rcu lockup detector to trigger, among other things. Fix this by keeping track of whether the timer base has been idle since it was last run or forwarded, and if so then forward it before adding a new timer. There is still a case where mod_timer optimises the case of a pending timer mod with the same expiry time, where the timer can see excessive granularity relative to the new, shorter interval. A comment is added, but it's not changed because it is an important fastpath for networking. This has been tested and found to fix the RCU softlockup messages. Testing was also done with tracing to measure requested versus achieved wakeup latencies for all non-deferrable timers in an idle system (with no lockup watchdogs running). Wakeup latency relative to absolute latency is calculated (note this suffers from round-up skew at low absolute times) and analysed: max avg std upstream 506.0 1.20 4.68 patched 2.0 1.08 0.15 The bug was noticed due to the lockup detector Kconfig changes dropping it out of people's .configs and resulting in larger base clk skew When the lockup detectors are enabled, no CPU can go idle for longer than 4 seconds, which limits the granularity errors. Sub-optimal timer behaviour is observable on a smaller scale in that case: max avg std upstream 9.0 1.05 0.19 patched 2.0 1.04 0.11 Fixes: Fixes: a683f390b93f ("timers: Forward the wheel clock whenever possible") Signed-off-by: Nicholas Piggin Signed-off-by: Thomas Gleixner Tested-by: Jonathan Cameron Tested-by: David Miller Cc: dzickus@redhat.com Cc: sfr@canb.auug.org.au Cc: mpe@ellerman.id.au Cc: Stephen Boyd Cc: linuxarm@huawei.com Cc: abdhalee@linux.vnet.ibm.com Cc: John Stultz Cc: akpm@linux-foundation.org Cc: paulmck@linux.vnet.ibm.com Cc: torvalds@linux-foundation.org Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20170822084348.21436-1-npiggin@gmail.com --- kernel/time/timer.c | 50 +++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 41 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 8f5d1bf18854..f2674a056c26 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -203,6 +203,7 @@ struct timer_base { bool migration_enabled; bool nohz_active; bool is_idle; + bool must_forward_clk; DECLARE_BITMAP(pending_map, WHEEL_SIZE); struct hlist_head vectors[WHEEL_SIZE]; } ____cacheline_aligned; @@ -856,13 +857,19 @@ get_target_base(struct timer_base *base, unsigned tflags) static inline void forward_timer_base(struct timer_base *base) { - unsigned long jnow = READ_ONCE(jiffies); + unsigned long jnow; /* - * We only forward the base when it's idle and we have a delta between - * base clock and jiffies. + * We only forward the base when we are idle or have just come out of + * idle (must_forward_clk logic), and have a delta between base clock + * and jiffies. In the common case, run_timers will take care of it. */ - if (!base->is_idle || (long) (jnow - base->clk) < 2) + if (likely(!base->must_forward_clk)) + return; + + jnow = READ_ONCE(jiffies); + base->must_forward_clk = base->is_idle; + if ((long)(jnow - base->clk) < 2) return; /* @@ -938,6 +945,11 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) * same array bucket then just return: */ if (timer_pending(timer)) { + /* + * The downside of this optimization is that it can result in + * larger granularity than you would get from adding a new + * timer with this expiry. + */ if (timer->expires == expires) return 1; @@ -948,6 +960,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) * dequeue/enqueue dance. */ base = lock_timer_base(timer, &flags); + forward_timer_base(base); clk = base->clk; idx = calc_wheel_index(expires, clk); @@ -964,6 +977,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) } } else { base = lock_timer_base(timer, &flags); + forward_timer_base(base); } ret = detach_if_pending(timer, base, false); @@ -991,12 +1005,10 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) raw_spin_lock(&base->lock); WRITE_ONCE(timer->flags, (timer->flags & ~TIMER_BASEMASK) | base->cpu); + forward_timer_base(base); } } - /* Try to forward a stale timer base clock */ - forward_timer_base(base); - timer->expires = expires; /* * If 'idx' was calculated above and the base time did not advance @@ -1112,6 +1124,7 @@ void add_timer_on(struct timer_list *timer, int cpu) WRITE_ONCE(timer->flags, (timer->flags & ~TIMER_BASEMASK) | cpu); } + forward_timer_base(base); debug_activate(timer, timer->expires); internal_add_timer(base, timer); @@ -1497,10 +1510,16 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) if (!is_max_delta) expires = basem + (u64)(nextevt - basej) * TICK_NSEC; /* - * If we expect to sleep more than a tick, mark the base idle: + * If we expect to sleep more than a tick, mark the base idle. + * Also the tick is stopped so any added timer must forward + * the base clk itself to keep granularity small. This idle + * logic is only maintained for the BASE_STD base, deferrable + * timers may still see large granularity skew (by design). */ - if ((expires - basem) > TICK_NSEC) + if ((expires - basem) > TICK_NSEC) { + base->must_forward_clk = true; base->is_idle = true; + } } raw_spin_unlock(&base->lock); @@ -1611,6 +1630,19 @@ static __latent_entropy void run_timer_softirq(struct softirq_action *h) { struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); + /* + * must_forward_clk must be cleared before running timers so that any + * timer functions that call mod_timer will not try to forward the + * base. idle trcking / clock forwarding logic is only used with + * BASE_STD timers. + * + * The deferrable base does not do idle tracking at all, so we do + * not forward it. This can result in very large variations in + * granularity for deferrable timers, but they can be deferred for + * long periods due to idle. + */ + base->must_forward_clk = false; + __run_timers(base); if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active) __run_timers(this_cpu_ptr(&timer_bases[BASE_DEF])); -- cgit v1.2.3 From a8f0f9e49956a74718874b800251455680085600 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Thu, 17 Aug 2017 16:37:25 -0400 Subject: ftrace: Check for null ret_stack on profile function graph entry function There's a small race when function graph shutsdown and the calling of the registered function graph entry callback. The callback must not reference the task's ret_stack without first checking that it is not NULL. Note, when a ret_stack is allocated for a task, it stays allocated until the task exits. The problem here, is that function_graph is shutdown, and a new task was created, which doesn't have its ret_stack allocated. But since some of the functions are still being traced, the callbacks can still be called. The normal function_graph code handles this, but starting with commit 8861dd303c ("ftrace: Access ret_stack->subtime only in the function profiler") the profiler code references the ret_stack on function entry, but doesn't check if it is NULL first. Link: https://bugzilla.kernel.org/show_bug.cgi?id=196611 Cc: stable@vger.kernel.org Fixes: 8861dd303c ("ftrace: Access ret_stack->subtime only in the function profiler") Reported-by: lilydjwg@gmail.com Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 02004ae91860..96cea88fa00f 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -889,6 +889,10 @@ static int profile_graph_entry(struct ftrace_graph_ent *trace) function_profile_call(trace->func, 0, NULL, NULL); + /* If function graph is shutting down, ret_stack can be NULL */ + if (!current->ret_stack) + return 0; + if (index >= 0 && index < FTRACE_RETFUNC_DEPTH) current->ret_stack[index].subtime = 0; -- cgit v1.2.3 From 475bb3c69ab05df2a6ecef6acc2393703d134180 Mon Sep 17 00:00:00 2001 From: Chunyu Hu Date: Mon, 14 Aug 2017 18:18:17 +0800 Subject: tracing: Fix kmemleak in tracing_map_array_free() kmemleak reported the below leak when I was doing clear of the hist trigger. With this patch, the kmeamleak is gone. unreferenced object 0xffff94322b63d760 (size 32): comm "bash", pid 1522, jiffies 4403687962 (age 2442.311s) hex dump (first 32 bytes): 00 01 00 00 04 00 00 00 08 00 00 00 ff 00 00 00 ................ 10 00 00 00 00 00 00 00 80 a8 7a f2 31 94 ff ff ..........z.1... backtrace: [] kmemleak_alloc+0x4a/0xa0 [] kmem_cache_alloc_trace+0xca/0x1d0 [] tracing_map_array_alloc+0x26/0x140 [] kretprobe_trampoline+0x0/0x50 [] create_hist_data+0x535/0x750 [] event_hist_trigger_func+0x1f7/0x420 [] event_trigger_write+0xfd/0x1a0 [] __vfs_write+0x37/0x170 [] vfs_write+0xb2/0x1b0 [] SyS_write+0x55/0xc0 [] do_syscall_64+0x67/0x150 [] return_from_SYSCALL_64+0x0/0x6a [] 0xffffffffffffffff unreferenced object 0xffff9431f27aa880 (size 128): comm "bash", pid 1522, jiffies 4403687962 (age 2442.311s) hex dump (first 32 bytes): 00 00 8c 2a 32 94 ff ff 00 f0 8b 2a 32 94 ff ff ...*2......*2... 00 e0 8b 2a 32 94 ff ff 00 d0 8b 2a 32 94 ff ff ...*2......*2... backtrace: [] kmemleak_alloc+0x4a/0xa0 [] __kmalloc+0xe8/0x220 [] tracing_map_array_alloc+0xb1/0x140 [] kretprobe_trampoline+0x0/0x50 [] create_hist_data+0x535/0x750 [] event_hist_trigger_func+0x1f7/0x420 [] event_trigger_write+0xfd/0x1a0 [] __vfs_write+0x37/0x170 [] vfs_write+0xb2/0x1b0 [] SyS_write+0x55/0xc0 [] do_syscall_64+0x67/0x150 [] return_from_SYSCALL_64+0x0/0x6a [] 0xffffffffffffffff Link: http://lkml.kernel.org/r/1502705898-27571-1-git-send-email-chuhu@redhat.com Cc: stable@vger.kernel.org Fixes: 08d43a5fa063 ("tracing: Add lock-free tracing_map") Signed-off-by: Chunyu Hu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/tracing_map.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c index 0a689bbb78ef..305039b122fa 100644 --- a/kernel/trace/tracing_map.c +++ b/kernel/trace/tracing_map.c @@ -221,16 +221,19 @@ void tracing_map_array_free(struct tracing_map_array *a) if (!a) return; - if (!a->pages) { - kfree(a); - return; - } + if (!a->pages) + goto free; for (i = 0; i < a->n_pages; i++) { if (!a->pages[i]) break; free_page((unsigned long)a->pages[i]); } + + kfree(a->pages); + + free: + kfree(a); } struct tracing_map_array *tracing_map_array_alloc(unsigned int n_elts, -- cgit v1.2.3 From 8b0db1a5bdfcee0dbfa89607672598ae203c9045 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Wed, 23 Aug 2017 12:46:27 -0400 Subject: tracing: Fix freeing of filter in create_filter() when set_str is false Performing the following task with kmemleak enabled: # cd /sys/kernel/tracing/events/irq/irq_handler_entry/ # echo 'enable_event:kmem:kmalloc:3 if irq >' > trigger # echo 'enable_event:kmem:kmalloc:3 if irq > 31' > trigger # echo scan > /sys/kernel/debug/kmemleak # cat /sys/kernel/debug/kmemleak unreferenced object 0xffff8800b9290308 (size 32): comm "bash", pid 1114, jiffies 4294848451 (age 141.139s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] kmemleak_alloc+0x4a/0xa0 [] kmem_cache_alloc_trace+0x158/0x290 [] create_filter_start.constprop.28+0x99/0x940 [] create_filter+0xa9/0x160 [] create_event_filter+0xc/0x10 [] set_trigger_filter+0xe5/0x210 [] event_enable_trigger_func+0x324/0x490 [] event_trigger_write+0x1a2/0x260 [] __vfs_write+0xd7/0x380 [] vfs_write+0x101/0x260 [] SyS_write+0xab/0x130 [] entry_SYSCALL_64_fastpath+0x1f/0xbe [] 0xffffffffffffffff The function create_filter() is passed a 'filterp' pointer that gets allocated, and if "set_str" is true, it is up to the caller to free it, even on error. The problem is that the pointer is not freed by create_filter() when set_str is false. This is a bug, and it is not up to the caller to free the filter on error if it doesn't care about the string. Link: http://lkml.kernel.org/r/1502705898-27571-2-git-send-email-chuhu@redhat.com Cc: stable@vger.kernel.org Fixes: 38b78eb85 ("tracing: Factorize filter creation") Reported-by: Chunyu Hu Tested-by: Chunyu Hu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events_filter.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 59a411ff60c7..181e139a8057 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1959,6 +1959,10 @@ static int create_filter(struct trace_event_call *call, if (err && set_str) append_filter_err(ps, filter); } + if (err && !set_str) { + free_event_filter(filter); + filter = NULL; + } create_filter_finish(ps); *filterp = filter; -- cgit v1.2.3 From 1c08c22c874ac88799cab1f78c40f46110274915 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Thu, 24 Aug 2017 12:04:29 -0400 Subject: cpuset: Fix incorrect memory_pressure control file mapping The memory_pressure control file was incorrectly set up without a private value (0, by default). As a result, this control file was treated like memory_migrate on read. By adding back the FILE_MEMORY_PRESSURE private value, the correct memory pressure value will be returned. Signed-off-by: Waiman Long Signed-off-by: Tejun Heo Fixes: 7dbdb199d3bf ("cgroup: replace cftype->mode with CFTYPE_WORLD_WRITABLE") Cc: stable@vger.kernel.org # v4.4+ --- kernel/cgroup/cpuset.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index ca8376e5008c..8362bac0d179 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1891,6 +1891,7 @@ static struct cftype files[] = { { .name = "memory_pressure", .read_u64 = cpuset_read_u64, + .private = FILE_MEMORY_PRESSURE, }, { -- cgit v1.2.3 From 3fd87127073292538047adf1c9c757e9cab0dd56 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Thu, 24 Aug 2017 14:38:51 -0700 Subject: strparser: initialize all callbacks commit bbb03029a899 ("strparser: Generalize strparser") added more function pointers to 'struct strp_callbacks'; however, kcm_attach() was not updated to initialize them. This could cause the ->lock() and/or ->unlock() function pointers to be set to garbage values, causing a crash in strp_work(). Fix the bug by moving the callback structs into static memory, so unspecified members are zeroed. Also constify them while we're at it. This bug was found by syzkaller, which encountered the following splat: IP: 0x55 PGD 3b1ca067 P4D 3b1ca067 PUD 3b12f067 PMD 0 Oops: 0010 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 2 PID: 1194 Comm: kworker/u8:1 Not tainted 4.13.0-rc4-next-20170811 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Workqueue: kstrp strp_work task: ffff88006bb0e480 task.stack: ffff88006bb10000 RIP: 0010:0x55 RSP: 0018:ffff88006bb17540 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffff88006ce4bd60 RCX: 0000000000000000 RDX: 1ffff1000d9c97bd RSI: 0000000000000000 RDI: ffff88006ce4bc48 RBP: ffff88006bb17558 R08: ffffffff81467ab2 R09: 0000000000000000 R10: ffff88006bb17438 R11: ffff88006bb17940 R12: ffff88006ce4bc48 R13: ffff88003c683018 R14: ffff88006bb17980 R15: ffff88003c683000 FS: 0000000000000000(0000) GS:ffff88006de00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000055 CR3: 000000003c145000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: process_one_work+0xbf3/0x1bc0 kernel/workqueue.c:2098 worker_thread+0x223/0x1860 kernel/workqueue.c:2233 kthread+0x35e/0x430 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 Code: Bad RIP value. RIP: 0x55 RSP: ffff88006bb17540 CR2: 0000000000000055 ---[ end trace f0e4920047069cee ]--- Here is a C reproducer (requires CONFIG_BPF_SYSCALL=y and CONFIG_AF_KCM=y): #include #include #include #include #include #include #include #include static const struct bpf_insn bpf_insns[3] = { { .code = 0xb7 }, /* BPF_MOV64_IMM(0, 0) */ { .code = 0x95 }, /* BPF_EXIT_INSN() */ }; static const union bpf_attr bpf_attr = { .prog_type = 1, .insn_cnt = 2, .insns = (uintptr_t)&bpf_insns, .license = (uintptr_t)"", }; int main(void) { int bpf_fd = syscall(__NR_bpf, BPF_PROG_LOAD, &bpf_attr, sizeof(bpf_attr)); int inet_fd = socket(AF_INET, SOCK_STREAM, 0); int kcm_fd = socket(AF_KCM, SOCK_DGRAM, 0); ioctl(kcm_fd, SIOCKCMATTACH, &(struct kcm_attach) { .fd = inet_fd, .bpf_fd = bpf_fd }); } Fixes: bbb03029a899 ("strparser: Generalize strparser") Cc: Dmitry Vyukov Cc: Tom Herbert Signed-off-by: Eric Biggers Signed-off-by: David S. Miller --- kernel/bpf/sockmap.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 78b2bb9370ac..617c239590c2 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -368,12 +368,12 @@ static int smap_read_sock_done(struct strparser *strp, int err) static int smap_init_sock(struct smap_psock *psock, struct sock *sk) { - struct strp_callbacks cb; + static const struct strp_callbacks cb = { + .rcv_msg = smap_read_sock_strparser, + .parse_msg = smap_parse_func_strparser, + .read_sock_done = smap_read_sock_done, + }; - memset(&cb, 0, sizeof(cb)); - cb.rcv_msg = smap_read_sock_strparser; - cb.parse_msg = smap_parse_func_strparser; - cb.read_sock_done = smap_read_sock_done; return strp_init(&psock->strp, sk, &cb); } -- cgit v1.2.3 From 64aee2a965cf2954a038b5522f11d2cd2f0f8f3e Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Thu, 22 Jun 2017 15:41:38 +0100 Subject: perf/core: Fix group {cpu,task} validation Regardless of which events form a group, it does not make sense for the events to target different tasks and/or CPUs, as this leaves the group inconsistent and impossible to schedule. The core perf code assumes that these are consistent across (successfully intialised) groups. Core perf code only verifies this when moving SW events into a HW context. Thus, we can violate this requirement for pure SW groups and pure HW groups, unless the relevant PMU driver happens to perform this verification itself. These mismatched groups subsequently wreak havoc elsewhere. For example, we handle watchpoints as SW events, and reserve watchpoint HW on a per-CPU basis at pmu::event_init() time to ensure that any event that is initialised is guaranteed to have a slot at pmu::add() time. However, the core code only checks the group leader's cpu filter (via event_filter_match()), and can thus install follower events onto CPUs violating thier (mismatched) CPU filters, potentially installing them into a CPU without sufficient reserved slots. This can be triggered with the below test case, resulting in warnings from arch backends. #define _GNU_SOURCE #include #include #include #include #include #include #include static int perf_event_open(struct perf_event_attr *attr, pid_t pid, int cpu, int group_fd, unsigned long flags) { return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags); } char watched_char; struct perf_event_attr wp_attr = { .type = PERF_TYPE_BREAKPOINT, .bp_type = HW_BREAKPOINT_RW, .bp_addr = (unsigned long)&watched_char, .bp_len = 1, .size = sizeof(wp_attr), }; int main(int argc, char *argv[]) { int leader, ret; cpu_set_t cpus; /* * Force use of CPU0 to ensure our CPU0-bound events get scheduled. */ CPU_ZERO(&cpus); CPU_SET(0, &cpus); ret = sched_setaffinity(0, sizeof(cpus), &cpus); if (ret) { printf("Unable to set cpu affinity\n"); return 1; } /* open leader event, bound to this task, CPU0 only */ leader = perf_event_open(&wp_attr, 0, 0, -1, 0); if (leader < 0) { printf("Couldn't open leader: %d\n", leader); return 1; } /* * Open a follower event that is bound to the same task, but a * different CPU. This means that the group should never be possible to * schedule. */ ret = perf_event_open(&wp_attr, 0, 1, leader, 0); if (ret < 0) { printf("Couldn't open mismatched follower: %d\n", ret); return 1; } else { printf("Opened leader/follower with mismastched CPUs\n"); } /* * Open as many independent events as we can, all bound to the same * task, CPU0 only. */ do { ret = perf_event_open(&wp_attr, 0, 0, -1, 0); } while (ret >= 0); /* * Force enable/disble all events to trigger the erronoeous * installation of the follower event. */ printf("Opened all events. Toggling..\n"); for (;;) { prctl(PR_TASK_PERF_EVENTS_DISABLE, 0, 0, 0, 0); prctl(PR_TASK_PERF_EVENTS_ENABLE, 0, 0, 0, 0); } return 0; } Fix this by validating this requirement regardless of whether we're moving events. Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Zhou Chengming Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1498142498-15758-1-git-send-email-mark.rutland@arm.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 39 +++++++++++++++++++-------------------- 1 file changed, 19 insertions(+), 20 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index ee20d4c546b5..3504125871d2 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10032,28 +10032,27 @@ SYSCALL_DEFINE5(perf_event_open, goto err_context; /* - * Do not allow to attach to a group in a different - * task or CPU context: + * Make sure we're both events for the same CPU; + * grouping events for different CPUs is broken; since + * you can never concurrently schedule them anyhow. */ - if (move_group) { - /* - * Make sure we're both on the same task, or both - * per-cpu events. - */ - if (group_leader->ctx->task != ctx->task) - goto err_context; + if (group_leader->cpu != event->cpu) + goto err_context; - /* - * Make sure we're both events for the same CPU; - * grouping events for different CPUs is broken; since - * you can never concurrently schedule them anyhow. - */ - if (group_leader->cpu != event->cpu) - goto err_context; - } else { - if (group_leader->ctx != ctx) - goto err_context; - } + /* + * Make sure we're both on the same task, or both + * per-CPU events. + */ + if (group_leader->ctx->task != ctx->task) + goto err_context; + + /* + * Do not allow to attach to a group in a different task + * or CPU context. If we're moving SW events, we'll fix + * this up later, so allow that. + */ + if (!move_group && group_leader->ctx != ctx) + goto err_context; /* * Only a group leader can be exclusive or pinned -- cgit v1.2.3 From 2ab346cfb0decf01523949e29f5cf542f2304611 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 16 Aug 2017 17:18:16 +0100 Subject: perf/aux: Make aux_{head,wakeup} ring_buffer members long The aux_head and aux_wakeup members of struct ring_buffer are defined using the local_t type, despite the fact that they are only accessed via the perf_aux_output_*() functions, which cannot race with each other for a given ring buffer. This patch changes the type of the members to long, so we can avoid using the local_*() API where it isn't needed. Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Linus Torvalds Cc: Mark Rutland Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1502900297-21839-1-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar --- kernel/events/internal.h | 4 ++-- kernel/events/ring_buffer.c | 31 ++++++++++++++----------------- 2 files changed, 16 insertions(+), 19 deletions(-) (limited to 'kernel') diff --git a/kernel/events/internal.h b/kernel/events/internal.h index 486fd78eb8d5..2941b868353c 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -38,9 +38,9 @@ struct ring_buffer { struct user_struct *mmap_user; /* AUX area */ - local_t aux_head; + long aux_head; local_t aux_nest; - local_t aux_wakeup; + long aux_wakeup; unsigned long aux_pgoff; int aux_nr_pages; int aux_overwrite; diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index ee97196bb151..25437fda56e3 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -367,7 +367,7 @@ void *perf_aux_output_begin(struct perf_output_handle *handle, if (WARN_ON_ONCE(local_xchg(&rb->aux_nest, 1))) goto err_put; - aux_head = local_read(&rb->aux_head); + aux_head = rb->aux_head; handle->rb = rb; handle->event = event; @@ -382,7 +382,7 @@ void *perf_aux_output_begin(struct perf_output_handle *handle, */ if (!rb->aux_overwrite) { aux_tail = ACCESS_ONCE(rb->user_page->aux_tail); - handle->wakeup = local_read(&rb->aux_wakeup) + rb->aux_watermark; + handle->wakeup = rb->aux_wakeup + rb->aux_watermark; if (aux_head - aux_tail < perf_aux_size(rb)) handle->size = CIRC_SPACE(aux_head, aux_tail, perf_aux_size(rb)); @@ -433,12 +433,12 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size) handle->aux_flags |= PERF_AUX_FLAG_OVERWRITE; aux_head = handle->head; - local_set(&rb->aux_head, aux_head); + rb->aux_head = aux_head; } else { handle->aux_flags &= ~PERF_AUX_FLAG_OVERWRITE; - aux_head = local_read(&rb->aux_head); - local_add(size, &rb->aux_head); + aux_head = rb->aux_head; + rb->aux_head += size; } if (size || handle->aux_flags) { @@ -450,11 +450,10 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size) handle->aux_flags); } - aux_head = rb->user_page->aux_head = local_read(&rb->aux_head); - - if (aux_head - local_read(&rb->aux_wakeup) >= rb->aux_watermark) { + rb->user_page->aux_head = rb->aux_head; + if (rb->aux_head - rb->aux_wakeup >= rb->aux_watermark) { wakeup = true; - local_add(rb->aux_watermark, &rb->aux_wakeup); + rb->aux_wakeup += rb->aux_watermark; } if (wakeup) { @@ -478,22 +477,20 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size) int perf_aux_output_skip(struct perf_output_handle *handle, unsigned long size) { struct ring_buffer *rb = handle->rb; - unsigned long aux_head; if (size > handle->size) return -ENOSPC; - local_add(size, &rb->aux_head); + rb->aux_head += size; - aux_head = rb->user_page->aux_head = local_read(&rb->aux_head); - if (aux_head - local_read(&rb->aux_wakeup) >= rb->aux_watermark) { + rb->user_page->aux_head = rb->aux_head; + if (rb->aux_head - rb->aux_wakeup >= rb->aux_watermark) { perf_output_wakeup(handle); - local_add(rb->aux_watermark, &rb->aux_wakeup); - handle->wakeup = local_read(&rb->aux_wakeup) + - rb->aux_watermark; + rb->aux_wakeup += rb->aux_watermark; + handle->wakeup = rb->aux_wakeup + rb->aux_watermark; } - handle->head = aux_head; + handle->head = rb->aux_head; handle->size -= size; return 0; -- cgit v1.2.3 From d9a50b0256f06bd39a1bed1ba40baec37c356b11 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 16 Aug 2017 17:18:17 +0100 Subject: perf/aux: Ensure aux_wakeup represents most recent wakeup index The aux_watermark member of struct ring_buffer represents the period (in terms of bytes) at which wakeup events should be generated when data is written to the aux buffer in non-snapshot mode. On hardware that cannot generate an interrupt when the aux_head reaches an arbitrary wakeup index (such as ARM SPE), the aux_head sampled from handle->head in perf_aux_output_{skip,end} may in fact be past the wakeup index. This can lead to wakeup slowly falling behind the head. For example, consider the case where hardware can only generate an interrupt on a page-boundary and the aux buffer is initialised as follows: // Buffer size is 2 * PAGE_SIZE rb->aux_head = rb->aux_wakeup = 0 rb->aux_watermark = PAGE_SIZE / 2 following the first perf_aux_output_begin call, the handle is initialised with: handle->head = 0 handle->size = 2 * PAGE_SIZE handle->wakeup = PAGE_SIZE / 2 and the hardware will be programmed to generate an interrupt at PAGE_SIZE. When the interrupt is raised, the hardware head will be at PAGE_SIZE, so calling perf_aux_output_end(handle, PAGE_SIZE) puts the ring buffer into the following state: rb->aux_head = PAGE_SIZE rb->aux_wakeup = PAGE_SIZE / 2 rb->aux_watermark = PAGE_SIZE / 2 and then the next call to perf_aux_output_begin will result in: handle->head = handle->wakeup = PAGE_SIZE for which the semantics are unclear and, for a smaller aux_watermark (e.g. PAGE_SIZE / 4), then the wakeup would in fact be behind head at this point. This patch fixes the problem by rounding down the aux_head (as sampled from the handle) to the nearest aux_watermark boundary when updating rb->aux_wakeup, therefore taking into account any overruns by the hardware. Reported-by: Mark Rutland Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Acked-by: Alexander Shishkin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1502900297-21839-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar --- kernel/events/internal.h | 2 +- kernel/events/ring_buffer.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/events/internal.h b/kernel/events/internal.h index 2941b868353c..5377c591c57a 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -40,7 +40,7 @@ struct ring_buffer { /* AUX area */ long aux_head; local_t aux_nest; - long aux_wakeup; + long aux_wakeup; /* last aux_watermark boundary crossed by aux_head */ unsigned long aux_pgoff; int aux_nr_pages; int aux_overwrite; diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index 25437fda56e3..af71a84e12ee 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -453,7 +453,7 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size) rb->user_page->aux_head = rb->aux_head; if (rb->aux_head - rb->aux_wakeup >= rb->aux_watermark) { wakeup = true; - rb->aux_wakeup += rb->aux_watermark; + rb->aux_wakeup = rounddown(rb->aux_head, rb->aux_watermark); } if (wakeup) { @@ -486,7 +486,7 @@ int perf_aux_output_skip(struct perf_output_handle *handle, unsigned long size) rb->user_page->aux_head = rb->aux_head; if (rb->aux_head - rb->aux_wakeup >= rb->aux_watermark) { perf_output_wakeup(handle); - rb->aux_wakeup += rb->aux_watermark; + rb->aux_wakeup = rounddown(rb->aux_head, rb->aux_watermark); handle->wakeup = rb->aux_wakeup + rb->aux_watermark; } -- cgit v1.2.3 From 1d953111b648e48923171c3c9cf17be2250544fa Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 22 Aug 2017 17:59:28 +0200 Subject: perf/core: Don't report zero PIDs for exiting tasks The exiting/dead task has no PIDs and in this case perf_event_pid/tid() return zero, change them to return -1 to distinguish this case from idle threads. Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170822155928.GA6892@redhat.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 1ac5015bab04..b411321b6c26 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1249,26 +1249,31 @@ unclone_ctx(struct perf_event_context *ctx) return parent_ctx; } -static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) +static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p, + enum pid_type type) { + u32 nr; /* * only top level events have the pid namespace they were created in */ if (event->parent) event = event->parent; - return task_tgid_nr_ns(p, event->ns); + nr = __task_pid_nr_ns(p, type, event->ns); + /* avoid -1 if it is idle thread or runs in another ns */ + if (!nr && !pid_alive(p)) + nr = -1; + return nr; } -static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) +static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) { - /* - * only top level events have the pid namespace they were created in - */ - if (event->parent) - event = event->parent; + return perf_event_pid_type(event, p, __PIDTYPE_TGID); +} - return task_pid_nr_ns(p, event->ns); +static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) +{ + return perf_event_pid_type(event, p, PIDTYPE_PID); } /* -- cgit v1.2.3 From d0618410eced4eb092295fad10312a4545fcdfaf Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Tue, 22 Aug 2017 19:22:43 +0200 Subject: tracing, perf: Adjust code layout in get_recursion_context() In an XDP redirect applications using tracepoint xdp:xdp_redirect to diagnose TX overrun, I noticed perf_swevent_get_recursion_context() was consuming 2% CPU. This was reduced to 1.85% with this simple change. Looking at the annotated asm code, it was clear that the unlikely case in_nmi() test was chosen (by the compiler) as the most likely event/branch. This small adjustment makes the compiler (GCC version 7.1.1 20170622 (Red Hat 7.1.1-3)) put in_nmi() as an unlikely branch. Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/150342256382.16595.986861478681783732.stgit@firesoul Signed-off-by: Ingo Molnar --- kernel/events/internal.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/events/internal.h b/kernel/events/internal.h index 5377c591c57a..843e97047335 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -208,7 +208,7 @@ static inline int get_recursion_context(int *recursion) { int rctx; - if (in_nmi()) + if (unlikely(in_nmi())) rctx = 3; else if (in_irq()) rctx = 2; -- cgit v1.2.3 From a1d14934ea4b9db816a8dbfeab1c3e7204a0d871 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 23 Aug 2017 12:52:32 +0200 Subject: workqueue/lockdep: 'Fix' flush_work() annotation The flush_work() annotation as introduced by commit: e159489baa71 ("workqueue: relax lockdep annotation on flush_work()") hits on the lockdep problem with recursive read locks. The situation as described is: Work W1: Work W2: Task: ARR(Q) ARR(Q) flush_workqueue(Q) A(W1) A(W2) A(Q) flush_work(W2) R(Q) A(W2) R(W2) if (special) A(Q) else ARR(Q) R(Q) where: A - acquire, ARR - acquire-read-recursive, R - release. Where under 'special' conditions we want to trigger a lock recursion deadlock, but otherwise allow the flush_work(). The allowing is done by using recursive read locks (ARR), but lockdep is broken for recursive stuff. However, there appears to be no need to acquire the lock if we're not 'special', so if we remove the 'else' clause things become much simpler and no longer need the recursion thing at all. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Tejun Heo Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: boqun.feng@gmail.com Cc: byungchul.park@lge.com Cc: david@fromorbit.com Cc: johannes@sipsolutions.net Cc: oleg@redhat.com Signed-off-by: Ingo Molnar --- kernel/workqueue.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/workqueue.c b/kernel/workqueue.c index f128b3becfe1..8ad214dc15a9 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2091,7 +2091,7 @@ __acquires(&pool->lock) spin_unlock_irq(&pool->lock); - lock_map_acquire_read(&pwq->wq->lockdep_map); + lock_map_acquire(&pwq->wq->lockdep_map); lock_map_acquire(&lockdep_map); crossrelease_hist_start(XHLOCK_PROC); trace_workqueue_execute_start(work); @@ -2826,16 +2826,18 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) spin_unlock_irq(&pool->lock); /* - * If @max_active is 1 or rescuer is in use, flushing another work - * item on the same workqueue may lead to deadlock. Make sure the - * flusher is not running on the same workqueue by verifying write - * access. + * Force a lock recursion deadlock when using flush_work() inside a + * single-threaded or rescuer equipped workqueue. + * + * For single threaded workqueues the deadlock happens when the work + * is after the work issuing the flush_work(). For rescuer equipped + * workqueues the deadlock happens when the rescuer stalls, blocking + * forward progress. */ - if (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer) + if (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer) { lock_map_acquire(&pwq->wq->lockdep_map); - else - lock_map_acquire_read(&pwq->wq->lockdep_map); - lock_map_release(&pwq->wq->lockdep_map); + lock_map_release(&pwq->wq->lockdep_map); + } return true; already_gone: -- cgit v1.2.3 From e6f3faa734a00c606b7b06c6b9f15e5627d3245b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 23 Aug 2017 13:23:30 +0200 Subject: locking/lockdep: Fix workqueue crossrelease annotation The new completion/crossrelease annotations interact unfavourable with the extant flush_work()/flush_workqueue() annotations. The problem is that when a single work class does: wait_for_completion(&C) and complete(&C) in different executions, we'll build dependencies like: lock_map_acquire(W) complete_acquire(C) and lock_map_acquire(W) complete_release(C) which results in the dependency chain: W->C->W, which lockdep thinks spells deadlock, even though there is no deadlock potential since works are ran concurrently. One possibility would be to change the work 'lock' to recursive-read, but that would mean hitting a lockdep limitation on recursive locks. Also, unconditinoally switching to recursive-read here would fail to detect the actual deadlock on single-threaded workqueues, which do have a problem with this. For now, forcefully disregard these locks for crossrelease. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Tejun Heo Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: boqun.feng@gmail.com Cc: byungchul.park@lge.com Cc: david@fromorbit.com Cc: johannes@sipsolutions.net Cc: oleg@redhat.com Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 56 +++++++++++++++++++++++++++++++----------------- kernel/workqueue.c | 23 +++++++++++++++++++- 2 files changed, 58 insertions(+), 21 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 66011c9f5df3..f73ca595b81e 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4629,7 +4629,7 @@ asmlinkage __visible void lockdep_sys_exit(void) * the index to point to the last entry, which is already invalid. */ crossrelease_hist_end(XHLOCK_PROC); - crossrelease_hist_start(XHLOCK_PROC); + crossrelease_hist_start(XHLOCK_PROC, false); } void lockdep_rcu_suspicious(const char *file, const int line, const char *s) @@ -4725,25 +4725,25 @@ static inline void invalidate_xhlock(struct hist_lock *xhlock) /* * Lock history stacks; we have 3 nested lock history stacks: * - * Hard IRQ - * Soft IRQ - * History / Task + * HARD(IRQ) + * SOFT(IRQ) + * PROC(ess) * - * The thing is that once we complete a (Hard/Soft) IRQ the future task locks - * should not depend on any of the locks observed while running the IRQ. + * The thing is that once we complete a HARD/SOFT IRQ the future task locks + * should not depend on any of the locks observed while running the IRQ. So + * what we do is rewind the history buffer and erase all our knowledge of that + * temporal event. * - * So what we do is rewind the history buffer and erase all our knowledge of - * that temporal event. - */ - -/* - * We need this to annotate lock history boundaries. Take for instance - * workqueues; each work is independent of the last. The completion of a future - * work does not depend on the completion of a past work (in general). - * Therefore we must not carry that (lock) dependency across works. + * The PROCess one is special though; it is used to annotate independence + * inside a task. + * + * Take for instance workqueues; each work is independent of the last. The + * completion of a future work does not depend on the completion of a past work + * (in general). Therefore we must not carry that (lock) dependency across + * works. * * This is true for many things; pretty much all kthreads fall into this - * pattern, where they have an 'idle' state and future completions do not + * pattern, where they have an invariant state and future completions do not * depend on past completions. Its just that since they all have the 'same' * form -- the kthread does the same over and over -- it doesn't typically * matter. @@ -4751,15 +4751,31 @@ static inline void invalidate_xhlock(struct hist_lock *xhlock) * The same is true for system-calls, once a system call is completed (we've * returned to userspace) the next system call does not depend on the lock * history of the previous system call. + * + * They key property for independence, this invariant state, is that it must be + * a point where we hold no locks and have no history. Because if we were to + * hold locks, the restore at _end() would not necessarily recover it's history + * entry. Similarly, independence per-definition means it does not depend on + * prior state. */ -void crossrelease_hist_start(enum xhlock_context_t c) +void crossrelease_hist_start(enum xhlock_context_t c, bool force) { struct task_struct *cur = current; - if (cur->xhlocks) { - cur->xhlock_idx_hist[c] = cur->xhlock_idx; - cur->hist_id_save[c] = cur->hist_id; + if (!cur->xhlocks) + return; + + /* + * We call this at an invariant point, no current state, no history. + */ + if (c == XHLOCK_PROC) { + /* verified the former, ensure the latter */ + WARN_ON_ONCE(!force && cur->lockdep_depth); + invalidate_xhlock(&xhlock(cur->xhlock_idx)); } + + cur->xhlock_idx_hist[c] = cur->xhlock_idx; + cur->hist_id_save[c] = cur->hist_id; } void crossrelease_hist_end(enum xhlock_context_t c) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 8ad214dc15a9..c0331891dec1 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2093,7 +2093,28 @@ __acquires(&pool->lock) lock_map_acquire(&pwq->wq->lockdep_map); lock_map_acquire(&lockdep_map); - crossrelease_hist_start(XHLOCK_PROC); + /* + * Strictly speaking we should do start(PROC) without holding any + * locks, that is, before these two lock_map_acquire()'s. + * + * However, that would result in: + * + * A(W1) + * WFC(C) + * A(W1) + * C(C) + * + * Which would create W1->C->W1 dependencies, even though there is no + * actual deadlock possible. There are two solutions, using a + * read-recursive acquire on the work(queue) 'locks', but this will then + * hit the lockdep limitation on recursive locks, or simly discard + * these locks. + * + * AFAICT there is no possible deadlock scenario between the + * flush_work() and complete() primitives (except for single-threaded + * workqueues), so hiding them isn't a problem. + */ + crossrelease_hist_start(XHLOCK_PROC, true); trace_workqueue_execute_start(work); worker->current_func(work); /* -- cgit v1.2.3 From 213c5a459ae0a7ef0a092f576aae2d5db6819360 Mon Sep 17 00:00:00 2001 From: Shu Wang Date: Thu, 10 Aug 2017 15:52:16 +0800 Subject: sched/topology: Fix memory leak in __sdt_alloc() Found this issue by kmemleak: the 'sg' and 'sgc' pointers from __sdt_alloc() might be leaked as each domain holds many groups' ref, but in destroy_sched_domain(), it only declined the first group ref. Onlining and offlining a CPU can trigger this leak, and cause OOM. Reproducer for my 6 CPUs machine: while true do echo 0 > /sys/devices/system/cpu/cpu5/online; echo 1 > /sys/devices/system/cpu/cpu5/online; done unreferenced object 0xffff88007d772a80 (size 64): comm "cpuhp/5", pid 39, jiffies 4294719962 (age 35.251s) hex dump (first 32 bytes): c0 22 77 7d 00 88 ff ff 02 00 00 00 01 00 00 00 ."w}............ 40 2a 77 7d 00 88 ff ff 00 00 00 00 00 00 00 00 @*w}............ backtrace: [] kmemleak_alloc+0x4a/0xa0 [] __kmalloc_node+0xf1/0x280 [] build_sched_domains+0x1e8/0xf20 [] partition_sched_domains+0x304/0x360 [] cpuset_update_active_cpus+0x17/0x40 [] sched_cpu_activate+0xae/0xc0 [] cpuhp_invoke_callback+0x90/0x400 [] cpuhp_up_callbacks+0x37/0xb0 [] cpuhp_thread_fun+0xd7/0xf0 [] smpboot_thread_fn+0x110/0x160 [] kthread+0x109/0x140 [] ret_from_fork+0x25/0x30 [] 0xffffffffffffffff unreferenced object 0xffff88007d772a40 (size 64): comm "cpuhp/5", pid 39, jiffies 4294719962 (age 35.251s) hex dump (first 32 bytes): 03 00 00 00 00 00 00 00 00 04 00 00 00 00 00 00 ................ 00 04 00 00 00 00 00 00 4f 3c fc ff 00 00 00 00 ........O<...... backtrace: [] kmemleak_alloc+0x4a/0xa0 [] __kmalloc_node+0xf1/0x280 [] build_sched_domains+0xead/0xf20 [] partition_sched_domains+0x304/0x360 [] cpuset_update_active_cpus+0x17/0x40 [] sched_cpu_activate+0xae/0xc0 [] cpuhp_invoke_callback+0x90/0x400 [] cpuhp_up_callbacks+0x37/0xb0 [] cpuhp_thread_fun+0xd7/0xf0 [] smpboot_thread_fn+0x110/0x160 [] kthread+0x109/0x140 [] ret_from_fork+0x25/0x30 [] 0xffffffffffffffff Reported-by: Chunyu Hu Signed-off-by: Shu Wang Signed-off-by: Peter Zijlstra (Intel) Acked-by: Chunyu Hu Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: liwang@redhat.com Link: http://lkml.kernel.org/r/1502351536-9108-1-git-send-email-shuwang@redhat.com Signed-off-by: Ingo Molnar --- kernel/sched/topology.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index bd8b6d6f5387..4197f1346153 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -335,7 +335,8 @@ static void free_sched_groups(struct sched_group *sg, int free_sgc) if (free_sgc && atomic_dec_and_test(&sg->sgc->ref)) kfree(sg->sgc); - kfree(sg); + if (atomic_dec_and_test(&sg->ref)) + kfree(sg); sg = tmp; } while (sg != first); } @@ -343,15 +344,11 @@ static void free_sched_groups(struct sched_group *sg, int free_sgc) static void destroy_sched_domain(struct sched_domain *sd) { /* - * If its an overlapping domain it has private groups, iterate and - * nuke them all. + * A sched domain has many groups' reference, and an overlapping + * domain has private groups, iterate and nuke them all. */ - if (sd->flags & SD_OVERLAP) { - free_sched_groups(sd->groups, 1); - } else if (atomic_dec_and_test(&sd->groups->ref)) { - kfree(sd->groups->sgc); - kfree(sd->groups); - } + free_sched_groups(sd->groups, 1); + if (sd->shared && atomic_dec_and_test(&sd->shared->ref)) kfree(sd->shared); kfree(sd); @@ -668,6 +665,7 @@ build_group_from_child_sched_domain(struct sched_domain *sd, int cpu) else cpumask_copy(sg_span, sched_domain_span(sd)); + atomic_inc(&sg->ref); return sg; } -- cgit v1.2.3 From a090c4f2cd2cfeb54eaf8ad1e726a6c485f3abc3 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 21 Aug 2017 15:42:52 +0200 Subject: sched/topology: Improve comments Mike provided a better comment for destroy_sched_domain() ... Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/sched/topology.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 4197f1346153..179b90b60ec6 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -344,8 +344,9 @@ static void free_sched_groups(struct sched_group *sg, int free_sgc) static void destroy_sched_domain(struct sched_domain *sd) { /* - * A sched domain has many groups' reference, and an overlapping - * domain has private groups, iterate and nuke them all. + * A normal sched domain may have multiple group references, an + * overlapping domain, having private groups, only one. Iterate, + * dropping group/capacity references, freeing where none remain. */ free_sched_groups(sd->groups, 1); -- cgit v1.2.3 From 77d1dfda0e79b41894880418f04794e92e4350e2 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 8 Aug 2017 12:16:24 +0200 Subject: sched/topology, cpuset: Avoid spurious/wrong domain rebuilds When disabling cpuset.sched_load_balance we expect to be able to online CPUs without generating sched_domains. However this is currently completely broken. What happens is that we generate the sched_domains and then destroy them. This is because of the spurious 'default' domain build in cpuset_update_active_cpus(). That builds a single machine wide domain and then schedules a work to build the 'real' domains. The work then finds there are _no_ domains and destroys the lot again. Furthermore, if there actually were cpusets, building the machine wide domain is actively wrong, because it would allow tasks to 'escape' their cpuset. Also I don't think its needed, the scheduler really should respect the active mask. Reported-by: Ofer Levi(SW) Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Tejun Heo Cc: Thomas Gleixner Cc: Vineet.Gupta1@synopsys.com Cc: rusty@rustcorp.com.au Signed-off-by: Ingo Molnar --- kernel/cgroup/cpuset.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 8d5151688504..1d2369451939 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -2343,13 +2343,7 @@ void cpuset_update_active_cpus(void) * We're inside cpu hotplug critical region which usually nests * inside cgroup synchronization. Bounce actual hotplug processing * to a work item to avoid reverse locking order. - * - * We still need to do partition_sched_domains() synchronously; - * otherwise, the scheduler will get confused and put tasks to the - * dead CPU. Fall back to the default single domain. - * cpuset_hotplug_workfn() will rebuild it as necessary. */ - partition_sched_domains(1, NULL, NULL); schedule_work(&cpuset_hotplug_work); } -- cgit v1.2.3 From 09e0dd8e0f2e197690d34fed8cb4737114d3dd5f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 8 Aug 2017 12:16:24 +0200 Subject: sched/topology: Avoid pointless rebuild Fix partition_sched_domains() to try and preserve the existing machine wide domain instead of unconditionally destroying it. We do this by attempting to allocate the new single domain, only when that fails to we reuse the fallback_doms. When using fallback_doms we need to first destroy and then recreate because both the old and new could be backed by it. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Ofer Levi(SW) Cc: Peter Zijlstra Cc: Tejun Heo Cc: Thomas Gleixner Cc: Vineet.Gupta1@synopsys.com Cc: rusty@rustcorp.com.au Signed-off-by: Ingo Molnar --- kernel/sched/topology.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 179b90b60ec6..727daa2a0abe 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -1851,7 +1851,17 @@ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], /* Let the architecture update CPU core mappings: */ new_topology = arch_update_cpu_topology(); - n = doms_new ? ndoms_new : 0; + if (!doms_new) { + WARN_ON_ONCE(dattr_new); + n = 0; + doms_new = alloc_sched_domains(1); + if (doms_new) { + n = 1; + cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); + } + } else { + n = ndoms_new; + } /* Destroy deleted domains: */ for (i = 0; i < ndoms_cur; i++) { @@ -1867,11 +1877,10 @@ match1: } n = ndoms_cur; - if (doms_new == NULL) { + if (!doms_new) { n = 0; doms_new = &fallback_doms; cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); - WARN_ON_ONCE(dattr_new); } /* Build new domains: */ -- cgit v1.2.3 From bbdacdfed2f5fa50a2cc9f500a36e05990a0837d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 10 Aug 2017 17:10:26 +0200 Subject: sched/debug: Optimize sched_domain sysctl generation Currently we unconditionally destroy all sysctl bits and regenerate them after we've rebuild the domains (even if that rebuild is a no-op). And since we unconditionally (re)build the sysctl for all possible CPUs, onlining all CPUs gets us O(n^2) time. Instead change this to only rebuild the bits for CPUs we've actually installed new domains on. Reported-by: Ofer Levi(SW) Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/sched/debug.c | 68 +++++++++++++++++++++++++++++++++++++++---------- kernel/sched/sched.h | 4 +++ kernel/sched/topology.c | 1 + 3 files changed, 59 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index cfd84f79e075..4a23bbc3111b 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -327,38 +327,78 @@ static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) return table; } +static cpumask_var_t sd_sysctl_cpus; static struct ctl_table_header *sd_sysctl_header; + void register_sched_domain_sysctl(void) { - int i, cpu_num = num_possible_cpus(); - struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); + static struct ctl_table *cpu_entries; + static struct ctl_table **cpu_idx; char buf[32]; + int i; - WARN_ON(sd_ctl_dir[0].child); - sd_ctl_dir[0].child = entry; + if (!cpu_entries) { + cpu_entries = sd_alloc_ctl_entry(num_possible_cpus() + 1); + if (!cpu_entries) + return; - if (entry == NULL) - return; + WARN_ON(sd_ctl_dir[0].child); + sd_ctl_dir[0].child = cpu_entries; + } - for_each_possible_cpu(i) { - snprintf(buf, 32, "cpu%d", i); - entry->procname = kstrdup(buf, GFP_KERNEL); - entry->mode = 0555; - entry->child = sd_alloc_ctl_cpu_table(i); - entry++; + if (!cpu_idx) { + struct ctl_table *e = cpu_entries; + + cpu_idx = kcalloc(nr_cpu_ids, sizeof(struct ctl_table*), GFP_KERNEL); + if (!cpu_idx) + return; + + /* deal with sparse possible map */ + for_each_possible_cpu(i) { + cpu_idx[i] = e; + e++; + } + } + + if (!cpumask_available(sd_sysctl_cpus)) { + if (!alloc_cpumask_var(&sd_sysctl_cpus, GFP_KERNEL)) + return; + + /* init to possible to not have holes in @cpu_entries */ + cpumask_copy(sd_sysctl_cpus, cpu_possible_mask); + } + + for_each_cpu(i, sd_sysctl_cpus) { + struct ctl_table *e = cpu_idx[i]; + + if (e->child) + sd_free_ctl_entry(&e->child); + + if (!e->procname) { + snprintf(buf, 32, "cpu%d", i); + e->procname = kstrdup(buf, GFP_KERNEL); + } + e->mode = 0555; + e->child = sd_alloc_ctl_cpu_table(i); + + __cpumask_clear_cpu(i, sd_sysctl_cpus); } WARN_ON(sd_sysctl_header); sd_sysctl_header = register_sysctl_table(sd_ctl_root); } +void dirty_sched_domain_sysctl(int cpu) +{ + if (cpumask_available(sd_sysctl_cpus)) + __cpumask_set_cpu(cpu, sd_sysctl_cpus); +} + /* may be called multiple times per register */ void unregister_sched_domain_sysctl(void) { unregister_sysctl_table(sd_sysctl_header); sd_sysctl_header = NULL; - if (sd_ctl_dir[0].child) - sd_free_ctl_entry(&sd_ctl_dir[0].child); } #endif /* CONFIG_SYSCTL */ #endif /* CONFIG_SMP */ diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index eeef1a3086d1..25e5cb1107f3 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1120,11 +1120,15 @@ extern int group_balance_cpu(struct sched_group *sg); #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) void register_sched_domain_sysctl(void); +void dirty_sched_domain_sysctl(int cpu); void unregister_sched_domain_sysctl(void); #else static inline void register_sched_domain_sysctl(void) { } +static inline void dirty_sched_domain_sysctl(int cpu) +{ +} static inline void unregister_sched_domain_sysctl(void) { } diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 727daa2a0abe..6f7b43982f73 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -459,6 +459,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) rq_attach_root(rq, rd); tmp = rq->sd; rcu_assign_pointer(rq->sd, sd); + dirty_sched_domain_sysctl(cpu); destroy_sched_domains(tmp); update_top_cache_domain(cpu); -- cgit v1.2.3 From ce8bdd6957202a38d67038e5ec940eed50f9f3eb Mon Sep 17 00:00:00 2001 From: kbuild test robot Date: Tue, 22 Aug 2017 15:50:53 +0800 Subject: genirq: Fix semicolon.cocci warnings kernel/irq/proc.c:69:2-3: Unneeded semicolon Remove unneeded semicolon. Generated by: scripts/coccinelle/misc/semicolon.cocci Fixes: 0d3f54257dc3 ("genirq: Introduce effective affinity mask") Signed-off-by: Fengguang Wu Signed-off-by: Thomas Gleixner Cc: kbuild-all@01.org Link: http://lkml.kernel.org/r/20170822075053.GA93890@lkp-hsx02 --- kernel/irq/proc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 0534781724d0..9f62f9a1a5e9 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -66,7 +66,7 @@ static int show_irq_affinity(int type, struct seq_file *m) #else return -EINVAL; #endif - }; + } switch (type) { case AFFINITY_LIST: -- cgit v1.2.3 From 20c4d49c0f304f3f945bbd560b26afa98f75a0c4 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 25 Aug 2017 15:14:09 +0300 Subject: irqdomain: Prevent potential NULL pointer dereference in irq_domain_push_irq() This code generates a Smatch warning: kernel/irq/irqdomain.c:1511 irq_domain_push_irq() warn: variable dereferenced before check 'root_irq_data' (see line 1508) irq_get_irq_data() can return a NULL pointer, but the code dereferences the returned pointer before checking it. Move the NULL pointer check before the dereference. [ tglx: Rewrote changelog to be precise and conforming to the instructions in submitting-patches and added a Fixes tag. Sigh! ] Fixes: 495c38d3001f ("irqdomain: Add irq_domain_{push,pop}_irq() functions") Signed-off-by: Dan Carpenter Signed-off-by: Thomas Gleixner Acked-by: David Daney Cc: Marc Zyngier Cc: kernel-janitors@vger.kernel.org Link: http://lkml.kernel.org/r/20170825121409.6rfv4vt6ztz2oqkt@mwanda --- kernel/irq/irqdomain.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 1ff9912211e9..d62351714f3e 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -1504,10 +1504,10 @@ int irq_domain_push_irq(struct irq_domain *domain, int virq, void *arg) if (WARN_ON(!irq_domain_is_hierarchy(domain))) return -EINVAL; - if (domain->parent != root_irq_data->domain) + if (!root_irq_data) return -EINVAL; - if (!root_irq_data) + if (domain->parent != root_irq_data->domain) return -EINVAL; child_irq_data = kzalloc_node(sizeof(*child_irq_data), GFP_KERNEL, -- cgit v1.2.3 From b33394ba5c0974a578c24b2fecbb91a984da5e09 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 25 Aug 2017 22:34:05 +0200 Subject: genirq/proc: Avoid uninitalized variable warning MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit kernel/irq/proc.c: In function ‘show_irq_affinity’: include/linux/cpumask.h:24:29: warning: ‘mask’ may be used uninitialized in this function [-Wmaybe-uninitialized] #define cpumask_bits(maskp) ((maskp)->bits) gcc is silly, but admittedly it can't know that this won't be called with anything else than the enumerated constants. Shut up the warning by creating a default clause. Fixes: 6bc6d4abd22e ("genirq/proc: Use the the accessor to report the effective affinity Signed-off-by: Thomas Gleixner --- kernel/irq/proc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 9f62f9a1a5e9..6376b4a598d3 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -63,9 +63,9 @@ static int show_irq_affinity(int type, struct seq_file *m) #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK mask = irq_data_get_effective_affinity_mask(&desc->irq_data); break; -#else - return -EINVAL; #endif + default: + return -EINVAL; } switch (type) { -- cgit v1.2.3 From 30d6e0a4190d37740e9447e4e4815f06992dd8c3 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Thu, 24 Aug 2017 09:31:05 +0200 Subject: futex: Remove duplicated code and fix undefined behaviour There is code duplicated over all architecture's headers for futex_atomic_op_inuser. Namely op decoding, access_ok check for uaddr, and comparison of the result. Remove this duplication and leave up to the arches only the needed assembly which is now in arch_futex_atomic_op_inuser. This effectively distributes the Will Deacon's arm64 fix for undefined behaviour reported by UBSAN to all architectures. The fix was done in commit 5f16a046f8e1 (arm64: futex: Fix undefined behaviour with FUTEX_OP_OPARG_SHIFT usage). Look there for an example dump. And as suggested by Thomas, check for negative oparg too, because it was also reported to cause undefined behaviour report. Note that s390 removed access_ok check in d12a29703 ("s390/uaccess: remove pointless access_ok() checks") as access_ok there returns true. We introduce it back to the helper for the sake of simplicity (it gets optimized away anyway). Signed-off-by: Jiri Slaby Signed-off-by: Thomas Gleixner Acked-by: Russell King Acked-by: Michael Ellerman (powerpc) Acked-by: Heiko Carstens [s390] Acked-by: Chris Metcalf [for tile] Reviewed-by: Darren Hart (VMware) Reviewed-by: Will Deacon [core/arm64] Cc: linux-mips@linux-mips.org Cc: Rich Felker Cc: linux-ia64@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: peterz@infradead.org Cc: Benjamin Herrenschmidt Cc: Max Filippov Cc: Paul Mackerras Cc: sparclinux@vger.kernel.org Cc: Jonas Bonn Cc: linux-s390@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: Yoshinori Sato Cc: linux-hexagon@vger.kernel.org Cc: Helge Deller Cc: "James E.J. Bottomley" Cc: Catalin Marinas Cc: Matt Turner Cc: linux-snps-arc@lists.infradead.org Cc: Fenghua Yu Cc: Arnd Bergmann Cc: linux-xtensa@linux-xtensa.org Cc: Stefan Kristiansson Cc: openrisc@lists.librecores.org Cc: Ivan Kokshaysky Cc: Stafford Horne Cc: linux-arm-kernel@lists.infradead.org Cc: Richard Henderson Cc: Chris Zankel Cc: Michal Simek Cc: Tony Luck Cc: linux-parisc@vger.kernel.org Cc: Vineet Gupta Cc: Ralf Baechle Cc: Richard Kuo Cc: linux-alpha@vger.kernel.org Cc: Martin Schwidefsky Cc: linuxppc-dev@lists.ozlabs.org Cc: "David S. Miller" Link: http://lkml.kernel.org/r/20170824073105.3901-1-jslaby@suse.cz --- kernel/futex.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) (limited to 'kernel') diff --git a/kernel/futex.c b/kernel/futex.c index 0939255fc750..3d38eaf05492 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1551,6 +1551,45 @@ out: return ret; } +static int futex_atomic_op_inuser(unsigned int encoded_op, u32 __user *uaddr) +{ + unsigned int op = (encoded_op & 0x70000000) >> 28; + unsigned int cmp = (encoded_op & 0x0f000000) >> 24; + int oparg = sign_extend32((encoded_op & 0x00fff000) >> 12, 12); + int cmparg = sign_extend32(encoded_op & 0x00000fff, 12); + int oldval, ret; + + if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) { + if (oparg < 0 || oparg > 31) + return -EINVAL; + oparg = 1 << oparg; + } + + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + return -EFAULT; + + ret = arch_futex_atomic_op_inuser(op, oparg, &oldval, uaddr); + if (ret) + return ret; + + switch (cmp) { + case FUTEX_OP_CMP_EQ: + return oldval == cmparg; + case FUTEX_OP_CMP_NE: + return oldval != cmparg; + case FUTEX_OP_CMP_LT: + return oldval < cmparg; + case FUTEX_OP_CMP_GE: + return oldval >= cmparg; + case FUTEX_OP_CMP_LE: + return oldval <= cmparg; + case FUTEX_OP_CMP_GT: + return oldval > cmparg; + default: + return -ENOSYS; + } +} + /* * Wake up all waiters hashed on the physical page that is mapped * to this virtual address: -- cgit v1.2.3 From 2b7e8665b4ff51c034c55df3cff76518d1a9ee3a Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Fri, 25 Aug 2017 15:55:43 -0700 Subject: fork: fix incorrect fput of ->exe_file causing use-after-free Commit 7c051267931a ("mm, fork: make dup_mmap wait for mmap_sem for write killable") made it possible to kill a forking task while it is waiting to acquire its ->mmap_sem for write, in dup_mmap(). However, it was overlooked that this introduced an new error path before a reference is taken on the mm_struct's ->exe_file. Since the ->exe_file of the new mm_struct was already set to the old ->exe_file by the memcpy() in dup_mm(), it was possible for the mmput() in the error path of dup_mm() to drop a reference to ->exe_file which was never taken. This caused the struct file to later be freed prematurely. Fix it by updating mm_init() to NULL out the ->exe_file, in the same place it clears other things like the list of mmaps. This bug was found by syzkaller. It can be reproduced using the following C program: #define _GNU_SOURCE #include #include #include #include #include #include static void *mmap_thread(void *_arg) { for (;;) { mmap(NULL, 0x1000000, PROT_READ, MAP_POPULATE|MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); } } static void *fork_thread(void *_arg) { usleep(rand() % 10000); fork(); } int main(void) { fork(); fork(); fork(); for (;;) { if (fork() == 0) { pthread_t t; pthread_create(&t, NULL, mmap_thread, NULL); pthread_create(&t, NULL, fork_thread, NULL); usleep(rand() % 10000); syscall(__NR_exit_group, 0); } wait(NULL); } } No special kernel config options are needed. It usually causes a NULL pointer dereference in __remove_shared_vm_struct() during exit, or in dup_mmap() (which is usually inlined into copy_process()) during fork. Both are due to a vm_area_struct's ->vm_file being used after it's already been freed. Google Bug Id: 64772007 Link: http://lkml.kernel.org/r/20170823211408.31198-1-ebiggers3@gmail.com Fixes: 7c051267931a ("mm, fork: make dup_mmap wait for mmap_sem for write killable") Signed-off-by: Eric Biggers Tested-by: Mark Rutland Acked-by: Michal Hocko Cc: Dmitry Vyukov Cc: Ingo Molnar Cc: Konstantin Khlebnikov Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Vlastimil Babka Cc: [v4.7+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index e075b7780421..cbbea277b3fb 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -806,6 +806,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, mm_init_cpumask(mm); mm_init_aio(mm); mm_init_owner(mm, p); + RCU_INIT_POINTER(mm->exe_file, NULL); mmu_notifier_mm_init(mm); init_tlb_flush_pending(mm); #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS -- cgit v1.2.3 From 0bcdc0987cce9880436b70836c6a92bb8e744fd1 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Fri, 25 Aug 2017 15:57:04 -0700 Subject: time: Fix ktime_get_raw() incorrect base accumulation In comqit fc6eead7c1e2 ("time: Clean up CLOCK_MONOTONIC_RAW time handling"), the following code got mistakenly added to the update of the raw timekeeper: /* Update the monotonic raw base */ seconds = tk->raw_sec; nsec = (u32)(tk->tkr_raw.xtime_nsec >> tk->tkr_raw.shift); tk->tkr_raw.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec); Which adds the raw_sec value and the shifted down raw xtime_nsec to the base value. But the read function adds the shifted down tk->tkr_raw.xtime_nsec value another time, The result of this is that ktime_get_raw() users (which are all internal users) see the raw time move faster then it should (the rate at which can vary with the current size of tkr_raw.xtime_nsec), which has resulted in at least problems with graphics rendering performance. The change tried to match the monotonic base update logic: seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec); nsec = (u32) tk->wall_to_monotonic.tv_nsec; tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec); Which adds the wall_to_monotonic.tv_nsec value, but not the tk->tkr_mono.xtime_nsec value to the base. To fix this, simplify the tkr_raw.base accumulation to only accumulate the raw_sec portion, and do not include the tkr_raw.xtime_nsec portion, which will be added at read time. Fixes: fc6eead7c1e2 ("time: Clean up CLOCK_MONOTONIC_RAW time handling") Reported-and-tested-by: Chris Wilson Signed-off-by: John Stultz Signed-off-by: Thomas Gleixner Cc: Prarit Bhargava Cc: Kevin Brodsky Cc: Richard Cochran Cc: Stephen Boyd Cc: Will Deacon Cc: Miroslav Lichvar Cc: Daniel Mentz Link: http://lkml.kernel.org/r/1503701824-1645-1-git-send-email-john.stultz@linaro.org --- kernel/time/timekeeping.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index cedafa008de5..7e7e61c00d61 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -637,9 +637,7 @@ static inline void tk_update_ktime_data(struct timekeeper *tk) tk->ktime_sec = seconds; /* Update the monotonic raw base */ - seconds = tk->raw_sec; - nsec = (u32)(tk->tkr_raw.xtime_nsec >> tk->tkr_raw.shift); - tk->tkr_raw.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec); + tk->tkr_raw.base = ns_to_ktime(tk->raw_sec * NSEC_PER_SEC); } /* must hold timekeeper_lock */ -- cgit v1.2.3 From 3510ca20ece0150af6b10c77a74ff1b5c198e3e2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 27 Aug 2017 13:55:12 -0700 Subject: Minor page waitqueue cleanups Tim Chen and Kan Liang have been battling a customer load that shows extremely long page wakeup lists. The cause seems to be constant NUMA migration of a hot page that is shared across a lot of threads, but the actual root cause for the exact behavior has not been found. Tim has a patch that batches the wait list traversal at wakeup time, so that we at least don't get long uninterruptible cases where we traverse and wake up thousands of processes and get nasty latency spikes. That is likely 4.14 material, but we're still discussing the page waitqueue specific parts of it. In the meantime, I've tried to look at making the page wait queues less expensive, and failing miserably. If you have thousands of threads waiting for the same page, it will be painful. We'll need to try to figure out the NUMA balancing issue some day, in addition to avoiding the excessive spinlock hold times. That said, having tried to rewrite the page wait queues, I can at least fix up some of the braindamage in the current situation. In particular: (a) we don't want to continue walking the page wait list if the bit we're waiting for already got set again (which seems to be one of the patterns of the bad load). That makes no progress and just causes pointless cache pollution chasing the pointers. (b) we don't want to put the non-locking waiters always on the front of the queue, and the locking waiters always on the back. Not only is that unfair, it means that we wake up thousands of reading threads that will just end up being blocked by the writer later anyway. Also add a comment about the layout of 'struct wait_page_key' - there is an external user of it in the cachefiles code that means that it has to match the layout of 'struct wait_bit_key' in the two first members. It so happens to match, because 'struct page *' and 'unsigned long *' end up having the same values simply because the page flags are the first member in struct page. Cc: Tim Chen Cc: Kan Liang Cc: Mel Gorman Cc: Christopher Lameter Cc: Andi Kleen Cc: Davidlohr Bueso Cc: Peter Zijlstra Signed-off-by: Linus Torvalds --- kernel/sched/wait.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index 17f11c6b0a9f..d6afed6d0752 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -70,9 +70,10 @@ static void __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode, list_for_each_entry_safe(curr, next, &wq_head->head, entry) { unsigned flags = curr->flags; - - if (curr->func(curr, mode, wake_flags, key) && - (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) + int ret = curr->func(curr, mode, wake_flags, key); + if (ret < 0) + break; + if (ret && (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) break; } } -- cgit v1.2.3 From 464bc0fd6273d518aee79fbd37211dd9bc35d863 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 28 Aug 2017 07:10:04 -0700 Subject: bpf: convert sockmap field attach_bpf_fd2 to type In the initial sockmap API we provided strparser and verdict programs using a single attach command by extending the attach API with a the attach_bpf_fd2 field. However, if we add other programs in the future we will be adding a field for every new possible type, attach_bpf_fd(3,4,..). This seems a bit clumsy for an API. So lets push the programs using two new type fields. BPF_SK_SKB_STREAM_PARSER BPF_SK_SKB_STREAM_VERDICT This has the advantage of having a readable name and can easily be extended in the future. Updates to samples and sockmap included here also generalize tests slightly to support upcoming patch for multiple map support. Signed-off-by: John Fastabend Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support") Suggested-by: Alexei Starovoitov Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/sockmap.c | 25 ++++++++++++++----------- kernel/bpf/syscall.c | 38 +++++++++++--------------------------- 2 files changed, 25 insertions(+), 38 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 617c239590c2..cf570d108fd5 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -723,20 +723,24 @@ out: return err; } -static int sock_map_attach_prog(struct bpf_map *map, - struct bpf_prog *parse, - struct bpf_prog *verdict) +int sock_map_attach_prog(struct bpf_map *map, struct bpf_prog *prog, u32 type) { struct bpf_stab *stab = container_of(map, struct bpf_stab, map); - struct bpf_prog *_parse, *_verdict; + struct bpf_prog *orig; - _parse = xchg(&stab->bpf_parse, parse); - _verdict = xchg(&stab->bpf_verdict, verdict); + switch (type) { + case BPF_SK_SKB_STREAM_PARSER: + orig = xchg(&stab->bpf_parse, prog); + break; + case BPF_SK_SKB_STREAM_VERDICT: + orig = xchg(&stab->bpf_verdict, prog); + break; + default: + return -EOPNOTSUPP; + } - if (_parse) - bpf_prog_put(_parse); - if (_verdict) - bpf_prog_put(_verdict); + if (orig) + bpf_prog_put(orig); return 0; } @@ -777,7 +781,6 @@ const struct bpf_map_ops sock_map_ops = { .map_get_next_key = sock_map_get_next_key, .map_update_elem = sock_map_update_elem, .map_delete_elem = sock_map_delete_elem, - .map_attach = sock_map_attach_prog, }; BPF_CALL_5(bpf_sock_map_update, struct bpf_sock_ops_kern *, bpf_sock, diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 9378f3ba2cbf..021a05d9d800 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1093,12 +1093,12 @@ static int bpf_obj_get(const union bpf_attr *attr) #ifdef CONFIG_CGROUP_BPF -#define BPF_PROG_ATTACH_LAST_FIELD attach_bpf_fd2 +#define BPF_PROG_ATTACH_LAST_FIELD attach_flags -static int sockmap_get_from_fd(const union bpf_attr *attr, int ptype) +static int sockmap_get_from_fd(const union bpf_attr *attr) { - struct bpf_prog *prog1, *prog2; int ufd = attr->target_fd; + struct bpf_prog *prog; struct bpf_map *map; struct fd f; int err; @@ -1108,29 +1108,16 @@ static int sockmap_get_from_fd(const union bpf_attr *attr, int ptype) if (IS_ERR(map)) return PTR_ERR(map); - if (!map->ops->map_attach) { - fdput(f); - return -EOPNOTSUPP; - } - - prog1 = bpf_prog_get_type(attr->attach_bpf_fd, ptype); - if (IS_ERR(prog1)) { + prog = bpf_prog_get_type(attr->attach_bpf_fd, BPF_PROG_TYPE_SK_SKB); + if (IS_ERR(prog)) { fdput(f); - return PTR_ERR(prog1); - } - - prog2 = bpf_prog_get_type(attr->attach_bpf_fd2, ptype); - if (IS_ERR(prog2)) { - fdput(f); - bpf_prog_put(prog1); - return PTR_ERR(prog2); + return PTR_ERR(prog); } - err = map->ops->map_attach(map, prog1, prog2); + err = sock_map_attach_prog(map, prog, attr->attach_type); if (err) { fdput(f); - bpf_prog_put(prog1); - bpf_prog_put(prog2); + bpf_prog_put(prog); return err; } @@ -1165,16 +1152,13 @@ static int bpf_prog_attach(const union bpf_attr *attr) case BPF_CGROUP_SOCK_OPS: ptype = BPF_PROG_TYPE_SOCK_OPS; break; - case BPF_CGROUP_SMAP_INGRESS: - ptype = BPF_PROG_TYPE_SK_SKB; - break; + case BPF_SK_SKB_STREAM_PARSER: + case BPF_SK_SKB_STREAM_VERDICT: + return sockmap_get_from_fd(attr); default: return -EINVAL; } - if (attr->attach_type == BPF_CGROUP_SMAP_INGRESS) - return sockmap_get_from_fd(attr, ptype); - prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype); if (IS_ERR(prog)) return PTR_ERR(prog); -- cgit v1.2.3 From 2f857d04601a1bb56958b95a9f180bce0e91e5e6 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 28 Aug 2017 07:10:25 -0700 Subject: bpf: sockmap, remove STRPARSER map_flags and add multi-map support The addition of map_flags BPF_SOCKMAP_STRPARSER flags was to handle a specific use case where we want to have BPF parse program disabled on an entry in a sockmap. However, Alexei found the API a bit cumbersome and I agreed. Lets remove the STRPARSER flag and support the use case by allowing socks to be in multiple maps. This allows users to create two maps one with programs attached and one without. When socks are added to maps they now inherit any programs attached to the map. This is a nice generalization and IMO improves the API. The API rules are less ambiguous and do not need a flag: - When a sock is added to a sockmap we have two cases, i. The sock map does not have any attached programs so we can add sock to map without inheriting bpf programs. The sock may exist in 0 or more other maps. ii. The sock map has an attached BPF program. To avoid duplicate bpf programs we only add the sock entry if it does not have an existing strparser/verdict attached, returning -EBUSY if a program is already attached. Otherwise attach the program and inherit strparser/verdict programs from the sock map. This allows for socks to be in a multiple maps for redirects and inherit a BPF program from a single map. Also this patch simplifies the logic around BPF_{EXIST|NOEXIST|ANY} flags. In the original patch I tried to be extra clever and only update map entries when necessary. Now I've decided the complexity is not worth it. If users constantly update an entry with the same sock for no reason (i.e. update an entry without actually changing any parameters on map or sock) we still do an alloc/release. Using this and allowing multiple entries of a sock to exist in a map the logic becomes much simpler. Note: Now that multiple maps are supported the "maps" pointer called when a socket is closed becomes a list of maps to remove the sock from. To keep the map up to date when a sock is added to the sockmap we must add the map/elem in the list. Likewise when it is removed we must remove it from the list. This results in searching the per psock list on delete operation. On TCP_CLOSE events we walk the list and remove the psock from all map/entry locations. I don't see any perf implications in this because at most I have a psock in