linux-stable.git/kernel, branch v5.2.16

modules: always page-align module section allocations

2019-09-19T07:11:07+00:00

commit 38f054d549a869f22a02224cd276a27bf14b6171 upstream.

Some arches (e.g., arm64, x86) have moved towards non-executable
module_alloc() allocations for security hardening reasons. That means
that the module loader will need to set the text section of a module to
executable, regardless of whether or not CONFIG_STRICT_MODULE_RWX is set.

When CONFIG_STRICT_MODULE_RWX=y, module section allocations are always
page-aligned to handle memory rwx permissions. On some arches with
CONFIG_STRICT_MODULE_RWX=n however, when setting the module text to
executable, the BUG_ON() in frob_text() gets triggered since module
section allocations are not page-aligned when CONFIG_STRICT_MODULE_RWX=n.
Since the set_memory_* API works with pages, and since we need to call
set_memory_x() regardless of whether CONFIG_STRICT_MODULE_RWX is set, we
might as well page-align all module section allocations for ease of
managing rwx permissions of module sections (text, rodata, etc).

Fixes: 2eef1399a866 ("modules: fix BUG when load module with rodata=n")
Reported-by: Martin Kaiser 
Reported-by: Bartosz Golaszewski 
Tested-by: David Lechner 
Tested-by: Martin Kaiser 
Tested-by: Bartosz Golaszewski 
Signed-off-by: Jessica Yu 
Signed-off-by: Greg Kroah-Hartman

modules: fix compile error if don't have strict module rwx

2019-09-19T07:11:07+00:00

commit 93651f80dcb616b8c9115cdafc8e57a781af22d0 upstream.

If CONFIG_ARCH_HAS_STRICT_MODULE_RWX is not defined,
we need stub for module_enable_nx() and module_enable_x().

If CONFIG_ARCH_HAS_STRICT_MODULE_RWX is defined, but
CONFIG_STRICT_MODULE_RWX is disabled, we need stub for
module_enable_nx.

Move frob_text() outside of the CONFIG_STRICT_MODULE_RWX,
because it is needed anyway.

Fixes: 2eef1399a866 ("modules: fix BUG when load module with rodata=n")
Signed-off-by: Yang Yingliang 
Signed-off-by: Jessica Yu 
Signed-off-by: Greg Kroah-Hartman

modules: fix BUG when load module with rodata=n

2019-09-19T07:11:07+00:00

commit 2eef1399a866c57687962e15142b141a4f8e7862 upstream.

When loading a module with rodata=n, it causes an executing
NX-protected page BUG.

[   32.379191] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
[   32.382917] BUG: unable to handle page fault for address: ffffffffc0005000
[   32.385947] #PF: supervisor instruction fetch in kernel mode
[   32.387662] #PF: error_code(0x0011) - permissions violation
[   32.389352] PGD 240c067 P4D 240c067 PUD 240e067 PMD 421a52067 PTE 8000000421a53063
[   32.391396] Oops: 0011 [#1] SMP PTI
[   32.392478] CPU: 7 PID: 2697 Comm: insmod Tainted: G           O      5.2.0-rc5+ #202
[   32.394588] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
[   32.398157] RIP: 0010:ko_test_init+0x0/0x1000 [ko_test]
[   32.399662] Code: Bad RIP value.
[   32.400621] RSP: 0018:ffffc900029f3ca8 EFLAGS: 00010246
[   32.402171] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   32.404332] RDX: 00000000000004c7 RSI: 0000000000000cc0 RDI: ffffffffc0005000
[   32.406347] RBP: ffffffffc0005000 R08: ffff88842fbebc40 R09: ffffffff810ede4a
[   32.408392] R10: ffffea00108e3480 R11: 0000000000000000 R12: ffff88842bee21a0
[   32.410472] R13: 0000000000000001 R14: 0000000000000001 R15: ffffc900029f3e78
[   32.412609] FS:  00007fb4f0c0a700(0000) GS:ffff88842fbc0000(0000) knlGS:0000000000000000
[   32.414722] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   32.416290] CR2: ffffffffc0004fd6 CR3: 0000000421a90004 CR4: 0000000000020ee0
[   32.418471] Call Trace:
[   32.419136]  do_one_initcall+0x41/0x1df
[   32.420199]  ? _cond_resched+0x10/0x40
[   32.421433]  ? kmem_cache_alloc_trace+0x36/0x160
[   32.422827]  do_init_module+0x56/0x1f7
[   32.423946]  load_module+0x1e67/0x2580
[   32.424947]  ? __alloc_pages_nodemask+0x150/0x2c0
[   32.426413]  ? map_vm_area+0x2d/0x40
[   32.427530]  ? __vmalloc_node_range+0x1ef/0x260
[   32.428850]  ? __do_sys_init_module+0x135/0x170
[   32.430060]  ? _cond_resched+0x10/0x40
[   32.431249]  __do_sys_init_module+0x135/0x170
[   32.432547]  do_syscall_64+0x43/0x120
[   32.433853]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Because if rodata=n, set_memory_x() can't be called, fix this by
calling set_memory_x in complete_formation();

