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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more MM updates from Andrew Morton:
- "Eliminate Dying Memory Cgroup" (Qi Zheng and Muchun Song)
Address the longstanding "dying memcg problem". A situation wherein a
no-longer-used memory control group will hang around for an extended
period pointlessly consuming memory
- "fix unexpected type conversions and potential overflows" (Qi Zheng)
Fix a couple of potential 32-bit/64-bit issues which were identified
during review of the "Eliminate Dying Memory Cgroup" series
- "kho: history: track previous kernel version and kexec boot count"
(Breno Leitao)
Use Kexec Handover (KHO) to pass the previous kernel's version string
and the number of kexec reboots since the last cold boot to the next
kernel, and print it at boot time
- "liveupdate: prevent double preservation" (Pasha Tatashin)
Teach LUO to avoid managing the same file across different active
sessions
- "liveupdate: Fix module unloading and unregister API" (Pasha
Tatashin)
Address an issue with how LUO handles module reference counting and
unregistration during module unloading
- "zswap pool per-CPU acomp_ctx simplifications" (Kanchana Sridhar)
Simplify and clean up the zswap crypto compression handling and
improve the lifecycle management of zswap pool's per-CPU acomp_ctx
resources
- "mm/damon/core: fix damon_call()/damos_walk() vs kdmond exit race"
(SeongJae Park)
Address unlikely but possible leaks and deadlocks in damon_call() and
damon_walk()
- "mm/damon/core: validate damos_quota_goal->nid" (SeongJae Park)
Fix a couple of root-only wild pointer dereferences
- "Docs/admin-guide/mm/damon: warn commit_inputs vs other params race"
(SeongJae Park)
Update the DAMON documentation to warn operators about potential
races which can occur if the commit_inputs parameter is altered at
the wrong time
- "Minor hmm_test fixes and cleanups" (Alistair Popple)
Bugfixes and a cleanup for the HMM kernel selftests
- "Modify memfd_luo code" (Chenghao Duan)
Cleanups, simplifications and speedups to the memfd_lou code
- "mm, kvm: allow uffd support in guest_memfd" (Mike Rapoport)
Support for userfaultfd in guest_memfd
- "selftests/mm: skip several tests when thp is not available" (Chunyu
Hu)
Fix several issues in the selftests code which were causing breakage
when the tests were run on CONFIG_THP=n kernels
- "mm/mprotect: micro-optimization work" (Pedro Falcato)
A couple of nice speedups for mprotect()
- "MAINTAINERS: update KHO and LIVE UPDATE entries" (Pratyush Yadav)
Document upcoming changes in the maintenance of KHO, LUO, memfd_luo,
kexec, crash, kdump and probably other kexec-based things - they are
being moved out of mm.git and into a new git tree
* tag 'mm-stable-2026-04-18-02-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (121 commits)
MAINTAINERS: add page cache reviewer
mm/vmscan: avoid false-positive -Wuninitialized warning
MAINTAINERS: update Dave's kdump reviewer email address
MAINTAINERS: drop include/linux/liveupdate from LIVE UPDATE
MAINTAINERS: drop include/linux/kho/abi/ from KHO
MAINTAINERS: update KHO and LIVE UPDATE maintainers
MAINTAINERS: update kexec/kdump maintainers entries
mm/migrate_device: remove dead migration entry check in migrate_vma_collect_huge_pmd()
selftests: mm: skip charge_reserved_hugetlb without killall
userfaultfd: allow registration of ranges below mmap_min_addr
mm/vmstat: fix vmstat_shepherd double-scheduling vmstat_update
mm/hugetlb: fix early boot crash on parameters without '=' separator
zram: reject unrecognized type= values in recompress_store()
docs: proc: document ProtectionKey in smaps
mm/mprotect: special-case small folios when applying permissions
mm/mprotect: move softleaf code out of the main function
mm: remove '!root_reclaim' checking in should_abort_scan()
mm/sparse: fix comment for section map alignment
mm/page_io: use sio->len for PSWPIN accounting in sio_read_complete()
selftests/mm: transhuge_stress: skip the test when thp not available
...
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To resolve the dying memcg issue, we need to reparent LRU folios of child
memcg to its parent memcg. This could cause problems for non-hierarchical
stats.
As Yosry Ahmed pointed out:
In short, if memory is charged to a dying cgroup at the time of
reparenting, when the memory gets uncharged the stats updates will occur
at the parent. This will update both hierarchical and non-hierarchical
stats of the parent, which would corrupt the parent's non-hierarchical
stats (because those counters were never incremented when the memory was
charged).
Now we have the following two types of non-hierarchical stats, and they
are only used in CONFIG_MEMCG_V1:
a. memcg->vmstats->state_local[i]
b. pn->lruvec_stats->state_local[i]
To ensure that these non-hierarchical stats work properly, we need to
reparent these non-hierarchical stats after reparenting LRU folios. To
this end, this commit makes the following preparations:
1. implement reparent_state_local() to reparent non-hierarchical stats
2. make css_killed_work_fn() to be called in rcu work, and implement
get_non_dying_memcg_start() and get_non_dying_memcg_end() to avoid race
between mod_memcg_state()/mod_memcg_lruvec_state()
and reparent_state_local()
Link: https://lore.kernel.org/e862995c45a7101a541284b6ebee5e5c32c89066.1772711148.git.zhengqi.arch@bytedance.com
Co-developed-by: Yosry Ahmed <yosry@kernel.org>
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Allen Pais <apais@linux.microsoft.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chen Ridong <chenridong@huawei.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Hamza Mahfooz <hamzamahfooz@linux.microsoft.com>
Cc: Harry Yoo <harry.yoo@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Imran Khan <imran.f.khan@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
- cgroup_file_notify() locking converted from a global lock to
per-cgroup_file spinlock with a lockless fast-path when no
notification is needed
- Misc changes including exposing cgroup helpers for sched_ext and
minor fixes
* tag 'cgroup-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup/rdma: fix swapped arguments in pr_warn() format string
cgroup/dmem: remove region parameter from dmemcg_parse_limit
cgroup: replace global cgroup_file_kn_lock with per-cgroup_file lock
cgroup: add lockless fast-path checks to cgroup_file_notify()
cgroup: reduce cgroup_file_kn_lock hold time in cgroup_file_notify()
cgroup: Expose some cgroup helpers
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The format string says "device %p ... rdma cgroup %p" but the arguments
were passed as (cg, device), printing them in the wrong order.