two maps. If a psock were to be in many maps its possibly this might be noticeable on delete but I can't think of a reason to dup a psock in many maps. The sk_callback_lock is used to protect read/writes to the list. This was convenient because in all locations we were taking the lock anyways just after working on the list. Also the lock is per sock so in normal cases we shouldn't see any contention. Suggested-by: Alexei Starovoitov Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support") Signed-off-by: John Fastabend Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/sockmap.c | 269 +++++++++++++++++++++++++++++++-------------------- 1 file changed, 165 insertions(+), 104 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index cf570d108fd5..a6882e54930b 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -13,15 +13,16 @@ /* A BPF sock_map is used to store sock objects. This is primarly used * for doing socket redirect with BPF helper routines. * - * A sock map may have two BPF programs attached to it, a program used - * to parse packets and a program to provide a verdict and redirect - * decision on the packet. If no BPF parse program is provided it is - * assumed that every skb is a "message" (skb->len). Otherwise the - * parse program is attached to strparser and used to build messages - * that may span multiple skbs. The verdict program will either select - * a socket to send/receive the skb on or provide the drop code indicating - * the skb should be dropped. More actions may be added later as needed. - * The default program will drop packets. + * A sock map may have BPF programs attached to it, currently a program + * used to parse packets and a program to provide a verdict and redirect + * decision on the packet are supported. Any programs attached to a sock + * map are inherited by sock objects when they are added to the map. If + * no BPF programs are attached the sock object may only be used for sock + * redirect. + * + * A sock object may be in multiple maps, but can only inherit a single + * parse or verdict program. If adding a sock object to a map would result + * in having multiple parsing programs the update will return an EBUSY error. * * For reference this program is similar to devmap used in XDP context * reviewing these together may be useful. For an example please review @@ -44,15 +45,21 @@ struct bpf_stab { struct sock **sock_map; struct bpf_prog *bpf_parse; struct bpf_prog *bpf_verdict; - refcount_t refcnt; }; enum smap_psock_state { SMAP_TX_RUNNING, }; +struct smap_psock_map_entry { + struct list_head list; + struct sock **entry; +}; + struct smap_psock { struct rcu_head rcu; + /* refcnt is used inside sk_callback_lock */ + u32 refcnt; /* datapath variables */ struct sk_buff_head rxqueue; @@ -66,10 +73,9 @@ struct smap_psock { struct strparser strp; struct bpf_prog *bpf_parse; struct bpf_prog *bpf_verdict; - struct bpf_stab *stab; + struct list_head maps; /* Back reference used when sock callback trigger sockmap operations */ - int key; struct sock *sock; unsigned long state; @@ -83,7 +89,7 @@ struct smap_psock { static inline struct smap_psock *smap_psock_sk(const struct sock *sk) { - return (struct smap_psock *)rcu_dereference_sk_user_data(sk); + return rcu_dereference_sk_user_data(sk); } static int smap_verdict_func(struct smap_psock *psock, struct sk_buff *skb) @@ -149,11 +155,12 @@ static void smap_report_sk_error(struct smap_psock *psock, int err) sk->sk_error_report(sk); } -static void smap_release_sock(struct sock *sock); +static void smap_release_sock(struct smap_psock *psock, struct sock *sock); /* Called with lock_sock(sk) held */ static void smap_state_change(struct sock *sk) { + struct smap_psock_map_entry *e, *tmp; struct smap_psock *psock; struct sock *osk; @@ -184,9 +191,15 @@ static void smap_state_change(struct sock *sk) psock = smap_psock_sk(sk); if (unlikely(!psock)) break; - osk = cmpxchg(&psock->stab->sock_map[psock->key], sk, NULL); - if (osk == sk) - smap_release_sock(sk); + write_lock_bh(&sk->sk_callback_lock); + list_for_each_entry_safe(e, tmp, &psock->maps, list) { + osk = cmpxchg(e->entry, sk, NULL); + if (osk == sk) { + list_del(&e->list); + smap_release_sock(psock, sk); + } + } + write_unlock_bh(&sk->sk_callback_lock); break; default: psock = smap_psock_sk(sk); @@ -289,9 +302,8 @@ static void smap_write_space(struct sock *sk) static void smap_stop_sock(struct smap_psock *psock, struct sock *sk) { - write_lock_bh(&sk->sk_callback_lock); if (!psock->strp_enabled) - goto out; + return; sk->sk_data_ready = psock->save_data_ready; sk->sk_write_space = psock->save_write_space; sk->sk_state_change = psock->save_state_change; @@ -300,8 +312,6 @@ static void smap_stop_sock(struct smap_psock *psock, struct sock *sk) psock->save_state_change = NULL; strp_stop(&psock->strp); psock->strp_enabled = false; -out: - write_unlock_bh(&sk->sk_callback_lock); } static void smap_destroy_psock(struct rcu_head *rcu) @@ -318,9 +328,11 @@ static void smap_destroy_psock(struct rcu_head *rcu) schedule_work(&psock->gc_work); } -static void smap_release_sock(struct sock *sock) +static void smap_release_sock(struct smap_psock *psock, struct sock *sock) { - struct smap_psock *psock = smap_psock_sk(sock); + psock->refcnt--; + if (psock->refcnt) + return; smap_stop_sock(psock, sock); clear_bit(SMAP_TX_RUNNING, &psock->state); @@ -414,6 +426,7 @@ static void sock_map_remove_complete(struct bpf_stab *stab) static void smap_gc_work(struct work_struct *w) { + struct smap_psock_map_entry *e, *tmp; struct smap_psock *psock; psock = container_of(w, struct smap_psock, gc_work); @@ -431,8 +444,10 @@ static void smap_gc_work(struct work_struct *w) if (psock->bpf_verdict) bpf_prog_put(psock->bpf_verdict); - if (refcount_dec_and_test(&psock->stab->refcnt)) - sock_map_remove_complete(psock->stab); + list_for_each_entry_safe(e, tmp, &psock->maps, list) { + list_del(&e->list); + kfree(e); + } sock_put(psock->sock); kfree(psock); @@ -453,6 +468,8 @@ static struct smap_psock *smap_init_psock(struct sock *sock, skb_queue_head_init(&psock->rxqueue); INIT_WORK(&psock->tx_work, smap_tx_work); INIT_WORK(&psock->gc_work, smap_gc_work); + INIT_LIST_HEAD(&psock->maps); + psock->refcnt = 1; rcu_assign_sk_user_data(sock, psock); sock_hold(sock); @@ -503,13 +520,24 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr) if (!stab->sock_map) goto free_stab; - refcount_set(&stab->refcnt, 1); return &stab->map; free_stab: kfree(stab); return ERR_PTR(err); } +static void smap_list_remove(struct smap_psock *psock, struct sock **entry) +{ + struct smap_psock_map_entry *e, *tmp; + + list_for_each_entry_safe(e, tmp, &psock->maps, list) { + if (e->entry == entry) { + list_del(&e->list); + break; + } + } +} + static void sock_map_free(struct bpf_map *map) { struct bpf_stab *stab = container_of(map, struct bpf_stab, map); @@ -526,13 +554,18 @@ static void sock_map_free(struct bpf_map *map) */ rcu_read_lock(); for (i = 0; i < stab->map.max_entries; i++) { + struct smap_psock *psock; struct sock *sock; sock = xchg(&stab->sock_map[i], NULL); if (!sock) continue; - smap_release_sock(sock); + write_lock_bh(&sock->sk_callback_lock); + psock = smap_psock_sk(sock); + smap_list_remove(psock, &stab->sock_map[i]); + smap_release_sock(psock, sock); + write_unlock_bh(&sock->sk_callback_lock); } rcu_read_unlock(); @@ -541,8 +574,7 @@ static void sock_map_free(struct bpf_map *map) if (stab->bpf_parse) bpf_prog_put(stab->bpf_parse); - if (refcount_dec_and_test(&stab->refcnt)) - sock_map_remove_complete(stab); + sock_map_remove_complete(stab); } static int sock_map_get_next_key(struct bpf_map *map, void *key, void *next_key) @@ -576,6 +608,7 @@ struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key) static int sock_map_delete_elem(struct bpf_map *map, void *key) { struct bpf_stab *stab = container_of(map, struct bpf_stab, map); + struct smap_psock *psock; int k = *(u32 *)key; struct sock *sock; @@ -586,7 +619,17 @@ static int sock_map_delete_elem(struct bpf_map *map, void *key) if (!sock) return -EINVAL; - smap_release_sock(sock); + write_lock_bh(&sock->sk_callback_lock); + psock = smap_psock_sk(sock); + if (!psock) + goto out; + + if (psock->bpf_parse) + smap_stop_sock(psock, sock); + smap_list_remove(psock, &stab->sock_map[k]); + smap_release_sock(psock, sock); +out: + write_unlock_bh(&sock->sk_callback_lock); return 0; } @@ -601,29 +644,34 @@ static int sock_map_delete_elem(struct bpf_map *map, void *key) * and syncd so we are certain all references from the update/lookup/delete * operations as well as references in the data path are no longer in use. * - * A psock object holds a refcnt on the sockmap it is attached to and this is - * not decremented until after a RCU grace period and garbage collection occurs. - * This ensures the map is not free'd until psocks linked to it are removed. The - * map link is used when the independent sock events trigger map deletion. + * Psocks may exist in multiple maps, but only a single set of parse/verdict + * programs may be inherited from the maps it belongs to. A reference count + * is kept with the total number of references to the psock from all maps. The + * psock will not be released until this reaches zero. The psock and sock + * user data data use the sk_callback_lock to protect critical data structures + * from concurrent access. This allows us to avoid two updates from modifying + * the user data in sock and the lock is required anyways for modifying + * callbacks, we simply increase its scope slightly. * - * Psocks may only participate in one sockmap at a time. Users that try to - * join a single sock to multiple maps will get an error. - * - * Last, but not least, it is possible the socket is closed while running - * an update on an existing psock. This will release the psock, but again - * not until the update has completed due to rcu grace period rules. + * Rules to follow, + * - psock must always be read inside RCU critical section + * - sk_user_data must only be modified inside sk_callback_lock and read + * inside RCU critical section. + * - psock->maps list must only be read & modified inside sk_callback_lock + * - sock_map must use READ_ONCE and (cmp)xchg operations + * - BPF verdict/parse programs must use READ_ONCE and xchg operations */ static int sock_map_ctx_update_elem(struct bpf_sock_ops_kern *skops, struct bpf_map *map, - void *key, u64 flags, u64 map_flags) + void *key, u64 flags) { struct bpf_stab *stab = container_of(map, struct bpf_stab, map); + struct smap_psock_map_entry *e = NULL; struct bpf_prog *verdict, *parse; - struct smap_psock *psock = NULL; - struct sock *old_sock, *sock; + struct sock *osock, *sock; + struct smap_psock *psock; u32 i = *(u32 *)key; - bool update = false; - int err = 0; + int err; if (unlikely(flags > BPF_EXIST)) return -EINVAL; @@ -631,35 +679,22 @@ static int sock_map_ctx_update_elem(struct bpf_sock_ops_kern *skops, if (unlikely(i >= stab->map.max_entries)) return -E2BIG; - if (unlikely(map_flags > BPF_SOCKMAP_STRPARSER)) - return -EINVAL; - - verdict = parse = NULL; sock = READ_ONCE(stab->sock_map[i]); - - if (flags == BPF_EXIST || flags == BPF_ANY) { - if (!sock && flags == BPF_EXIST) { - return -ENOENT; - } else if (sock && sock != skops->sk) { - return -EINVAL; - } else if (sock) { - psock = smap_psock_sk(sock); - if (unlikely(!psock)) - return -EBUSY; - update = true; - } - } else if (sock && BPF_NOEXIST) { + if (flags == BPF_EXIST && !sock) + return -ENOENT; + else if (flags == BPF_NOEXIST && sock) return -EEXIST; - } - /* reserve BPF programs early so can abort easily on failures */ - if (map_flags & BPF_SOCKMAP_STRPARSER) { - verdict = READ_ONCE(stab->bpf_verdict); - parse = READ_ONCE(stab->bpf_parse); + sock = skops->sk; - if (!verdict || !parse) - return -ENOENT; + /* 1. If sock map has BPF programs those will be inherited by the + * sock being added. If the sock is already attached to BPF programs + * this results in an error. + */ + verdict = READ_ONCE(stab->bpf_verdict); + parse = READ_ONCE(stab->bpf_parse); + if (parse && verdict) { /* bpf prog refcnt may be zero if a concurrent attach operation * removes the program after the above READ_ONCE() but before * we increment the refcnt. If this is the case abort with an @@ -676,50 +711,78 @@ static int sock_map_ctx_update_elem(struct bpf_sock_ops_kern *skops, } } - if (!psock) { - sock = skops->sk; - if (rcu_dereference_sk_user_data(sock)) - return -EEXIST; + write_lock_bh(&sock->sk_callback_lock); + psock = smap_psock_sk(sock); + + /* 2. Do not allow inheriting programs if psock exists and has + * already inherited programs. This would create confusion on + * which parser/verdict program is running. If no psock exists + * create one. Inside sk_callback_lock to ensure concurrent create + * doesn't update user data. + */ + if (psock) { + if (READ_ONCE(psock->bpf_parse) && parse) { + err = -EBUSY; + goto out_progs; + } + psock->refcnt++; + } else { psock = smap_init_psock(sock, stab); if (IS_ERR(psock)) { - if (verdict) - bpf_prog_put(verdict); - if (parse) - bpf_prog_put(parse); - return PTR_ERR(psock); + err = PTR_ERR(psock); + goto out_progs; } - psock->key = i; - psock->stab = stab; - refcount_inc(&stab->refcnt); + set_bit(SMAP_TX_RUNNING, &psock->state); } - if (map_flags & BPF_SOCKMAP_STRPARSER) { - write_lock_bh(&sock->sk_callback_lock); - if (psock->strp_enabled) - goto start_done; + e = kzalloc(sizeof(*e), GFP_ATOMIC | __GFP_NOWARN); + if (!e) { + err = -ENOMEM; + goto out_progs; + } + e->entry = &stab->sock_map[i]; + + /* 3. At this point we have a reference to a valid psock that is + * running. Attach any BPF programs needed. + */ + if (parse && verdict && !psock->strp_enabled) { err = smap_init_sock(psock, sock); if (err) - goto out; + goto out_free; smap_init_progs(psock, stab, verdict, parse); smap_start_sock(psock, sock); -start_done: - write_unlock_bh(&sock->sk_callback_lock); - } else if (update) { - smap_stop_sock(psock, sock); } - if (!update) { - old_sock = xchg(&stab->sock_map[i], skops->sk); - if (old_sock) - smap_release_sock(old_sock); - } + /* 4. Place psock in sockmap for use and stop any programs on + * the old sock assuming its not the same sock we are replacing + * it with. Because we can only have a single set of programs if + * old_sock has a strp we can stop it. + */ + list_add_tail(&e->list, &psock->maps); + write_unlock_bh(&sock->sk_callback_lock); + osock = xchg(&stab->sock_map[i], sock); + if (osock) { + struct smap_psock *opsock = smap_psock_sk(osock); + + write_lock_bh(&osock->sk_callback_lock); + if (osock != sock && parse) + smap_stop_sock(opsock, osock); + smap_list_remove(opsock, &stab->sock_map[i]); + smap_release_sock(opsock, osock); + write_unlock_bh(&osock->sk_callback_lock); + } return 0; -out: +out_free: + smap_release_sock(psock, sock); +out_progs: + if (verdict) + bpf_prog_put(verdict); + if (parse) + bpf_prog_put(parse); write_unlock_bh(&sock->sk_callback_lock); - if (!update) - smap_release_sock(sock); + kfree(e); return err; } @@ -768,8 +831,7 @@ static int sock_map_update_elem(struct bpf_map *map, return -EINVAL; } - err = sock_map_ctx_update_elem(&skops, map, key, - flags, BPF_SOCKMAP_STRPARSER); + err = sock_map_ctx_update_elem(&skops, map, key, flags); fput(socket->file); return err; } @@ -783,11 +845,11 @@ const struct bpf_map_ops sock_map_ops = { .map_delete_elem = sock_map_delete_elem, }; -BPF_CALL_5(bpf_sock_map_update, struct bpf_sock_ops_kern *, bpf_sock, - struct bpf_map *, map, void *, key, u64, flags, u64, map_flags) +BPF_CALL_4(bpf_sock_map_update, struct bpf_sock_ops_kern *, bpf_sock, + struct bpf_map *, map, void *, key, u64, flags) { WARN_ON_ONCE(!rcu_read_lock_held()); - return sock_map_ctx_update_elem(bpf_sock, map, key, flags, map_flags); + return sock_map_ctx_update_elem(bpf_sock, map, key, flags); } const struct bpf_func_proto bpf_sock_map_update_proto = { @@ -799,5 +861,4 @@ const struct bpf_func_proto bpf_sock_map_update_proto = { .arg2_type = ARG_CONST_MAP_PTR, .arg3_type = ARG_PTR_TO_MAP_KEY, .arg4_type = ARG_ANYTHING, - .arg5_type = ARG_ANYTHING, }; -- cgit v1.2.3 From d26e597d87635d90128fafb3f6bb0a14d972d952 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 28 Aug 2017 07:10:45 -0700 Subject: bpf: sockmap add missing rcu_read_(un)lock in smap_data_ready References to psock must be done inside RCU critical section. Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support") Signed-off-by: John Fastabend Signed-off-by: David S. Miller --- kernel/bpf/sockmap.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index a6882e54930b..266011c822ec 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -227,11 +227,14 @@ static void smap_data_ready(struct sock *sk) { struct smap_psock *psock; - write_lock_bh(&sk->sk_callback_lock); + rcu_read_lock(); psock = smap_psock_sk(sk); - if (likely(psock)) + if (likely(psock)) { + write_lock_bh(&sk->sk_callback_lock); strp_data_ready(&psock->strp); - write_unlock_bh(&sk->sk_callback_lock); + write_unlock_bh(&sk->sk_callback_lock); + } + rcu_read_unlock(); } static void smap_tx_work(struct work_struct *w) -- cgit v1.2.3 From 81374aaa2693f8d3cd6cf3656a02ac8cf5c7ebea Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 28 Aug 2017 07:11:43 -0700 Subject: bpf: harden sockmap program attach to ensure correct map type When attaching a program to sockmap we need to check map type is correct. Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support") Signed-off-by: John Fastabend Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/sockmap.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 266011c822ec..38bf4e4ae2fd 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -794,6 +794,9 @@ int sock_map_attach_prog(struct bpf_map *map, struct bpf_prog *prog, u32 type) struct bpf_stab *stab = container_of(map, struct bpf_stab, map); struct bpf_prog *orig; + if (unlikely(map->map_type != BPF_MAP_TYPE_SOCKMAP)) + return -EINVAL; + switch (type) { case BPF_SK_SKB_STREAM_PARSER: orig = xchg(&stab->bpf_parse, prog); -- cgit v1.2.3 From 78aeaaef997db7096a17d0d3572a7940ffa5c9a0 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 28 Aug 2017 07:12:01 -0700 Subject: bpf: sockmap indicate sock events to listeners After userspace pushes sockets into a sockmap it may not be receiving data (assuming stream_{parser|verdict} programs are attached). But, it may still want to manage the socks. A common pattern is to poll/select for a POLLRDHUP event so we can close the sock. This patch adds the logic to wake up these listeners. Also add TCP_SYN_SENT to the list of events to handle. We don't want to break the connection just because we happen to be in this state. Signed-off-by: John Fastabend Signed-off-by: David S. Miller --- kernel/bpf/sockmap.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 38bf4e4ae2fd..bcc326a2e5ce 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -162,6 +162,7 @@ static void smap_state_change(struct sock *sk) { struct smap_psock_map_entry *e, *tmp; struct smap_psock *psock; + struct socket_wq *wq; struct sock *osk; rcu_read_lock(); @@ -171,6 +172,7 @@ static void smap_state_change(struct sock *sk) * is established. */ switch (sk->sk_state) { + case TCP_SYN_SENT: case TCP_SYN_RECV: case TCP_ESTABLISHED: break; @@ -208,6 +210,10 @@ static void smap_state_change(struct sock *sk) smap_report_sk_error(psock, EPIPE); break; } + + wq = rcu_dereference(sk->sk_wq); + if (skwq_has_sleeper(wq)) + wake_up_interruptible_all(&wq->wait); rcu_read_unlock(); } -- cgit v1.2.3 From f740c34ee5cf62e1fff5ebec6d0e63efcc3cdfe9 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 25 Aug 2017 23:27:14 +0300 Subject: bpf: fix oops on allocation failure "err" is set to zero if bpf_map_area_alloc() fails so it means we return ERR_PTR(0) which is NULL. The caller, find_and_alloc_map(), is not expecting NULL returns and will oops. Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support") Signed-off-by: Dan Carpenter Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Acked-by: John Fastabend Signed-off-by: David S. Miller --- kernel/bpf/sockmap.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index bcc326a2e5ce..db0d99d2fe18 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -523,6 +523,7 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr) if (err) goto free_stab; + err = -ENOMEM; stab->sock_map = bpf_map_area_alloc(stab->map.max_entries * sizeof(struct sock *), stab->map.numa_node); -- cgit v1.2.3 From f12f42acdbb577a12eecfcebbbec41c81505c4dc Mon Sep 17 00:00:00 2001 From: Meng Xu Date: Wed, 23 Aug 2017 17:07:50 -0400 Subject: perf/core: Fix potential double-fetch bug While examining the kernel source code, I found a dangerous operation that could turn into a double-fetch situation (a race condition bug) where the same userspace memory region are fetched twice into kernel with sanity checks after the first fetch while missing checks after the second fetch. 1. The first fetch happens in line 9573 get_user(size, &uattr->size). 2. Subsequently the 'size' variable undergoes a few sanity checks and transformations (line 9577 to 9584). 3. The second fetch happens in line 9610 copy_from_user(attr, uattr, size) 4. Given that 'uattr' can be fully controlled in userspace, an attacker can race condition to override 'uattr->size' to arbitrary value (say, 0xFFFFFFFF) after the first fetch but before the second fetch. The changed value will be copied to 'attr->size'. 5. There is no further checks on 'attr->size' until the end of this function, and once the function returns, we lose the context to verify that 'attr->size' conforms to the sanity checks performed in step 2 (line 9577 to 9584). 6. My manual analysis shows that 'attr->size' is not used elsewhere later, so, there is no working exploit against it right now. However, this could easily turns to an exploitable one if careless developers start to use 'attr->size' later. To fix this, override 'attr->size' from the second fetch to the one from the first fetch, regardless of what is actually copied in. In this way, it is assured that 'attr->size' is consistent with the checks performed after the first fetch. Signed-off-by: Meng Xu Acked-by: Peter Zijlstra Cc: Linus Torvalds Cc: Thomas Gleixner Cc: acme@kernel.org Cc: alexander.shishkin@linux.intel.com Cc: meng.xu@gatech.edu Cc: sanidhya@gatech.edu Cc: taesoo@gatech.edu Link: http://lkml.kernel.org/r/1503522470-35531-1-git-send-email-meng.xu@gatech.edu Signed-off-by: Ingo Molnar --- kernel/events/core.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 3504125871d2..ce131d25622a 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9611,6 +9611,8 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr, if (ret) return -EFAULT; + attr->size = size; + if (attr->__reserved_1) return -EINVAL; -- cgit v1.2.3 From 75e8387685f6c65feb195a4556110b58f852b848 Mon Sep 17 00:00:00 2001 From: Zhou Chengming Date: Fri, 25 Aug 2017 21:49:37 +0800 Subject: perf/ftrace: Fix double traces of perf on ftrace:function When running perf on the ftrace:function tracepoint, there is a bug which can be reproduced by: perf record -e ftrace:function -a sleep 20 & perf record -e ftrace:function ls perf script ls 10304 [005] 171.853235: ftrace:function: perf_output_begin ls 10304 [005] 171.853237: ftrace:function: perf_output_begin ls 10304 [005] 171.853239: ftrace:function: task_tgid_nr_ns ls 10304 [005] 171.853240: ftrace:function: task_tgid_nr_ns ls 10304 [005] 171.853242: ftrace:function: __task_pid_nr_ns ls 10304 [005] 171.853244: ftrace:function: __task_pid_nr_ns We can see that all the function traces are doubled. The problem is caused by the inconsistency of the register function perf_ftrace_event_register() with the probe function perf_ftrace_function_call(). The former registers one probe for every perf_event. And the latter handles all perf_events on the current cpu. So when two perf_events on the current cpu, the traces of them will be doubled. So this patch adds an extra parameter "event" for perf_tp_event, only send sample data to this event when it's not NULL. Signed-off-by: Zhou Chengming Reviewed-by: Jiri Olsa Acked-by: Steven Rostedt (VMware) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: acme@kernel.org Cc: alexander.shishkin@linux.intel.com Cc: huawei.libin@huawei.com Link: http://lkml.kernel.org/r/1503668977-12526-1-git-send-email-zhouchengming1@huawei.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 13 +++++++++---- kernel/trace/trace_event_perf.c | 4 +++- kernel/trace/trace_kprobe.c | 4 ++-- kernel/trace/trace_syscalls.c | 4 ++-- kernel/trace/trace_uprobe.c | 2 +- 5 files changed, 17 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index ce131d25622a..03ac9c8b02fb 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7906,16 +7906,15 @@ void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, } } perf_tp_event(call->event.type, count, raw_data, size, regs, head, - rctx, task); + rctx, task, NULL); } EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit); void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, struct pt_regs *regs, struct hlist_head *head, int rctx, - struct task_struct *task) + struct task_struct *task, struct perf_event *event) { struct perf_sample_data data; - struct perf_event *event; struct perf_raw_record raw = { .frag = { @@ -7929,9 +7928,15 @@ void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, perf_trace_buf_update(record, event_type); - hlist_for_each_entry_rcu(event, head, hlist_entry) { + /* Use the given event instead of the hlist */ + if (event) { if (perf_tp_event_match(event, &data, regs)) perf_swevent_event(event, count, &data, regs); + } else { + hlist_for_each_entry_rcu(event, head, hlist_entry) { + if (perf_tp_event_match(event, &data, regs)) + perf_swevent_event(event, count, &data, regs); + } } /* diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 562fa69df5d3..13ba2d3f6a91 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -306,6 +306,7 @@ static void perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *ops, struct pt_regs *pt_regs) { + struct perf_event *event; struct ftrace_entry *entry; struct hlist_head *head; struct pt_regs regs; @@ -329,8 +330,9 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip, entry->ip = ip; entry->parent_ip = parent_ip; + event = container_of(ops, struct perf_event, ftrace_ops); perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, TRACE_FN, - 1, ®s, head, NULL); + 1, ®s, head, NULL, event); #undef ENTRY_SIZE } diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index c9b5aa10fbf9..8a907e12b6b9 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1200,7 +1200,7 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) memset(&entry[1], 0, dsize); store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, - head, NULL); + head, NULL, NULL); } NOKPROBE_SYMBOL(kprobe_perf_func); @@ -1236,7 +1236,7 @@ kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, entry->ret_ip = (unsigned long)ri->ret_addr; store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, - head, NULL); + head, NULL, NULL); } NOKPROBE_SYMBOL(kretprobe_perf_func); #endif /* CONFIG_PERF_EVENTS */ diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 5e10395da88e..74d9a86eccc0 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -596,7 +596,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) (unsigned long *)&rec->args); perf_trace_buf_submit(rec, size, rctx, sys_data->enter_event->event.type, 1, regs, - head, NULL); + head, NULL, NULL); } static int perf_sysenter_enable(struct trace_event_call *call) @@ -667,7 +667,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret) rec->nr = syscall_nr; rec->ret = syscall_get_return_value(current, regs); perf_trace_buf_submit(rec, size, rctx, sys_data->exit_event->event.type, - 1, regs, head, NULL); + 1, regs, head, NULL, NULL); } static int perf_sysexit_enable(struct trace_event_call *call) diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index a7581fec9681..4525e0271a53 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -1156,7 +1156,7 @@ static void __uprobe_perf_func(struct trace_uprobe *tu, } perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, - head, NULL); + head, NULL, NULL); out: preempt_enable(); } -- cgit v1.2.3 From 8d4e6c4caa12dafbcba138e5450b7af17b0b2194 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Thu, 30 Mar 2017 18:39:56 +0300 Subject: perf/core, pt, bts: Get rid of itrace_started I just noticed that hw.itrace_started and hw.config are aliased to the same location. Now, the PT driver happens to use both, which works out fine by sheer luck: - STORE(hw.itrace_start) is ordered before STORE(hw.config), in the program order, although there are no compiler barriers to ensure that, - to the perf_log_itrace_start() hw.itrace_start looks set at the same time as when it is intended to be set because both stores happen in the same path, - hw.config is never reset to zero in the PT driver. Now, the use of hw.config by the PT driver makes more sense (it being a HW PMU) than messing around with itrace_started, which is an awkward API to begin with. This patch replaces hw.itrace_started with an attach_state bit and an API call for the PMU drivers to use to communicate the condition. Signed-off-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: vince@deater.net Link: http://lkml.kernel.org/r/20170330153956.25994-1-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index e5467e107624..77fd6b11ef22 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7301,6 +7301,11 @@ static void perf_log_throttle(struct perf_event *event, int enable) perf_output_end(&handle); } +void perf_event_itrace_started(struct perf_event *event) +{ + event->attach_state |= PERF_ATTACH_ITRACE; +} + static void perf_log_itrace_start(struct perf_event *event) { struct perf_output_handle handle; @@ -7316,7 +7321,7 @@ static void perf_log_itrace_start(struct perf_event *event) event = event->parent; if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) || - event->hw.itrace_started) + event->attach_state & PERF_ATTACH_ITRACE) return; rec.header.type = PERF_RECORD_ITRACE_START; -- cgit v1.2.3 From fc7ce9c74c3ad232b084d80148654f926d01ece7 Mon Sep 17 00:00:00 2001 From: Kan Liang Date: Mon, 28 Aug 2017 20:52:49 -0400 Subject: perf/core, x86: Add PERF_SAMPLE_PHYS_ADDR For understanding how the workload maps to memory channels and hardware behavior, it's very important to collect address maps with physical addresses. For example, 3D XPoint access can only be found by filtering the physical address. Add a new sample type for physical address. perf already has a facility to collect data virtual address. This patch introduces a function to convert the virtual address to physical address. The function is quite generic and can be extended to any architecture as long as a virtual address is provided. - For kernel direct mapping addresses, virt_to_phys is used to convert the virtual addresses to physical address. - For user virtual addresses, __get_user_pages_fast is used to walk the pages tables for user physical address. - This does not work for vmalloc addresses right now. These are not resolved, but code to do that could be added. The new sample type requires collecting the virtual address. The virtual address will not be output unless SAMPLE_ADDR is applied. For security, the physical address can only be exposed to root or privileged user. Tested-by: Madhavan Srinivasan Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: acme@kernel.org Cc: mpe@ellerman.id.au Link: http://lkml.kernel.org/r/1503967969-48278-1-git-send-email-kan.liang@intel.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 77fd6b11ef22..ce64f3fed5c6 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1575,6 +1575,9 @@ static void __perf_event_header_size(struct perf_event *event, u64 sample_type) if (sample_type & PERF_SAMPLE_TRANSACTION) size += sizeof(data->txn); + if (sample_type & PERF_SAMPLE_PHYS_ADDR) + size += sizeof(data->phys_addr); + event->header_size = size; } @@ -6017,6 +6020,9 @@ void perf_output_sample(struct perf_output_handle *handle, } } + if (sample_type & PERF_SAMPLE_PHYS_ADDR) + perf_output_put(handle, data->phys_addr); + if (!event->attr.watermark) { int wakeup_events = event->attr.wakeup_events; @@ -6032,6 +6038,38 @@ void perf_output_sample(struct perf_output_handle *handle, } } +static u64 perf_virt_to_phys(u64 virt) +{ + u64 phys_addr = 0; + struct page *p = NULL; + + if (!virt) + return 0; + + if (virt >= TASK_SIZE) { + /* If it's vmalloc()d memory, leave phys_addr as 0 */ + if (virt_addr_valid((void *)(uintptr_t)virt) && + !