Fixes: f2c65fb3221a ("x86/modules: Avoid breaking W^X while loading modules")
Suggested-by: Jian Cheng 
Reviewed-by: Nadav Amit 
Signed-off-by: Yang Yingliang 
Signed-off-by: Jessica Yu 
Signed-off-by: Greg Kroah-Hartman

kernel/module: Fix mem leak in module_add_modinfo_attrs

2019-09-19T07:11:01+00:00

commit bc6f2a757d525e001268c3658bd88822e768f8db upstream.

In module_add_modinfo_attrs if sysfs_create_file
fails, we forget to free allocated modinfo_attrs
and roll back the sysfs files.

Fixes: 03e88ae1b13d ("[PATCH] fix module sysfs files reference counting")
Reviewed-by: Miroslav Benes 
Signed-off-by: YueHaibing 
Signed-off-by: Jessica Yu 
Signed-off-by: Greg Kroah-Hartman

genirq: Prevent NULL pointer dereference in resend_irqs()

2019-09-19T07:10:58+00:00

commit eddf3e9c7c7e4d0707c68d1bb22cc6ec8aef7d4a upstream.

The following crash was observed:

  Unable to handle kernel NULL pointer dereference at 0000000000000158
  Internal error: Oops: 96000004 [#1] SMP
  pc : resend_irqs+0x68/0xb0
  lr : resend_irqs+0x64/0xb0
  ...
  Call trace:
   resend_irqs+0x68/0xb0
   tasklet_action_common.isra.6+0x84/0x138
   tasklet_action+0x2c/0x38
   __do_softirq+0x120/0x324
   run_ksoftirqd+0x44/0x60
   smpboot_thread_fn+0x1ac/0x1e8
   kthread+0x134/0x138
   ret_from_fork+0x10/0x18

The reason for this is that the interrupt resend mechanism happens in soft
interrupt context, which is a asynchronous mechanism versus other
operations on interrupts. free_irq() does not take resend handling into
account. Thus, the irq descriptor might be already freed before the resend
tasklet is executed. resend_irqs() does not check the return value of the
interrupt descriptor lookup and derefences the return value
unconditionally.

  1):
  __setup_irq
    irq_startup
      check_irq_resend  // activate softirq to handle resend irq
  2):
  irq_domain_free_irqs
    irq_free_descs
      free_desc
        call_rcu(&desc->rcu, delayed_free_desc)
  3):
  __do_softirq
    tasklet_action
      resend_irqs
        desc = irq_to_desc(irq)
        desc->handle_irq(desc)  // desc is NULL --> Ooops

Fix this by adding a NULL pointer check in resend_irqs() before derefencing
the irq descriptor.

Fixes: a4633adcdbc1 ("[PATCH] genirq: add genirq sw IRQ-retrigger")
Signed-off-by: Yunfeng Ye 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Zhiqiang Liu 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1630ae13-5c8e-901e-de09-e740b6a426a7@huawei.com
Signed-off-by: Greg Kroah-Hartman

cgroup: freezer: fix frozen state inheritance

2019-09-19T07:10:54+00:00

commit 97a61369830ab085df5aed0ff9256f35b07d425a upstream.