Signed-off-by: cuitao <cuitao@kylinos.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>
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When a CPU hot removal causes a v1 cpuset to lose all its CPUs, the
cpuset hotplug handler will schedule a work function to migrate tasks
in that cpuset with no CPU to its ancestor to enable those tasks to
continue running.
If a strict security policy is in place, however, the task migration
may fail when security_task_setscheduler() call in cpuset_can_attach()
returns a -EACCES error. That will mean that those tasks will have
no CPU to run on. The system administrators will have to explicitly
intervene to either add CPUs to that cpuset or move the tasks elsewhere
if they are aware of it.
This problem was found by a reported test failure in the LTP's
cpuset_hotplug_test.sh. Fix this problem by treating this special case as
an exception to skip the setsched security check in cpuset_can_attach()
when a v1 cpuset with tasks have no CPU left.
With that patch applied, the cpuset_hotplug_test.sh test can be run
successfully without failure.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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cpuset_can_attach()
Centralize the check required to run security_task_setscheduler() in
the task iteration loop of cpuset_can_attach() outside of the loop as
it has no dependency on the characteristics of the tasks themselves.
There is no functional change.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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cgroup_drain_dying() was using cgroup_is_populated() to test whether there are
dying tasks to wait for. cgroup_is_populated() tests nr_populated_csets,
nr_populated_domain_children and nr_populated_threaded_children, but
cgroup_drain_dying() only needs to care about this cgroup's own tasks - whether
there are children is cgroup_destroy_locked()'s concern.
This caused hangs during shutdown. When systemd tried to rmdir a cgroup that had
no direct tasks but had a populated child, cgroup_drain_dying() would enter its
wait loop because cgroup_is_populated() was true from
nr_populated_domain_children. The task iterator found nothing to wait for, yet
the populated state never cleared because it was driven by live tasks in the
child cgroup.
Fix it by using cgroup_has_tasks() which only tests nr_populated_csets.
v3: Fix cgroup_is_populated() -> cgroup_has_tasks() (Sebastian).
v2: https://lore.kernel.org/r/20260323200205.1063629-1-tj@kernel.org
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Fixes: 1b164b876c36 ("cgroup: Wait for dying tasks to leave on rmdir")
Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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a72f73c4dd9b ("cgroup: Don't expose dead tasks in cgroup") hid PF_EXITING
tasks from cgroup.procs so that systemd doesn't see tasks that have already
been reaped via waitpid(). However, the populated counter (nr_populated_csets)
is only decremented when the task later passes through cgroup_task_dead() in
finish_task_switch(). This means cgroup.procs can appear empty while the
cgroup is still populated, causing rmdir to fail with -EBUSY.
Fix this by making cgroup_rmdir() wait for dying tasks to fully leave. If the
cgroup is populated but all remaining tasks have PF_EXITING set (the task
iterator returns none due to the existing filter), wait for a kick from
cgroup_task_dead() and retry. The wait is brief as tasks are removed from the
cgroup's css_set between PF_EXITING assertion in do_exit() and
cgroup_task_dead() in finish_task_switch().
v2: cgroup_is_populated() true to false transition happens under css_set_lock
not cgroup_mutex, so retest under css_set_lock before sleeping to avoid
missed wakeups (Sebastian).
Fixes: a72f73c4dd9b ("cgroup: Don't expose dead tasks in cgroup")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202603222104.2c81684e-lkp@intel.com
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Bert Karwatzki <spasswolf@web.de>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: cgroups@vger.kernel.org
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dmemcg_parse_limit does not use the region parameter. Remove it.
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Replace the global cgroup_file_kn_lock with a per-cgroup_file spinlock
to eliminate cross-cgroup contention as it is not really protecting
data shared between different cgroups.
The lock is initialized in cgroup_add_file() alongside timer_setup().
No lock acquisition is needed during initialization since the cgroup
directory is being populated under cgroup_mutex and no concurrent
accessors exist at that point.
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Add lockless checks before acquiring cgroup_file_kn_lock:
1. READ_ONCE(cfile->kn) NULL check to skip torn-down files.
2. READ_ONCE(cfile->notified_at) rate-limit check to skip when
within the notification interval. If within the interval, arm
the deferred timer via timer_reduce() and confirm it is pending
before returning -- if the timer fired in between, fall through
to the lock path so the notification is not lost.
Both checks have safe error directions -- a stale read can only
cause unnecessary lock acquisition, never a missed notification.
The critical section is simplified to just taking a kernfs_get()
reference and updating notified_at.
Annotate cfile->kn and cfile->notified_at write sites with
WRITE_ONCE() to pair with the lockless readers.
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Tejun Heo <tj@kernel.org>
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cgroup_file_notify() calls kernfs_notify() while holding the global
cgroup_file_kn_lock. kernfs_notify() does non-trivial work including
wake_up_interruptible() and acquisition of a second global spinlock
(kernfs_notify_lock), inflating the hold time.
Take a kernfs_get() reference under the lock and call kernfs_notify()
after dropping it, following the pattern from cgroup_file_show().
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Once a task exits it has its state set to TASK_DEAD and then it is
removed from the cgroup it belonged to. The last step happens on the task
gets out of its last schedule() invocation and is delayed on PREEMPT_RT
due to locking constraints.
As a result it is possible to receive a pid via waitpid() of a task
which is still listed in cgroup.procs for the cgroup it belonged
to. This is something that systemd does not expect and as a result it
waits for its exit until a time out occurs.