(virt >= VMALLOC_START && virt < VMALLOC_END)) + phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt); + } else { + /* + * Walking the pages tables for user address. + * Interrupts are disabled, so it prevents any tear down + * of the page tables. + * Try IRQ-safe __get_user_pages_fast first. + * If failed, leave phys_addr as 0. + */ + if ((current->mm != NULL) && + (__get_user_pages_fast(virt, 1, 0, &p) == 1)) + phys_addr = page_to_phys(p) + virt % PAGE_SIZE; + + if (p) + put_page(p); + } + + return phys_addr; +} + void perf_prepare_sample(struct perf_event_header *header, struct perf_sample_data *data, struct perf_event *event, @@ -6150,6 +6188,9 @@ void perf_prepare_sample(struct perf_event_header *header, header->size += size; } + + if (sample_type & PERF_SAMPLE_PHYS_ADDR) + data->phys_addr = perf_virt_to_phys(data->addr); } static void __always_inline @@ -9909,6 +9950,11 @@ SYSCALL_DEFINE5(perf_event_open, return -EINVAL; } + /* Only privileged users can get physical addresses */ + if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) && + perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) + return -EACCES; + if (!attr.sample_max_stack) attr.sample_max_stack = sysctl_perf_event_max_stack; -- cgit v1.2.3 From f52be5708076b75a045ac52c6fef3fffb8300525 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 29 Aug 2017 10:59:39 +0200 Subject: locking/lockdep: Untangle xhlock history save/restore from task independence Where XHLOCK_{SOFT,HARD} are save/restore points in the xhlocks[] to ensure the temporal IRQ events don't interact with task state, the XHLOCK_PROC is a fundament different beast that just happens to share the interface. The purpose of XHLOCK_PROC is to annotate independent execution inside one task. For example workqueues, each work should appear to run in its own 'pristine' 'task'. Remove XHLOCK_PROC in favour of its own interface to avoid confusion. Signed-off-by: Peter Zijlstra (Intel) Cc: Byungchul Park Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: boqun.feng@gmail.com Cc: david@fromorbit.com Cc: johannes@sipsolutions.net Cc: kernel-team@lge.com Cc: oleg@redhat.com Cc: tj@kernel.org Link: http://lkml.kernel.org/r/20170829085939.ggmb6xiohw67micb@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 79 +++++++++++++++++++++++------------------------- kernel/workqueue.c | 9 +++--- 2 files changed, 42 insertions(+), 46 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index f73ca595b81e..44c8d0d17170 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4623,13 +4623,8 @@ asmlinkage __visible void lockdep_sys_exit(void) /* * The lock history for each syscall should be independent. So wipe the * slate clean on return to userspace. - * - * crossrelease_hist_end() works well here even when getting here - * without starting (i.e. just after forking), because it rolls back - * the index to point to the last entry, which is already invalid. */ - crossrelease_hist_end(XHLOCK_PROC); - crossrelease_hist_start(XHLOCK_PROC, false); + lockdep_invariant_state(false); } void lockdep_rcu_suspicious(const char *file, const int line, const char *s) @@ -4723,19 +4718,47 @@ static inline void invalidate_xhlock(struct hist_lock *xhlock) } /* - * Lock history stacks; we have 3 nested lock history stacks: + * Lock history stacks; we have 2 nested lock history stacks: * * HARD(IRQ) * SOFT(IRQ) - * PROC(ess) * * The thing is that once we complete a HARD/SOFT IRQ the future task locks * should not depend on any of the locks observed while running the IRQ. So * what we do is rewind the history buffer and erase all our knowledge of that * temporal event. - * - * The PROCess one is special though; it is used to annotate independence - * inside a task. + */ + +void crossrelease_hist_start(enum xhlock_context_t c) +{ + struct task_struct *cur = current; + + if (!cur->xhlocks) + return; + + cur->xhlock_idx_hist[c] = cur->xhlock_idx; + cur->hist_id_save[c] = cur->hist_id; +} + +void crossrelease_hist_end(enum xhlock_context_t c) +{ + struct task_struct *cur = current; + + if (cur->xhlocks) { + unsigned int idx = cur->xhlock_idx_hist[c]; + struct hist_lock *h = &xhlock(idx); + + cur->xhlock_idx = idx; + + /* Check if the ring was overwritten. */ + if (h->hist_id != cur->hist_id_save[c]) + invalidate_xhlock(h); + } +} + +/* + * lockdep_invariant_state() is used to annotate independence inside a task, to + * make one task look like multiple independent 'tasks'. * * Take for instance workqueues; each work is independent of the last. The * completion of a future work does not depend on the completion of a past work @@ -4758,40 +4781,14 @@ static inline void invalidate_xhlock(struct hist_lock *xhlock) * entry. Similarly, independence per-definition means it does not depend on * prior state. */ -void crossrelease_hist_start(enum xhlock_context_t c, bool force) +void lockdep_invariant_state(bool force) { - struct task_struct *cur = current; - - if (!cur->xhlocks) - return; - /* * We call this at an invariant point, no current state, no history. + * Verify the former, enforce the latter. */ - if (c == XHLOCK_PROC) { - /* verified the former, ensure the latter */ - WARN_ON_ONCE(!force && cur->lockdep_depth); - invalidate_xhlock(&xhlock(cur->xhlock_idx)); - } - - cur->xhlock_idx_hist[c] = cur->xhlock_idx; - cur->hist_id_save[c] = cur->hist_id; -} - -void crossrelease_hist_end(enum xhlock_context_t c) -{ - struct task_struct *cur = current; - - if (cur->xhlocks) { - unsigned int idx = cur->xhlock_idx_hist[c]; - struct hist_lock *h = &xhlock(idx); - - cur->xhlock_idx = idx; - - /* Check if the ring was overwritten. */ - if (h->hist_id != cur->hist_id_save[c]) - invalidate_xhlock(h); - } + WARN_ON_ONCE(!force && current->lockdep_depth); + invalidate_xhlock(&xhlock(current->xhlock_idx)); } static int cross_lock(struct lockdep_map *lock) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index c0331891dec1..ab3c0dc8c7ed 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2094,8 +2094,8 @@ __acquires(&pool->lock) lock_map_acquire(&pwq->wq->lockdep_map); lock_map_acquire(&lockdep_map); /* - * Strictly speaking we should do start(PROC) without holding any - * locks, that is, before these two lock_map_acquire()'s. + * Strictly speaking we should mark the invariant state without holding + * any locks, that is, before these two lock_map_acquire()'s. * * However, that would result in: * @@ -2107,14 +2107,14 @@ __acquires(&pool->lock) * Which would create W1->C->W1 dependencies, even though there is no * actual deadlock possible. There are two solutions, using a * read-recursive acquire on the work(queue) 'locks', but this will then - * hit the lockdep limitation on recursive locks, or simly discard + * hit the lockdep limitation on recursive locks, or simply discard * these locks. * * AFAICT there is no possible deadlock scenario between the * flush_work() and complete() primitives (except for single-threaded * workqueues), so hiding them isn't a problem. */ - crossrelease_hist_start(XHLOCK_PROC, true); + lockdep_invariant_state(true); trace_workqueue_execute_start(work); worker->current_func(work); /* @@ -2122,7 +2122,6 @@ __acquires(&pool->lock) * point will only record its address. */ trace_workqueue_execute_end(work); - crossrelease_hist_end(XHLOCK_PROC); lock_map_release(&lockdep_map); lock_map_release(&pwq->wq->lockdep_map); -- cgit v1.2.3 From 966a967116e699762dbf4af7f9e0d1955c25aa37 Mon Sep 17 00:00:00 2001 From: Ying Huang Date: Tue, 8 Aug 2017 12:30:00 +0800 Subject: smp: Avoid using two cache lines for struct call_single_data struct call_single_data is used in IPIs to transfer information between CPUs. Its size is bigger than sizeof(unsigned long) and less than cache line size. Currently it is not allocated with any explicit alignment requirements. This makes it possible for allocated call_single_data to cross two cache lines, which results in double the number of the cache lines that need to be transferred among CPUs. This can be fixed by requiring call_single_data to be aligned with the size of call_single_data. Currently the size of call_single_data is the power of 2. If we add new fields to call_single_data, we may need to add padding to make sure the size of new definition is the power of 2 as well. Fortunately, this is enforced by GCC, which will report bad sizes. To set alignment requirements of call_single_data to the size of call_single_data, a struct definition and a typedef is used. To test the effect of the patch, I used the vm-scalability multiple thread swap test case (swap-w-seq-mt). The test will create multiple threads and each thread will eat memory until all RAM and part of swap is used, so that huge number of IPIs are triggered when unmapping memory. In the test, the throughput of memory writing improves ~5% compared with misaligned call_single_data, because of faster IPIs. Suggested-by: Peter Zijlstra Signed-off-by: Huang, Ying [ Add call_single_data_t and align with size of call_single_data. ] Signed-off-by: Peter Zijlstra (Intel) Cc: Aaron Lu Cc: Borislav Petkov Cc: Eric Dumazet Cc: Juergen Gross Cc: Linus Torvalds Cc: Michael Ellerman Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/87bmnqd6lz.fsf@yhuang-mobile.sh.intel.com Signed-off-by: Ingo Molnar --- kernel/sched/sched.h | 2 +- kernel/smp.c | 32 +++++++++++++++++--------------- kernel/up.c | 2 +- 3 files changed, 19 insertions(+), 17 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index eeef1a3086d1..f29a7d2b57e1 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -769,7 +769,7 @@ struct rq { #ifdef CONFIG_SCHED_HRTICK #ifdef CONFIG_SMP int hrtick_csd_pending; - struct call_single_data hrtick_csd; + call_single_data_t hrtick_csd; #endif struct hrtimer hrtick_timer; #endif diff --git a/kernel/smp.c b/kernel/smp.c index 3061483cb3ad..81cfca9b4cc3 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -28,7 +28,7 @@ enum { }; struct call_function_data { - struct call_single_data __percpu *csd; + call_single_data_t __percpu *csd; cpumask_var_t cpumask; cpumask_var_t cpumask_ipi; }; @@ -51,7 +51,7 @@ int smpcfd_prepare_cpu(unsigned int cpu) free_cpumask_var(cfd->cpumask); return -ENOMEM; } - cfd->csd = alloc_percpu(struct call_single_data); + cfd->csd = alloc_percpu(call_single_data_t); if (!cfd->csd) { free_cpumask_var(cfd->cpumask); free_cpumask_var(cfd->cpumask_ipi); @@ -103,12 +103,12 @@ void __init call_function_init(void) * previous function call. For multi-cpu calls its even more interesting * as we'll have to ensure no other cpu is observing our csd. */ -static __always_inline void csd_lock_wait(struct call_single_data *csd) +static __always_inline void csd_lock_wait(call_single_data_t *csd) { smp_cond_load_acquire(&csd->flags, !(VAL & CSD_FLAG_LOCK)); } -static __always_inline void csd_lock(struct call_single_data *csd) +static __always_inline void csd_lock(call_single_data_t *csd) { csd_lock_wait(csd); csd->flags |= CSD_FLAG_LOCK; @@ -116,12 +116,12 @@ static __always_inline void csd_lock(struct call_single_data *csd) /* * prevent CPU from reordering the above assignment * to ->flags with any subsequent assignments to other - * fields of the specified call_single_data structure: + * fields of the specified call_single_data_t structure: */ smp_wmb(); } -static __always_inline void csd_unlock(struct call_single_data *csd) +static __always_inline void csd_unlock(call_single_data_t *csd) { WARN_ON(!(csd->flags & CSD_FLAG_LOCK)); @@ -131,14 +131,14 @@ static __always_inline void csd_unlock(struct call_single_data *csd) smp_store_release(&csd->flags, 0); } -static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data); +static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data); /* - * Insert a previously allocated call_single_data element + * Insert a previously allocated call_single_data_t element * for execution on the given CPU. data must already have * ->func, ->info, and ->flags set. */ -static int generic_exec_single(int cpu, struct call_single_data *csd, +static int generic_exec_single(int cpu, call_single_data_t *csd, smp_call_func_t func, void *info) { if (cpu == smp_processor_id()) { @@ -210,7 +210,7 @@ static void flush_smp_call_function_queue(bool warn_cpu_offline) { struct llist_head *head; struct llist_node *entry; - struct call_single_data *csd, *csd_next; + call_single_data_t *csd, *csd_next; static bool warned; WARN_ON(!irqs_disabled()); @@ -268,8 +268,10 @@ static void flush_smp_call_function_queue(bool warn_cpu_offline) int smp_call_function_single(int cpu, smp_call_func_t func, void *info, int wait) { - struct call_single_data *csd; - struct call_single_data csd_stack = { .flags = CSD_FLAG_LOCK | CSD_FLAG_SYNCHRONOUS }; + call_single_data_t *csd; + call_single_data_t csd_stack = { + .flags = CSD_FLAG_LOCK | CSD_FLAG_SYNCHRONOUS, + }; int this_cpu; int err; @@ -321,7 +323,7 @@ EXPORT_SYMBOL(smp_call_function_single); * NOTE: Be careful, there is unfortunately no current debugging facility to * validate the correctness of this serialization. */ -int smp_call_function_single_async(int cpu, struct call_single_data *csd) +int smp_call_function_single_async(int cpu, call_single_data_t *csd) { int err = 0; @@ -444,7 +446,7 @@ void smp_call_function_many(const struct cpumask *mask, cpumask_clear(cfd->cpumask_ipi); for_each_cpu(cpu, cfd->cpumask) { - struct call_single_data *csd = per_cpu_ptr(cfd->csd, cpu); + call_single_data_t *csd = per_cpu_ptr(cfd->csd, cpu); csd_lock(csd); if (wait) @@ -460,7 +462,7 @@ void smp_call_function_many(const struct cpumask *mask, if (wait) { for_each_cpu(cpu, cfd->cpumask) { - struct call_single_data *csd; + call_single_data_t *csd; csd = per_cpu_ptr(cfd->csd, cpu); csd_lock_wait(csd); diff --git a/kernel/up.c b/kernel/up.c index ee81ac9af4ca..42c46bf3e0a5 100644 --- a/kernel/up.c +++ b/kernel/up.c @@ -23,7 +23,7 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, } EXPORT_SYMBOL(smp_call_function_single); -int smp_call_function_single_async(int cpu, struct call_single_data *csd) +int smp_call_function_single_async(int cpu, call_single_data_t *csd) { unsigned long flags; -- cgit v1.2.3 From 34d54f3d6917f519693dbe873ee59cd06fb515ed Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Mon, 14 Aug 2017 16:07:02 -0400 Subject: locking/pvqspinlock: Relax cmpxchg's to improve performance on some architectures All the locking related cmpxchg's in the following functions are replaced with the _acquire variants: - pv_queued_spin_steal_lock() - trylock_clear_pending() This change should help performance on architectures that use LL/SC. The cmpxchg in pv_kick_node() is replaced with a relaxed version with explicit memory barrier to make sure that it is fully ordered in the writing of next->lock and the reading of pn->state whether the cmpxchg is a success or failure without affecting performance in non-LL/SC architectures. On a 2-socket 12-core 96-thread Power8 system with pvqspinlock explicitly enabled, the performance of a locking microbenchmark with and without this patch on a 4.13-rc4 kernel with Xinhui's PPC qspinlock patch were as follows: # of thread w/o patch with patch % Change ----------- --------- ---------- -------- 8 5054.8 Mop/s 5209.4 Mop/s +3.1% 16 3985.0 Mop/s 4015.0 Mop/s +0.8% 32 2378.2 Mop/s 2396.0 Mop/s +0.7% Suggested-by: Peter Zijlstra Signed-off-by: Waiman Long Signed-off-by: Peter Zijlstra (Intel) Cc: Andrea Parri Cc: Boqun Feng Cc: Linus Torvalds Cc: Pan Xinhui Cc: Thomas Gleixner Cc: Will Deacon Link: http://lkml.kernel.org/r/1502741222-24360-1-git-send-email-longman@redhat.com Signed-off-by: Ingo Molnar --- kernel/locking/qspinlock_paravirt.h | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h index 4ccfcaae5b89..43555681c40b 100644 --- a/kernel/locking/qspinlock_paravirt.h +++ b/kernel/locking/qspinlock_paravirt.h @@ -72,7 +72,7 @@ static inline bool pv_queued_spin_steal_lock(struct qspinlock *lock) struct __qspinlock *l = (void *)lock; if (!(atomic_read(&lock->val) & _Q_LOCKED_PENDING_MASK) && - (cmpxchg(&l->locked, 0, _Q_LOCKED_VAL) == 0)) { + (cmpxchg_acquire(&l->locked, 0, _Q_LOCKED_VAL) == 0)) { qstat_inc(qstat_pv_lock_stealing, true); return true; } @@ -101,16 +101,16 @@ static __always_inline void clear_pending(struct qspinlock *lock) /* * The pending bit check in pv_queued_spin_steal_lock() isn't a memory - * barrier. Therefore, an atomic cmpxchg() is used to acquire the lock - * just to be sure that it will get it. + * barrier. Therefore, an atomic cmpxchg_acquire() is used to acquire the + * lock just to be sure that it will get it. */ static __always_inline int trylock_clear_pending(struct qspinlock *lock) { struct __qspinlock *l = (void *)lock; return !READ_ONCE(l->locked) && - (cmpxchg(&l->locked_pending, _Q_PENDING_VAL, _Q_LOCKED_VAL) - == _Q_PENDING_VAL); + (cmpxchg_acquire(&l->locked_pending, _Q_PENDING_VAL, + _Q_LOCKED_VAL) == _Q_PENDING_VAL); } #else /* _Q_PENDING_BITS == 8 */ static __always_inline void set_pending(struct qspinlock *lock) @@ -138,7 +138,7 @@ static __always_inline int trylock_clear_pending(struct qspinlock *lock) */ old = val; new = (val & ~_Q_PENDING_MASK) | _Q_LOCKED_VAL; - val = atomic_cmpxchg(&lock->val, old, new); + val = atomic_cmpxchg_acquire(&lock->val, old, new); if (val == old) return 1; @@ -362,8 +362,18 @@ static void pv_kick_node(struct qspinlock *lock, struct mcs_spinlock *node) * observe its next->locked value and advance itself. * * Matches with smp_store_mb() and cmpxchg() in pv_wait_node() + * + * The write to next->locked in arch_mcs_spin_unlock_contended() + * must be ordered before the read of pn->state in the cmpxchg() + * below for the code to work correctly. To guarantee full ordering + * irrespective of the success or failure of the cmpxchg(), + * a relaxed version with explicit barrier is used. The control + * dependency will order the reading of pn->state before any + * subsequent writes. */ - if (cmpxchg(&pn->state, vcpu_halted, vcpu_hashed) != vcpu_halted) + smp_mb__before_atomic(); + if (cmpxchg_relaxed(&pn->state, vcpu_halted, vcpu_hashed) + != vcpu_halted) return; /* -- cgit v1.2.3 From 51218298a25e6942957c5595f2abf130d47d5df9 Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Mon, 21 Aug 2017 00:01:46 +0200 Subject: alarmtimer: Ensure RTC module is not unloaded When registering the rtc device to be used to handle alarm timers, get_device is used to ensure the device doesn't go away but the module can still be unloaded. Call try_module_get to ensure the rtc driver will not go away. Reported-and-tested-by: Michal Simek Signed-off-by: Alexandre Belloni Signed-off-by: Thomas Gleixner Acked-by: John Stultz Cc: Stephen Boyd Link: http://lkml.kernel.org/r/20170820220146.30969-1-alexandre.belloni@free-electrons.com --- kernel/time/alarmtimer.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel') diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 73a2b476e59f..ec09ce9a6012 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -28,6 +28,7 @@ #include #include #include +#include #include "posix-timers.h" @@ -103,6 +104,11 @@ static int alarmtimer_rtc_add_device(struct device *dev, spin_lock_irqsave(&rtcdev_lock, flags); if (!rtcdev) { + if (!try_module_get(rtc->owner)) { + spin_unlock_irqrestore(&rtcdev_lock, flags); + return -1; + } + rtcdev = rtc; /* hold a reference so it doesn't go away */ get_device(dev); -- cgit v1.2.3 From 065e63f951432068ba89a844fcbff68ea16ee186 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Thu, 31 Aug 2017 17:03:47 -0400 Subject: tracing: Only have rmmod clear buffers that its events were active in Currently, when a module event is enabled, when that module is removed, it clears all ring buffers. This is to prevent another module from being loaded and having one of its trace event IDs from reusing a trace event ID of the removed module. This could cause undesirable effects as the trace event of the new module would be using its own processing algorithms to process raw data of another event. To prevent this, when a module is loaded, if any of its events have been used (signified by the WAS_ENABLED event call flag, which is never cleared), all ring buffers are cleared, just in case any one of them contains event data of the removed event. The problem is, there's no reason to clear all ring buffers if only one (or less than all of them) uses one of the events. Instead, only clear the ring buffers that recorded the events of a module that is being removed. To do this, instead of keeping the WAS_ENABLED flag with the trace event call, move it to the per instance (per ring buffer) event file descriptor. The event file descriptor maps each event to a separate ring buffer instance. Then when the module is removed, only the ring buffers that activated one of the module's events get cleared. The rest are not touched. Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 3 +++ kernel/trace/trace.h | 1 + kernel/trace/trace_events.c | 15 +++++++-------- 3 files changed, 11 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 44004d8aa3b3..30338a835a51 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1702,6 +1702,9 @@ void tracing_reset_all_online_cpus(void) struct trace_array *tr; list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (!tr->clear_trace) + continue; + tr->clear_trace = false; tracing_reset_online_cpus(&tr->trace_buffer); #ifdef CONFIG_TRACER_MAX_TRACE tracing_reset_online_cpus(&tr->max_buffer); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 490ba229931d..fb5d54d0d1b3 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -245,6 +245,7 @@ struct trace_array { int stop_count; int clock_id; int nr_topts; + bool clear_trace; struct tracer *current_trace; unsigned int trace_flags; unsigned char trace_flags_index[TRACE_FLAGS_MAX_SIZE]; diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 36132f9280e6..c93540c5df21 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -466,7 +466,7 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file, set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags); /* WAS_ENABLED gets set but never cleared. */ - call->flags |= TRACE_EVENT_FL_WAS_ENABLED; + set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags); } break; } @@ -2058,6 +2058,10 @@ static void event_remove(struct trace_event_call *call) do_for_each_event_file(tr, file) { if (file->event_call != call) continue; + + if (file->flags & EVENT_FILE_FL_WAS_ENABLED) + tr->clear_trace = true; + ftrace_event_enable_disable(file, 0); /* * The do_for_each_event_file() is @@ -2396,15 +2400,11 @@ static void trace_module_add_events(struct module *mod) static void trace_module_remove_events(struct module *mod) { struct trace_event_call *call, *p; - bool clear_trace = false; down_write(&trace_event_sem); list_for_each_entry_safe(call, p, &ftrace_events, list) { - if (call->mod == mod) { - if (call->flags & TRACE_EVENT_FL_WAS_ENABLED) - clear_trace = true; + if (call->mod == mod) __trace_remove_event_call(call); - } } up_write(&trace_event_sem); @@ -2416,8 +2416,7 @@ static void trace_module_remove_events(struct module *mod) * over from this module may be passed to the new module events and * unexpected results may occur. */ - if (clear_trace) - tracing_reset_all_online_cpus(); + tracing_reset_all_online_cpus(); } static int trace_module_notify(struct notifier_block *self, -- cgit v1.2.3 From 22cf8bc6cb0d48c6d31da8eccbd4201ab9b0c4c6 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Thu, 31 Aug 2017 16:15:23 -0700 Subject: kernel/kthread.c: kthread_worker: don't hog the cpu If the worker thread continues getting work, it will hog the cpu and rcu stall complains. Make it a good citizen. This is triggered in a loop block device test. Link: http://lkml.kernel.org/r/5de0a179b3184e1a2183fc503448b0269f24d75b.1503697127.git.shli@fb.com Signed-off-by: Shaohua Li Cc: Petr Mladek Cc: Thomas Gleixner Cc: Tejun Heo Cc: Oleg Nesterov Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kthread.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/kthread.c b/kernel/kthread.c index 26db528c1d88..1c19edf82427 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -637,6 +637,7 @@ repeat: schedule(); try_to_freeze(); + cond_resched(); goto repeat; } EXPORT_SYMBOL_GPL(kthread_worker_fn); -- cgit v1.2.3 From 355627f518978b5167256d27492fe0b343aaf2f2 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Thu, 31 Aug 2017 16:15:26 -0700 Subject: mm, uprobes: fix multiple free of ->uprobes_state.xol_area Commit 7c051267931a ("mm, fork: make dup_mmap wait for mmap_sem for write killable") made it possible to kill a forking task while it is waiting to acquire its ->mmap_sem for write, in dup_mmap(). However, it was overlooked that this introduced an new error path before the new mm_struct's ->uprobes_state.xol_area has been set to NULL after being copied from the old mm_struct by the memcpy in dup_mm(). For a task that has previously hit a uprobe tracepoint, this resulted in the 'struct xol_area' being freed multiple times if the task was killed at just the right time while forking. Fix it by setting ->uprobes_state.xol_area to NULL in mm_init() rather than in uprobe_dup_mmap(). With CONFIG_UPROBE_EVENTS=y, the bug can be reproduced by the same C program given by commit 2b7e8665b4ff ("fork: fix incorrect fput of ->exe_file causing use-after-free"), provided that a uprobe tracepoint has been set on the fork_thread() function. For example: $ gcc reproducer.c -o reproducer -lpthread $ nm reproducer | grep fork_thread 0000000000400719 t fork_thread $ echo "p $PWD/reproducer:0x719" > /sys/kernel/debug/tracing/uprobe_events $ echo 1 > /sys/kernel/debug/tracing/events/uprobes/enable $ ./reproducer Here is the use-after-free reported by KASAN: BUG: KASAN: use-after-free in uprobe_clear_state+0x1c4/0x200 Read of size 8 at addr ffff8800320a8b88 by task reproducer/198 CPU: 1 PID: 198 Comm: reproducer Not tainted 4.13.0-rc7-00015-g36fde05f3fb5 #255 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014 Call Trace: dump_stack+0xdb/0x185 print_address_description+0x7e/0x290 kasan_report+0x23b/0x350 __asan_report_load8_noabort+0x19/0x20 uprobe_clear_state+0x1c4/0x200 mmput+0xd6/0x360 do_exit+0x740/0x1670 do_group_exit+0x13f/0x380 get_signal+0x597/0x17d0 do_signal+0x99/0x1df0 exit_to_usermode_loop+0x166/0x1e0 syscall_return_slowpath+0x258/0x2c0 entry_SYSCALL_64_fastpath+0xbc/0xbe ... Allocated by task 199: save_stack_trace+0x1b/0x20 kasan_kmalloc+0xfc/0x180 kmem_cache_alloc_trace+0xf3/0x330 __create_xol_area+0x10f/0x780 uprobe_notify_resume+0x1674/0x2210 exit_to_usermode_loop+0x150/0x1e0 prepare_exit_to_usermode+0x14b/0x180 retint_user+0x8/0x20 Freed by task 199: save_stack_trace+0x1b/0x20 kasan_slab_free+0xa8/0x1a0 kfree+0xba/0x210 uprobe_clear_state+0x151/0x200 mmput+0xd6/0x360 copy_process.part.8+0x605f/0x65d0 _do_fork+0x1a5/0xbd0 SyS_clone+0x19/0x20 do_syscall_64+0x22f/0x660 return_from_SYSCALL_64+0x0/0x7a Note: without KASAN, you may instead see a "Bad page state" message, or simply a general protection fault. Link: http://lkml.kernel.org/r/20170830033303.17927-1-ebiggers3@gmail.com Fixes: 7c051267931a ("mm, fork: make dup_mmap wait for mmap_sem for write killable") Signed-off-by: Eric Biggers Reported-by: Oleg Nesterov Acked-by: Oleg Nesterov Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Dmitry Vyukov Cc: Ingo Molnar Cc: Konstantin Khlebnikov Cc: Mark Rutland Cc: Michal Hocko Cc: Peter Zijlstra Cc: Vlastimil Babka Cc: [4.7+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/events/uprobes.c | 2 -- kernel/fork.c | 8 ++++++++ 2 files changed, 8 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 0e137f98a50c..267f6ef91d97 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1262,8 +1262,6 @@ void uprobe_end_dup_mmap(void) void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm) { - newmm->uprobes_state.xol_area = NULL; - if (test_bit(MMF_HAS_UPROBES, &oldmm->flags)) { set_bit(MMF_HAS_UPROBES, &newmm->flags); /* unconditionally, dup_mmap() skips VM_DONTCOPY vmas */ diff --git a/kernel/fork.c b/kernel/fork.c index cbbea277b3fb..b7e9e57b71ea 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -785,6 +785,13 @@ static void mm_init_owner(struct mm_struct *mm, struct task_struct *p) #endif } +static void mm_init_uprobes_state(struct mm_struct *mm) +{ +#ifdef CONFIG_UPROBES + mm->uprobes_state.xol_area = NULL; +#endif +} + static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, struct user_namespace *user_ns) { @@ -812,6 +819,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS mm->pmd_huge_pte = NULL; #endif + mm_init_uprobes_state(mm); if (current->mm) { mm->flags = current->mm->flags & MMF_INIT_MASK; -- cgit v1.2.3 From 2a5bfe47624bfc835aa0632a0505ba55576c98db Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Thu, 31 Aug 2017 17:36:51 -0400 Subject: ftrace: Zero out ftrace hashes when a module is removed When a ftrace filter has a module function, and that module is removed, the filter still has its address as being enabled. This can cause interesting side effects. Nothing dangerous, but unwanted functions can be traced because of it. # cd /sys/kernel/tracing # echo ':mod:snd_seq' > set_ftrace_filter # cat set_ftrace_filter snd_use_lock_sync_helper [snd_seq] check_event_type_and_length [snd_seq] snd_seq_ioctl_pversion [snd_seq] snd_seq_ioctl_client_id [snd_seq] snd_seq_ioctl_get_queue_tempo [snd_seq] update_timestamp_of_queue [snd_seq] snd_seq_ioctl_get_queue_status [snd_seq] snd_seq_set_queue_tempo [snd_seq] snd_seq_ioctl_set_queue_tempo [snd_seq] snd_seq_ioctl_get_queue_timer [snd_seq] seq_free_client1 [snd_seq] [..] # rmmod snd_seq # cat set_ftrace_filter # modprobe kvm # cat set_ftrace_filter kvm_set_cr4 [kvm] kvm_emulate_hypercall [kvm] kvm_set_dr [kvm] This is because removing the snd_seq module after it was being filtered, left the address of the snd_seq functions in the hash. When the kvm module was loaded, some of its functions were loaded at the same address as the snd_seq module. This would enable them to be filtered and traced. Now we don't want to clear the hash completely. That would cause removing a module where only its functions are filtered, to cause the tracing to enable all functions, as an empty filter means to trace all functions. Instead, just set the hash ip address to zero. Then it will never match any function. Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 55 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 96cea88fa00f..165b149ccb1a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5690,10 +5690,51 @@ static int referenced_filters(struct dyn_ftrace *rec) return cnt; } +static void +clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash) +{ + struct ftrace_func_entry *entry; + struct dyn_ftrace *rec; + int i; + + if (ftrace_hash_empty(hash)) + return; + + for (i = 0; i < pg->index; i++) { + rec = &pg->records[i]; + entry = __ftrace_lookup_ip(hash, rec->ip); + /* + * Do not allow this rec to match again. + * Yeah, it may waste some memory, but will be removed + * if/when the hash is modified again. + */ + if (entry) + entry->ip = 0; + } +} + +/* Clear any records from hashs */ +static void clear_mod_from_hashes(struct ftrace_page *pg) +{ + struct trace_array *tr; + + mutex_lock(&trace_types_lock); + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (!tr->ops || !tr->ops->func_hash) + continue; + mutex_lock(&tr->ops->func_hash->regex_lock); + clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash); + clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash); + mutex_unlock(&tr->ops->func_hash->regex_lock); + } + mutex_unlock(&trace_types_lock); +} + void ftrace_release_mod(struct module *mod) { struct dyn_ftrace *rec; struct ftrace_page **last_pg; + struct ftrace_page *tmp_page = NULL; struct ftrace_page *pg; int order; @@ -5723,14 +5764,25 @@ void ftrace_release_mod(struct module *mod) ftrace_update_tot_cnt -= pg->index; *last_pg = pg->next; - order = get_count_order(pg->size / ENTRIES_PER_PAGE); - free_pages((unsigned long)pg->records, order); - kfree(pg); + + pg->next = tmp_page; + tmp_page = pg; } else last_pg = &pg->next; } out_unlock: mutex_unlock(&ftrace_lock); + + for (pg = tmp_page; pg; pg = tmp_page) { + + /* Needs to be called outside of ftrace_lock */ + clear_mod_from_hashes(pg); + + order = get_count_order(pg->size / ENTRIES_PER_PAGE); + free_pages((unsigned long)pg->records, order); + tmp_page = pg->next; + kfree(pg); + } } void ftrace_module_enable(struct module *mod) -- cgit v1.2.3 From 46320a6acc4fb58f04bcf78c4c942cc43b20f986 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Fri, 1 Sep 2017 12:04:09 -0400 Subject: ftrace: Fix selftest goto location on error In the second iteration of trace_selftest_ops(), the error goto label is wrong in the case where trace_selftest_test_global_cnt is off. In the case of error, it leaks the dynamic ops that was allocated. Cc: stable@vger.kernel.org Fixes: 95950c2e ("ftrace: Add self-tests for multiple function trace users") Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_selftest.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index cb917cebae29..b17ec642793b 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -273,7 +273,7 @@ static int trace_selftest_ops(struct trace_array *tr, int cnt) goto out_free; if (cnt > 1) { if (trace_selftest_test_global_cnt == 0) - goto out; + goto out_free; } if (trace_selftest_test_dyn_cnt == 0) goto out_free; -- cgit v1.2.3 From cc555421bc118edd070f41258d6f55f1ccfc2558 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Thu, 31 Aug 2017 23:27:12 -0700 Subject: bpf: Inline LRU map lookup Inline the lru map lookup to save the cost in making calls to bpf_map_lookup_elem() and htab_lru_map_lookup_elem(). Different LRU hash size is tested. The benefit diminishes when the cache miss starts to dominate in the bigger LRU hash. Considering the change is simple, it is still worth to optimize. First column: Size of the LRU hash Second column: Number of lookups/s Before: > for i in $(seq 9 20); do echo "$((2**i+1)): $(./map_perf_test 1024 1 $((2**i+1)) 10000000 | awk '{print $3}')"; done 513: 1132020 1025: 1056826 2049: 1007024 4097: 853298 8193: 742723 16385: 712600 32769: 688142 65537: 677028 131073: 619437 262145: 498770 524289: 316695 1048577: 260038 After: > for i in $(seq 9 20); do echo "$((2**i+1)): $(./map_perf_test 1024 1 $((2**i+1)) 10000000 | awk '{print $3}')"; done 513: 1221851 1025: 1144695 2049: 1049902 4097: 884460 8193: 773731 16385: 729673 32769: 721989 65537: 715530 131073: 671665 262145: 516987 524289: 321125 1048577: 260048 Signed-off-by: Martin KaFai Lau Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/hashtab.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index d246905f2bb1..682f4543fefa 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -514,6 +514,24 @@ static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key) return NULL; } +static u32 htab_lru_map_gen_lookup(struct bpf_map *map, + struct bpf_insn *insn_buf) +{ + struct bpf_insn *insn = insn_buf; + const int ret = BPF_REG_0; + + *insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__htab_map_lookup_elem); + *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2); + *insn++ = BPF_ST_MEM(BPF_B, ret, + offsetof(struct htab_elem, lru_node) + + offsetof(struct bpf_lru_node, ref), + 1); + *insn++ = BPF_ALU64_IMM(BPF_ADD, ret, + offsetof(struct htab_elem, key) + + round_up(map->key_size, 8)); + return insn - insn_buf; +} + /* It is called from the bpf_lru_list when the LRU needs to delete * older elements from the htab. */ @@ -1137,6 +1155,7 @@ const struct bpf_map_ops htab_lru_map_ops = { .map_lookup_elem = htab_lru_map_lookup_elem, .map_update_elem = htab_lru_map_update_elem, .map_delete_elem = htab_lru_map_delete_elem, + .map_gen_lookup = htab_lru_map_gen_lookup, }; /* Called from eBPF program */ -- cgit v1.2.3 From bb9b9f8802212d98e70c63045b1734162945eaa5 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Thu, 31 Aug 2017 23:27:13 -0700 Subject: bpf: Only set node->ref = 1 if it has not been set This patch writes 'node->ref = 1' only if node->ref is 0. The number of lookups/s for a ~1M entries LRU map increased by ~30% (260097 to 343313). Other writes on 'node->ref = 0' is not changed. In those cases, the same cache line has to be changed anyway. First column: Size of the LRU hash Second column: Number of lookups/s Before: > echo "$((2**20+1)): $(./map_perf_test 1024 1 $((2**20+1)) 10000000 | awk '{print $3}')" 1048577: 260097 After: > echo "$((2**20+1)): $(./map_perf_test 1024 1 $((2**20+1)) 10000000 | awk '{print $3}')" 1048577: 343313 Signed-off-by: Martin KaFai Lau Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/bpf_lru_list.h | 3 ++- kernel/bpf/hashtab.c | 7 ++++++- 2 files changed, 8 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/bpf_lru_list.h b/kernel/bpf/bpf_lru_list.h index 5c35a98d02bf..7d4f89b7cb84 100644 --- a/kernel/bpf/bpf_lru_list.h +++ b/kernel/bpf/bpf_lru_list.h @@ -69,7 +69,8 @@ static inline void bpf_lru_node_set_ref(struct bpf_lru_node *node) /* ref is an approximation on access frequency. It does not * have to be very accurate. Hence, no protection is used. */ - node->ref = 1; + if (!node->ref) + node->ref = 1; } int bpf_lru_init(struct bpf_lru *lru, bool percpu, u32 hash_offset, diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 682f4543fefa..431126f31ea3 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -519,9 +519,14 @@ static u32 htab_lru_map_gen_lookup(struct bpf_map *map, { struct bpf_insn *insn = insn_buf; const int ret = BPF_REG_0; + const int ref_reg = BPF_REG_1; *insn++ = BPF_EMIT_CALL((u64 (*)(u64, u64, u64, u64, u64))__htab_map_lookup_elem); - *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2); + *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4); + *insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret, + offsetof(struct htab_elem, lru_node) + + offsetof(struct bpf_lru_node, ref)); + *insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1); *insn++ = BPF_ST_MEM(BPF_B, ret, offsetof(struct htab_elem, lru_node) + offsetof(struct bpf_lru_node, ref), -- cgit v1.2.3 From edb096e00724f02db5f6ec7900f3bbd465c6c76f Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Fri, 1 Sep 2017 12:18:28 -0400 Subject: ftrace: Fix memleak when unregistering dynamic ops when tracing disabled If function tracing is disabled by the user via the function-trace option or the proc sysctl file, and a ftrace_ops that was allocated on the heap is unregistered, then the shutdown code exits out without doing the proper clean up. This was found via kmemleak and running the ftrace selftests, as one of the tests unregisters with function tracing disabled. # cat kmemleak unreferenced object 0xffffffffa0020000 (size 4096): comm "swapper/0", pid 1, jiffies 4294668889 (age 569.209s) hex dump (first 32 bytes): 55 ff 74 24 10 55 48 89 e5 ff 74 24 18 55 48 89 U.t$.UH...t$.UH. e5 48 81 ec a8 00 00 00 48 89 44 24 50 48 89 4c .H......H.D$PH.L backtrace: [] kmemleak_vmalloc+0x85/0xf0 [] __vmalloc_node_range+0x281/0x3e0 [] module_alloc+0x4f/0x90 [] arch_ftrace_update_trampoline+0x160/0x420 [] ftrace_startup+0xe7/0x300 [] register_ftrace_function+0x72/0x90 [] trace_selftest_ops+0x204/0x397 [] trace_selftest_startup_function+0x394/0x624 [] run_tracer_selftest+0x15c/0x1d7 [] init_trace_selftests+0x75/0x192 [] do_one_initcall+0x90/0x1e2 [] kernel_init_freeable+0x350/0x3fe [] kernel_init+0x13/0x122 [] ret_from_fork+0x2a/0x40 [] 0xffffffffffffffff Cc: stable@vger.kernel.org Fixes: 12cce594fa ("ftrace/x86: Allow !CONFIG_PREEMPT dynamic ops to use allocated trampolines") Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 165b149ccb1a..6abfafd7f173 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2828,13 +2828,14 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) if (!command || !ftrace_enabled) { /* - * If these are per_cpu ops, they still need their - * per_cpu field freed. Since, function tracing is + * If these are dynamic or per_cpu ops, they still + * need their data freed. Since, function tracing is * not currently active, we can just free them * without synchronizing all CPUs. */ - if (ops->flags & FTRACE_OPS_FL_PER_CPU) - per_cpu_ops_free(ops); + if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) + goto free_ops; + return 0; } @@ -2900,6 +2901,7 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) if (IS_ENABLED(CONFIG_PREEMPT)) synchronize_rcu_tasks(); + free_ops: arch_ftrace_trampoline_free(ops); if (ops->flags & FTRACE_OPS_FL_PER_CPU) -- cgit v1.2.3 From 90a9631cf8c27a2b4702af600cad390fcabb88fb Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Fri, 1 Sep 2017 11:29:26 -0700 Subject: bpf: sockmap update/simplify memory accounting scheme Instead of tracking wmem_queued and sk_mem_charge by incrementing in the verdict SK_REDIRECT paths and decrementing in the tx work path use skb_set_owner_w and sock_writeable helpers. This solves a few issues with the current code. First, in SK_REDIRECT inc on sk_wmem_queued and sk_mem_charge were being done without the peers sock lock being held. Under stress this can result in accounting errors when tx work and/or multiple verdict decisions are working on the peer psock. Additionally, this cleans up the code because we can rely on the default destructor to decrement memory accounting on kfree_skb. Also this will trigger sk_write_space when space becomes available on kfree_skb() which wasn't happening before and prevent __sk_free from being called until all in-flight packets are completed. Fixes: 174a79ff9515 ("bpf: sockmap with sk redirect support") Signed-off-by: John Fastabend Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/sockmap.