If a new child cgroup is created in the frozen cgroup hierarchy
(one or more of ancestor cgroups is frozen), the CGRP_FREEZE cgroup
flag should be set. Otherwise if a process will be attached to the
child cgroup, it won't become frozen.

The problem can be reproduced with the test_cgfreezer_mkdir test.

This is the output before this patch:
  ~/test_freezer
  ok 1 test_cgfreezer_simple
  ok 2 test_cgfreezer_tree
  ok 3 test_cgfreezer_forkbomb
  Cgroup /sys/fs/cgroup/cg_test_mkdir_A/cg_test_mkdir_B isn't frozen
  not ok 4 test_cgfreezer_mkdir
  ok 5 test_cgfreezer_rmdir
  ok 6 test_cgfreezer_migrate
  ok 7 test_cgfreezer_ptrace
  ok 8 test_cgfreezer_stopped
  ok 9 test_cgfreezer_ptraced
  ok 10 test_cgfreezer_vfork

And with this patch:
  ~/test_freezer
  ok 1 test_cgfreezer_simple
  ok 2 test_cgfreezer_tree
  ok 3 test_cgfreezer_forkbomb
  ok 4 test_cgfreezer_mkdir
  ok 5 test_cgfreezer_rmdir
  ok 6 test_cgfreezer_migrate
  ok 7 test_cgfreezer_ptrace
  ok 8 test_cgfreezer_stopped
  ok 9 test_cgfreezer_ptraced
  ok 10 test_cgfreezer_vfork

Reported-by: Mark Crossen 
Signed-off-by: Roman Gushchin 
Fixes: 76f969e8948d ("cgroup: cgroup v2 freezer")
Cc: Tejun Heo 
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

sched/fair: Don't assign runtime for throttled cfs_rq

2019-09-16T06:23:18+00:00

commit 5e2d2cc2588bd3307ce3937acbc2ed03c830a861 upstream.

do_sched_cfs_period_timer() will refill cfs_b runtime and call
distribute_cfs_runtime to unthrottle cfs_rq, sometimes cfs_b->runtime
will allocate all quota to one cfs_rq incorrectly, then other cfs_rqs
attached to this cfs_b can't get runtime and will be throttled.

We find that one throttled cfs_rq has non-negative
cfs_rq->runtime_remaining and cause an unexpetced cast from s64 to u64
in snippet:

  distribute_cfs_runtime() {
    runtime = -cfs_rq->runtime_remaining + 1;
  }

The runtime here will change to a large number and consume all
cfs_b->runtime in this cfs_b period.

According to Ben Segall, the throttled cfs_rq can have
account_cfs_rq_runtime called on it because it is throttled before
idle_balance, and the idle_balance calls update_rq_clock to add time
that is accounted to the task.

This commit prevents cfs_rq to be assgined new runtime if it has been
throttled until that distribute_cfs_runtime is called.

Signed-off-by: Liangyan 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Valentin Schneider 
Reviewed-by: Ben Segall 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: shanpeic@linux.alibaba.com
Cc: stable@vger.kernel.org
Cc: xlpang@linux.alibaba.com
Fixes: d3d9dc330236 ("sched: Throttle entities exceeding their allowed bandwidth")
Link: https://lkml.kernel.org/r/20190826121633.6538-1-liangyan.peng@linux.alibaba.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

kprobes: Fix potential deadlock in kprobe_optimizer()

2019-09-10T09:35:19+00:00

[ Upstream commit f1c6ece23729257fb46562ff9224cf5f61b818da ]

lockdep reports the following deadlock scenario:

 WARNING: possible circular locking dependency detected

 kworker/1:1/48 is trying to acquire lock:
 000000008d7a62b2 (text_mutex){+.+.}, at: kprobe_optimizer+0x163/0x290

 but task is already holding lock:
 00000000850b5e2d (module_mutex){+.+.}, at: kprobe_optimizer+0x31/0x290