This can also be reproduced on !PREEMPT_RT kernel with a significant
delay in do_exit() after exit_notify().
Hide the task from the output which have PF_EXITING set which is done
before the parent is notified. Keeping zombies with live threads
shouldn't break anything (suggested by Tejun).
Reported-by: Bert Karwatzki <spasswolf@web.de>
Closes: https://lore.kernel.org/all/20260219164648.3014-1-spasswolf@web.de/
Tested-by: Bert Karwatzki <spasswolf@web.de>
Fixes: 9311e6c29b34 ("cgroup: Fix sleeping from invalid context warning on PREEMPT_RT")
Cc: stable@vger.kernel.org # v6.19+
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Besides deferring the call to housekeeping_update(), commit 6df415aa46ec
("cgroup/cpuset: Defer housekeeping_update() calls from CPU hotplug
to workqueue") also defers the rebuild_sched_domains() call to
the workqueue. So a new offline CPU may still be in a sched domain
or new online CPU not showing up in the sched domains for a short
transition period. That could be a problem in some corner cases and
can be the cause of a reported test failure[1]. Fix it by calling
rebuild_sched_domains_cpuslocked() directly in hotplug as before. If
isolated partition invalidation or recreation is being done, the
housekeeping_update() call to update the housekeeping cpumasks will
still be deferred to a workqueue.
In commit 3bfe47967191 ("cgroup/cpuset: Move
housekeeping_update()/rebuild_sched_domains() together"),
housekeeping_update() is called before rebuild_sched_domains() because
it needs to access the HK_TYPE_DOMAIN housekeeping cpumask. That is now
changed to use the static HK_TYPE_DOMAIN_BOOT cpumask as HK_TYPE_DOMAIN
cpumask is now changeable at run time. As a result, we can move the
rebuild_sched_domains() call before housekeeping_update() with
the slight advantage that it will be done in the same cpus_read_lock
critical section without the possibility of interference by a concurrent
cpu hot add/remove operation.
As it doesn't make sense to acquire cpuset_mutex/cpuset_top_mutex after
calling housekeeping_update() and immediately release them again, move
the cpuset_full_unlock() operation inside update_hk_sched_domains()
and rename it to cpuset_update_sd_hk_unlock() to signify that it will
release the full set of locks.
[1] https://lore.kernel.org/lkml/1a89aceb-48db-4edd-a730-b445e41221fe@nvidia.com
Fixes: 6df415aa46ec ("cgroup/cpuset: Defer housekeeping_update() calls from CPU hotplug to workqueue")
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Chen Ridong <chenridong@huaweicloud.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Expose the following through cgroup.h:
- cgroup_on_dfl()
- cgroup_is_dead()
- cgroup_for_each_live_child()
- cgroup_for_each_live_descendant_pre()
- cgroup_for_each_live_descendant_post()
Until now, these didn't need to be exposed because controllers only cared
about the css hierarchy. The planned sched_ext hierarchical scheduler
support will be based on the default cgroup hierarchy, which is in line
with the existing BPF cgroup support, and thus needs these exposed.
Signed-off-by: Tejun Heo <tj@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
- Fix circular locking dependency in cpuset partition code by
deferring housekeeping_update() calls to a workqueue instead
of calling them directly under cpus_read_lock
- Fix null-ptr-deref in rebuild_sched_domains_cpuslocked() when
generate_sched_domains() returns NULL due to kmalloc failure
- Fix incorrect cpuset behavior for effective_xcpus in
partition_xcpus_del() and cpuset_update_tasks_cpumask()
in update_cpumasks_hier()
- Fix race between task migration and cgroup iteration
* tag 'cgroup-for-7.0-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup/cpuset: fix null-ptr-deref in rebuild_sched_domains_cpuslocked
cgroup/cpuset: Call housekeeping_update() without holding cpus_read_lock
cgroup/cpuset: Defer housekeeping_update() calls from CPU hotplug to workqueue
cgroup/cpuset: Move housekeeping_update()/rebuild_sched_domains() together
kselftest/cgroup: Simplify test_cpuset_prs.sh by removing "S+" command
cgroup/cpuset: Set isolated_cpus_updating only if isolated_cpus is changed
cgroup/cpuset: Clarify exclusion rules for cpuset internal variables
cgroup/cpuset: Fix incorrect use of cpuset_update_tasks_cpumask() in update_cpumasks_hier()
cgroup/cpuset: Fix incorrect change to effective_xcpus in partition_xcpus_del()
cgroup: fix race between task migration and iteration
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A null-pointer-dereference bug was reported by syzbot:
Oops: general protection fault, probably for address 0xdffffc0000000000:
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:bitmap_subset include/linux/bitmap.h:433 [inline]
RIP: 0010:cpumask_subset include/linux/cpumask.h:836 [inline]
RIP: 0010:rebuild_sched_domains_locked kernel/cgroup/cpuset.c:967
RSP: 0018:ffffc90003ecfbc0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000020
RDX: ffff888028de0000 RSI: ffffffff8200f003 RDI: ffffffff8df14f28
RBP: 0000000000000000 R08: 0000000000000cc0 R09: 00000000ffffffff
R10: ffffffff8e7d95b3 R11: 0000000000000001 R12: 0000000000000000
R13: 00000000000f4240 R14: dffffc0000000000 R15: 0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f463fff CR3: 000000003704c000 CR4: 00000000003526f0
Call Trace:
<TASK>
rebuild_sched_domains_cpuslocked kernel/cgroup/cpuset.c:983 [inline]
rebuild_sched_domains+0x21/0x40 kernel/cgroup/cpuset.c:990
sched_rt_handler+0xb5/0xe0 kernel/sched/rt.c:2911
proc_sys_call_handler+0x47f/0x5a0 fs/proc/proc_sysctl.c:600
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1070 fs/read_write.c:688
ksys_write+0x12a/0x250 fs/read_write.c:740
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The issue occurs when generate_sched_domains() returns ndoms = 1 and
doms = NULL due to a kmalloc failure. This leads to a null-pointer
dereference when accessing doms in rebuild_sched_domains_locked().