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index db0d99d2fe18..f6ffde9c6a68 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -111,7 +111,7 @@ static int smap_verdict_func(struct smap_psock *psock, struct sk_buff *skb) static void smap_do_verdict(struct smap_psock *psock, struct sk_buff *skb) { - struct sock *sock; + struct sock *sk; int rc; /* Because we use per cpu values to feed input from sock redirect @@ -123,16 +123,16 @@ static void smap_do_verdict(struct smap_psock *psock, struct sk_buff *skb) rc = smap_verdict_func(psock, skb); switch (rc) { case SK_REDIRECT: - sock = do_sk_redirect_map(); + sk = do_sk_redirect_map(); preempt_enable(); - if (likely(sock)) { - struct smap_psock *peer = smap_psock_sk(sock); + if (likely(sk)) { + struct smap_psock *peer = smap_psock_sk(sk); if (likely(peer && test_bit(SMAP_TX_RUNNING, &peer->state) && - sk_stream_memory_free(peer->sock))) { - peer->sock->sk_wmem_queued += skb->truesize; - sk_mem_charge(peer->sock, skb->truesize); + !sock_flag(sk, SOCK_DEAD) && + sock_writeable(sk))) { + skb_set_owner_w(skb, sk); skb_queue_tail(&peer->rxqueue, skb); schedule_work(&peer->tx_work); break; @@ -282,16 +282,12 @@ start: /* Hard errors break pipe and stop xmit */ smap_report_sk_error(psock, n ? -n : EPIPE); clear_bit(SMAP_TX_RUNNING, &psock->state); - sk_mem_uncharge(psock->sock, skb->truesize); - psock->sock->sk_wmem_queued -= skb->truesize; kfree_skb(skb); goto out; } rem -= n; off += n; } while (rem); - sk_mem_uncharge(psock->sock, skb->truesize); - psock->sock->sk_wmem_queued -= skb->truesize; kfree_skb(skb); } out: -- cgit v1.2.3 From b9047726386bb538cf5e4f52a9f04eb556eebc67 Mon Sep 17 00:00:00 2001 From: Deepa Dinamani Date: Wed, 2 Aug 2017 19:51:11 -0700 Subject: ipc: mqueue: Replace timespec with timespec64 struct timespec is not y2038 safe. Replace all uses of timespec by y2038 safe struct timespec64. Even though timespec is used here to represent timeouts, replace these with timespec64 so that it facilitates in verification by creating a y2038 safe kernel image that is free of timespec. The syscall interfaces themselves are not changed as part of the patch. They will be part of a different series. Signed-off-by: Deepa Dinamani Cc: Paul Moore Cc: Richard Guy Briggs Reviewed-by: Richard Guy Briggs Reviewed-by: Arnd Bergmann Acked-by: Paul Moore Signed-off-by: Al Viro --- kernel/audit.h | 2 +- kernel/auditsc.c | 12 ++++++------ 2 files changed, 7 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/audit.h b/kernel/audit.h index b331d9b83f63..9b110ae17ee3 100644 --- a/kernel/audit.h +++ b/kernel/audit.h @@ -182,7 +182,7 @@ struct audit_context { mqd_t mqdes; size_t msg_len; unsigned int msg_prio; - struct timespec abs_timeout; + struct timespec64 abs_timeout; } mq_sendrecv; struct { int oflag; diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 3260ba2312a9..daee2d5bd03a 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -1235,11 +1235,11 @@ static void show_special(struct audit_context *context, int *call_panic) case AUDIT_MQ_SENDRECV: audit_log_format(ab, "mqdes=%d msg_len=%zd msg_prio=%u " - "abs_timeout_sec=%ld abs_timeout_nsec=%ld", + "abs_timeout_sec=%lld abs_timeout_nsec=%ld", context->mq_sendrecv.mqdes, context->mq_sendrecv.msg_len, context->mq_sendrecv.msg_prio, - context->mq_sendrecv.abs_timeout.tv_sec, + (long long) context->mq_sendrecv.abs_timeout.tv_sec, context->mq_sendrecv.abs_timeout.tv_nsec); break; case AUDIT_MQ_NOTIFY: @@ -2083,15 +2083,15 @@ void __audit_mq_open(int oflag, umode_t mode, struct mq_attr *attr) * */ void __audit_mq_sendrecv(mqd_t mqdes, size_t msg_len, unsigned int msg_prio, - const struct timespec *abs_timeout) + const struct timespec64 *abs_timeout) { struct audit_context *context = current->audit_context; - struct timespec *p = &context->mq_sendrecv.abs_timeout; + struct timespec64 *p = &context->mq_sendrecv.abs_timeout; if (abs_timeout) - memcpy(p, abs_timeout, sizeof(struct timespec)); + memcpy(p, abs_timeout, sizeof(*p)); else - memset(p, 0, sizeof(struct timespec)); + memset(p, 0, sizeof(*p)); context->mq_sendrecv.mqdes = mqdes; context->mq_sendrecv.msg_len = msg_len; -- cgit v1.2.3 From bdd1d2d3d251c65b74ac4493e08db18971c09240 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 1 Sep 2017 17:39:13 +0200 Subject: fs: fix kernel_read prototype Use proper ssize_t and size_t types for the return value and count argument, move the offset last and make it an in/out argument like all other read/write helpers, and make the buf argument a void pointer to get rid of lots of casts in the callers. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- kernel/sysctl_binary.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c index 02e1859f2ca8..243fa1c28b4a 100644 --- a/kernel/sysctl_binary.c +++ b/kernel/sysctl_binary.c @@ -986,8 +986,9 @@ static ssize_t bin_intvec(struct file *file, size_t length = oldlen / sizeof(*vec); char *str, *end; int i; + loff_t pos = 0; - result = kernel_read(file, 0, buffer, BUFSZ - 1); + result = kernel_read(file, buffer, BUFSZ - 1, &pos); if (result < 0) goto out_kfree; @@ -1057,8 +1058,9 @@ static ssize_t bin_ulongvec(struct file *file, size_t length = oldlen / sizeof(*vec); char *str, *end; int i; + loff_t pos = 0; - result = kernel_read(file, 0, buffer, BUFSZ - 1); + result = kernel_read(file, buffer, BUFSZ - 1, &pos); if (result < 0) goto out_kfree; @@ -1120,8 +1122,9 @@ static ssize_t bin_uuid(struct file *file, if (oldval && oldlen) { char buf[UUID_STRING_LEN + 1]; uuid_t uuid; + loff_t pos = 0; - result = kernel_read(file, 0, buf, sizeof(buf) - 1); + result = kernel_read(file, buf, sizeof(buf) - 1, &pos); if (result < 0) goto out; @@ -1154,8 +1157,9 @@ static ssize_t bin_dn_node_address(struct file *file, char buf[15], *nodep; unsigned long area, node; __le16 dnaddr; + loff_t pos = 0; - result = kernel_read(file, 0, buf, sizeof(buf) - 1); + result = kernel_read(file, buf, sizeof(buf) - 1, &pos); if (result < 0) goto out; -- cgit v1.2.3 From e13ec939e96b13e664bb6cee361cc976a0ee621a Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 1 Sep 2017 17:39:14 +0200 Subject: fs: fix kernel_write prototype Make the position an in/out argument like all the other read/write helpers and and make the buf argument a void pointer. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- kernel/sysctl_binary.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c index 243fa1c28b4a..58ea8c03662e 100644 --- a/kernel/sysctl_binary.c +++ b/kernel/sysctl_binary.c @@ -1017,6 +1017,7 @@ static ssize_t bin_intvec(struct file *file, size_t length = newlen / sizeof(*vec); char *str, *end; int i; + loff_t pos = 0; str = buffer; end = str + BUFSZ; @@ -1030,7 +1031,7 @@ static ssize_t bin_intvec(struct file *file, str += scnprintf(str, end - str, "%lu\t", value); } - result = kernel_write(file, buffer, str - buffer, 0); + result = kernel_write(file, buffer, str - buffer, &pos); if (result < 0) goto out_kfree; } @@ -1089,6 +1090,7 @@ static ssize_t bin_ulongvec(struct file *file, size_t length = newlen / sizeof(*vec); char *str, *end; int i; + loff_t pos = 0; str = buffer; end = str + BUFSZ; @@ -1102,7 +1104,7 @@ static ssize_t bin_ulongvec(struct file *file, str += scnprintf(str, end - str, "%lu\t", value); } - result = kernel_write(file, buffer, str - buffer, 0); + result = kernel_write(file, buffer, str - buffer, &pos); if (result < 0) goto out_kfree; } @@ -1192,6 +1194,7 @@ static ssize_t bin_dn_node_address(struct file *file, __le16 dnaddr; char buf[15]; int len; + loff_t pos = 0; result = -EINVAL; if (newlen != sizeof(dnaddr)) @@ -1205,7 +1208,7 @@ static ssize_t bin_dn_node_address(struct file *file, le16_to_cpu(dnaddr) >> 10, le16_to_cpu(dnaddr) & 0x3ff); - result = kernel_write(file, buf, len, 0); + result = kernel_write(file, buf, len, &pos); if (result < 0) goto out; } -- cgit v1.2.3 From 73e18f7c0b3e1432353cdd86672c27cace7e6a7e Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 1 Sep 2017 17:39:15 +0200 Subject: fs: make the buf argument to __kernel_write a void pointer This matches kernel_read and kernel_write and avoids any need for casts in the callers. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- kernel/acct.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/acct.c b/kernel/acct.c index 5b1284370367..5e72af29ab73 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -516,7 +516,7 @@ static void do_acct_process(struct bsd_acct_struct *acct) if (file_start_write_trylock(file)) { /* it's been opened O_APPEND, so position is irrelevant */ loff_t pos = 0; - __kernel_write(file, (char *)&ac, sizeof(acct_t), &pos); + __kernel_write(file, &ac, sizeof(acct_t), &pos); file_end_write(file); } out: -- cgit v1.2.3 From e832bf48c8e12f3b39e40fee35c4ea269d685875 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 4 Jul 2017 13:11:43 +0100 Subject: audit: Reduce overhead using a coarse clock Commit 2115bb250f26 ("audit: Use timespec64 to represent audit timestamps") noted that audit timestamps were not y2038 safe and used a 64-bit timestamp. In itself, this makes sense but the conversion was from CURRENT_TIME to ktime_get_real_ts64() which is a heavier call to record an accurate timestamp which is required in some, but not all, cases. The impact is that when auditd is running without any rules that all syscalls have higher overhead. This is visible in the sysbench-thread benchmark as a 11.5% performance hit. That benchmark is dumb as rocks but it's also visible in redis as an 8-10% hit on all operations which is of greater concern. It is somewhat stupid of audit to track syscalls without any rules related to syscalls but that is how it behaves. The overhead can be directly measured with perf comparing 4.9 with 4.12 4.9 7.76% sysbench [kernel.vmlinux] [k] __schedule 7.62% sysbench [kernel.vmlinux] [k] _raw_spin_lock 7.37% sysbench libpthread-2.22.so [.] __lll_lock_elision 7.29% sysbench [kernel.vmlinux] [.] syscall_return_via_sysret 6.59% sysbench [kernel.vmlinux] [k] native_sched_clock 5.21% sysbench libc-2.22.so [.] __sched_yield 4.38% sysbench [kernel.vmlinux] [k] entry_SYSCALL_64 4.28% sysbench [kernel.vmlinux] [k] do_syscall_64 3.49% sysbench libpthread-2.22.so [.] __lll_unlock_elision 3.13% sysbench [kernel.vmlinux] [k] __audit_syscall_exit 2.87% sysbench [kernel.vmlinux] [k] update_curr 2.73% sysbench [kernel.vmlinux] [k] pick_next_task_fair 2.31% sysbench [kernel.vmlinux] [k] syscall_trace_enter 2.20% sysbench [kernel.vmlinux] [k] __audit_syscall_entry ..... 0.00% swapper [kernel.vmlinux] [k] read_tsc 4.12 7.84% sysbench [kernel.vmlinux] [k] __schedule 7.05% sysbench [kernel.vmlinux] [k] _raw_spin_lock 6.57% sysbench libpthread-2.22.so [.] __lll_lock_elision 6.50% sysbench [kernel.vmlinux] [.] syscall_return_via_sysret 5.95% sysbench [kernel.vmlinux] [k] read_tsc 5.71% sysbench [kernel.vmlinux] [k] native_sched_clock 4.78% sysbench libc-2.22.so [.] __sched_yield 4.30% sysbench [kernel.vmlinux] [k] entry_SYSCALL_64 3.94% sysbench [kernel.vmlinux] [k] do_syscall_64 3.37% sysbench libpthread-2.22.so [.] __lll_unlock_elision 3.32% sysbench [kernel.vmlinux] [k] __audit_syscall_exit 2.91% sysbench [kernel.vmlinux] [k] __getnstimeofday64 Note the additional overhead from read_tsc which goes from 0% to 5.95%. This is on a single-socket E3-1230 but similar overheads have been measured on an older machine which the patch also eliminates. The patch in question has no explanation as to why a fully-accurate timestamp is required and is likely an oversight. Using a coarser, but monotically increasing, timestamp the overhead can be eliminated. While it can be worked around by configuring or disabling audit, it's tricky enough to detect that a kernel fix is justified. With this patch, we see the following; sysbenchthread 4.9.0 4.12.0 4.12.0 vanilla vanilla coarse-v1r1 Amean 1 1.49 ( 0.00%) 1.66 ( -11.42%) 1.51 ( -1.34%) Amean 3 1.48 ( 0.00%) 1.65 ( -11.45%) 1.50 ( -0.96%) Amean 5 1.49 ( 0.00%) 1.67 ( -12.31%) 1.51 ( -1.83%) Amean 7 1.49 ( 0.00%) 1.66 ( -11.72%) 1.50 ( -0.67%) Amean 12 1.48 ( 0.00%) 1.65 ( -11.57%) 1.52 ( -2.89%) Amean 16 1.49 ( 0.00%) 1.65 ( -11.13%) 1.51 ( -1.73%) The benchmark is reporting the time required for different thread counts to lock/unlock a private mutex which, while dense, demonstrates the syscall overhead. This is showing that 4.12 took a 11-12% hit but the overhead is almost eliminated by the patch. While the variance is not reported here, it's well within the noise with the patch applied. Signed-off-by: Mel Gorman Acked-by: Arnd Bergmann Acked-by: Deepa Dinamani Signed-off-by: Paul Moore --- kernel/audit.c | 2 +- kernel/auditsc.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/audit.c b/kernel/audit.c index 6dd556931739..0cf15c77c5eb 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -1662,7 +1662,7 @@ static inline void audit_get_stamp(struct audit_context *ctx, struct timespec64 *t, unsigned int *serial) { if (!ctx || !auditsc_get_stamp(ctx, t, serial)) { - ktime_get_real_ts64(t); + *t = current_kernel_time64(); *serial = audit_serial(); } } diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 3260ba2312a9..fd72e11acfb2 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -1536,7 +1536,7 @@ void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2, return; context->serial = 0; - ktime_get_real_ts64(&context->ctime); + context->ctime = current_kernel_time64(); context->in_syscall = 1; context->current_state = state; context->ppid = 0; -- cgit v1.2.3 From 196a5085592c62ffa4eb739d7ce49c040c2953a1 Mon Sep 17 00:00:00 2001 From: Geliang Tang Date: Mon, 7 Aug 2017 21:44:24 +0800 Subject: audit: update the function comments Update the function comments to match the code. Signed-off-by: Geliang Tang Signed-off-by: Paul Moore --- kernel/audit.c | 2 +- kernel/auditsc.c | 18 +++++++++--------- 2 files changed, 10 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/audit.c b/kernel/audit.c index 0cf15c77c5eb..be1c28fd4d57 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -1833,7 +1833,7 @@ void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) } /** - * audit_log_hex - convert a buffer to hex and append it to the audit skb + * audit_log_n_hex - convert a buffer to hex and append it to the audit skb * @ab: the audit_buffer * @buf: buffer to convert to hex * @len: length of @buf to be converted diff --git a/kernel/auditsc.c b/kernel/auditsc.c index fd72e11acfb2..aac1a41f82bd 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -1462,7 +1462,7 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts } /** - * audit_free - free a per-task audit context + * __audit_free - free a per-task audit context * @tsk: task whose audit context block to free * * Called from copy_process and do_exit @@ -1489,7 +1489,7 @@ void __audit_free(struct task_struct *tsk) } /** - * audit_syscall_entry - fill in an audit record at syscall entry + * __audit_syscall_entry - fill in an audit record at syscall entry * @major: major syscall type (function) * @a1: additional syscall register 1 * @a2: additional syscall register 2 @@ -1543,7 +1543,7 @@ void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2, } /** - * audit_syscall_exit - deallocate audit context after a system call + * __audit_syscall_exit - deallocate audit context after a system call * @success: success value of the syscall * @return_code: return value of the syscall * @@ -1705,7 +1705,7 @@ static struct audit_names *audit_alloc_name(struct audit_context *context, } /** - * audit_reusename - fill out filename with info from existing entry + * __audit_reusename - fill out filename with info from existing entry * @uptr: userland ptr to pathname * * Search the audit_names list for the current audit context. If there is an @@ -1730,7 +1730,7 @@ __audit_reusename(const __user char *uptr) } /** - * audit_getname - add a name to the list + * __audit_getname - add a name to the list * @name: name to add * * Add a name to the list of audit names for this context. @@ -2135,7 +2135,7 @@ void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat) } /** - * audit_ipc_obj - record audit data for ipc object + * __audit_ipc_obj - record audit data for ipc object * @ipcp: ipc permissions * */ @@ -2151,7 +2151,7 @@ void __audit_ipc_obj(struct kern_ipc_perm *ipcp) } /** - * audit_ipc_set_perm - record audit data for new ipc permissions + * __audit_ipc_set_perm - record audit data for new ipc permissions * @qbytes: msgq bytes * @uid: msgq user id * @gid: msgq group id @@ -2180,7 +2180,7 @@ void __audit_bprm(struct linux_binprm *bprm) /** - * audit_socketcall - record audit data for sys_socketcall + * __audit_socketcall - record audit data for sys_socketcall * @nargs: number of args, which should not be more than AUDITSC_ARGS. * @args: args array * @@ -2211,7 +2211,7 @@ void __audit_fd_pair(int fd1, int fd2) } /** - * audit_sockaddr - record audit data for sys_bind, sys_connect, sys_sendto + * __audit_sockaddr - record audit data for sys_bind, sys_connect, sys_sendto * @len: data length in user space * @a: data address in kernel space * -- cgit v1.2.3 From 3d9622c12c8873911f4cc0ccdabd0362c2fca06b Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 5 Sep 2017 11:32:01 -0400 Subject: tracing: Add barrier to trace_printk() buffer nesting modification trace_printk() uses 4 buffers, one for each context (normal, softirq, irq and NMI), such that it does not need to worry about one context preempting the other. There's a nesting counter that gets incremented to figure out which buffer to use. If the context gets preempted by another context which calls trace_printk() it will increment the counter and use the next buffer, and restore the counter when it is finished. The problem is that gcc may optimize the modification of the buffer nesting counter and it may not be incremented in memory before the buffer is used. If this happens, and the context gets interrupted by another context, it could pick the same buffer and corrupt the one that is being used. Compiler barriers need to be added after the nesting variable is incremented and before it is decremented to prevent usage of the context buffers by more than one context at the same time. Cc: Andy Lutomirski Cc: stable@vger.kernel.org Fixes: e2ace00117 ("tracing: Choose static tp_printk buffer by explicit nesting count") Hat-tip-to: Peter Zijlstra Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 30338a835a51..78842557eea0 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2802,11 +2802,17 @@ static char *get_trace_buf(void) if (!buffer || buffer->nesting >= 4) return NULL; - return &buffer->buffer[buffer->nesting++][0]; + buffer->nesting++; + + /* Interrupts must see nesting incremented before we use the buffer */ + barrier(); + return &buffer->buffer[buffer->nesting][0]; } static void put_trace_buf(void) { + /* Don't let the decrement of nesting leak before this */ + barrier(); this_cpu_dec(trace_percpu_buffer->nesting); } -- cgit v1.2.3 From 7685ab6c58557c6234f3540260195ecbee7fc4b3 Mon Sep 17 00:00:00 2001 From: Chunyu Hu Date: Tue, 5 Sep 2017 13:36:46 +0800 Subject: tracing: Fix clear of RECORDED_TGID flag when disabling trace event When disabling one trace event, the RECORDED_TGID flag in the event file is not correctly cleared. It's clearing RECORDED_CMD flag when it should clear RECORDED_TGID flag. Link: http://lkml.kernel.org/r/1504589806-8425-1-git-send-email-chuhu@redhat.com Cc: Joel Fernandes Cc: stable@vger.kernel.org Fixes: d914ba37d7 ("tracing: Add support for recording tgid of tasks") Signed-off-by: Chunyu Hu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index c93540c5df21..87468398b9ed 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -406,7 +406,7 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file, if (file->flags & EVENT_FILE_FL_RECORDED_TGID) { tracing_stop_tgid_record(); - clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags); + clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags); } call->class->reg(call, TRACE_REG_UNREGISTER, file); -- cgit v1.2.3 From 96e5ae4e76f1ea950d493f510399b49308bea731 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 4 Sep 2017 22:41:02 -0700 Subject: bpf: fix numa_node validation syzkaller reported crashes in bpf map creation or map update [1] Problem is that nr_node_ids is a signed integer, NUMA_NO_NODE is also an integer, so it is very tempting to declare numa_node as a signed integer. This means the typical test to validate a user provided value : if (numa_node != NUMA_NO_NODE && (numa_node >= nr_node_ids || !node_online(numa_node))) must be written : if (numa_node != NUMA_NO_NODE && ((unsigned int)numa_node >= nr_node_ids || !node_online(numa_node))) [1] kernel BUG at mm/slab.c:3256! invalid opcode: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 2946 Comm: syzkaller916108 Not tainted 4.13.0-rc7+ #35 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801d2bc60c0 task.stack: ffff8801c0c90000 RIP: 0010:____cache_alloc_node+0x1d4/0x1e0 mm/slab.c:3292 RSP: 0018:ffff8801c0c97638 EFLAGS: 00010096 RAX: ffffffffffff8b7b RBX: 0000000001080220 RCX: 0000000000000000 RDX: 00000000ffff8b7b RSI: 0000000001080220 RDI: ffff8801dac00040 RBP: ffff8801c0c976c0 R08: 0000000000000000 R09: 0000000000000000 R10: ffff8801c0c97620 R11: 0000000000000001 R12: ffff8801dac00040 R13: ffff8801dac00040 R14: 0000000000000000 R15: 00000000ffff8b7b FS: 0000000002119940(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020001fec CR3: 00000001d2980000 CR4: 00000000001406f0 Call Trace: __do_kmalloc_node mm/slab.c:3688 [inline] __kmalloc_node+0x33/0x70 mm/slab.c:3696 kmalloc_node include/linux/slab.h:535 [inline] alloc_htab_elem+0x2a8/0x480 kernel/bpf/hashtab.c:740 htab_map_update_elem+0x740/0xb80 kernel/bpf/hashtab.c:820 map_update_elem kernel/bpf/syscall.c:587 [inline] SYSC_bpf kernel/bpf/syscall.c:1468 [inline] SyS_bpf+0x20c5/0x4c40 kernel/bpf/syscall.c:1443 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x440409 RSP: 002b:00007ffd1f1792b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440409 RDX: 0000000000000020 RSI: 0000000020006000 RDI: 0000000000000002 RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401d70 R13: 0000000000401e00 R14: 0000000000000000 R15: 0000000000000000 Code: 83 c2 01 89 50 18 4c 03 70 08 e8 38 f4 ff ff 4d 85 f6 0f 85 3e ff ff ff 44 89 fe 4c 89 ef e8 94 fb ff ff 49 89 c6 e9 2b ff ff ff <0f> 0b 0f 0b 0f 0b 66 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 RIP: ____cache_alloc_node+0x1d4/0x1e0 mm/slab.c:3292 RSP: ffff8801c0c97638 ---[ end trace d745f355da2e33ce ]--- Kernel panic - not syncing: Fatal exception Fixes: 96eabe7a40aa ("bpf: Allow selecting numa node during map creation") Signed-off-by: Eric Dumazet Cc: Martin KaFai Lau Cc: Alexei Starovoitov Cc: Daniel Borkmann Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/syscall.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 021a05d9d800..70ad8e220343 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -323,7 +323,8 @@ static int map_create(union bpf_attr *attr) return -EINVAL; if (numa_node != NUMA_NO_NODE && - (numa_node >= nr_node_ids || !node_online(numa_node))) + ((unsigned int)numa_node >= nr_node_ids || + !node_online(numa_node))) return -EINVAL; /* find map type and init map: hashtable vs rbtree vs bloom vs ... */ -- cgit v1.2.3 From 596a7a1d0989c621c3ae49be73a1d1f9de22eb5a Mon Sep 17 00:00:00 2001 From: John Keeping Date: Wed, 6 Sep 2017 10:35:40 +0100 Subject: genirq/msi: Fix populating multiple interrupts On allocating the interrupts routed via a wire-to-MSI bridge, the allocator iterates over the MSI descriptors to build the hierarchy, but fails to use the descriptor interrupt number, and instead uses the base number, generating the wrong IRQ domain mappings. The fix is to use the MSI descriptor interrupt number when setting up the interrupt instead of the base interrupt for the allocation range. The only saving grace is that although the MSI descriptors are allocated in bulk, the wired interrupts are only allocated one by one (so desc->irq == virq) and the bug went unnoticed so far. Fixes: 2145ac9310b60 ("genirq/msi: Add msi_domain_populate_irqs") Signed-off-by: John Keeping Signed-off-by: Thomas Gleixner Reviewed-by: Marc Zyngier Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20170906103540.373864a2.john@metanate.com --- kernel/irq/msi.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c index 48eadf416c24..3fa4bd59f569 100644 --- a/kernel/irq/msi.c +++ b/kernel/irq/msi.c @@ -315,11 +315,12 @@ int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev, ops->set_desc(arg, desc); /* Assumes the domain mutex is held! */ - ret = irq_domain_alloc_irqs_hierarchy(domain, virq, 1, arg); + ret = irq_domain_alloc_irqs_hierarchy(domain, desc->irq, 1, + arg); if (ret) break; - irq_set_msi_desc_off(virq, 0, desc); + irq_set_msi_desc_off(desc->irq, 0, desc); } if (ret) { -- cgit v1.2.3 From 65f3975f3584eee2da88b11f06f66e2d39fd30d0 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Wed, 6 Sep 2017 16:21:50 -0700 Subject: cgroup: revert fa06235b8eb0 ("cgroup: reset css on destruction") Commit fa06235b8eb0 ("cgroup: reset css on destruction") caused css_reset callback to be called from the offlining path. Although it solves the problem mentioned in the commit description ("For instance, memory cgroup needs to reset memory.low, otherwise pages charged to a dead cgroup might never get reclaimed."), generally speaking, it's not correct. An offline cgroup can still be a resource domain, and we shouldn't grant it more resources than it had before deletion. For instance, if an offline memory cgroup has dirty pages, we should still imply i/o limits during writeback. The css_reset callback is designed to return the cgroup state into the original state, that means reset all limits and counters. It's spomething different from the offlining, and we shouldn't use it from the offlining path. Instead, we should adjust necessary settings from the per-controller css_offline callbacks (e.g. reset memory.low). Link: http://lkml.kernel.org/r/20170727130428.28856-2-guro@fb.com Signed-off-by: Roman Gushchin Acked-by: Tejun Heo Acked-by: Johannes Weiner Cc: Vladimir Davydov Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cgroup/cgroup.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index df2e0f14a95d..f64fc967a9ef 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4100,9 +4100,6 @@ static void offline_css(struct cgroup_subsys_state *css) if (!(css->flags & CSS_ONLINE)) return; - if (ss->css_reset) - ss->css_reset(css); - if (ss->css_offline) ss->css_offline(css); -- cgit v1.2.3 From ab1b597ee0e4208a1db227bb7b2c9512c8234b48 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 6 Sep 2017 16:24:13 -0700 Subject: mm, devm_memremap_pages: use multi-order radix for ZONE_DEVICE lookups devm_memremap_pages() records mapped ranges in pgmap_radix with an entry per section's worth of memory (128MB). The key for each of those entries is a section number. This leads to false positives when devm_memremap_pages() is passed a section-unaligned range as lookups in the misalignment fail to return NULL. We can close this hole by using the pfn as the key for entries in the tree. The number of entries required to describe a remapped range is reduced by leveraging multi-order entries. In practice this approach usually yields just one entry in the tree if the size and starting address are of the same power-of-2 alignment. Previously we always needed nr_entries = mapping_size / 128MB. Link: https://lists.01.org/pipermail/linux-nvdimm/2016-August/006666.html Link: http://lkml.kernel.org/r/150215410565.39310.13767886055248249438.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Reported-by: Toshi Kani Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/memremap.c | 52 ++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 38 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/memremap.c b/kernel/memremap.c index 9afdc434fb49..066e73c2fcc9 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -194,18 +194,41 @@ struct page_map { struct vmem_altmap altmap; }; -static void pgmap_radix_release(struct resource *res) +static unsigned long order_at(struct resource *res, unsigned long pgoff) { - resource_size_t key, align_start, align_size, align_end; + unsigned long phys_pgoff = PHYS_PFN(res->start) + pgoff; + unsigned long nr_pages, mask; - align_start = res->start & ~(SECTION_SIZE - 1); - align_size = ALIGN(resource_size(res), SECTION_SIZE); - align_end = align_start + align_size - 1; + nr_pages = PHYS_PFN(resource_size(res)); + if (nr_pages == pgoff) + return ULONG_MAX; + + /* + * What is the largest aligned power-of-2 range available from + * this resource pgoff to the end of the resource range, + * considering the alignment of the current pgoff? + */ + mask = phys_pgoff | rounddown_pow_of_two(nr_pages - pgoff); + if (!mask) + return ULONG_MAX; + + return find_first_bit(&mask, BITS_PER_LONG); +} + +#define foreach_order_pgoff(res, order, pgoff) \ + for (pgoff = 0, order = order_at((res), pgoff); order < ULONG_MAX; \ + pgoff += 1UL << order, order = order_at((res), pgoff)) + +static void pgmap_radix_release(struct resource *res) +{ + unsigned long pgoff, order; mutex_lock(&pgmap_lock); - for (key = res->start; key <= res->end; key += SECTION_SIZE) - radix_tree_delete(&pgmap_radix, key >> PA_SECTION_SHIFT); + foreach_order_pgoff(res, order, pgoff) + radix_tree_delete(&pgmap_radix, PHYS_PFN(res->start) + pgoff); mutex_unlock(&pgmap_lock); + + synchronize_rcu(); } static unsigned long pfn_first(struct page_map *page_map) @@ -268,7 +291,7 @@ struct dev_pagemap *find_dev_pagemap(resource_size_t phys) WARN_ON_ONCE(!rcu_read_lock_held()); - page_map = radix_tree_lookup(&pgmap_radix, phys >> PA_SECTION_SHIFT); + page_map = radix_tree_lookup(&pgmap_radix, PHYS_PFN(phys)); return page_map ? &page_map->pgmap : NULL; } @@ -293,12 +316,12 @@ struct dev_pagemap *find_dev_pagemap(resource_size_t phys) void *devm_memremap_pages(struct device *dev, struct resource *res, struct percpu_ref *ref, struct vmem_altmap *altmap) { - resource_size_t key, align_start, align_size, align_end; + resource_size_t align_start, align_size, align_end; + unsigned long pfn, pgoff, order; pgprot_t pgprot = PAGE_KERNEL; struct dev_pagemap *pgmap; struct page_map *page_map; int error, nid, is_ram; - unsigned long pfn; align_start = res->start & ~(SECTION_SIZE - 1); align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) @@ -337,11 +360,12 @@ void *devm_memremap_pages(struct device *dev, struct resource *res, mutex_lock(&pgmap_lock); error = 0; align_end = align_start + align_size - 1; - for (key = align_start; key <= align_end; key += SECTION_SIZE) { + + foreach_order_pgoff(res, order, pgoff) { struct dev_pagemap *dup; rcu_read_lock(); - dup = find_dev_pagemap(key); + dup = find_dev_pagemap(res->start + PFN_PHYS(pgoff)); rcu_read_unlock(); if (dup) { dev_err(dev, "%s: %pr collides with mapping for %s\n", @@ -349,8 +373,8 @@ void *devm_memremap_pages(struct device *dev, struct resource *res, error = -EBUSY; break; } - error = radix_tree_insert(&pgmap_radix, key >> PA_SECTION_SHIFT, - page_map); + error = __radix_tree_insert(&pgmap_radix, + PHYS_PFN(res->start) + pgoff, order, page_map); if (error) { dev_err(dev, "%s: failed: %d\n", __func__, error); break; -- cgit v1.2.3 From da99ecf117fce6570bd3989263d68ee0007e1249 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Wed, 6 Sep 2017 16:24:53 -0700 Subject: mm: replace TIF_MEMDIE checks by tsk_is_oom_victim TIF_MEMDIE is set only to the tasks whick were either directly selected by the OOM killer or passed through mark_oom_victim from the allocator path. tsk_is_oom_victim is more generic and allows to identify all tasks (threads) which share the mm with the oom victim. Please note that the freezer still needs to check TIF_MEMDIE because we cannot thaw tasks which do not participage in oom_victims counting otherwise a !TIF_MEMDIE task could interfere after oom_disbale returns. Link: http://lkml.kernel.org/r/20170810075019.28998-3-mhocko@kernel.org Signed-off-by: Michal Hocko Cc: Mel Gorman Cc: Tetsuo Handa Cc: David Rientjes Cc: Johannes Weiner Cc: Roman Gushchin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cgroup/cpuset.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 2f4039bafebb..e7485786db9b 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -56,6 +56,7 @@ #include #include #include +#include #include #include @@ -2500,12 +2501,12 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs) * If we're in interrupt, yes, we can always allocate. If @node is set in * current's mems_allowed, yes. If it's not a __GFP_HARDWALL request and this * node is set in the nearest hardwalled cpuset ancestor to current's cpuset, - * yes. If current has access to memory reserves due to TIF_MEMDIE, yes. + * yes. If current has access to memory reserves as an oom victim, yes. * Otherwise, no. * * GFP_USER allocations are marked with the __GFP_HARDWALL bit, * and do not allow allocations outside the current tasks cpuset - * unless the task has been OOM killed as is marked TIF_MEMDIE. + * unless the task has been OOM killed. * GFP_KERNEL allocations are not so marked, so can escape to the * nearest enclosing hardwalled ancestor cpuset. * @@ -2528,7 +2529,7 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs) * affect that: * in_interrupt - any node ok (current task context irrelevant) * GFP_ATOMIC - any node ok - * TIF_MEMDIE - any node ok + * tsk_is_oom_victim - any node ok * GFP_KERNEL - any node in enclosing hardwalled cpuset ok * GFP_USER - only nodes in current tasks mems allowed ok. */ @@ -2546,7 +2547,7 @@ bool __cpuset_node_allowed(int node, gfp_t gfp_mask) * Allow tasks that have access to memory reserves because they have * been OOM killed to get memory anywhere. */ - if (unlikely(test_thread_flag(TIF_MEMDIE))) + if (unlikely(tsk_is_oom_victim(current))) return true; if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */ return false; -- cgit v1.2.3 From 212925802454672e6cd2949a727f5e2c1377bf06 Mon Sep 17 00:00:00 2001 From: Andrea Arcangeli Date: Wed, 6 Sep 2017 16:25:00 -0700 Subject: mm: oom: let oom_reap_task and exit_mmap run concurrently This is purely required because exit_aio() may block and exit_mmap() may never start, if the oom_reap_task cannot start running on a mm with mm_users == 0. At the same time if the OOM reaper doesn't wait at all for the memory of the current OOM candidate to be freed by exit_mmap->unmap_vmas, it would generate a spurious OOM kill. If it wasn't because of the exit_aio or similar blocking functions in the last mmput, it would be enough to change the oom_reap_task() in the case it finds mm_users == 0, to wait for a timeout or to wait for __mmput to set MMF_OOM_SKIP itself, but it's not just exit_mmap the problem here so the concurrency of exit_mmap and oom_reap_task is apparently warranted. It's a non standard runtime, exit_mmap() runs without mmap_sem, and oom_reap_task runs with the mmap_sem for reading as usual (kind of MADV_DONTNEED). The race between the two is solved with a combination of tsk_is_oom_victim() (serialized by task_lock) and MMF_OOM_SKIP (serialized by a dummy down_write/up_write cycle on the same lines of the ksm_exit method). If the oom_reap_task() may be running concurrently during exit_mmap, exit_mmap will wait it to finish in down_write (before taking down mm structures that would make the oom_reap_task fail with use after free). If exit_mmap comes first, oom_reap_task() will skip the mm if MMF_OOM_SKIP is already set and in turn all memory is already freed and furthermore the mm data structures may already have been taken down by free_pgtables. [aarcange@redhat.com: incremental one liner] Link: http://lkml.kernel.org/r/20170726164319.GC29716@redhat.com [rientjes@google.com: remove unused mmput_async] Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1708141733130.50317@chino.kir.corp.google.com [aarcange@redhat.com: microoptimization] Link: http://lkml.kernel.org/r/20170817171240.GB5066@redhat.com Link: http://lkml.kernel.org/r/20170726162912.GA29716@redhat.com Fixes: 26db62f179d1 ("oom: keep mm of the killed task available") Signed-off-by: Andrea Arcangeli Signed-off-by: David Rientjes Reported-by: David Rientjes Tested-by: David Rientjes Reviewed-by: Michal Hocko Cc: Tetsuo Handa Cc: Oleg Nesterov Cc: Hugh Dickins Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 17 ----------------- 1 file changed, 17 deletions(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index 4e5345c07344..7ed64600da6c 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -922,7 +922,6 @@ static inline void __mmput(struct mm_struct *mm) } if (mm->binfmt) module_put(mm->binfmt->module); - set_bit(MMF_OOM_SKIP, &mm->flags); mmdrop(mm); } @@ -938,22 +937,6 @@ void mmput(struct mm_struct *mm) } EXPORT_SYMBOL_GPL(mmput); -#ifdef CONFIG_MMU -static void mmput_async_fn(struct work_struct *work) -{ - struct mm_struct *mm = container_of(work, struct mm_struct, async_put_work); - __mmput(mm); -} - -void mmput_async(struct mm_struct *mm) -{ - if (atomic_dec_and_test(&mm->mm_users)) { - INIT_WORK(&mm->async_put_work, mmput_async_fn); - schedule_work(&mm->async_put_work); - } -} -#endif - /** * set_mm_exe_file - change a reference to the mm's executable file * -- cgit v1.2.3 From d2cd9ede6e193dd7d88b6d27399e96229a551b19 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Wed, 6 Sep 2017 16:25:15 -0700 Subject: mm,fork: introduce MADV_WIPEONFORK MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Introduce MADV_WIPEONFORK semantics, which result in a VMA being empty in the child process after fork. This differs from MADV_DONTFORK in one important way. If a child process accesses memory that was MADV_WIPEONFORK, it will get zeroes. The address ranges are still valid, they are just empty. If a child process accesses memory that was MADV_DONTFORK, it will get a segmentation fault, since those address ranges are no longer valid in the child after fork. Since MADV_DONTFORK also seems to be used to allow very large programs to fork in systems with strict memory overcommit restrictions, changing the semantics of MADV_DONTFORK might break existing programs. MADV_WIPEONFORK only works on private, anonymous VMAs. The use case is libraries that store or cache information, and want to know that they need to regenerate it in the child process after fork. Examples of this would be: - systemd/pulseaudio API checks (fail after fork) (replacing a getpid check, which is too slow without a PID cache) - PKCS#11 API reinitialization check (mandated by specification) - glibc's upcoming PRNG (reseed after fork) - OpenSSL PRNG (reseed after fork) The security benefits of a forking server having a re-inialized PRNG in every child process are pretty obvious. However, due to libraries having all kinds of internal state, and programs getting compiled with many different versions of each library, it is unreasonable to expect calling programs to re-initialize everything manually after fork. A further complication is the proliferation of clone flags, programs bypassing glibc's functions to call clone directly, and programs calling unshare, causing the glibc pthread_atfork hook to not get called. It would be better to have the kernel take care of this automatically. The patch also adds MADV_KEEPONFORK, to undo the effects of a prior MADV_WIPEONFORK. This is similar to the OpenBSD minherit syscall with MAP_INHERIT_ZERO: https://man.openbsd.org/minherit.2 [akpm@linux-foundation.org: numerically order arch/parisc/include/uapi/asm/mman.h #defines] Link: http://lkml.kernel.org/r/20170811212829.29186-3-riel@redhat.com Signed-off-by: Rik van Riel Reported-by: Florian Weimer Reported-by: Colm MacCártaigh Reviewed-by: Mike Kravetz Cc: "H. Peter Anvin" Cc: "Kirill A. Shutemov" Cc: Andy Lutomirski Cc: Dave Hansen Cc: Ingo Molnar Cc: Helge Deller Cc: Kees Cook Cc: Matthew Wilcox Cc: Thomas Gleixner Cc: Will Drewry Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index 7ed64600da6c..24a4c0be80d5 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -657,7 +657,12 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, retval = dup_userfaultfd(tmp, &uf); if (retval) goto fail_nomem_anon_vma_fork; - if (anon_vma_fork(tmp, mpnt)) + if (tmp->vm_flags & VM_WIPEONFORK) { + /* VM_WIPEONFORK gets a clean slate in the child. */ + tmp->anon_vma = NULL; + if (anon_vma_prepare(tmp)) + goto fail_nomem_anon_vma_fork; + } else if (anon_vma_fork(tmp, mpnt)) goto fail_nomem_anon_vma_fork; tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT); tmp->vm_next = tmp->vm_prev = NULL; @@ -701,7 +706,8 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, rb_parent = &tmp->vm_rb; mm->map_count++; - retval = copy_page_range(mm, oldmm, mpnt); + if (!