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (module_mutex){+.+.}:
        __mutex_lock+0xac/0x9f0
        mutex_lock_nested+0x1b/0x20
        set_all_modules_text_rw+0x22/0x90
        ftrace_arch_code_modify_prepare+0x1c/0x20
        ftrace_run_update_code+0xe/0x30
        ftrace_startup_enable+0x2e/0x50
        ftrace_startup+0xa7/0x100
        register_ftrace_function+0x27/0x70
        arm_kprobe+0xb3/0x130
        enable_kprobe+0x83/0xa0
        enable_trace_kprobe.part.0+0x2e/0x80
        kprobe_register+0x6f/0xc0
        perf_trace_event_init+0x16b/0x270
        perf_kprobe_init+0xa7/0xe0
        perf_kprobe_event_init+0x3e/0x70
        perf_try_init_event+0x4a/0x140
        perf_event_alloc+0x93a/0xde0
        __do_sys_perf_event_open+0x19f/0xf30
        __x64_sys_perf_event_open+0x20/0x30
        do_syscall_64+0x65/0x1d0
        entry_SYSCALL_64_after_hwframe+0x49/0xbe

 -> #0 (text_mutex){+.+.}:
        __lock_acquire+0xfcb/0x1b60
        lock_acquire+0xca/0x1d0
        __mutex_lock+0xac/0x9f0
        mutex_lock_nested+0x1b/0x20
        kprobe_optimizer+0x163/0x290
        process_one_work+0x22b/0x560
        worker_thread+0x50/0x3c0
        kthread+0x112/0x150
        ret_from_fork+0x3a/0x50

 other info that might help us debug this:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(module_mutex);
                                lock(text_mutex);
                                lock(module_mutex);
   lock(text_mutex);

  *** DEADLOCK ***

As a reproducer I've been using bcc's funccount.py
(https://github.com/iovisor/bcc/blob/master/tools/funccount.py),
for example:

 # ./funccount.py '*interrupt*'

That immediately triggers the lockdep splat.

Fix by acquiring text_mutex before module_mutex in kprobe_optimizer().

Signed-off-by: Andrea Righi 
Acked-by: Masami Hiramatsu 
Cc: Anil S Keshavamurthy 
Cc: David S. Miller 
Cc: Linus Torvalds 
Cc: Naveen N. Rao 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: d5b844a2cf50 ("ftrace/x86: Remove possible deadlock between register_kprobe() and ftrace_run_update_code()")
Link: http://lkml.kernel.org/r/20190812184302.GA7010@xps-13
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

sched/core: Schedule new worker even if PI-blocked

2019-09-10T09:35:19+00:00

[ Upstream commit b0fdc01354f45d43f082025636ef808968a27b36 ]

If a task is PI-blocked (blocking on sleeping spinlock) then we don't want to
schedule a new kworker if we schedule out due to lock contention because !RT
does not do that as well. A spinning spinlock disables preemption and a worker
does not schedule out on lock contention (but spin).

On RT the RW-semaphore implementation uses an rtmutex so
tsk_is_pi_blocked() will return true if a task blocks on it. In this case we
will now start a new worker which may deadlock if one worker is waiting on
progress from another worker. Since a RW-semaphore starts a new worker on !RT,
we should do the same on RT.

XFS is able to trigger this deadlock.

Allow to schedule new worker if the current worker is PI-blocked.

Signed-off-by: Sebastian Andrzej Siewior 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20190816160626.12742-1-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

bpf: fix use after free in prog symbol exposure

2019-09-06T08:23:51+00:00

commit c751798aa224fadc5124b49eeb38fb468c0fa039 upstream.

syzkaller managed to trigger the warning in bpf_jit_free() which checks via
bpf_prog_kallsyms_verify_off() for potentially unlinked JITed BPF progs
in kallsyms, and subsequently trips over GPF when walking kallsyms entries:

  [...]
  8021q: adding VLAN 0 to HW filter on device batadv0
  8021q: adding VLAN 0 to HW filter on device batadv0
  WARNING: CPU: 0 PID: 9869 at kernel/bpf/core.c:810 bpf_jit_free+0x1e8/0x2a0
  Kernel panic - not syncing: panic_on_warn set ...
  CPU: 0 PID: 9869 Comm: kworker/0:7 Not tainted 5.0.0-rc8+ #1
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Workqueue: events bpf_prog_free_deferred
  Call Trace:
   __dump_stack lib/dump_stack.c:77 [inline]
   dump_stack+0x113/0x167 lib/dump_stack.c:113
   panic+0x212/0x40b kernel/panic.c:214
   __warn.cold.8+0x1b/0x38 kernel/panic.c:571
   report_bug+0x1a4/0x200 lib/bug.c:186
   fixup_bug arch/x86/kernel/traps.c:178 [inline]
   do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
   do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
   invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
  RIP: 0010:bpf_jit_free+0x1e8/0x2a0
  Code: 02 4c 89 e2 83 e2 07 38 d0 7f 08 84 c0 0f 85 86 00 00 00 48 ba 00 02 00 00 00 00 ad de 0f b6 43 02 49 39 d6 0f 84 5f fe ff ff <0f> 0b e9 58 fe ff ff 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1
  RSP: 0018:ffff888092f67cd8 EFLAGS: 00010202
  RAX: 0000000000000007 RBX: ffffc90001947000 RCX: ffffffff816e9d88
  RDX: dead000000000200 RSI: 0000000000000008 RDI: ffff88808769f7f0
  RBP: ffff888092f67d00 R08: fffffbfff1394059 R09: fffffbfff1394058
  R10: fffffbfff1394058 R11: ffffffff89ca02c7 R12: ffffc90001947002
  R13: ffffc90001947020 R14: ffffffff881eca80 R15: ffff88808769f7e8
  BUG: unable to handle kernel paging request at fffffbfff400d000
  #PF error: [normal kernel read fault]
  PGD 21ffee067 P4D 21ffee067 PUD 21ffed067 PMD 9f942067 PTE 0
  Oops: 0000 [#1] PREEMPT SMP KASAN
  CPU: 0 PID: 9869 Comm: kworker/0:7 Not tainted 5.0.0-rc8+ #1
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Workqueue: events bpf_prog_free_deferred
  RIP: 0010:bpf_get_prog_addr_region kernel/bpf/core.c:495 [inline]
  RIP: 0010:bpf_tree_comp kernel/bpf/core.c:558 [inline]
  RIP: 0010:__lt_find include/linux/rbtree_latch.h:115 [inline]
  RIP: 0010:latch_tree_find include/linux/rbtree_latch.h:208 [inline]
  RIP: 0010:bpf_prog_kallsyms_find+0x107/0x2e0 kernel/bpf/core.c:632
  Code: 00 f0 ff ff 44 38 c8 7f 08 84 c0 0f 85 fa 00 00 00 41 f6 45 02 01 75 02 0f 0b 48 39 da 0f 82 92 00 00 00 48 89 d8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 74 08 3c 03 0f 8e 45 01 00 00 8b 03 48 c1 e0
  [...]

Upon further debugging, it turns out that whenever we trigger this
issue, the kallsyms removal in bpf_prog_ksym_node_del() was /skipped/
but yet bpf_jit_free() reported that the entry is /in use/.

Problem is that symbol exposure via bpf_prog_kallsyms_add() but also
perf_event_bpf_event() were done /after/ bpf_prog_new_fd(). Once the
fd is exposed to the public, a parallel close request came in right
before we attempted to do the bpf_prog_kallsyms_add().

Given at this time the prog reference count is one, we start to rip
everything underneath us via bpf_prog_release() -> bpf_prog_put().
The memory is eventually released via deferred free, so we're seeing
that bpf_jit_free() has a kallsym entry because we added it from
bpf_prog_load() but /after/ bpf_prog_put() from the remote CPU.

Therefore, move both notifications /before/ we install the fd. The
issue was never seen between bpf_prog_alloc_id() and bpf_prog_new_fd()
because upon bpf_prog_get_fd_by_id() we'll take another reference to
the BPF prog, so we're still holding the original reference from the
bpf_prog_load().

Fixes: 6ee52e2a3fe4 ("perf, bpf: Introduce PERF_RECORD_BPF_EVENT")
Fixes: 74451e66d516 ("bpf: make jited programs visible in traces")
Reported-by: syzbot+bd3bba6ff3fcea7a6ec6@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann 
Cc: Song Liu 
Signed-off-by: Greg Kroah-Hartman