Fix this by adding a NULL check for doms before accessing it.
Fixes: 6ee43047e8ad ("cpuset: Remove unnecessary checks in rebuild_sched_domains_locked")
Reported-by: syzbot+460792609a79c085f79f@syzkaller.appspotmail.com
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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The current cpuset partition code is able to dynamically update
the sched domains of a running system and the corresponding
HK_TYPE_DOMAIN housekeeping cpumask to perform what is essentially the
"isolcpus=domain,..." boot command line feature at run time.
The housekeeping cpumask update requires flushing a number of different
workqueues which may not be safe with cpus_read_lock() held as the
workqueue flushing code may acquire cpus_read_lock() or acquiring locks
which have locking dependency with cpus_read_lock() down the chain. Below
is an example of such circular locking problem.
======================================================
WARNING: possible circular locking dependency detected
6.18.0-test+ #2 Tainted: G S
------------------------------------------------------
test_cpuset_prs/10971 is trying to acquire lock:
ffff888112ba4958 ((wq_completion)sync_wq){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x7a/0x180
but task is already holding lock:
ffffffffae47f450 (cpuset_mutex){+.+.}-{4:4}, at: cpuset_partition_write+0x85/0x130
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (cpuset_mutex){+.+.}-{4:4}:
-> #3 (cpu_hotplug_lock){++++}-{0:0}:
-> #2 (rtnl_mutex){+.+.}-{4:4}:
-> #1 ((work_completion)(&arg.work)){+.+.}-{0:0}:
-> #0 ((wq_completion)sync_wq){+.+.}-{0:0}:
Chain exists of:
(wq_completion)sync_wq --> cpu_hotplug_lock --> cpuset_mutex
5 locks held by test_cpuset_prs/10971:
#0: ffff88816810e440 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0xf9/0x1d0
#1: ffff8891ab620890 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x260/0x5f0
#2: ffff8890a78b83e8 (kn->active#187){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2b6/0x5f0
#3: ffffffffadf32900 (cpu_hotplug_lock){++++}-{0:0}, at: cpuset_partition_write+0x77/0x130
#4: ffffffffae47f450 (cpuset_mutex){+.+.}-{4:4}, at: cpuset_partition_write+0x85/0x130
Call Trace:
<TASK>
:
touch_wq_lockdep_map+0x93/0x180
__flush_workqueue+0x111/0x10b0
housekeeping_update+0x12d/0x2d0
update_parent_effective_cpumask+0x595/0x2440
update_prstate+0x89d/0xce0
cpuset_partition_write+0xc5/0x130
cgroup_file_write+0x1a5/0x680
kernfs_fop_write_iter+0x3df/0x5f0
vfs_write+0x525/0xfd0
ksys_write+0xf9/0x1d0
do_syscall_64+0x95/0x520
entry_SYSCALL_64_after_hwframe+0x76/0x7e
To avoid such a circular locking dependency problem, we have to
call housekeeping_update() without holding the cpus_read_lock() and
cpuset_mutex. The current set of wq's flushed by housekeeping_update()
may not have work functions that call cpus_read_lock() directly,
but we are likely to extend the list of wq's that are flushed in the
future. Moreover, the current set of work functions may hold locks that
may have cpu_hotplug_lock down the dependency chain.
So housekeeping_update() is now called after releasing cpus_read_lock
and cpuset_mutex at the end of a cpuset operation. These two locks are
then re-acquired later before calling rebuild_sched_domains_locked().
To enable mutual exclusion between the housekeeping_update() call and
other cpuset control file write actions, a new top level cpuset_top_mutex
is introduced. This new mutex will be acquired first to allow sharing
variables used by both code paths. However, cpuset update from CPU
hotplug can still happen in parallel with the housekeeping_update()
call, though that should be rare in production environment.
As cpus_read_lock() is now no longer held when
tmigr_isolated_exclude_cpumask() is called, it needs to acquire it
directly.
The lockdep_is_cpuset_held() is also updated to return true if either
cpuset_top_mutex or cpuset_mutex is held.
Fixes: 03ff73510169 ("cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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The cpuset_handle_hotplug() may need to invoke housekeeping_update(),
for instance, when an isolated partition is invalidated because its
last active CPU has been put offline.
As we are going to enable dynamic update to the nozh_full housekeeping
cpumask (HK_TYPE_KERNEL_NOISE) soon with the help of CPU hotplug,
allowing the CPU hotplug path to call into housekeeping_update() directly
from update_isolation_cpumasks() will likely cause deadlock. So we
have to defer any call to housekeeping_update() after the CPU hotplug
operation has finished. This is now done via the workqueue where
the update_hk_sched_domains() function will be invoked via the
hk_sd_workfn().
An concurrent cpuset control file write may have executed the required
update_hk_sched_domains() function before the work function is called. So
the work function call may become a no-op when it is invoked.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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With the latest changes in sched/isolation.c, rebuild_sched_domains*()
requires the HK_TYPE_DOMAIN housekeeping cpumask to be properly
updated first, if needed, before the sched domains can be
rebuilt. So the two naturally fit together. Do that by creating a new
update_hk_sched_domains() helper to house both actions.
The name of the isolated_cpus_updating flag to control the
call to housekeeping_update() is now outdated. So change it to
update_housekeeping to better reflect its purpose. Also move the call
to update_hk_sched_domains() to the end of cpuset and hotplug operations
before releasing the cpuset_mutex.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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As cpuset is updating HK_TYPE_DOMAIN housekeeping mask when there is
a change in the set of isolated CPUs, making this change is now more
costly than before. Right now, the isolated_cpus_updating flag can be
set even if there is no real change in isolated_cpus. Put in additional
checks to make sure that isolated_cpus_updating is set only if there
is a real change in isolated_cpus.