(tmp->vm_flags & VM_WIPEONFORK)) + retval = copy_page_range(mm, oldmm, mpnt); if (tmp->vm_ops && tmp->vm_ops->open) tmp->vm_ops->open(tmp); -- cgit v1.2.3 From 170b3b1050e28d1ba0700e262f0899ffa4fccc52 Mon Sep 17 00:00:00 2001 From: Baohong Liu Date: Tue, 5 Sep 2017 16:57:19 -0500 Subject: tracing: Apply trace_clock changes to instance max buffer Currently trace_clock timestamps are applied to both regular and max buffers only for global trace. For instance trace, trace_clock timestamps are applied only to regular buffer. But, regular and max buffers can be swapped, for example, following a snapshot. So, for instance trace, bad timestamps can be seen following a snapshot. Let's apply trace_clock timestamps to instance max buffer as well. Link: http://lkml.kernel.org/r/ebdb168d0be042dcdf51f81e696b17fabe3609c1.1504642143.git.tom.zanussi@linux.intel.com Cc: stable@vger.kernel.org Fixes: 277ba0446 ("tracing: Add interface to allow multiple trace buffers") Signed-off-by: Baohong Liu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 78842557eea0..5360b7aec57a 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6229,7 +6229,7 @@ static int tracing_set_clock(struct trace_array *tr, const char *clockstr) tracing_reset_online_cpus(&tr->trace_buffer); #ifdef CONFIG_TRACER_MAX_TRACE - if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer) + if (tr->max_buffer.buffer) ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func); tracing_reset_online_cpus(&tr->max_buffer); #endif -- cgit v1.2.3 From a731ebe6f17bff9e7ca12ef227f9da4d5bdf8425 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 6 Sep 2017 12:51:31 +0200 Subject: sched/fair: Fix wake_affine_llc() balancing rules Chris Wilson reported that the SMT balance rules got the +1 on the wrong side, resulting in a bias towards the current LLC; which the load-balancer would then try and undo. Reported-by: Chris Wilson Tested-by: Chris Wilson Signed-off-by: Peter Zijlstra (Intel) Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Fixes: 90001d67be2f ("sched/fair: Fix wake_affine() for !NUMA_BALANCING") Link: http://lkml.kernel.org/r/20170906105131.gqjmaextmn3u6tj2@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 8d5868771cb3..9dd2ce1e5ca2 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5435,7 +5435,7 @@ wake_affine_llc(struct sched_domain *sd, struct task_struct *p, return false; /* if this cache has capacity, come here */ - if (this_stats.has_capacity && this_stats.nr_running < prev_stats.nr_running+1) + if (this_stats.has_capacity && this_stats.nr_running+1 < prev_stats.nr_running) return true; /* -- cgit v1.2.3 From 12ac1d0f6c3e95732d144ffa65c8b20fbd9aa462 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 5 Sep 2017 10:12:20 +0200 Subject: genirq: Make sparse_irq_lock protect what it should protect for_each_active_irq() iterates the sparse irq allocation bitmap. The caller must hold sparse_irq_lock. Several code pathes expect that an active bit in the sparse bitmap also has a valid interrupt descriptor. Unfortunately that's not true. The (de)allocation is a two step process, which holds the sparse_irq_lock only across the queue/remove from the radix tree and the set/clear in the allocation bitmap. If a iteration locks sparse_irq_lock between the two steps, then it might see an active bit but the corresponding irq descriptor is NULL. If that is dereferenced unconditionally, then the kernel oopses. Of course, all iterator sites could be audited and fixed, but.... There is no reason why the sparse_irq_lock needs to be dropped between the two steps, in fact the code becomes simpler when the mutex is held across both and the semantics become more straight forward, so future problems of missing NULL pointer checks in the iteration are avoided and all existing sites are fixed in one go. Expand the lock held sections so both operations are covered and the bitmap and the radixtree are in sync. Fixes: a05a900a51c7 ("genirq: Make sparse_lock a mutex") Reported-and-tested-by: Huang Ying Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org --- kernel/irq/irqdesc.c | 24 +++++++----------------- 1 file changed, 7 insertions(+), 17 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 73be2b3909bd..82afb7ed369f 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -421,10 +421,8 @@ static void free_desc(unsigned int irq) * The sysfs entry must be serialized against a concurrent * irq_sysfs_init() as well. */ - mutex_lock(&sparse_irq_lock); kobject_del(&desc->kobj); delete_irq_desc(irq); - mutex_unlock(&sparse_irq_lock); /* * We free the descriptor, masks and stat fields via RCU. That @@ -462,20 +460,15 @@ static int alloc_descs(unsigned int start, unsigned int cnt, int node, desc = alloc_desc(start + i, node, flags, mask, owner); if (!desc) goto err; - mutex_lock(&sparse_irq_lock); irq_insert_desc(start + i, desc); irq_sysfs_add(start + i, desc); - mutex_unlock(&sparse_irq_lock); } + bitmap_set(allocated_irqs, start, cnt); return start; err: for (i--; i >= 0; i--) free_desc(start + i); - - mutex_lock(&sparse_irq_lock); - bitmap_clear(allocated_irqs, start, cnt); - mutex_unlock(&sparse_irq_lock); return -ENOMEM; } @@ -575,6 +568,7 @@ static inline int alloc_descs(unsigned int start, unsigned int cnt, int node, desc->owner = owner; } + bitmap_set(allocated_irqs, start, cnt); return start; } @@ -670,10 +664,10 @@ void irq_free_descs(unsigned int from, unsigned int cnt) if (from >= nr_irqs || (from + cnt) > nr_irqs) return; + mutex_lock(&sparse_irq_lock); for (i = 0; i < cnt; i++) free_desc(from + i); - mutex_lock(&sparse_irq_lock); bitmap_clear(allocated_irqs, from, cnt); mutex_unlock(&sparse_irq_lock); } @@ -720,19 +714,15 @@ __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node, from, cnt, 0); ret = -EEXIST; if (irq >=0 && start != irq) - goto err; + goto unlock; if (start + cnt > nr_irqs) { ret = irq_expand_nr_irqs(start + cnt); if (ret) - goto err; + goto unlock; } - - bitmap_set(allocated_irqs, start, cnt); - mutex_unlock(&sparse_irq_lock); - return alloc_descs(start, cnt, node, affinity, owner); - -err: + ret = alloc_descs(start, cnt, node, affinity, owner); +unlock: mutex_unlock(&sparse_irq_lock); return ret; } -- cgit v1.2.3 From 50e76632339d4655859523a39249dd95ee5e93e7 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Sep 2017 11:13:38 +0200 Subject: sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs Cpusets vs. suspend-resume is _completely_ broken. And it got noticed because it now resulted in non-cpuset usage breaking too. On suspend cpuset_cpu_inactive() doesn't call into cpuset_update_active_cpus() because it doesn't want to move tasks about, there is no need, all tasks are frozen and won't run again until after we've resumed everything. But this means that when we finally do call into cpuset_update_active_cpus() after resuming the last frozen cpu in cpuset_cpu_active(), the top_cpuset will not have any difference with the cpu_active_mask and this it will not in fact do _anything_. So the cpuset configuration will not be restored. This was largely hidden because we would unconditionally create identity domains and mobile users would not in fact use cpusets much. And servers what do use cpusets tend to not suspend-resume much. An addition problem is that we'd not in fact wait for the cpuset work to finish before resuming the tasks, allowing spurious migrations outside of the specified domains. Fix the rebuild by introducing cpuset_force_rebuild() and fix the ordering with cpuset_wait_for_hotplug(). Reported-by: Andy Lutomirski Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Tejun Heo Cc: Thomas Gleixner Fixes: deb7aa308ea2 ("cpuset: reorganize CPU / memory hotplug handling") Link: http://lkml.kernel.org/r/20170907091338.orwxrqkbfkki3c24@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- kernel/cgroup/cpuset.c | 16 +++++++++++++++- kernel/power/process.c | 5 ++++- kernel/sched/core.c | 7 +++---- 3 files changed, 22 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 2f4039bafebb..0513ee39698b 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -2267,6 +2267,13 @@ retry: mutex_unlock(&cpuset_mutex); } +static bool force_rebuild; + +void cpuset_force_rebuild(void) +{ + force_rebuild = true; +} + /** * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset * @@ -2341,8 +2348,10 @@ static void cpuset_hotplug_workfn(struct work_struct *work) } /* rebuild sched domains if cpus_allowed has changed */ - if (cpus_updated) + if (cpus_updated || force_rebuild) { + force_rebuild = false; rebuild_sched_domains(); + } } void cpuset_update_active_cpus(void) @@ -2355,6 +2364,11 @@ void cpuset_update_active_cpus(void) schedule_work(&cpuset_hotplug_work); } +void cpuset_wait_for_hotplug(void) +{ + flush_work(&cpuset_hotplug_work); +} + /* * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY]. * Call this routine anytime after node_states[N_MEMORY] changes. diff --git a/kernel/power/process.c b/kernel/power/process.c index 78672d324a6e..50f25cb370c6 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -20,8 +20,9 @@ #include #include #include +#include -/* +/* * Timeout for stopping processes */ unsigned int __read_mostly freeze_timeout_msecs = 20 * MSEC_PER_SEC; @@ -202,6 +203,8 @@ void thaw_processes(void) __usermodehelper_set_disable_depth(UMH_FREEZING); thaw_workqueues(); + cpuset_wait_for_hotplug(); + read_lock(&tasklist_lock); for_each_process_thread(g, p) { /* No other threads should have PF_SUSPEND_TASK set */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 6d2c7ff9ba98..136a76d80dbf 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5556,16 +5556,15 @@ static void cpuset_cpu_active(void) * operation in the resume sequence, just build a single sched * domain, ignoring cpusets. */ - num_cpus_frozen--; - if (likely(num_cpus_frozen)) { - partition_sched_domains(1, NULL, NULL); + partition_sched_domains(1, NULL, NULL); + if (--num_cpus_frozen) return; - } /* * This is the last CPU online operation. So fall through and * restore the original sched domains by considering the * cpuset configurations. */ + cpuset_force_rebuild(); } cpuset_update_active_cpus(); } -- cgit v1.2.3 From 133ff0eac95b7dc6edf89dc51bd139a0630bbae7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= Date: Fri, 8 Sep 2017 16:11:23 -0700 Subject: mm/hmm: heterogeneous memory management (HMM for short) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit HMM provides 3 separate types of functionality: - Mirroring: synchronize CPU page table and device page table - Device memory: allocating struct page for device memory - Migration: migrating regular memory to device memory This patch introduces some common helpers and definitions to all of those 3 functionality. Link: http://lkml.kernel.org/r/20170817000548.32038-3-jglisse@redhat.com Signed-off-by: Jérôme Glisse Signed-off-by: Evgeny Baskakov Signed-off-by: John Hubbard Signed-off-by: Mark Hairgrove Signed-off-by: Sherry Cheung Signed-off-by: Subhash Gutti Cc: Aneesh Kumar Cc: Balbir Singh Cc: Benjamin Herrenschmidt Cc: Dan Williams Cc: David Nellans Cc: Johannes Weiner Cc: Kirill A. Shutemov Cc: Michal Hocko Cc: Paul E. McKenney Cc: Ross Zwisler Cc: Vladimir Davydov Cc: Bob Liu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index 24a4c0be80d5..2ccbbbfcb7b8 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include #include @@ -824,6 +825,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, mm_init_owner(mm, p); RCU_INIT_POINTER(mm->exe_file, NULL); mmu_notifier_mm_init(mm); + hmm_mm_init(mm); init_tlb_flush_pending(mm); #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS mm->pmd_huge_pte = NULL; @@ -903,6 +905,7 @@ void __mmdrop(struct mm_struct *mm) BUG_ON(mm == &init_mm); mm_free_pgd(mm); destroy_context(mm); + hmm_mm_destroy(mm); mmu_notifier_mm_destroy(mm); check_mm(mm); put_user_ns(mm->user_ns); -- cgit v1.2.3 From 5042db43cc26f51eed51c56192e2c2317e44315f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= Date: Fri, 8 Sep 2017 16:11:43 -0700 Subject: mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit HMM (heterogeneous memory management) need struct page to support migration from system main memory to device memory. Reasons for HMM and migration to device memory is explained with HMM core patch. This patch deals with device memory that is un-addressable memory (ie CPU can not access it). Hence we do not want those struct page to be manage like regular memory. That is why we extend ZONE_DEVICE to support different types of memory. A persistent memory type is define for existing user of ZONE_DEVICE and a new device un-addressable type is added for the un-addressable memory type. There is a clear separation between what is expected from each memory type and existing user of ZONE_DEVICE are un-affected by new requirement and new use of the un-addressable type. All specific code path are protect with test against the memory type. Because memory is un-addressable we use a new special swap type for when a page is migrated to device memory (this reduces the number of maximum swap file). The main two additions beside memory type to ZONE_DEVICE is two callbacks. First one, page_free() is call whenever page refcount reach 1 (which means the page is free as ZONE_DEVICE page never reach a refcount of 0). This allow device driver to manage its memory and associated struct page. The second callback page_fault() happens when there is a CPU access to an address that is back by a device page (which are un-addressable by the CPU). This callback is responsible to migrate the page back to system main memory. Device driver can not block migration back to system memory, HMM make sure that such page can not be pin into device memory. If device is in some error condition and can not migrate memory back then a CPU page fault to device memory should end with SIGBUS. [arnd@arndb.de: fix warning] Link: http://lkml.kernel.org/r/20170823133213.712917-1-arnd@arndb.de Link: http://lkml.kernel.org/r/20170817000548.32038-8-jglisse@redhat.com Signed-off-by: Jérôme Glisse Signed-off-by: Arnd Bergmann Acked-by: Dan Williams Cc: Ross Zwisler Cc: Aneesh Kumar Cc: Balbir Singh Cc: Benjamin Herrenschmidt Cc: David Nellans Cc: Evgeny Baskakov Cc: Johannes Weiner Cc: John Hubbard Cc: Kirill A. Shutemov Cc: Mark Hairgrove Cc: Michal Hocko Cc: Paul E. McKenney Cc: Sherry Cheung Cc: Subhash Gutti Cc: Vladimir Davydov Cc: Bob Liu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/memremap.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'kernel') diff --git a/kernel/memremap.c b/kernel/memremap.c index 066e73c2fcc9..f1d1e0dfe8b4 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -18,6 +18,8 @@ #include #include #include +#include +#include #ifndef ioremap_cache /* temporary while we convert existing ioremap_cache users to memremap */ @@ -219,6 +221,34 @@ static unsigned long order_at(struct resource *res, unsigned long pgoff) for (pgoff = 0, order = order_at((res), pgoff); order < ULONG_MAX; \ pgoff += 1UL << order, order = order_at((res), pgoff)) +#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) +int device_private_entry_fault(struct vm_area_struct *vma, + unsigned long addr, + swp_entry_t entry, + unsigned int flags, + pmd_t *pmdp) +{ + struct page *page = device_private_entry_to_page(entry); + + /* + * The page_fault() callback must migrate page back to system memory + * so that CPU can access it. This might fail for various reasons + * (device issue, device was unsafely unplugged, ...). When such + * error conditions happen, the callback must return VM_FAULT_SIGBUS. + * + * Note that because memory cgroup charges are accounted to the device + * memory, this should never fail because of memory restrictions (but + * allocation of regular system page might still fail because we are + * out of memory). + * + * There is a more in-depth description of what that callback can and + * cannot do, in include/linux/memremap.h + */ + return page->pgmap->page_fault(vma, addr, page, flags, pmdp); +} +EXPORT_SYMBOL(device_private_entry_fault); +#endif /* CONFIG_DEVICE_PRIVATE */ + static void pgmap_radix_release(struct resource *res) { unsigned long pgoff, order; @@ -356,6 +386,10 @@ void *devm_memremap_pages(struct device *dev, struct resource *res, } pgmap->ref = ref; pgmap->res = &page_map->res; + pgmap->type = MEMORY_DEVICE_HOST; + pgmap->page_fault = NULL; + pgmap->page_free = NULL; + pgmap->data = NULL; mutex_lock(&pgmap_lock); error = 0; -- cgit v1.2.3 From 7b2d55d2c8961ae9d456d3133f4ae2f0fbd3e14f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= Date: Fri, 8 Sep 2017 16:11:46 -0700 Subject: mm/ZONE_DEVICE: special case put_page() for device private pages MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A ZONE_DEVICE page that reach a refcount of 1 is free ie no longer have any user. For device private pages this is important to catch and thus we need to special case put_page() for this. Link: http://lkml.kernel.org/r/20170817000548.32038-9-jglisse@redhat.com Signed-off-by: Jérôme Glisse Cc: Kirill A. Shutemov Cc: Dan Williams Cc: Ross Zwisler Cc: Aneesh Kumar Cc: Balbir Singh Cc: Benjamin Herrenschmidt Cc: David Nellans Cc: Evgeny Baskakov Cc: Johannes Weiner Cc: John Hubbard Cc: Mark Hairgrove Cc: Michal Hocko Cc: Paul E. McKenney Cc: Sherry Cheung Cc: Subhash Gutti Cc: Vladimir Davydov Cc: Bob Liu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/memremap.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/memremap.c b/kernel/memremap.c index f1d1e0dfe8b4..1403cf16fa61 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -11,7 +11,6 @@ * General Public License for more details. */ #include -#include #include #include #include @@ -500,3 +499,27 @@ struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start) return pgmap ? pgmap->altmap : NULL; } #endif /* CONFIG_ZONE_DEVICE */ + + +#ifdef CONFIG_DEVICE_PRIVATE +void put_zone_device_private_page(struct page *page) +{ + int count = page_ref_dec_return(page); + + /* + * If refcount is 1 then page is freed and refcount is stable as nobody + * holds a reference on the page. + */ + if (count == 1) { + /* Clear Active bit in case of parallel mark_page_accessed */ + __ClearPageActive(page); + __ClearPageWaiters(page); + + page->mapping = NULL; + + page->pgmap->page_free(page, page->pgmap->data); + } else if (!count) + __put_page(page); +} +EXPORT_SYMBOL(put_zone_device_private_page); +#endif /* CONFIG_DEVICE_PRIVATE */ -- cgit v1.2.3 From c733a82874a79261866a4178edbb608847df4879 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= Date: Fri, 8 Sep 2017 16:11:54 -0700 Subject: mm/memcontrol: support MEMORY_DEVICE_PRIVATE MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit HMM pages (private or public device pages) are ZONE_DEVICE page and thus need special handling when it comes to lru or refcount. This patch make sure that memcontrol properly handle those when it face them. Those pages are use like regular pages in a process address space either as anonymous page or as file back page. So from memcg point of view we want to handle them like regular page for now at least. Link: http://lkml.kernel.org/r/20170817000548.32038-11-jglisse@redhat.com Signed-off-by: Jérôme Glisse Acked-by: Balbir Singh Cc: Johannes Weiner Cc: Michal Hocko Cc: Vladimir Davydov Cc: Aneesh Kumar Cc: Benjamin Herrenschmidt Cc: Dan Williams Cc: David Nellans Cc: Evgeny Baskakov Cc: John Hubbard Cc: Kirill A. Shutemov Cc: Mark Hairgrove Cc: Paul E. McKenney Cc: Ross Zwisler Cc: Sherry Cheung Cc: Subhash Gutti Cc: Bob Liu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/memremap.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/memremap.c b/kernel/memremap.c index 1403cf16fa61..ea0e18a2a5f2 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -516,6 +516,7 @@ void put_zone_device_private_page(struct page *page) __ClearPageWaiters(page); page->mapping = NULL; + mem_cgroup_uncharge(page); page->pgmap->page_free(page, page->pgmap->data); } else if (!count) -- cgit v1.2.3 From df6ad69838fc9dcdbee0dcf2fc2c6f1113f8d609 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= Date: Fri, 8 Sep 2017 16:12:24 -0700 Subject: mm/device-public-memory: device memory cache coherent with CPU MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Platform with advance system bus (like CAPI or CCIX) allow device memory to be accessible from CPU in a cache coherent fashion. Add a new type of ZONE_DEVICE to represent such memory. The use case are the same as for the un-addressable device memory but without all the corners cases. Link: http://lkml.kernel.org/r/20170817000548.32038-19-jglisse@redhat.com Signed-off-by: Jérôme Glisse Cc: Aneesh Kumar Cc: Paul E. McKenney Cc: Benjamin Herrenschmidt Cc: Dan Williams Cc: Ross Zwisler Cc: Balbir Singh Cc: David Nellans Cc: Evgeny Baskakov Cc: Johannes Weiner Cc: John Hubbard Cc: Kirill A. Shutemov Cc: Mark Hairgrove Cc: Michal Hocko Cc: Sherry Cheung Cc: Subhash Gutti Cc: Vladimir Davydov Cc: Bob Liu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/memremap.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/memremap.c b/kernel/memremap.c index ea0e18a2a5f2..6bcbfbf1a8fd 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -501,8 +501,8 @@ struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start) #endif /* CONFIG_ZONE_DEVICE */ -#ifdef CONFIG_DEVICE_PRIVATE -void put_zone_device_private_page(struct page *page) +#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC) +void put_zone_device_private_or_public_page(struct page *page) { int count = page_ref_dec_return(page); @@ -522,5 +522,5 @@ void put_zone_device_private_page(struct page *page) } else if (!count) __put_page(page); } -EXPORT_SYMBOL(put_zone_device_private_page); -#endif /* CONFIG_DEVICE_PRIVATE */ +EXPORT_SYMBOL(put_zone_device_private_or_public_page); +#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ -- cgit v1.2.3 From 9b130ad5bb8255ee8534d92d67e12b2a4887eacb Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Fri, 8 Sep 2017 16:14:18 -0700 Subject: treewide: make "nr_cpu_ids" unsigned First, number of CPUs can't be negative number. Second, different signnnedness leads to suboptimal code in the following cases: 1) kmalloc(nr_cpu_ids * sizeof(X)); "int" has to be sign extended to size_t. 2) while (loff_t *pos < nr_cpu_ids) MOVSXD is 1 byte longed than the same MOV. Other cases exist as well. Basically compiler is told that nr_cpu_ids can't be negative which can't be deduced if it is "int". Code savings on allyesconfig kernel: -3KB add/remove: 0/0 grow/shrink: 25/264 up/down: 261/-3631 (-3370) function old new delta coretemp_cpu_online 450 512 +62 rcu_init_one 1234 1272 +38 pci_device_probe 374 399 +25 ... pgdat_reclaimable_pages 628 556 -72 select_fallback_rq 446 369 -77 task_numa_find_cpu 1923 1807 -116 Link: http://lkml.kernel.org/r/20170819114959.GA30580@avx2 Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/rcu/tree.c | 2 +- kernel/rcu/tree_plugin.h | 2 +- kernel/sched/topology.c | 2 +- kernel/smp.c | 2 +- kernel/trace/trace_functions_graph.c | 2 +- 5 files changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 84fe96641b2e..1250e4bd4b85 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -4091,7 +4091,7 @@ static void __init rcu_init_geometry(void) if (rcu_fanout_leaf == RCU_FANOUT_LEAF && nr_cpu_ids == NR_CPUS) return; - pr_info("RCU: Adjusting geometry for rcu_fanout_leaf=%d, nr_cpu_ids=%d\n", + pr_info("RCU: Adjusting geometry for rcu_fanout_leaf=%d, nr_cpu_ids=%u\n", rcu_fanout_leaf, nr_cpu_ids); /* diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 55bde94b9572..e012b9be777e 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -89,7 +89,7 @@ static void __init rcu_bootup_announce_oddness(void) if (rcu_fanout_leaf != RCU_FANOUT_LEAF) pr_info("\tBoot-time adjustment of leaf fanout to %d.\n", rcu_fanout_leaf); if (nr_cpu_ids != NR_CPUS) - pr_info("\tRCU restricting CPUs from NR_CPUS=%d to nr_cpu_ids=%d.\n", NR_CPUS, nr_cpu_ids); + pr_info("\tRCU restricting CPUs from NR_CPUS=%d to nr_cpu_ids=%u.\n", NR_CPUS, nr_cpu_ids); #ifdef CONFIG_RCU_BOOST pr_info("\tRCU priority boosting: priority %d delay %d ms.\n", kthread_prio, CONFIG_RCU_BOOST_DELAY); #endif diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 6f7b43982f73..5d0062cc10cb 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -473,7 +473,7 @@ static int __init isolated_cpu_setup(char *str) alloc_bootmem_cpumask_var(&cpu_isolated_map); ret = cpulist_parse(str, cpu_isolated_map); if (ret) { - pr_err("sched: Error, all isolcpus= values must be between 0 and %d\n", nr_cpu_ids); + pr_err("sched: Error, all isolcpus= values must be between 0 and %u\n", nr_cpu_ids); return 0; } return 1; diff --git a/kernel/smp.c b/kernel/smp.c index 81cfca9b4cc3..c94dd85c8d41 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -550,7 +550,7 @@ static int __init maxcpus(char *str) early_param("maxcpus", maxcpus); /* Setup number of possible processor ids */ -int nr_cpu_ids __read_mostly = NR_CPUS; +unsigned int nr_cpu_ids __read_mostly = NR_CPUS; EXPORT_SYMBOL(nr_cpu_ids); /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index d56123cdcc89..b8f1f54731af 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -1543,7 +1543,7 @@ fs_initcall(init_graph_tracefs); static __init int init_graph_trace(void) { - max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1); + max_bytes_for_cpu = snprintf(NULL, 0, "%u", nr_cpu_ids - 1); if (!register_trace_event(&graph_trace_entry_event)) { pr_warn("Warning: could not register graph trace events\n"); -- cgit v1.2.3 From bfb068892d30dcf0a32b89302fe293347adeaaaa Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Fri, 8 Sep 2017 16:14:55 -0700 Subject: sched/fair: replace cfs_rq->rb_leftmost ... with the generic rbtree flavor instead. No changes in semantics whatsoever. Link: http://lkml.kernel.org/r/20170719014603.19029-8-dave@stgolabs.net Signed-off-by: Davidlohr Bueso Acked-by: Peter Zijlstra (Intel) Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sched/debug.c | 2 +- kernel/sched/fair.c | 39 +++++++++++++-------------------------- kernel/sched/sched.h | 3 +-- 3 files changed, 15 insertions(+), 29 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 4a23bbc3111b..8e536d963652 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -530,7 +530,7 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) SPLIT_NS(cfs_rq->exec_clock)); raw_spin_lock_irqsave(&rq->lock, flags); - if (cfs_rq->rb_leftmost) + if (rb_first_cached(&cfs_rq->tasks_timeline)) MIN_vruntime = (__pick_first_entity(cfs_rq))->vruntime; last = __pick_last_entity(cfs_rq); if (last) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 8bc0a883d190..a5d83ed8dd82 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -513,6 +513,7 @@ static inline int entity_before(struct sched_entity *a, static void update_min_vruntime(struct cfs_rq *cfs_rq) { struct sched_entity *curr = cfs_rq->curr; + struct rb_node *leftmost = rb_first_cached(&cfs_rq->tasks_timeline); u64 vruntime = cfs_rq->min_vruntime; @@ -523,10 +524,9 @@ static void update_min_vruntime(struct cfs_rq *cfs_rq) curr = NULL; } - if (cfs_rq->rb_leftmost) { - struct sched_entity *se = rb_entry(cfs_rq->rb_leftmost, - struct sched_entity, - run_node); + if (leftmost) { /* non-empty tree */ + struct sched_entity *se; + se = rb_entry(leftmost, struct sched_entity, run_node); if (!curr) vruntime = se->vruntime; @@ -547,10 +547,10 @@ static void update_min_vruntime(struct cfs_rq *cfs_rq) */ static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) { - struct rb_node **link = &cfs_rq->tasks_timeline.rb_node; + struct rb_node **link = &cfs_rq->tasks_timeline.rb_root.rb_node; struct rb_node *parent = NULL; struct sched_entity *entry; - int leftmost = 1; + bool leftmost = true; /* * Find the right place in the rbtree: @@ -566,36 +566,23 @@ static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) link = &parent->rb_left; } else { link = &parent->rb_right; - leftmost = 0; + leftmost = false; } } - /* - * Maintain a cache of leftmost tree entries (it is frequently - * used): - */ - if (leftmost) - cfs_rq->rb_leftmost = &se->run_node; - rb_link_node(&se->run_node, parent, link); - rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline); + rb_insert_color_cached(&se->run_node, + &cfs_rq->tasks_timeline, leftmost); } static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) { - if (cfs_rq->rb_leftmost == &se->run_node) { - struct rb_node *next_node; - - next_node = rb_next(&se->run_node); - cfs_rq->rb_leftmost = next_node; - } - - rb_erase(&se->run_node, &cfs_rq->tasks_timeline); + rb_erase_cached(&se->run_node, &cfs_rq->tasks_timeline); } struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq) { - struct rb_node *left = cfs_rq->rb_leftmost; + struct rb_node *left = rb_first_cached(&cfs_rq->tasks_timeline); if (!left) return NULL; @@ -616,7 +603,7 @@ static struct sched_entity *__pick_next_entity(struct sched_entity *se) #ifdef CONFIG_SCHED_DEBUG struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) { - struct rb_node *last = rb_last(&cfs_rq->tasks_timeline); + struct rb_node *last = rb_last(&cfs_rq->tasks_timeline.rb_root); if (!last) return NULL; @@ -9312,7 +9299,7 @@ static void set_curr_task_fair(struct rq *rq) void init_cfs_rq(struct cfs_rq *cfs_rq) { - cfs_rq->tasks_timeline = RB_ROOT; + cfs_rq->tasks_timeline = RB_ROOT_CACHED; cfs_rq->min_vruntime = (u64)(-(1LL << 20)); #ifndef CONFIG_64BIT cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 6ed7962dc896..c30c57563dbc 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -426,8 +426,7 @@ struct cfs_rq { u64 min_vruntime_copy; #endif - struct rb_root tasks_timeline; - struct rb_node *rb_leftmost; + struct rb_root_cached tasks_timeline; /* * 'curr' points to currently running entity on this cfs_rq. -- cgit v1.2.3 From 2161573ecd6931565936cb66793b2d2bf805c088 Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Fri, 8 Sep 2017 16:14:58 -0700 Subject: sched/deadline: replace earliest dl and rq leftmost caching ... with the generic rbtree flavor instead. No changes in semantics whatsoever. Link: http://lkml.kernel.org/r/20170719014603.19029-9-dave@stgolabs.net Signed-off-by: Davidlohr Bueso Acked-by: Peter Zijlstra (Intel) Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sched/deadline.c | 50 +++++++++++++++++++------------------------------ kernel/sched/sched.h | 6 ++---- 2 files changed, 21 insertions(+), 35 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 9e38df7649f4..0191ec7667c3 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -296,7 +296,7 @@ static inline int is_leftmost(struct task_struct *p, struct dl_rq *dl_rq) { struct sched_dl_entity *dl_se = &p->dl; - return dl_rq->rb_leftmost == &dl_se->rb_node; + return dl_rq->root.rb_leftmost == &dl_se->rb_node; } void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime) @@ -320,7 +320,7 @@ void init_dl_bw(struct dl_bw *dl_b) void init_dl_rq(struct dl_rq *dl_rq) { - dl_rq->rb_root = RB_ROOT; + dl_rq->root = RB_ROOT_CACHED; #ifdef CONFIG_SMP /* zero means no -deadline tasks */ @@ -328,7 +328,7 @@ void init_dl_rq(struct dl_rq *dl_rq) dl_rq->dl_nr_migratory = 0; dl_rq->overloaded = 0; - dl_rq->pushable_dl_tasks_root = RB_ROOT; + dl_rq->pushable_dl_tasks_root = RB_ROOT_CACHED; #else init_dl_bw(&dl_rq->dl_bw); #endif @@ -410,10 +410,10 @@ static void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) static void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p) { struct dl_rq *dl_rq = &rq->dl; - struct rb_node **link = &dl_rq->pushable_dl_tasks_root.rb_node; + struct rb_node **link = &dl_rq->pushable_dl_tasks_root.rb_root.rb_node; struct rb_node *parent = NULL; struct task_struct *entry; - int leftmost = 1; + bool leftmost = true; BUG_ON(!RB_EMPTY_NODE(&p->pushable_dl_tasks)); @@ -425,17 +425,16 @@ static void enqueue_pushable_dl_task(struct rq *rq, struct task_struct *p) link = &parent->rb_left; else { link = &parent->rb_right; - leftmost = 0; + leftmost = false; } } - if (leftmost) { - dl_rq->pushable_dl_tasks_leftmost = &p->pushable_dl_tasks; + if (leftmost) dl_rq->earliest_dl.next = p->dl.deadline; - } rb_link_node(&p->pushable_dl_tasks, parent, link); - rb_insert_color(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root); + rb_insert_color_cached(&p->pushable_dl_tasks, + &dl_rq->pushable_dl_tasks_root, leftmost); } static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p) @@ -445,24 +444,23 @@ static void dequeue_pushable_dl_task(struct rq *rq, struct task_struct *p) if (RB_EMPTY_NODE(&p->pushable_dl_tasks)) return; - if (dl_rq->pushable_dl_tasks_leftmost == &p->pushable_dl_tasks) { + if (dl_rq->pushable_dl_tasks_root.rb_leftmost == &p->pushable_dl_tasks) { struct rb_node *next_node; next_node = rb_next(&p->pushable_dl_tasks); - dl_rq->pushable_dl_tasks_leftmost = next_node; if (next_node) { dl_rq->earliest_dl.next = rb_entry(next_node, struct task_struct, pushable_dl_tasks)->dl.deadline; } } - rb_erase(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root); + rb_erase_cached(&p->pushable_dl_tasks, &dl_rq->pushable_dl_tasks_root); RB_CLEAR_NODE(&p->pushable_dl_tasks); } static inline int has_pushable_dl_tasks(struct rq *rq) { - return !RB_EMPTY_ROOT(&rq->dl.pushable_dl_tasks_root); + return !RB_EMPTY_ROOT(&rq->dl.pushable_dl_tasks_root.rb_root); } static int push_dl_task(struct rq *rq); @@ -1266,7 +1264,7 @@ static void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline) dl_rq->earliest_dl.next = 0; cpudl_clear(&rq->rd->cpudl, rq->cpu); } else { - struct rb_node *leftmost = dl_rq->rb_leftmost; + struct rb_node *leftmost = dl_rq->root.rb_leftmost; struct sched_dl_entity *entry; entry = rb_entry(leftmost, struct sched_dl_entity, rb_node); @@ -1313,7 +1311,7 @@ void dec_dl_tasks(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) static void __enqueue_dl_entity(struct sched_dl_entity *dl_se) { struct dl_rq *dl_rq = dl_rq_of_se(dl_se); - struct rb_node **link = &dl_rq->rb_root.rb_node; + struct rb_node **link = &dl_rq->root.rb_root.rb_node; struct rb_node *parent = NULL; struct sched_dl_entity *entry; int leftmost = 1; @@ -1331,11 +1329,8 @@ static void __enqueue_dl_entity(struct sched_dl_entity *dl_se) } } - if (leftmost) - dl_rq->rb_leftmost = &dl_se->rb_node; - rb_link_node(&dl_se->rb_node, parent, link); - rb_insert_color(&dl_se->rb_node, &dl_rq->rb_root); + rb_insert_color_cached(&dl_se->rb_node, &dl_rq->root, leftmost); inc_dl_tasks(dl_se, dl_rq); } @@ -1347,14 +1342,7 @@ static void __dequeue_dl_entity(struct sched_dl_entity *dl_se) if (RB_EMPTY_NODE(&dl_se->rb_node)) return; - if (dl_rq->rb_leftmost == &dl_se->rb_node) { - struct rb_node *next_node; - - next_node = rb_next(&dl_se->rb_node); - dl_rq->rb_leftmost = next_node; - } - - rb_erase(&dl_se->rb_node, &dl_rq->rb_root); + rb_erase_cached(&dl_se->rb_node, &dl_rq->root); RB_CLEAR_NODE(&dl_se->rb_node); dec_dl_tasks(dl_se, dl_rq); @@ -1647,7 +1635,7 @@ static void start_hrtick_dl(struct rq *rq, struct task_struct *p) static struct sched_dl_entity *pick_next_dl_entity(struct rq *rq, struct dl_rq *dl_rq) { - struct rb_node *left = dl_rq->rb_leftmost; + struct rb_node *left = rb_first_cached(&dl_rq->root); if (!left) return NULL; @@ -1771,7 +1759,7 @@ static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu) */ static struct task_struct *pick_earliest_pushable_dl_task(struct rq *rq, int cpu) { - struct rb_node *next_node = rq->dl.pushable_dl_tasks_leftmost; + struct rb_node *next_node = rq->dl.pushable_dl_tasks_root.rb_leftmost; struct task_struct *p = NULL; if (!has_pushable_dl_tasks(rq)) @@ -1945,7 +1933,7 @@ static struct task_struct *pick_next_pushable_dl_task(struct rq *rq) if (!has_pushable_dl_tasks(rq)) return NULL; - p = rb_entry(rq->dl.pushable_dl_tasks_leftmost, + p = rb_entry(rq->dl.pushable_dl_tasks_root.rb_leftmost, struct task_struct, pushable_dl_tasks); BUG_ON(rq->cpu != task_cpu(p)); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index c30c57563dbc..746ac78ff492 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -549,8 +549,7 @@ struct rt_rq { /* Deadline class' related fields in a runqueue */ struct dl_rq { /* runqueue is an rbtree, ordered by deadline */ - struct rb_root rb_root; - struct rb_node *rb_leftmost; + struct rb_root_cached root; unsigned long dl_nr_running; @@ -574,8 +573,7 @@ struct dl_rq { * an rb-tree, ordered by tasks' deadlines, with caching * of the leftmost (earliest deadline) element. */ - struct rb_root pushable_dl_tasks_root; - struct rb_node *pushable_dl_tasks_leftmost; + struct rb_root_cached pushable_dl_tasks_root; #else struct dl_bw dl_bw; #endif -- cgit v1.2.3 From a23ba907d5e65d6aeea3e59c82fda9cd206a7aad Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Fri, 8 Sep 2017 16:15:01 -0700 Subject: locking/rtmutex: replace top-waiter and pi_waiters leftmost caching ... with the generic rbtree flavor instead. No changes in semantics whatsoever. Link: http://lkml.kernel.org/r/20170719014603.19029-10-dave@stgolabs.net Signed-off-by: Davidlohr Bueso Acked-by: Peter Zijlstra (Intel) Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 3 +-- kernel/locking/rtmutex-debug.c | 2 +- kernel/locking/rtmutex.c | 35 +++++++++++------------------------ kernel/locking/rtmutex_common.h | 12 ++++++------ 4 files changed, 19 insertions(+), 33 deletions(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index 2ccbbbfcb7b8..6f1b0af00bda 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1462,8 +1462,7 @@ static void rt_mutex_init_task(struct task_struct *p) { raw_spin_lock_init(&p->pi_lock); #ifdef CONFIG_RT_MUTEXES - p->pi_waiters = RB_ROOT; - p->pi_waiters_leftmost = NULL; + p->pi_waiters = RB_ROOT_CACHED; p->pi_top_task = NULL; p->pi_blocked_on = NULL; #endif diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c index ac35e648b0e5..f4a74e78d467 100644 --- a/kernel/locking/rtmutex-debug.c +++ b/kernel/locking/rtmutex-debug.c @@ -58,7 +58,7 @@ static void printk_lock(struct rt_mutex *lock, int print_owner) void rt_mutex_debug_task_free(struct task_struct *task) { - DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters)); + DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root)); DEBUG_LOCKS_WARN_ON(task->pi_blocked_on); } diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 649dc9d3951a..6f3dba6e4e9e 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -271,10 +271,10 @@ rt_mutex_waiter_equal(struct rt_mutex_waiter *left, static void rt_mutex_enqueue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter) { - struct rb_node **link = &lock->waiters.rb_node; + struct rb_node **link = &lock->waiters.rb_root.rb_node; struct rb_node *parent = NULL; struct rt_mutex_waiter *entry; - int leftmost = 1; + bool leftmost = true; while (*link) { parent = *link; @@ -283,15 +283,12 @@ rt_mutex_enqueue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter) link = &parent->rb_left; } else { link = &parent->rb_right; - leftmost = 0; + leftmost = false; } } - if (leftmost) - lock->waiters_leftmost = &waiter->tree_entry; - rb_link_node(&waiter->tree_entry, parent, link); - rb_insert_color(&waiter->tree_entry, &lock->waiters); + rb_insert_color_cached(&waiter->tree_entry, &lock->waiters, leftmost); } static void @@ -300,20 +297,17 @@ rt_mutex_dequeue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter) if (RB_EMPTY_NODE(&waiter->tree_entry)) return; - if (lock->waiters_leftmost == &waiter->tree_entry) - lock->waiters_leftmost = rb_next(&waiter->tree_entry); - - rb_erase(&waiter->tree_entry, &lock->waiters); + rb_erase_cached(&waiter->tree_entry, &lock->waiters); RB_CLEAR_NODE(&waiter->tree_entry); } static void rt_mutex_enqueue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter) { - struct rb_node **link = &task->pi_waiters.rb_node; + struct rb_node **link = &task->pi_waiters.rb_root.rb_node; struct rb_node *parent = NULL; struct rt_mutex_waiter *entry; - int leftmost = 1; + bool leftmost = true; while (*link) { parent = *link; @@ -322,15 +316,12 @@ rt_mutex_enqueue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter) link = &parent->rb_left; } else { link = &parent->rb_right; - leftmost = 0; + leftmost = false; } } - if (leftmost) - task->pi_waiters_leftmost = &waiter->pi_tree_entry; - rb_link_node(&waiter->pi_tree_entry, parent, link); - rb_insert_color(&waiter->pi_tree_entry, &task->pi_waiters); + rb_insert_color_cached(&waiter->pi_tree_entry, &task->pi_waiters, leftmost); } static void @@ -339,10 +330,7 @@ rt_mutex_dequeue_pi(struct task_struct *task, struct rt_mutex_waiter *waiter) if (RB_EMPTY_NODE(&waiter->pi_tree_entry)) return; - if (task->pi_waiters_leftmost == &waiter->pi_tree_entry) - task->pi_waiters_leftmost = rb_next(&waiter->pi_tree_entry); - - rb_erase(&waiter->pi_tree_entry, &task->pi_waiters); + rb_erase_cached(&waiter->pi_tree_entry, &task->pi_waiters); RB_CLEAR_NODE(&waiter->pi_tree_entry); } @@ -1657,8 +1645,7 @@ void __rt_mutex_init(struct rt_mutex *lock, const char *name, { lock->owner = NULL; raw_spin_lock_init(&lock->wait_lock); - lock->waiters = RB_ROOT; - lock->waiters_leftmost = NULL; + lock->waiters = RB_ROOT_CACHED; if (name && key) debug_rt_mutex_init(lock, name, key); diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h index 8d039b928d61..7453be0485a5 100644 --- a/kernel/locking/rtmutex_common.h +++ b/kernel/locking/rtmutex_common.h @@ -45,7 +45,7 @@ struct rt_mutex_waiter { static inline int rt_mutex_has_waiters(struct rt_mutex *lock) { - return !RB_EMPTY_ROOT(&lock->waiters); + return !RB_EMPTY_ROOT(&lock->waiters.rb_root); } static inline struct rt_mutex_waiter * @@ -53,8 +53,8 @@ rt_mutex_top_waiter(struct rt_mutex *lock) { struct rt_mutex_waiter *w; - w = rb_entry(lock->waiters_leftmost, struct rt_mutex_waiter, - tree_entry); + w = rb_entry(lock->waiters.rb_leftmost, + struct rt_mutex_waiter, tree_entry); BUG_ON(w->lock != lock); return w; @@ -62,14 +62,14 @@ rt_mutex_top_waiter(struct rt_mutex *lock) static inline int task_has_pi_waiters(struct task_struct *p) { - return !RB_EMPTY_ROOT(&p->pi_waiters); + return !RB_EMPTY_ROOT(&p->pi_waiters.rb_root); } static inline struct rt_mutex_waiter * task_top_pi_waiter(struct task_struct *p) { - return rb_entry(p->pi_waiters_leftmost, struct rt_mutex_waiter, - pi_tree_entry); + return rb_entry(p->pi_waiters.rb_leftmost, + struct rt_mutex_waiter, pi_tree_entry); } #else -- cgit v1.2.3 From 235586939d7fe4833ada9e988f92af543ee6851f Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Fri, 8 Sep 2017 16:17:00 -0700 Subject: kmod: split out umh code into its own file Patch series "kmod: few code cleanups to split out umh code" The usermode helper has a provenance from the old usb code which first required a usermode helper. Eventually this was shoved into kmod.c and the kernel's modprobe calls was converted over eventually to share the same code. Over time the list of usermode helpers in the kernel has grown -- so kmod is just but one user of the API. This series is a simple logical cleanup which acknowledges the code evolution of the usermode helper and shoves the UMH API into its own dedicated file. This way users of the API can later just include umh.h instead of kmod.h. Note despite the diff state the first patch really is just a code shove, no functional changes are done there. I did use git format-patch -M to generate the patch, but in the end the split was not enough for git to consider it a rename hence the large diffstat. I've put this through 0-day and it gives me their machine compilation blessings with all tests as OK. This patch (of 4): There's a slew of usermode helper users and kmod is just one of them. Split out the usermode helper code into its own file to keep the logic and focus split up. This change provides no functional changes. Link: http://lkml.kernel.org/r/20170810180618.22457-2-mcgrof@kernel.org Signed-off-by: Luis R. Rodriguez Cc: Kees Cook Cc: Dmitry Torokhov Cc: Jessica Yu Cc: Rusty Russell Cc: Michal Marek Cc: Petr Mladek Cc: Miroslav Benes Cc: Josh Poimboeuf Cc: Guenter Roeck Cc: "Eric W. Biederman" Cc: Matt Redfearn Cc: Dan Carpenter Cc: Colin Ian King Cc: Daniel Mentz Cc: David Binderman Cc: Greg Kroah-Hartman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/Makefile | 2 +- kernel/kmod.c | 560 +------------------------------------------------------ kernel/umh.c | 568 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 571 insertions(+), 559 deletions(-) create mode 100644 kernel/umh.c (limited to 'kernel') diff --git a/kernel/Makefile b/kernel/Makefile index 9c323a6daa46..44abbb0104b6 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -5,7 +5,7 @@ obj-y = fork.o exec_domain.o panic.o \ cpu.o exit.o softirq.o resource.o \ sysctl.o sysctl_binary.o capability.o ptrace.o user.o \ - signal.o sys.o kmod.o workqueue.o pid.o task_work.o \ + signal.o sys.o umh.o kmod.o workqueue.o pid.o task_work.o \ extable.o params.o \ kthread.o sys_ni.o nsproxy.o \ notifier.o ksysfs.o cred.o reboot.o \ diff --git a/kernel/kmod.c b/kernel/kmod.c index 2f37acde640b..cdff52974d18 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -1,23 +1,6 @@ /* - kmod, the new module loader (replaces kerneld) - Kirk Petersen - - Reorganized not to be a daemon by Adam Richter, with guidance - from Greg Zornetzer. - - Modified to avoid chroot and file sharing problems. - Mikael Pettersson - - Limit the concurrent number of kmod modprobes to catch loops from - "modprobe needs a service that is in a module". - Keith Owens December 1999 - - Unblock all signals when we exec a usermode process. - Shuu Yamaguchi December 2000 - - call_usermodehelper wait flag, and remove exec_usermodehelper. - Rusty Russell Jan 2003 -*/ + * kmod - the kernel module loader + */ #include #include #include @@ -45,14 +28,6 @@ #include -#define CAP_BSET (void *)1 -#define CAP_PI (void *)2 - -static kernel_cap_t usermodehelper_bset = CAP_FULL_SET; -static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET; -static DEFINE_SPINLOCK(umh_sysctl_lock); -static DECLARE_RWSEM(umhelper_sem); - #ifdef CONFIG_MODULES /* * Assuming: @@ -204,534 +179,3 @@ int __request_module(bool wait, const char *fmt, ...) EXPORT_SYMBOL(__request_module); #endif /* CONFIG_MODULES */ - -static void call_usermodehelper_freeinfo(struct subprocess_info *info) -{ - if (info->cleanup) - (*info->cleanup)(info); - kfree(info); -} - -static void umh_complete(struct subprocess_info *sub_info) -{ - struct completion *comp = xchg(&sub_info->complete, NULL); - /* - * See call_usermodehelper_exec(). If xchg() returns NULL - * we own sub_info, the UMH_KILLABLE caller has gone away - * or the caller used UMH_NO_WAIT. - */ - if (comp) - complete(comp); - else - call_usermodehelper_freeinfo(sub_info); -} - -/* - * This is the task which runs the usermode application - */ -static int call_usermodehelper_exec_async(void *data) -{ - struct subprocess_info *sub_info = data; - struct cred *new; - int retval; - - spin_lock_irq(¤t->sighand->siglock); - flush_signal_handlers(current, 1); - spin_unlock_irq(¤t->sighand->siglock); - - /* - * Our parent (unbound workqueue) runs with elevated scheduling - * priority. Avoid propagating that into the userspace child. - */ - set_user_nice(current, 0); - - retval = -ENOMEM; - new = prepare_kernel_cred(current); - if (!new) - goto out; - - spin_lock(&umh_sysctl_lock); - new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset); - new->cap_inheritable = cap_intersect(usermodehelper_inheritable, - new->cap_inheritable); - spin_unlock(&umh_sysctl_lock); - - if (sub_info->init) { - retval = sub_info->init(sub_info, new); - if (retval) { - abort_creds(new); - goto out; - } - } - - commit_creds(new); - - retval = do_execve(getname_kernel(sub_info->path), - (const char __user *const __user *)sub_info->argv, - (const char __user *const __user *)sub_info->envp); -out: - sub_info->retval = retval; - /* - * call_usermodehelper_exec_sync() will call umh_complete - * if UHM_WAIT_PROC. - */ - if (!(sub_info->wait & UMH_WAIT_PROC)) - umh_complete(sub_info); - if (!retval) - return 0; - do_exit(0); -} - -/* Handles UMH_WAIT_PROC. */ -static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info) -{ - pid_t pid; - - /* If SIGCLD is ignored sys_wait4 won't populate the status. */ - kernel_sigaction(SIGCHLD, SIG_DFL); - pid = kernel_thread(call_usermodehelper_exec_async, sub_info, SIGCHLD); - if (pid < 0) { - sub_info->retval = pid; - } else { - int ret = -ECHILD; - /* - * Normally it is bogus to call wait4() from in-kernel because - * wait4() wants to write the exit code to a userspace address. - * But call_usermodehelper_exec_sync() always runs as kernel - * thread (workqueue) and put_user() to a kernel address works - * OK for kernel threads, due to their having an mm_segment_t - * which spans the entire address space. - * - * Thus the __user pointer cast is valid here. - */ - sys_wait4(pid, (int __user *)&ret, 0, NULL); - - /* - * If ret is 0, either call_usermodehelper_exec_async failed and - * the real error code is already in sub_info->retval or - * sub_info->retval is 0 anyway, so don't mess with it then. - */ - if (ret) - sub_info->retval = ret; - } - - /* Restore default kernel sig handler */ - kernel_sigaction(SIGCHLD, SIG_IGN); - - umh_complete(sub_info); -} - -/* - * We need to create the usermodehelper kernel thread from a task that is affine - * to an optimized set of CPUs (or nohz housekeeping ones) such that they - * inherit a widest affinity irrespective of call_usermodehelper() callers with - * possibly reduced affinity (eg: per-cpu workqueues). We don't want - * usermodehelper targets to contend a busy CPU. - * - * Unbound workqueues provide such wide affinity and allow to block on - * UMH_WAIT_PROC requests without blocking pending request (up to some limit). - * - * Besides, workqueues provide the privilege level that caller might not have - * to perform the usermodehelper request. - * - */ -static void call_usermodehelper_exec_work(struct work_struct *work) -{ - struct subprocess_info *sub_info = - container_of(work, struct subprocess_info, work); - - if (sub_info->wait & UMH_WAIT_PROC) { - call_usermodehelper_exec_sync(sub_info); - } else { - pid_t pid; - /* - * Use CLONE_PARENT to reparent it to kthreadd; we do not - * want to pollute current->children, and we need a parent - * that always ignores SIGCHLD to ensure auto-reaping. - */ - pid = kernel_thread(call_usermodehelper_exec_async, sub_info, - CLONE_PARENT | SIGCHLD); - if (pid < 0) { - sub_info->retval = pid; - umh_complete(sub_info); - } - } -} - -/* - * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY - * (used for preventing user land processes from being created after the user - * land has been frozen during a system-wide hibernation or suspend operation). - * Should always be manipulated under umhelper_sem acquired for write. - */ -static enum umh_disable_depth usermodehelper_disabled = UMH_DISABLED; - -/* Number of helpers running */ -static atomic_t running_helpers = ATOMIC_INIT(0); - -/* - * Wait queue head used by usermodehelper_disable() to wait for all running - * helpers to finish. - */ -static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq); - -/* - * Used by usermodehelper_read_lock_wait() to wait for usermodehelper_disabled - * to become 'false'. - */ -static DECLARE_WAIT_QUEUE_HEAD(usermodehelper_disabled_waitq); - -/* - * Time to wait for running_helpers to become zero before the setting of - * usermodehelper_disabled in usermodehelper_disable() fails - */ -#define RUNNING_HELPERS_TIMEOUT (5 * HZ) - -int usermodehelper_read_trylock(void) -{ - DEFINE_WAIT(wait); - int ret = 0; - - down_read(&umhelper_sem); - for (;;) { - prepare_to_wait(&usermodehelper_disabled_waitq, &wait, - TASK_INTERRUPTIBLE); - if (!usermodehelper_disabled) - break; - - if (usermodehelper_disabled == UMH_DISABLED) - ret = -EAGAIN; - - up_read(&umhelper_sem); - - if (ret) - break; - - schedule(); - try_to_freeze(); - - down_read(&umhelper_sem); - } - finish_wait(&usermodehelper_disabled_waitq, &wait); - return ret; -} -EXPORT_SYMBOL_GPL(usermodehelper_read_trylock); - -long usermodehelper_read_lock_wait(long timeout) -{ - DEFINE_WAIT(wait); - - if (timeout < 0) - return -EINVAL; - - down_read(&umhelper_sem); - for (;;) { - prepare_to_wait(&usermodehelper_disabled_waitq, &wait, - TASK_UNINTERRUPTIBLE); - if (!usermodehelper_disabled) - break; - - up_read(&umhelper_sem); - - timeout = schedule_timeout(timeout); - if (!timeout) - break; - - down_read(&umhelper_sem); - } - finish_wait(&usermodehelper_disabled_waitq, &wait); - return timeout; -} -EXPORT_SYMBOL_GPL(usermodehelper_read_lock_wait); - -void usermodehelper_read_unlock(void) -{ - up_read(&umhelper_sem); -} -EXPORT_SYMBOL_GPL(usermodehelper_read_unlock); - -/** - * __usermodehelper_set_disable_depth - Modify usermodehelper_disabled. - * @depth: New value to assign to usermodehelper_disabled. - * - * Change the value of usermodehelper_disabled (under umhelper_sem locked for - * writing) and wakeup tasks waiting for it to change. - */ -void __usermodehelper_set_disable_depth(enum umh_disable_depth depth) -{ - down_write(&umhelper_sem); - usermodehelper_disabled = depth; - wake_up(&usermodehelper_disabled_waitq); - up_write(&umhelper_sem); -} - -/** - * __usermodehelper_disable - Prevent new helpers from being started. - * @depth: New value to assign to usermodehelper_disabled. - * - * Set usermodehelper_disabled to @depth and wait for running helpers to exit. - */ -int __usermodehelper_disable(enum umh_disable_depth depth) -{ - long retval; - - if (!depth) - return -EINVAL; - - down_write(&umhelper_sem); - usermodehelper_disabled = depth; - up_write(&umhelper_sem); - - /* - * From now on call_usermodehelper_exec() won't start any new - * helpers, so it is sufficient if running_helpers turns out to - * be zero at one point (it may be increased later, but that - * doesn't matter). - */ - retval = wait_event_timeout(running_helpers_waitq, - atomic_read(&running_helpers) == 0, - RUNNING_HELPERS_TIMEOUT); - if (retval) - return 0; - - __usermodehelper_set_disable_depth(UMH_ENABLED); - return -EAGAIN; -} - -static void helper_lock(void) -{ - atomic_inc(&running_helpers); - smp_mb__after_atomic(); -} - -static void helper_unlock(void) -{ - if (atomic_dec_and_test(&running_helpers)) - wake_up(&running_helpers_waitq); -} - -/** - * call_usermodehelper_setup - prepare to call a usermode helper - * @path: path to usermode executable - * @argv: arg vector for process - * @envp: environment for process - * @gfp_mask: gfp mask for memory allocation - * @cleanup: a cleanup function - * @init: an init function - * @data: arbitrary context sensitive data - * - * Returns either %NULL on allocation failure, or a subprocess_info - * structure. This should be passed to call_usermodehelper_exec to - * exec the process and free the structure. - * - * The init function is used to customize the helper process prior to - * exec. A non-zero return code causes the process to error out, exit, - * and return the failure to the calling process - * - * The cleanup function is just before ethe subprocess_info is about to - * be freed. This can be used for freeing the argv and envp. The - * Function must be runnable in either a process context or the - * context in which call_usermodehelper_exec is called. - */ -struct subprocess_info *call_usermodehelper_setup(const char *path, char **argv, - char **envp, gfp_t gfp_mask, - int (*init)(struct subprocess_info *info, struct cred *new), - void (*cleanup)(struct subprocess_info *info), - void *data) -{ - struct subprocess_info *sub_info; - sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask); - if (!sub_info) - goto out; - - INIT_WORK(&sub_info->work, call_usermodehelper_exec_work); - -#ifdef CONFIG_STATIC_USERMODEHELPER - sub_info->path = CONFIG_STATIC_USERMODEHELPER_PATH; -#else - sub_info->path = path; -#endif - sub_info->argv = argv; - sub_info->envp = envp; - - sub_info->cleanup = cleanup; - sub_info->init = init; - sub_info->data = data; - out: - return sub_info; -} -EXPORT_SYMBOL(call_usermodehelper_setup); - -/** - * call_usermodehelper_exec - start a usermode application - * @sub_info: information about the subprocessa - * @wait: wait for the application to finish and return status. - * when UMH_NO_WAIT don't wait at all, but you get no useful error back - * when the program couldn't be exec'ed. This makes it safe to call - * from interrupt context. - * - * Runs a user-space application. The application is started - * asynchronously if wait is not set, and runs as a child of system workqueues. - * (ie. it runs with full root capabilities and optimized affinity). - */ -int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait) -{ - DECLARE_COMPLETION_ONSTACK(done); - int retval = 0; - - if (!sub_info->path) { - call_usermodehelper_freeinfo(sub_info); - return -EINVAL; - } - helper_lock(); - if (usermodehelper_disabled) { - retval = -EBUSY; - goto out; - } - - /* - * If there is no binary for us to call, then just return and get out of - * here. This allows us to set STATIC_USERMODEHELPER_PATH to "" and - * disable all call_usermodehelper() calls. - */ - if (strlen(sub_info->path) == 0) - goto out; - - /* - * Set the completion pointer only if there is a waiter. - * This makes it possible to use umh_complete to free - * the data structure in case of UMH_NO_WAIT. - */ - sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done; - sub_info->wait = wait; - - queue_work(system_unbound_wq, &sub_info->work); - if (wait == UMH_NO_WAIT) /* task has freed sub_info */ - goto unlock; - - if (wait & UMH_KILLABLE) { - retval = wait_for_completion_killable(&done); - if (!retval) - goto wait_done; - - /* umh_complete() will see NULL and free sub_info */ - if (xchg(&sub_info->complete, NULL)) - goto unlock; - /* fallthrough, umh_complete() was already called */ - } - - wait_for_completion(&done); -wait_done: - retval = sub_info->retval; -out: - call_usermodehelper_freeinfo(sub_info); -unlock: - helper_unlock(); - return retval; -} -EXPORT_SYMBOL(call_usermodehelper_exec); - -/** - * call_usermodehelper() - prepare and start a usermode application - * @path: path to usermode executable - * @argv: arg vector for process - * @envp: environment for process - * @wait: wait for the application to finish and return status. - * when UMH_NO_WAIT don't wait at all, but you get no useful error back - * when the program couldn't be exec'ed. This makes it safe to call - * from interrupt context. - * - * This function is the equivalent to use call_usermodehelper_setup() and - * call_usermodehelper_exec(). - */ -int call_usermodehelper(const char *path, char **argv, char **envp, int wait) -{ - struct subprocess_info *info; - gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL; - - info = call_usermodehelper_setup(path, argv, envp, gfp_mask, - NULL, NULL, NULL); - if (info == NULL) - return -ENOMEM; - - return call_usermodehelper_exec(info, wait); -} -EXPORT_SYMBOL(call_usermodehelper); - -static int proc_cap_handler(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) -{ - struct ctl_table t; - unsigned long cap_array[_KERNEL_CAPABILITY_U32S]; - kernel_cap_t new_cap; - int err, i; - - if (write && (!capable(CAP_SETPCAP) || - !capable(CAP_SYS_MODULE))) - return -EPERM; - - /* - * convert from the global kernel_cap_t to the ulong array to print to - * userspace if this is a read. - */ - spin_lock(&umh_sysctl_lock); - for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) { - if (table->data == CAP_BSET) - cap_array[i] = usermodehelper_bset.cap[i]; - else if (table->data == CAP_PI) - cap_array[i] = usermodehelper_inheritable.cap[i]; - else - BUG(); - } - spin_unlock(&umh_sysctl_lock); - - t = *table; - t.data = &cap_array; - - /* - * actually read or write and array of ulongs from userspace. Remember - * these are least significant 32 bits first - */ - err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos); - if (err < 0) - return err; - - /* - * convert from the sysctl array of ulongs to the kernel_cap_t - * internal representation - */ - for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) - new_cap.cap[i] = cap_array[i]; - - /* - * Drop everything not in the new_cap (but don't add things) - */ - spin_lock(&umh_sysctl_lock); - if (write) { - if (table->data == CAP_BSET) - usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap); - if (table->data == CAP_PI) - usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap); - } - spin_unlock(&umh_sysctl_lock); - - return 0; -} - -struct ctl_table usermodehelper_table[] = { - { - .procname = "bset", - .data = CAP_BSET, - .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), - .mode = 0600, - .proc_handler = proc_cap_handler, - }, - { - .procname = "inheritable", - .data = CAP_PI, - .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), - .mode = 0600, - .proc_handler = proc_cap_handler, - }, - { } -}; diff --git a/kernel/umh.c b/kernel/umh.c new file mode 100644 index 000000000000..6ff9905250ff --- /dev/null +++ b/kernel/umh.c @@ -0,0 +1,568 @@ +/* + * umh - the kernel usermode helper + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#define CAP_BSET (void *)1 +#define CAP_PI (void *)2 + +static kernel_cap_t usermodehelper_bset = CAP_FULL_SET; +static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET; +static DEFINE_SPINLOCK(umh_sysctl_lock); +static DECLARE_RWSEM(umhelper_sem); + +static void call_usermodehelper_freeinfo(struct subprocess_info *info) +{ + if (info->cleanup) + (*info->cleanup)(info); + kfree(info); +} + +static void umh_complete(struct subprocess_info *sub_info) +{ + struct completion *comp = xchg(&sub_info->complete, NULL); + /* + * See call_usermodehelper_exec(). If xchg() returns NULL + * we own sub_info, the UMH_KILLABLE caller has gone away + * or the caller used UMH_NO_WAIT. + */ + if (comp) + complete(comp); + else + call_usermodehelper_freeinfo(sub_info); +} + +/* + * This is the task which runs the usermode application + */ +static int call_usermodehelper_exec_async(void *data) +{ + struct subprocess_info *sub_info = data; + struct cred *new; + int retval; + + spin_lock_irq(¤t->sighand->siglock); + flush_signal_handlers(current, 1); + spin_unlock_irq(¤t->sighand->siglock); + + /* + * Our parent (unbound workqueue) runs with elevated scheduling + * priority. Avoid propagating that into the userspace child. + */ + set_user_nice(current, 0); + + retval = -ENOMEM; + new = prepare_kernel_cred(current); + if (!new) + goto out; + + spin_lock(&umh_sysctl_lock); + new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset); + new->cap_inheritable = cap_intersect(usermodehelper_inheritable, + new->cap_inheritable); + spin_unlock(&umh_sysctl_lock); + + if (sub_info->init) { + retval = sub_info->init(sub_info, new); + if (retval) { + abort_creds(new); + goto out; + } + } + + commit_creds(new); + + retval = do_execve(getname_kernel(sub_info->path), + (const char __user *const __user *)sub_info->argv, + (const char __user *const __user *)sub_info->envp); +out: + sub_info->retval = retval; + /* + * call_usermodehelper_exec_sync() will call umh_complete + * if UHM_WAIT_PROC. + */ + if (!(sub_info->wait & UMH_WAIT_PROC)) + umh_complete(sub_info); + if (!retval) + return 0; + do_exit(0); +} + +/* Handles UMH_WAIT_PROC. */ +static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info) +{ + pid_t pid; + + /* If SIGCLD is ignored sys_wait4 won't populate the status. */ + kernel_sigaction(SIGCHLD, SIG_DFL); + pid = kernel_thread(call_usermodehelper_exec_async, sub_info, SIGCHLD); + if (pid < 0) { + sub_info->retval = pid; + } else { + int ret = -ECHILD; + /* + * Normally it is bogus to call wait4() from in-kernel because + * wait4() wants to write the exit code to a userspace address. + * But call_usermodehelper_exec_sync() always runs as kernel + * thread (workqueue) and put_user() to a kernel address works + * OK for kernel threads, due to their having an mm_segment_t + * which spans the entire address space. + * + * Thus the __user pointer cast is valid here. + */ + sys_wait4(pid, (int __user *)&ret, 0, NULL); + + /* + * If ret is 0, either call_usermodehelper_exec_async failed and + * the real error code is already in sub_info->retval or + * sub_info->retval is 0 anyway, so don't mess with it then. + */ + if (ret) + sub_info->retval = ret; + } + + /* Restore default kernel sig handler */ + kernel_sigaction(SIGCHLD, SIG_IGN); + + umh_complete(sub_info); +} + +/* + * We need to create the usermodehelper kernel thread from a task that is affine + * to an optimized set of CPUs (or nohz housekeeping ones) such that they + * inherit a widest affinity irrespective of call_usermodehelper() callers with + * possibly reduced affinity (eg: per-cpu workqueues). We don't want + * usermodehelper targets to contend a busy CPU. + * + * Unbound workqueues provide such wide affinity and allow to block on + * UMH_WAIT_PROC requests without blocking pending request (up to some limit). + * + * Besides, workqueues provide the privilege level that caller might not have + * to perform the usermodehelper request. + * + */ +static void call_usermodehelper_exec_work(struct work_struct *work) +{ + struct subprocess_info *sub_info = + container_of(work, struct subprocess_info, work); + + if (sub_info->wait & UMH_WAIT_PROC) { + call_usermodehelper_exec_sync(sub_info); + } else { + pid_t pid; + /* + * Use CLONE_PARENT to reparent it to kthreadd; we do not + * want to pollute current->children, and we need a parent + * that always ignores SIGCHLD to ensure auto-reaping. + */ + pid = kernel_thread(call_usermodehelper_exec_async, sub_info, + CLONE_PARENT | SIGCHLD); + if (pid < 0) { + sub_info->retval = pid; + umh_complete(sub_info); + } + } +} + +/* + * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY + * (used for preventing user land processes from being created after the user + * land has been frozen during a system-wide hibernation or suspend operation). + * Should always be manipulated under umhelper_sem acquired for write. + */ +static enum umh_disable_depth usermodehelper_disabled = UMH_DISABLED; + +/* Number of helpers running */ +static atomic_t running_helpers = ATOMIC_INIT(0); + +/* + * Wait queue head used by usermodehelper_disable() to wait for all running + * helpers to finish. + */ +static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq); + +/* + * Used by usermodehelper_read_lock_wait() to wait for usermodehelper_disabled + * to become 'false'. + */ +static DECLARE_WAIT_QUEUE_HEAD(usermodehelper_disabled_waitq); + +/* + * Time to wait for running_helpers to become zero before the setting of + * usermodehelper_disabled in usermodehelper_disable() fails + */ +#define RUNNING_HELPERS_TIMEOUT (5 * HZ) + +int usermodehelper_read_trylock(void) +{ + DEFINE_WAIT(wait); + int ret = 0; + + down_read(&umhelper_sem); + for (;;) { + prepare_to_wait(&usermodehelper_disabled_waitq, &wait, + TASK_INTERRUPTIBLE); + if (!usermodehelper_disabled) + break; + + if (usermodehelper_disabled == UMH_DISABLED) + ret = -EAGAIN; + + up_read(&umhelper_sem); + + if (ret) + break; + + schedule(); + try_to_freeze(); + + down_read(&umhelper_sem); + } + finish_wait(&usermodehelper_disabled_waitq, &wait); + return ret; +} +EXPORT_SYMBOL_GPL(usermodehelper_read_trylock); + +long usermodehelper_read_lock_wait(long timeout) +{ + DEFINE_WAIT(wait); + + if (timeout < 0) + return -EINVAL; + + down_read(&umhelper_sem); + for (;;) { + prepare_to_wait(&usermodehelper_disabled_waitq, &wait, + TASK_UNINTERRUPTIBLE); + if (!usermodehelper_disabled) + break; + + up_read(&umhelper_sem); + + timeout = schedule_timeout(timeout); + if (!timeout) + break; + + down_read(&umhelper_sem); + } + finish_wait(&usermodehelper_disabled_waitq, &wait); + return timeout; +} +EXPORT_SYMBOL_GPL(usermodehelper_read_lock_wait); + +void usermodehelper_read_unlock(void) +{ + up_read(&umhelper_sem); +} +EXPORT_SYMBOL_GPL(usermodehelper_read_unlock); + +/** + * __usermodehelper_set_disable_depth - Modify usermodehelper_disabled. + * @depth: New value to assign to usermodehelper_disabled. + * + * Change the value of usermodehelper_disabled (under umhelper_sem locked for + * writing) and wakeup tasks waiting for it to change. + */ +void __usermodehelper_set_disable_depth(enum umh_disable_depth depth) +{ + down_write(&umhelper_sem); + usermodehelper_disabled = depth; + wake_up(&usermodehelper_disabled_waitq); + up_write(&umhelper_sem); +} + +/** + * __usermodehelper_disable - Prevent new helpers from being started. + * @depth: New value to assign to usermodehelper_disabled. + * + * Set usermodehelper_disabled to @depth and wait for running helpers to exit. + */ +int __usermodehelper_disable(enum umh_disable_depth depth) +{ + long retval; + + if (!depth) + return -EINVAL; + + down_write(&umhelper_sem); + usermodehelper_disabled = depth; + up_write(&umhelper_sem); + + /* + * From now on call_usermodehelper_exec() won't start any new + * helpers, so it is sufficient if running_helpers turns out to + * be zero at one point (it may be increased later, but that + * doesn't matter). + */ + retval = wait_event_timeout(running_helpers_waitq, + atomic_read(&running_helpers) == 0, + RUNNING_HELPERS_TIMEOUT); + if (retval) + return 0; + + __usermodehelper_set_disable_depth(UMH_ENABLED); + return -EAGAIN; +} + +static void helper_lock(void) +{ + atomic_inc(&running_helpers); + smp_mb__after_atomic(); +} + +static void helper_unlock(void) +{ + if (atomic_dec_and_test(&running_helpers)) + wake_up(&running_helpers_waitq); +} + +/** + * call_usermodehelper_setup - prepare to call a usermode helper + * @path: path to usermode executable + * @argv: arg vector for process + * @envp: environment for process + * @gfp_mask: gfp mask for memory allocation + * @cleanup: a cleanup function + * @init: an init function + * @data: arbitrary context sensitive data + * + * Returns either %NULL on allocation failure, or a subprocess_info + * structure. This should be passed to call_usermodehelper_exec to + * exec the process and free the structure. + * + * The init function is used to customize the helper process prior to + * exec. A non-zero return code causes the process to error out, exit, + * and return the failure to the calling process + * + * The cleanup function is just before ethe subprocess_info is about to + * be freed. This can be used for freeing the argv and envp. The + * Function must be runnable in either a process context or the + * context in which call_usermodehelper_exec is called. + */ +struct subprocess_info *call_usermodehelper_setup(const char *path, char **argv, + char **envp, gfp_t gfp_mask, + int (*init)(struct subprocess_info *info, struct cred *new), + void (*cleanup)(struct subprocess_info *info), + void *data) +{ + struct subprocess_info *sub_info; + sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask); + if (!sub_info) + goto out; + + INIT_WORK(&sub_info->work, call_usermodehelper_exec_work); + +#ifdef CONFIG_STATIC_USERMODEHELPER + sub_info->path = CONFIG_STATIC_USERMODEHELPER_PATH; +#else + sub_info->path = path; +#endif + sub_info->argv = argv; + sub_info->envp = envp; + + sub_info->cleanup = cleanup; + sub_info->init = init; + sub_info->data = data; + out: + return sub_info; +} +EXPORT_SYMBOL(call_usermodehelper_setup); + +/** + * call_usermodehelper_exec - start a usermode application + * @sub_info: information about the subprocessa + * @wait: wait for the application to finish and return status. + * when UMH_NO_WAIT don't wait at all, but you get no useful error back + * when the program couldn't be exec'ed. This makes it safe to call + * from interrupt context. + * + * Runs a user-space application. The application is started + * asynchronously if wait is not set, and runs as a child of system workqueues. + * (ie. it runs with full root capabilities and optimized affinity). + */ +int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait) +{ + DECLARE_COMPLETION_ONSTACK(done); + int retval = 0; + + if (!sub_info->path) { + call_usermodehelper_freeinfo(sub_info); + return -EINVAL; + } + helper_lock(); + if (usermodehelper_disabled) { + retval = -EBUSY; + goto out; + } + + /* + * If there is no binary for us to call, then just return and get out of + * here. This allows us to set STATIC_USERMODEHELPER_PATH to "" and + * disable all call_usermodehelper() calls. + */ + if (strlen(sub_info->path) == 0) + goto out; + + /* + * Set the completion pointer only if there is a waiter. + * This makes it possible to use umh_complete to free + * the data structure in case of UMH_NO_WAIT. + */ + sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done; + sub_info->wait = wait; + + queue_work(system_unbound_wq, &sub_info->work); + if (wait == UMH_NO_WAIT) /* task has freed sub_info */ + goto unlock; + + if (wait & UMH_KILLABLE) { + retval = wait_for_completion_killable(&done); + if (!retval) + goto wait_done; + + /* umh_complete() will see NULL and free sub_info */ + if (xchg(&sub_info->complete, NULL)) + goto unlock; + /* fallthrough, umh_complete() was already called */ + } + + wait_for_completion(&done); +wait_done: + retval = sub_info->retval; +out: + call_usermodehelper_freeinfo(sub_info); +unlock: + helper_unlock(); + return retval; +} +EXPORT_SYMBOL(call_usermodehelper_exec); + +/** + * call_usermodehelper() - prepare and start a usermode application + * @path: path to usermode executable + * @argv: arg vector for process + * @envp: environment for process + * @wait: wait for the application to finish and return status. + * when UMH_NO_WAIT don't wait at all, but you get no useful error back + * when the program couldn't be exec'ed. This makes it safe to call + * from interrupt context. + * + * This function is the equivalent to use call_usermodehelper_setup() and + * call_usermodehelper_exec(). + */ +int call_usermodehelper(const char *path, char **argv, char **envp, int wait) +{ + struct subprocess_info *info; + gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL; + + info = call_usermodehelper_setup(path, argv, envp, gfp_mask, + NULL, NULL, NULL); + if (info == NULL) + return -ENOMEM; + + return call_usermodehelper_exec(info, wait); +} +EXPORT_SYMBOL(call_usermodehelper); + +static int proc_cap_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table t; + unsigned long cap_array[_KERNEL_CAPABILITY_U32S]; + kernel_cap_t new_cap; + int err, i; + + if (write && (!capable(CAP_SETPCAP) || + !capable(CAP_SYS_MODULE))) + return -EPERM; + + /* + * convert from the global kernel_cap_t to the ulong array to print to + * userspace if this is a read. + */ + spin_lock(&umh_sysctl_lock); + for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) { + if (table->data == CAP_BSET) + cap_array[i] = usermodehelper_bset.cap[i]; + else if (table->data == CAP_PI) + cap_array[i] = usermodehelper_inheritable.cap[i]; + else + BUG(); + } + spin_unlock(&umh_sysctl_lock); + + t = *table; + t.data = &cap_array; + + /* + * actually read or write and array of ulongs from userspace. Remember + * these are least significant 32 bits first + */ + err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos); + if (err < 0) + return err; + + /* + * convert from the sysctl array of ulongs to the kernel_cap_t + * internal representation + */ + for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++) + new_cap.cap[i] = cap_array[i]; + + /* + * Drop everything not in the new_cap (but don't add things) + */ + spin_lock(&umh_sysctl_lock); + if (write) { + if (table->data == CAP_BSET) + usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap); + if (table->data == CAP_PI) + usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap); + } + spin_unlock(&umh_sysctl_lock); + + return 0; +} + +struct ctl_table usermodehelper_table[] = { + { + .procname = "bset", + .data = CAP_BSET, + .