Reviewed-by: Chen Ridong <chenridong@huaweicloud.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Clarify the locking rules associated with file level internal variables
inside the cpuset code. There is no functional change.
Reviewed-by: Chen Ridong <chenridong@huaweicloud.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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update_cpumasks_hier()
Commit e2ffe502ba45 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2")
incorrectly changed the 2nd parameter of cpuset_update_tasks_cpumask()
from tmp->new_cpus to cp->effective_cpus. This second parameter is just
a temporary cpumask for internal use. The cpuset_update_tasks_cpumask()
function was originally called update_tasks_cpumask() before commit
381b53c3b549 ("cgroup/cpuset: rename functions shared between v1
and v2").
This mistake can incorrectly change the effective_cpus of the
cpuset when it is the top_cpuset or in arm64 architecture where
task_cpu_possible_mask() may differ from cpu_possible_mask. So far
top_cpuset hasn't been passed to update_cpumasks_hier() yet, but arm64
arch can still be impacted. Fix it by reverting the incorrect change.
Fixes: e2ffe502ba45 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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The effective_xcpus of a cpuset can contain offline CPUs. In
partition_xcpus_del(), the xcpus parameter is incorrectly used as
a temporary cpumask to mask out offline CPUs. As xcpus can be the
effective_xcpus of a cpuset, this can result in unexpected changes
in that cpumask. Fix this problem by not making any changes to the
xcpus parameter.
Fixes: 11e5f407b64a ("cgroup/cpuset: Keep track of CPUs in isolated partitions")
Reviewed-by: Chen Ridong <chenridong@huaweicloud.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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This is the exact same thing as the 'alloc_obj()' version, only much
smaller because there are a lot fewer users of the *alloc_flex()
interface.
As with alloc_obj() version, this was done entirely with mindless brute
force, using the same script, except using 'flex' in the pattern rather
than 'objs*'.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more MM updates from Andrew Morton:
- "mm/vmscan: fix demotion targets checks in reclaim/demotion" fixes a
couple of issues in the demotion code - pages were failed demotion
and were finding themselves demoted into disallowed nodes (Bing Jiao)
- "Remove XA_ZERO from error recovery of dup_mmap()" fixes a rare
mapledtree race and performs a number of cleanups (Liam Howlett)
- "mm: add bitmap VMA flag helpers and convert all mmap_prepare to use
them" implements a lot of cleanups following on from the conversion
of the VMA flags into a bitmap (Lorenzo Stoakes)
- "support batch checking of references and unmapping for large folios"
implements batching to greatly improve the performance of reclaiming
clean file-backed large folios (Baolin Wang)
- "selftests/mm: add memory failure selftests" does as claimed (Miaohe
Lin)
* tag 'mm-stable-2026-02-18-19-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (36 commits)
mm/page_alloc: clear page->private in free_pages_prepare()
selftests/mm: add memory failure dirty pagecache test
selftests/mm: add memory failure clean pagecache test
selftests/mm: add memory failure anonymous page test
mm: rmap: support batched unmapping for file large folios
arm64: mm: implement the architecture-specific clear_flush_young_ptes()
arm64: mm: support batch clearing of the young flag for large folios
arm64: mm: factor out the address and ptep alignment into a new helper
mm: rmap: support batched checks of the references for large folios
tools/testing/vma: add VMA userland tests for VMA flag functions
tools/testing/vma: separate out vma_internal.h into logical headers
tools/testing/vma: separate VMA userland tests into separate files
mm: make vm_area_desc utilise vma_flags_t only
mm: update all remaining mmap_prepare users to use vma_flags_t
mm: update shmem_[kernel]_file_*() functions to use vma_flags_t
mm: update secretmem to use VMA flags on mmap_prepare
mm: update hugetlbfs to use VMA flags on mmap_prepare
mm: add basic VMA flag operation helper functions
tools: bitmap: add missing bitmap_[subset(), andnot()]
mm: add mk_vma_flags() bitmap flag macro helper
...
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Patch series "mm/vmscan: fix demotion targets checks in reclaim/demotion",
v9.
This patch series addresses two issues in demote_folio_list(),
can_demote(), and next_demotion_node() in reclaim/demotion.
1. demote_folio_list() and can_demote() do not correctly check
demotion target against cpuset.mems_effective, which will cause (a)
pages to be demoted to not-allowed nodes and (b) pages fail demotion
even if the system still has allowed demotion nodes.
Patch 1 fixes this bug by updating cpuset_node_allowed() and
mem_cgroup_node_allowed() to return effective_mems, allowing directly
logic-and operation against demotion targets.
2. next_demotion_node() returns a preferred demotion target, but it
does not check the node against allowed nodes.
Patch 2 ensures that next_demotion_node() filters against the allowed
node mask and selects the closest demotion target to the source node.
This patch (of 2):
Fix two bugs in demote_folio_list() and can_demote() due to incorrect
demotion target checks against cpuset.mems_effective in reclaim/demotion.
Commit 7d709f49babc ("vmscan,cgroup: apply mems_effective to reclaim")
introduces the cpuset.mems_effective check and applies it to can_demote().
However:
1. It does not apply this check in demote_folio_list(), which leads
to situations where pages are demoted to nodes that are
explicitly excluded from the task's cpuset.mems.
2. It checks only the nodes in the immediate next demotion hierarchy
and does not check all allowed demotion targets in can_demote().
This can cause pages to never be demoted if the nodes in the next
demotion hierarchy are not set in mems_effective.
These bugs break resource isolation provided by cpuset.mems. This is
visible from userspace because pages can either fail to be demoted
entirely or are demoted to nodes that are not allowed in multi-tier memory
systems.
To address these bugs, update cpuset_node_allowed() and
mem_cgroup_node_allowed() to return effective_mems, allowing directly
logic-and operation against demotion targets. Also update can_demote()
and demote_folio_list() accordingly.
Bug 1 reproduction:
Assume a system with 4 nodes, where nodes 0-1 are top-tier and
nodes 2-3 are far-tier memory. All nodes have equal capacity.
Test script:
echo 1 > /sys/kernel/mm/numa/demotion_enabled
mkdir /sys/fs/cgroup/test
echo +cpuset > /sys/fs/cgroup/cgroup.subtree_control
echo "0-2" > /sys/fs/cgroup/test/cpuset.mems
echo $$ > /sys/fs/cgroup/test/cgroup.procs
swapoff -a
# Expectation: Should respect node 0-2 limit.
# Observation: Node 3 shows significant allocation (MemFree drops)
stress-ng --oomable --vm 1 --vm-bytes 150% --mbind 0,1
Bug 2 reproduction:
Assume a system with 6 nodes, where nodes 0-2 are top-tier,
node 3 is a far-tier node, and nodes 4-5 are the farthest-tier nodes.
All nodes have equal capacity.
Test script:
echo 1 > /sys/kernel/mm/numa/demotion_enabled
mkdir /sys/fs/cgroup/test
echo +cpuset > /sys/fs/cgroup/cgroup.subtree_control
echo "0-2,4-5" > /sys/fs/cgroup/test/cpuset.mems
echo $$ > /sys/fs/cgroup/test/cgroup.procs
swapoff -a
# Expectation: Pages are demoted to Nodes 4-5
# Observation: No pages are demoted before oom.
stress-ng --oomable --vm 1 --vm-bytes 150% --mbind 0,1,2
Link: https://lkml.kernel.org/r/20260114205305.2869796-1-bingjiao@google.com
Link: https://lkml.kernel.org/r/20260114205305.2869796-2-bingjiao@google.com
Fixes: 7d709f49babc ("vmscan,cgroup: apply mems_effective to reclaim")
Signed-off-by: Bing Jiao <bingjiao@google.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Gregory Price <gourry@gourry.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- "powerpc/64s: do not re-activate batched TLB flush" makes
arch_{enter|leave}_lazy_mmu_mode() nest properly (Alexander Gordeev)
It adds a generic enter/leave layer and switches architectures to use
it. Various hacks were removed in the process.
- "zram: introduce compressed data writeback" implements data
compression for zram writeback (Richard Chang and Sergey Senozhatsky)
- "mm: folio_zero_user: clear page ranges" adds clearing of contiguous
page ranges for hugepages. Large improvements during demand faulting
are demonstrated (David Hildenbrand)
- "memcg cleanups" tidies up some memcg code (Chen Ridong)
- "mm/damon: introduce {,max_}nr_snapshots and tracepoint for damos
stats" improves DAMOS stat's provided information, deterministic
control, and readability (SeongJae Park)
- "selftests/mm: hugetlb cgroup charging: robustness fixes" fixes a few
issues in the hugetlb cgroup charging selftests (Li Wang)
- "Fix va_high_addr_switch.sh test failure - again" addresses several
issues in the va_high_addr_switch test (Chunyu Hu)
- "mm/damon/tests/core-kunit: extend existing test scenarios" improves
the KUnit test coverage for DAMON (Shu Anzai)
- "mm/khugepaged: fix dirty page handling for MADV_COLLAPSE" fixes a
glitch in khugepaged which was causing madvise(MADV_COLLAPSE) to
transiently return -EAGAIN (Shivank Garg)
- "arch, mm: consolidate hugetlb early reservation" reworks and
consolidates a pile of straggly code related to reservation of
hugetlb memory from bootmem and creation of CMA areas for hugetlb
(Mike Rapoport)
- "mm: clean up anon_vma implementation" cleans up the anon_vma
implementation in various ways (Lorenzo Stoakes)
- "tweaks for __alloc_pages_slowpath()" does a little streamlining of
the page allocator's slowpath code (Vlastimil Babka)
- "memcg: separate private and public ID namespaces" cleans up the
memcg ID code and prevents the internal-only private IDs from being
exposed to userspace (Shakeel Butt)
- "mm: hugetlb: allocate frozen gigantic folio" cleans up the
allocation of frozen folios and avoids some atomic refcount
operations (Kefeng Wang)
- "mm/damon: advance DAMOS-based LRU sorting" improves DAMOS's movement
of memory betewwn the active and inactive LRUs and adds auto-tuning
of the ratio-based quotas and of monitoring intervals (SeongJae Park)
- "Support page table check on PowerPC" makes
CONFIG_PAGE_TABLE_CHECK_ENFORCED work on powerpc (Andrew Donnellan)
- "nodemask: align nodes_and{,not} with underlying bitmap ops" makes
nodes_and() and nodes_andnot() propagate the return values from the
underlying bit operations, enabling some cleanup in calling code
(Yury Norov)
- "mm/damon: hide kdamond and kdamond_lock from API callers" cleans up
some DAMON internal interfaces (SeongJae Park)
- "mm/khugepaged: cleanups and scan limit fix" does some cleanup work
in khupaged and fixes a scan limit accounting issue (Shivank Garg)
- "mm: balloon infrastructure cleanups" goes to town on the balloon
infrastructure and its page migration function. Mainly cleanups, also
some locking simplification (David Hildenbrand)
- "mm/vmscan: add tracepoint and reason for kswapd_failures reset" adds
additional tracepoints to the page reclaim code (Jiayuan Chen)
- "Replace wq users and add WQ_PERCPU to alloc_workqueue() users" is
part of Marco's kernel-wide migration from the legacy workqueue APIs
over to the preferred unbound workqueues (Marco Crivellari)
- "Various mm kselftests improvements/fixes" provides various unrelated
improvements/fixes for the mm kselftests (Kevin Brodsky)
- "mm: accelerate gigantic folio allocation" greatly speeds up gigantic