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), + .mode = 0600, + .proc_handler = proc_cap_handler, + }, + { + .procname = "inheritable", + .data = CAP_PI, + .maxlen = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long), + .mode = 0600, + .proc_handler = proc_cap_handler, + }, + { } +}; -- cgit v1.2.3 From 0ce2c2029312ed78e37b56b08fa0f59ba97ef50b Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Fri, 8 Sep 2017 16:17:12 -0700 Subject: kmod: move #ifdef CONFIG_MODULES wrapper to Makefile The entire file is now conditionally compiled only when CONFIG_MODULES is enabled, and this this is a bool. Just move this conditional to the Makefile as its easier to read this way. Link: http://lkml.kernel.org/r/20170810180618.22457-5-mcgrof@kernel.org Signed-off-by: Luis R. Rodriguez Cc: Kees Cook Cc: Dmitry Torokhov Cc: Jessica Yu Cc: Rusty Russell Cc: Michal Marek Cc: Petr Mladek Cc: Miroslav Benes Cc: Josh Poimboeuf Cc: Guenter Roeck Cc: "Eric W. Biederman" Cc: Matt Redfearn Cc: Dan Carpenter Cc: Colin Ian King Cc: Daniel Mentz Cc: David Binderman Cc: Greg Kroah-Hartman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/Makefile | 3 ++- kernel/kmod.c | 3 --- 2 files changed, 2 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/Makefile b/kernel/Makefile index 44abbb0104b6..ed470aac53da 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -5,12 +5,13 @@ obj-y = fork.o exec_domain.o panic.o \ cpu.o exit.o softirq.o resource.o \ sysctl.o sysctl_binary.o capability.o ptrace.o user.o \ - signal.o sys.o umh.o kmod.o workqueue.o pid.o task_work.o \ + signal.o sys.o umh.o workqueue.o pid.o task_work.o \ extable.o params.o \ kthread.o sys_ni.o nsproxy.o \ notifier.o ksysfs.o cred.o reboot.o \ async.o range.o smpboot.o ucount.o +obj-$(CONFIG_MODULES) += kmod.o obj-$(CONFIG_MULTIUSER) += groups.o ifdef CONFIG_FUNCTION_TRACER diff --git a/kernel/kmod.c b/kernel/kmod.c index cdff52974d18..bc6addd9152b 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -28,7 +28,6 @@ #include -#ifdef CONFIG_MODULES /* * Assuming: * @@ -177,5 +176,3 @@ int __request_module(bool wait, const char *fmt, ...) return ret; } EXPORT_SYMBOL(__request_module); - -#endif /* CONFIG_MODULES */ -- cgit v1.2.3 From a2d818030135c293f878fbb772cf40e7a14c5acc Mon Sep 17 00:00:00 2001 From: "Robert P. J. Day" Date: Fri, 8 Sep 2017 16:17:19 -0700 Subject: drivers/pps: aesthetic tweaks to PPS-related content Collection of aesthetic adjustments to various PPS-related files, directories and Documentation, some quite minor just for the sake of consistency, including: * Updated example of pps device tree node (courtesy Rodolfo G.) * "PPS-API" -> "PPS API" * "pps_source_info_s" -> "pps_source_info" * "ktimer driver" -> "pps-ktimer driver" * "ppstest /dev/pps0" -> "ppstest /dev/pps1" to match example * Add missing PPS-related entries to MAINTAINERS file * Other trivialities Link: http://lkml.kernel.org/r/alpine.LFD.2.20.1708261048220.8106@localhost.localdomain Signed-off-by: Robert P. J. Day Acked-by: Rodolfo Giometti Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/time/timekeeping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 8ea4fb315719..2cafb49aa65e 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -2316,7 +2316,7 @@ void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts) raw_spin_unlock_irqrestore(&timekeeper_lock, flags); } EXPORT_SYMBOL(hardpps); -#endif +#endif /* CONFIG_NTP_PPS */ /** * xtime_update() - advances the timekeeping infrastructure -- cgit v1.2.3 From 7483e5d420d9d5aa1732c5efb0da59e095a8b24e Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov Date: Fri, 8 Sep 2017 16:17:35 -0700 Subject: kcov: support compat processes Support compat processes in KCOV by providing compat_ioctl callback. Compat mode uses the same ioctl callback: we have 2 commands that do not use the argument and 1 that already checks that the arg does not overflow INT_MAX. This allows to use KCOV-guided fuzzing in compat processes. Link: http://lkml.kernel.org/r/20170823100553.55812-1-dvyukov@google.com Signed-off-by: Dmitry Vyukov Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kcov.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/kcov.c b/kernel/kcov.c index cd771993f96f..3f693a0f6f3e 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -270,6 +270,7 @@ static long kcov_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) static const struct file_operations kcov_fops = { .open = kcov_open, .unlocked_ioctl = kcov_ioctl, + .compat_ioctl = kcov_ioctl, .mmap = kcov_mmap, .release = kcov_close, }; -- cgit v1.2.3 From 109980b894e9dae66c37c3d804a415aa68b19c7e Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 8 Sep 2017 00:14:51 +0200 Subject: bpf: don't select potentially stale ri->map from buggy xdp progs We can potentially run into a couple of issues with the XDP bpf_redirect_map() helper. The ri->map in the per CPU storage can become stale in several ways, mostly due to misuse, where we can then trigger a use after free on the map: i) prog A is calling bpf_redirect_map(), returning XDP_REDIRECT and running on a driver not supporting XDP_REDIRECT yet. The ri->map on that CPU becomes stale when the XDP program is unloaded on the driver, and a prog B loaded on a different driver which supports XDP_REDIRECT return code. prog B would have to omit calling to bpf_redirect_map() and just return XDP_REDIRECT, which would then access the freed map in xdp_do_redirect() since not cleared for that CPU. ii) prog A is calling bpf_redirect_map(), returning a code other than XDP_REDIRECT. prog A is then detached, which triggers release of the map. prog B is attached which, similarly as in i), would just return XDP_REDIRECT without having called bpf_redirect_map() and thus be accessing the freed map in xdp_do_redirect() since not cleared for that CPU. iii) prog A is attached to generic XDP, calling the bpf_redirect_map() helper and returning XDP_REDIRECT. xdp_do_generic_redirect() is currently not handling ri->map (will be fixed by Jesper), so it's not being reset. Later loading a e.g. native prog B which would, say, call bpf_xdp_redirect() and then returns XDP_REDIRECT would find in xdp_do_redirect() that a map was set and uses that causing use after free on map access. Fix thus needs to avoid accessing stale ri->map pointers, naive way would be to call a BPF function from drivers that just resets it to NULL for all XDP return codes but XDP_REDIRECT and including XDP_REDIRECT for drivers not supporting it yet (and let ri->map being handled in xdp_do_generic_redirect()). There is a less intrusive way w/o letting drivers call a reset for each BPF run. The verifier knows we're calling into bpf_xdp_redirect_map() helper, so it can do a small insn rewrite transparent to the prog itself in the sense that it fills R4 with a pointer to the own bpf_prog. We have that pointer at verification time anyway and R4 is allowed to be used as per calling convention we scratch R0 to R5 anyway, so they become inaccessible and program cannot read them prior to a write. Then, the helper would store the prog pointer in the current CPUs struct redirect_info. Later in xdp_do_*_redirect() we check whether the redirect_info's prog pointer is the same as passed xdp_prog pointer, and if that's the case then all good, since the prog holds a ref on the map anyway, so it is always valid at that point in time and must have a reference count of at least 1. If in the unlikely case they are not equal, it means we got a stale pointer, so we clear and bail out right there. Also do reset map and the owning prog in bpf_xdp_redirect(), so that bpf_xdp_redirect_map() and bpf_xdp_redirect() won't get mixed up, only the last call should take precedence. A tc bpf_redirect() doesn't use map anywhere yet, so no need to clear it there since never accessed in that layer. Note that in case the prog is released, and thus the map as well we're still under RCU read critical section at that time and have preemption disabled as well. Once we commit with the __dev_map_insert_ctx() from xdp_do_redirect_map() and set the map to ri->map_to_flush, we still wait for a xdp_do_flush_map() to finish in devmap dismantle time once flush_needed bit is set, so that is fine. Fixes: 97f91a7cf04f ("bpf: add bpf_redirect_map helper routine") Reported-by: Jesper Dangaard Brouer Signed-off-by: Daniel Borkmann Signed-off-by: John Fastabend Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index d690c7dd1f1a..477b6932c3c1 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4203,6 +4203,22 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) continue; } + if (insn->imm == BPF_FUNC_redirect_map) { + u64 addr = (unsigned long)prog; + struct bpf_insn r4_ld[] = { + BPF_LD_IMM64(BPF_REG_4, addr), + *insn, + }; + cnt = ARRAY_SIZE(r4_ld); + + new_prog = bpf_patch_insn_data(env, i + delta, r4_ld, cnt); + if (!new_prog) + return -ENOMEM; + + delta += cnt - 1; + env->prog = prog = new_prog; + insn = new_prog->insnsi + i + delta; + } patch_call_imm: fn = prog->aux->ops->get_func_proto(insn->imm); /* all functions that have prototype and verifier allowed -- cgit v1.2.3 From 5a67da2a71c64daeb456f6f3e87b5c7cecdc5ffa Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Fri, 8 Sep 2017 14:00:49 -0700 Subject: bpf: add support for sockmap detach programs The bpf map sockmap supports adding programs via attach commands. This patch adds the detach command to keep the API symmetric and allow users to remove previously added programs. Otherwise the user would have to delete the map and re-add it to get in this state. This also adds a series of additional tests to capture detach operation and also attaching/detaching invalid prog types. API note: socks will run (or not run) programs depending on the state of the map at the time the sock is added. We do not for example walk the map and remove programs from previously attached socks. Acked-by: Daniel Borkmann Signed-off-by: John Fastabend Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/sockmap.c | 2 +- kernel/bpf/syscall.c | 27 +++++++++++++++++---------- 2 files changed, 18 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index f6ffde9c6a68..6424ce0e4969 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -792,7 +792,7 @@ out_progs: return err; } -int sock_map_attach_prog(struct bpf_map *map, struct bpf_prog *prog, u32 type) +int sock_map_prog(struct bpf_map *map, struct bpf_prog *prog, u32 type) { struct bpf_stab *stab = container_of(map, struct bpf_stab, map); struct bpf_prog *orig; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 70ad8e220343..cb17e1cd1d43 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1096,10 +1096,10 @@ static int bpf_obj_get(const union bpf_attr *attr) #define BPF_PROG_ATTACH_LAST_FIELD attach_flags -static int sockmap_get_from_fd(const union bpf_attr *attr) +static int sockmap_get_from_fd(const union bpf_attr *attr, bool attach) { + struct bpf_prog *prog = NULL; int ufd = attr->target_fd; - struct bpf_prog *prog; struct bpf_map *map; struct fd f; int err; @@ -1109,16 +1109,20 @@ static int sockmap_get_from_fd(const union bpf_attr *attr) if (IS_ERR(map)) return PTR_ERR(map); - prog = bpf_prog_get_type(attr->attach_bpf_fd, BPF_PROG_TYPE_SK_SKB); - if (IS_ERR(prog)) { - fdput(f); - return PTR_ERR(prog); + if (attach) { + prog = bpf_prog_get_type(attr->attach_bpf_fd, + BPF_PROG_TYPE_SK_SKB); + if (IS_ERR(prog)) { + fdput(f); + return PTR_ERR(prog); + } } - err = sock_map_attach_prog(map, prog, attr->attach_type); + err = sock_map_prog(map, prog, attr->attach_type); if (err) { fdput(f); - bpf_prog_put(prog); + if (prog) + bpf_prog_put(prog); return err; } @@ -1155,7 +1159,7 @@ static int bpf_prog_attach(const union bpf_attr *attr) break; case BPF_SK_SKB_STREAM_PARSER: case BPF_SK_SKB_STREAM_VERDICT: - return sockmap_get_from_fd(attr); + return sockmap_get_from_fd(attr, true); default: return -EINVAL; } @@ -1204,7 +1208,10 @@ static int bpf_prog_detach(const union bpf_attr *attr) ret = cgroup_bpf_update(cgrp, NULL, attr->attach_type, false); cgroup_put(cgrp); break; - + case BPF_SK_SKB_STREAM_PARSER: + case BPF_SK_SKB_STREAM_VERDICT: + ret = sockmap_get_from_fd(attr, false); + break; default: return -EINVAL; } -- cgit v1.2.3 From 374fb014fc5b15e420faa00af036868a635eadd3 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Fri, 8 Sep 2017 14:01:10 -0700 Subject: bpf: devmap, use cond_resched instead of cpu_relax Be a bit more friendly about waiting for flush bits to complete. Replace the cpu_relax() with a cond_resched(). Suggested-by: Daniel Borkmann Acked-by: Daniel Borkmann Signed-off-by: John Fastabend Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/devmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index ecf9f99ecc57..959c9a07f318 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -159,7 +159,7 @@ static void dev_map_free(struct bpf_map *map) unsigned long *bitmap = per_cpu_ptr(dtab->flush_needed, cpu); while (!bitmap_empty(bitmap, dtab->map.max_entries)) - cpu_relax(); + cond_resched(); } for (i = 0; i < dtab->map.max_entries; i++) { -- cgit v1.2.3 From 46123355af729514e6fa8b8a9dd1e645e61a6466 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Sun, 10 Sep 2017 09:55:05 -0700 Subject: sched/fair: Fix nuisance kernel-doc warning Work around kernel-doc warning ('*' in Sphinx doc means "emphasis"): ../kernel/sched/fair.c:7584: WARNING: Inline emphasis start-string without end-string. Signed-off-by: Randy Dunlap Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/f18b30f9-6251-6d86-9d44-16501e386891@infradead.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 9dd2ce1e5ca2..8415d1ec2b84 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7719,7 +7719,7 @@ next_group: * number. * * Return: 1 when packing is required and a task should be moved to - * this CPU. The amount of the imbalance is returned in *imbalance. + * this CPU. The amount of the imbalance is returned in env->imbalance. * * @env: The load balancing environment. * @sds: Statistics of the sched_domain which is to be packed -- cgit v1.2.3 From 609320c8a22715b74b39796930c3542719f8ab62 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Thu, 7 Sep 2017 18:36:15 -0700 Subject: perf/bpf: fix a clang compilation issue clang does not support variable length array for structure member. It has the following error during compilation: kernel/trace/trace_syscalls.c:568:17: error: fields must have a constant size: 'variable length array in structure' extension will never be supported unsigned long args[sys_data->nb_args]; ^ The fix is to use a fixed array length instead. Reported-by: Nick Desaulniers Signed-off-by: Yonghong Song Signed-off-by: David S. Miller --- kernel/trace/trace_syscalls.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 9c4eef20301c..696afe72d3b1 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -565,7 +565,7 @@ static int perf_call_bpf_enter(struct bpf_prog *prog, struct pt_regs *regs, struct syscall_tp_t { unsigned long long regs; unsigned long syscall_nr; - unsigned long args[sys_data->nb_args]; + unsigned long args[SYSCALL_DEFINE_MAXARGS]; } param; int i; -- cgit v1.2.3 From 2800486ee34825d954f64c6f98037daea328f121 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Sep 2017 17:03:50 +0200 Subject: sched/fair: Avoid newidle balance for !active CPUs On CPU hot unplug, when parking the last kthread we'll try and schedule into idle to kill the CPU. This last schedule can (and does) trigger newidle balance because at this point the sched domains are still up because of commit: 77d1dfda0e79 ("sched/topology, cpuset: Avoid spurious/wrong domain rebuilds") Obviously pulling tasks to an already offline CPU is a bad idea, and all balancing operations _should_ be subject to cpu_active_mask, make it so. Reported-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Fixes: 77d1dfda0e79 ("sched/topology, cpuset: Avoid spurious/wrong domain rebuilds") Link: http://lkml.kernel.org/r/20170907150613.994135806@infradead.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 8415d1ec2b84..3bcea40d3029 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8447,6 +8447,12 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf) */ this_rq->idle_stamp = rq_clock(this_rq); + /* + * Do not pull tasks towards !active CPUs... + */ + if (!cpu_active(this_cpu)) + return 0; + /* * This is OK, because current is on_cpu, which avoids it being picked * for load-balance and preemption/IRQs are still disabled avoiding -- cgit v1.2.3 From edd8e41d2e3cbd6ebe13ead30eb1adc6f48cbb33 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Sep 2017 17:03:51 +0200 Subject: sched/fair: Plug hole between hotplug and active_load_balance() The load balancer applies cpu_active_mask to whatever sched_domains it finds, however in the case of active_balance there is a hole between setting rq->{active_balance,push_cpu} and running the stop_machine work doing the actual migration. The @push_cpu can go offline in this window, which would result in us moving a task onto a dead cpu, which is a fairly bad thing. Double check the active mask before the stop work does the migration. CPU0 CPU1 stop_machine(takedown_cpu) load_balance() cpu_stopper_thread() ... work = multi_cpu_stop stop_one_cpu_nowait( /* wait for CPU0 */ .func = active_load_balance_cpu_stop ); cpu_stopper_thread() work = multi_cpu_stop /* sync with CPU1 */ take_cpu_down() play_dead(); work = active_load_balance_cpu_stop set_task_cpu(p, CPU1); /* oops!! */ Reported-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20170907150614.044460912@infradead.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 3bcea40d3029..efeebed935ae 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8560,6 +8560,13 @@ static int active_load_balance_cpu_stop(void *data) struct rq_flags rf; rq_lock_irq(busiest_rq, &rf); + /* + * Between queueing the stop-work and running it is a hole in which + * CPUs can become inactive. We should not move tasks from or to + * inactive CPUs. + */ + if (!cpu_active(busiest_cpu) || !cpu_active(target_cpu)) + goto out_unlock; /* make sure the requested cpu hasn't gone down in the meantime */ if (unlikely(busiest_cpu != smp_processor_id() || -- cgit v1.2.3 From 4ff9083b8a9a80bdf4ebbbec22cda4cbfb60f7aa Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Sep 2017 17:03:52 +0200 Subject: sched/core: WARN() when migrating to an offline CPU Migrating tasks to offline CPUs is a pretty big fail, warn about it. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170907150614.094206976@infradead.org Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 136a76d80dbf..18a6966567da 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1173,6 +1173,10 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || lockdep_is_held(&task_rq(p)->lock))); #endif + /* + * Clearly, migrating tasks to offline CPUs is a fairly daft thing. + */ + WARN_ON_ONCE(!cpu_online(new_cpu)); #endif trace_sched_migrate_task(p, new_cpu); -- cgit v1.2.3 From 9469eb01db891b55367ee7539f1b9f7f6fd2819d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 7 Sep 2017 17:03:53 +0200 Subject: sched/debug: Add debugfs knob for "sched_debug" I'm forever late for editing my kernel cmdline, add a runtime knob to disable the "sched_debug" thing. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170907150614.142924283@infradead.org Signed-off-by: Ingo Molnar --- kernel/sched/debug.c | 5 +++++ kernel/sched/sched.h | 2 ++ kernel/sched/topology.c | 4 +--- 3 files changed, 8 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 4a23bbc3111b..b19d06ea6e10 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -181,11 +181,16 @@ static const struct file_operations sched_feat_fops = { .release = single_release, }; +__read_mostly bool sched_debug_enabled; + static __init int sched_init_debug(void) { debugfs_create_file("sched_features", 0644, NULL, NULL, &sched_feat_fops); + debugfs_create_bool("sched_debug", 0644, NULL, + &sched_debug_enabled); + return 0; } late_initcall(sched_init_debug); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index ab1c7f5409a0..7ea2a0339771 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1954,6 +1954,8 @@ extern struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq); extern struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq); #ifdef CONFIG_SCHED_DEBUG +extern bool sched_debug_enabled; + extern void print_cfs_stats(struct seq_file *m, int cpu); extern void print_rt_stats(struct seq_file *m, int cpu); extern void print_dl_stats(struct seq_file *m, int cpu); diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 6f7b43982f73..2ab2aa68c796 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -14,11 +14,9 @@ cpumask_var_t sched_domains_tmpmask2; #ifdef CONFIG_SCHED_DEBUG -static __read_mostly int sched_debug_enabled; - static int __init sched_debug_setup(char *str) { - sched_debug_enabled = 1; + sched_debug_enabled = true; return 0; } -- cgit v1.2.3 From 0ee931c4e31a5efb134c76440405e9219f896e33 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Wed, 13 Sep 2017 16:28:29 -0700 Subject: mm: treewide: remove GFP_TEMPORARY allocation flag GFP_TEMPORARY was introduced by commit e12ba74d8ff3 ("Group short-lived and reclaimable kernel allocations") along with __GFP_RECLAIMABLE. It's primary motivation was to allow users to tell that an allocation is short lived and so the allocator can try to place such allocations close together and prevent long term fragmentation. As much as this sounds like a reasonable semantic it becomes much less clear when to use the highlevel GFP_TEMPORARY allocation flag. How long is temporary? Can the context holding that memory sleep? Can it take locks? It seems there is no good answer for those questions. The current implementation of GFP_TEMPORARY is basically GFP_KERNEL | __GFP_RECLAIMABLE which in itself is tricky because basically none of the existing caller provide a way to reclaim the allocated memory. So this is rather misleading and hard to evaluate for any benefits. I have checked some random users and none of them has added the flag with a specific justification. I suspect most of them just copied from other existing users and others just thought it might be a good idea to use without any measuring. This suggests that GFP_TEMPORARY just motivates for cargo cult usage without any reasoning. I believe that our gfp flags are quite complex already and especially those with highlevel semantic should be clearly defined to prevent from confusion and abuse. Therefore I propose dropping GFP_TEMPORARY and replace all existing users to simply use GFP_KERNEL. Please note that SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and so they will be placed properly for memory fragmentation prevention. I can see reasons we might want some gfp flag to reflect shorterm allocations but I propose starting from a clear semantic definition and only then add users with proper justification. This was been brought up before LSF this year by Matthew [1] and it turned out that GFP_TEMPORARY really doesn't have a clear semantic. It seems to be a heuristic without any measured advantage for most (if not all) its current users. The follow up discussion has revealed that opinions on what might be temporary allocation differ a lot between developers. So rather than trying to tweak existing users into a semantic which they haven't expected I propose to simply remove the flag and start from scratch if we really need a semantic for short term allocations. [1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org [akpm@linux-foundation.org: fix typo] [akpm@linux-foundation.org: coding-style fixes] [sfr@canb.auug.org.au: drm/i915: fix up] Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org Signed-off-by: Michal Hocko Signed-off-by: Stephen Rothwell Acked-by: Mel Gorman Acked-by: Vlastimil Babka Cc: Matthew Wilcox Cc: Neil Brown Cc: "Theodore Ts'o" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/locking/test-ww_mutex.c | 2 +- kernel/trace/trace_events_filter.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c index 39f56c870051..0e4cd64ad2c0 100644 --- a/kernel/locking/test-ww_mutex.c +++ b/kernel/locking/test-ww_mutex.c @@ -362,7 +362,7 @@ static int *get_random_order(int count) int *order; int n, r, tmp; - order = kmalloc_array(count, sizeof(*order), GFP_TEMPORARY); + order = kmalloc_array(count, sizeof(*order), GFP_KERNEL); if (!order) return order; diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 181e139a8057..61e7f0678d33 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -702,7 +702,7 @@ static void append_filter_err(struct filter_parse_state *ps, int pos = ps->lasterr_pos; char *buf, *pbuf; - buf = (char *)__get_free_page(GFP_TEMPORARY); + buf = (char *)__get_free_page(GFP_KERNEL); if (!buf) return; -- cgit v1.2.3 From 2554db916586b228ce93e6f74a12fd7fe430a004 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Fri, 25 Aug 2017 09:13:54 -0700 Subject: sched/wait: Break up long wake list walk We encountered workloads that have very long wake up list on large systems. A waker takes a long time to traverse the entire wake list and execute all the wake functions. We saw page wait list that are up to 3700+ entries long in tests of large 4 and 8 socket systems. It took 0.8 sec to traverse such list during wake up. Any other CPU that contends for the list spin lock will spin for a long time. It is a result of the numa balancing migration of hot pages that are shared by many threads. Multiple CPUs waking are queued up behind the lock, and the last one queued has to wait until all CPUs did all the wakeups. The page wait list is traversed with interrupt disabled, which caused various problems. This was the original cause that triggered the NMI watch dog timer in: https://patchwork.kernel.org/patch/9800303/ . Only extending the NMI watch dog timer there helped. This patch bookmarks the waker's scan position in wake list and break the wake up walk, to allow access to the list before the waker resume its walk down the rest of the wait list. It lowers the interrupt and rescheduling latency. This patch also provides a performance boost when combined with the next patch to break up page wakeup list walk. We saw 22% improvement in the will-it-scale file pread2 test on a Xeon Phi system running 256 threads. [ v2: Merged in Linus' changes to remove the bookmark_wake_function, and simply access to flags. ] Reported-by: Kan Liang Tested-by: Kan Liang Signed-off-by: Tim Chen Signed-off-by: Linus Torvalds --- kernel/sched/wait.c | 78 ++++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 63 insertions(+), 15 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index d6afed6d0752..70701ef50465 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -53,6 +53,12 @@ void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry } EXPORT_SYMBOL(remove_wait_queue); +/* + * Scan threshold to break wait queue walk. + * This allows a waker to take a break from holding the + * wait queue lock during the wait queue walk. + */ +#define WAITQUEUE_WALK_BREAK_CNT 64 /* * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just @@ -63,18 +69,67 @@ EXPORT_SYMBOL(remove_wait_queue); * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns * zero in this (rare) case, and we handle it by continuing to scan the queue. */ -static void __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode, - int nr_exclusive, int wake_flags, void *key) +static int __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode, + int nr_exclusive, int wake_flags, void *key, + wait_queue_entry_t *bookmark) { wait_queue_entry_t *curr, *next; + int cnt = 0; + + if (bookmark && (bookmark->flags & WQ_FLAG_BOOKMARK)) { + curr = list_next_entry(bookmark, entry); - list_for_each_entry_safe(curr, next, &wq_head->head, entry) { + list_del(&bookmark->entry); + bookmark->flags = 0; + } else + curr = list_first_entry(&wq_head->head, wait_queue_entry_t, entry); + + if (&curr->entry == &wq_head->head) + return nr_exclusive; + + list_for_each_entry_safe_from(curr, next, &wq_head->head, entry) { unsigned flags = curr->flags; - int ret = curr->func(curr, mode, wake_flags, key); + int ret; + + if (flags & WQ_FLAG_BOOKMARK) + continue; + + ret = curr->func(curr, mode, wake_flags, key); if (ret < 0) break; if (ret && (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) break; + + if (bookmark && (++cnt > WAITQUEUE_WALK_BREAK_CNT) && + (&next->entry != &wq_head->head)) { + bookmark->flags = WQ_FLAG_BOOKMARK; + list_add_tail(&bookmark->entry, &next->entry); + break; + } + } + return nr_exclusive; +} + +static void __wake_up_common_lock(struct wait_queue_head *wq_head, unsigned int mode, + int nr_exclusive, int wake_flags, void *key) +{ + unsigned long flags; + wait_queue_entry_t bookmark; + + bookmark.flags = 0; + bookmark.private = NULL; + bookmark.func = NULL; + INIT_LIST_HEAD(&bookmark.entry); + + spin_lock_irqsave(&wq_head->lock, flags); + nr_exclusive = __wake_up_common(wq_head, mode, nr_exclusive, wake_flags, key, &bookmark); + spin_unlock_irqrestore(&wq_head->lock, flags); + + while (bookmark.flags & WQ_FLAG_BOOKMARK) { + spin_lock_irqsave(&wq_head->lock, flags); + nr_exclusive = __wake_up_common(wq_head, mode, nr_exclusive, + wake_flags, key, &bookmark); + spin_unlock_irqrestore(&wq_head->lock, flags); } } @@ -91,11 +146,7 @@ static void __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode, void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr_exclusive, void *key) { - unsigned long flags; - - spin_lock_irqsave(&wq_head->lock, flags); - __wake_up_common(wq_head, mode, nr_exclusive, 0, key); - spin_unlock_irqrestore(&wq_head->lock, flags); + __wake_up_common_lock(wq_head, mode, nr_exclusive, 0, key); } EXPORT_SYMBOL(__wake_up); @@ -104,13 +155,13 @@ EXPORT_SYMBOL(__wake_up); */ void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr) { - __wake_up_common(wq_head, mode, nr, 0, NULL); + __wake_up_common(wq_head, mode, nr, 0, NULL, NULL); } EXPORT_SYMBOL_GPL(__wake_up_locked); void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key) { - __wake_up_common(wq_head, mode, 1, 0, key); + __wake_up_common(wq_head, mode, 1, 0, key, NULL); } EXPORT_SYMBOL_GPL(__wake_up_locked_key); @@ -134,7 +185,6 @@ EXPORT_SYMBOL_GPL(__wake_up_locked_key); void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, int nr_exclusive, void *key) { - unsigned long flags; int wake_flags = 1; /* XXX WF_SYNC */ if (unlikely(!wq_head)) @@ -143,9 +193,7 @@ void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, if (unlikely(nr_exclusive != 1)) wake_flags = 0; - spin_lock_irqsave(&wq_head->lock, flags); - __wake_up_common(wq_head, mode, nr_exclusive, wake_flags, key); - spin_unlock_irqrestore(&wq_head->lock, flags); + __wake_up_common_lock(wq_head, mode, nr_exclusive, wake_flags, key); } EXPORT_SYMBOL_GPL(__wake_up_sync_key); -- cgit v1.2.3 From 11a19c7b099f96d00a8dec52bfbb8475e89b6745 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Fri, 25 Aug 2017 09:13:55 -0700 Subject: sched/wait: Introduce wakeup boomark in wake_up_page_bit Now that we have added breaks in the wait queue scan and allow bookmark on scan position, we put this logic in the wake_up_page_bit function. We can have very long page wait list in large system where multiple pages share the same wait list. We break the wake up walk here to allow other cpus a chance to access the list, and not to disable the interrupts when traversing the list for too long. This reduces the interrupt and rescheduling latency, and excessive page wait queue lock hold time. [ v2: Remove bookmark_wake_function ] Signed-off-by: Tim Chen Signed-off-by: Linus Torvalds --- kernel/sched/wait.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel') diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index 70701ef50465..98feab7933c7 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -165,6 +165,13 @@ void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, vo } EXPORT_SYMBOL_GPL(__wake_up_locked_key); +void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head, + unsigned int mode, void *key, wait_queue_entry_t *bookmark) +{ + __wake_up_common(wq_head, mode, 1, 0, key, bookmark); +} +EXPORT_SYMBOL_GPL(__wake_up_locked_key_bookmark); + /** * __wake_up_sync_key - wake up threads blocked on a waitqueue. * @wq_head: the waitqueue -- cgit v1.2.3 From e67b8a685c7c984e834e3181ef4619cd7025a136 Mon Sep 17 00:00:00 2001 From: Edward Cree Date: Fri, 15 Sep 2017 14:37:38 +0100 Subject: bpf/verifier: reject BPF_ALU64|BPF_END Neither ___bpf_prog_run nor the JITs accept it. Also adds a new test case. Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)") Signed-off-by: Edward Cree Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 477b6932c3c1..799b2451ef2d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2292,7 +2292,8 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) } } else { if (insn->src_reg != BPF_REG_0 || insn->off != 0 || - (insn->imm != 16 && insn->imm != 32 && insn->imm != 64)) { + (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) || + BPF_CLASS(insn->code) == BPF_ALU64) { verbose("BPF_END uses reserved fields\n"); return -EINVAL; } -- cgit v1.2.3