folio allocation, mainly by avoiding unnecessary work in
pfn_range_valid_contig() (Kefeng Wang)
- "selftests/damon: improve leak detection and wss estimation
reliability" improves the reliability of two of the DAMON selftests
(SeongJae Park)
- "mm/damon: cleanup kdamond, damon_call(), damos filter and
DAMON_MIN_REGION" does some cleanup work in the core DAMON code
(SeongJae Park)
- "Docs/mm/damon: update intro, modules, maintainer profile, and misc"
performs maintenance work on the DAMON documentation (SeongJae Park)
- "mm: add and use vma_assert_stabilised() helper" refactors and cleans
up the core VMA code. The main aim here is to be able to use the mmap
write lock's lockdep state to perform various assertions regarding
the locking which the VMA code requires (Lorenzo Stoakes)
- "mm, swap: swap table phase II: unify swapin use" removes some old
swap code (swap cache bypassing and swap synchronization) which
wasn't working very well. Various other cleanups and simplifications
were made. The end result is a 20% speedup in one benchmark (Kairui
Song)
- "enable PT_RECLAIM on more 64-bit architectures" makes PT_RECLAIM
available on 64-bit alpha, loongarch, mips, parisc, and um. Various
cleanups were performed along the way (Qi Zheng)
* tag 'mm-stable-2026-02-11-19-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (325 commits)
mm/memory: handle non-split locks correctly in zap_empty_pte_table()
mm: move pte table reclaim code to memory.c
mm: make PT_RECLAIM depends on MMU_GATHER_RCU_TABLE_FREE
mm: convert __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config
um: mm: enable MMU_GATHER_RCU_TABLE_FREE
parisc: mm: enable MMU_GATHER_RCU_TABLE_FREE
mips: mm: enable MMU_GATHER_RCU_TABLE_FREE
LoongArch: mm: enable MMU_GATHER_RCU_TABLE_FREE
alpha: mm: enable MMU_GATHER_RCU_TABLE_FREE
mm: change mm/pt_reclaim.c to use asm/tlb.h instead of asm-generic/tlb.h
mm/damon/stat: remove __read_mostly from memory_idle_ms_percentiles
zsmalloc: make common caches global
mm: add SPDX id lines to some mm source files
mm/zswap: use %pe to print error pointers
mm/vmscan: use %pe to print error pointers
mm/readahead: fix typo in comment
mm: khugepaged: fix NR_FILE_PAGES and NR_SHMEM in collapse_file()
mm: refactor vma_map_pages to use vm_insert_pages
mm/damon: unify address range representation with damon_addr_range
mm/cma: replace snprintf with strscpy in cma_new_area
...
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When a task is migrated out of a css_set, cgroup_migrate_add_task()
first moves it from cset->tasks to cset->mg_tasks via:
list_move_tail(&task->cg_list, &cset->mg_tasks);
If a css_task_iter currently has it->task_pos pointing to this task,
css_set_move_task() calls css_task_iter_skip() to keep the iterator
valid. However, since the task has already been moved to ->mg_tasks,
the iterator is advanced relative to the mg_tasks list instead of the
original tasks list. As a result, remaining tasks on cset->tasks, as
well as tasks queued on cset->mg_tasks, can be skipped by iteration.
Fix this by calling css_set_skip_task_iters() before unlinking
task->cg_list from cset->tasks. This advances all active iterators to
the next task on cset->tasks, so iteration continues correctly even
when a task is concurrently being migrated.
This race is hard to hit in practice without instrumentation, but it
can be reproduced by artificially slowing down cgroup_procs_show().
For example, on an Android device a temporary
/sys/kernel/cgroup/cgroup_test knob can be added to inject a delay
into cgroup_procs_show(), and then:
1) Spawn three long-running tasks (PIDs 101, 102, 103).
2) Create a test cgroup and move the tasks into it.
3) Enable a large delay via /sys/kernel/cgroup/cgroup_test.
4) In one shell, read cgroup.procs from the test cgroup.
5) Within the delay window, in another shell migrate PID 102 by
writing it to a different cgroup.procs file.
Under this setup, cgroup.procs can intermittently show only PID 101
while skipping PID 103. Once the migration completes, reading the
file again shows all tasks as expected.
Note that this change does not allow removing the existing
css_set_skip_task_iters() call in css_set_move_task(). The new call
in cgroup_migrate_add_task() only handles iterators that are racing
with migration while the task is still on cset->tasks. Iterators may
also start after the task has been moved to cset->mg_tasks. If we
dropped css_set_skip_task_iters() from css_set_move_task(), such
iterators could keep task_pos pointing to a migrating task, causing
css_task_iter_advance() to malfunction on the destination css_set,
up to and including crashes or infinite loops.
The race window between migration and iteration is very small, and
css_task_iter is not on a hot path. In the worst case, when an
iterator is positioned on the first thread of the migrating process,
cgroup_migrate_add_task() may have to skip multiple tasks via
css_set_skip_task_iters(). However, this only happens when migration
and iteration actually race, so the performance impact is negligible
compared to the correctness fix provided here.
Fixes: b636fd38dc40 ("cgroup: Implement css_task_iter_skip()")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Qingye Zhao <zhaoqingye@honor.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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|
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
- cpuset changes:
- Continue separating v1 and v2 implementations by moving more
v1-specific logic into cpuset-v1.c
- Improve partition handling. Sibling partitions are no longer
invalidated on cpuset.cpus conflict, cpuset.cpus changes no longer
fail in v2, and effective_xcpus computation is made consistent
- Fix partition effective CPUs overlap that caused a warning on
cpuset removal when sibling partitions shared CPUs
- Increase the maximum cgroup subsystem count from 16 to 32 to
accommodate future subsystem additions
- Misc cleanups and selftest improvements including switching to
css_is_online() helper, removing dead code and stale documentation
references, using lockdep_assert_cpuset_lock_held() consistently, and
adding polling helpers for asynchronously updated cgroup statistics
* tag 'cgroup-for-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (21 commits)
cpuset: fix overlap of partition effective CPUs
cgroup: increase maximum subsystem count from 16 to 32
cgroup: Remove stale cpu.rt.max reference from documentation
cpuset: replace direct lockdep_assert_held() with lockdep_assert_cpuset_lock_held()
cgroup/cpuset: Move the v1 empty cpus/mems check to cpuset1_validate_change()
cgroup/cpuset: Don't invalidate sibling partitions on cpuset.cpus conflict
cgroup/cpuset: Don't fail cpuset.cpus change in v2
cgroup/cpuset: Consistently compute effective_xcpus in update_cpumasks_hier()
cgroup/cpuset: Streamline rm_siblings_excl_cpus()
cpuset: remove dead code in cpuset-v1.c
cpuset: remove v1-specific code from generate_sched_domains
cpuset: separate generate_sched_domains for v1 and v2
cpuset: move update_domain_attr_tree to cpuset_v1.c
cpuset: add cpuset1_init helper for v1 initialization
cpuset: add cpuset1_online_css helper for v1-specific operations
cpuset: add lockdep_assert_cpuset_lock_held helper
cpuset: Remove unnecessary checks in rebuild_sched_domains_locked
cgroup: switch to css_is_online() helper
selftests: cgroup: Replace sleep with cg_read_key_long_poll() for waiting on nr_dying_descendants
selftests: cgroup: make test_memcg_sock robust against delayed sock stats
...
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git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks
Pull kthread updates from Frederic Weisbecker:
"The kthread code provides an infrastructure which manages the
preferred affinity of unbound kthreads (node or custom cpumask)
against housekeeping (CPU isolation) constraints and CPU hotplug
events.
One crucial missing piece is the handling of cpuset: when an isolated
partition is created, deleted, or its CPUs updated, all the unbound
kthreads in the top cpuset become indifferently affine to _all_ the
non-isolated CPUs, possibly breaking their preferred affinity along
the way.
Solve this with performing the kthreads affinity update from cpuset to
the kthreads consolidated relevant code instead so that preferred
affinities are honoured and applied against the updated cpuset
isolated partitions.
The dispatch of the new isolated cpumasks to timers, workqueues and
kthreads is performed by housekeeping, as per the nice Tejun's
suggestion.
As a welcome side effect, HK_TYPE_DOMAIN then integrates both the set
from boot defined domain isolation (through isolcpus=) and cpuset
isolated partitions. Housekeeping cpumasks are now modifiable with a
specific RCU based synchronization. A big step toward making
nohz_full= also mutable through cpuset in the future"
* tag 'kthread-for-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks: (33 commits)
doc: Add housekeeping documentation
kthread: Document kthread_affine_preferred()
kthread: Comment on the purpose and placement of kthread_affine_node() call
kthread: Honour kthreads preferred affinity after cpuset changes
sched/arm64: Move fallback task cpumask to HK_TYPE_DOMAIN
sched: Switch the fallback task allowed cpumask to HK_TYPE_DOMAIN
kthread: Rely on HK_TYPE_DOMAIN for preferred affinity management
kthread: Include kthreadd to the managed affinity list
kthread: Include unbound kthreads in the managed affinity list
kthread: Refine naming of affinity related fields
PCI: Remove superfluous HK_TYPE_WQ check
sched/isolation: Remove HK_TYPE_TICK test from cpu_is_isolated()
cpuset: Remove cpuset_cpu_is_isolated()
timers/migration: Remove superfluous cpuset isolation test
cpuset: Propagate cpuset isolation update to timers through housekeeping
cpuset: Propagate cpuset isolation update to workqueue through housekeeping
PCI: Flush PCI probe workqueue on cpuset isolated partition change
sched/isolation: Flush vmstat workqueues on cpuset isolated partition change
sched/isolation: Flush memcg workqueues on cpuset isolated partition change
cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset
...
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When cpuset isolated partitions get updated, unbound kthreads get
indifferently affine to all non isolated CPUs, regardless of their
individual affinity preferences.
For example kswapd is a per-node kthread that prefers to be affine to
the node it refers to. Whenever an isolated partition is created,
updated or deleted, kswapd's node affinity is going to be broken if any
CPU in the related node is not isolated because kswapd will be affine
globally.
Fix this with letting the consolidated kthread managed affinity code do
the affinity update on behalf of cpuset.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
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The set of cpuset isolated CPUs is now included in HK_TYPE_DOMAIN
housekeeping cpumask. There is no usecase left interested in just
checking what is isolated by cpuset and not by the isolcpus= kernel
boot parameter.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
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Until now, cpuset would propagate isolated partition changes to
timer migration so that unbound timers don't get migrated to isolated
CPUs.
Since housekeeping now centralizes, synchronize and propagates isolation
cpumask changes, perform the work from that subsystem for consolidation
and consistency purposes.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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Until now, cpuset would propagate isolated partition changes to
workqueues so that unbound workers get properly reaffined.
Since housekeeping now centralizes, synchronize and propagates isolation
cpumask changes, perform the work from that subsystem for consolidation
and consistency purposes.
For simplification purpose, the target function is adapted to take the
new housekeeping mask instead of the isolated mask.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
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Until now, HK_TYPE_DOMAIN used to only include boot defined isolated
CPUs passed through isolcpus= boot option. Users interested in also
knowing the runtime defined isolated CPUs through cpuset must use
different APIs: cpuset_cpu_is_isolated(), cpu_is_isolated(), etc...
There are many drawbacks to that approach:
1) Most interested subsystems want to know about all isolated CPUs, not
just those defined on boot time.
2) cpuset_cpu_is_isolated() / cpu_is_isolated() are not synchronized with
concurrent cpuset changes.
3) Further cpuset modifications are not propagated to subsystems
Solve 1) and 2) and centralize all isolated CPUs within the
HK_TYPE_DOMAIN housekeeping cpumask.
Subsystems can rely on RCU to synchronize against concurrent changes.
The propagation mentioned in 3) will be handled in further patches.
[Chen Ridong: Fix cpu_hotplug_lock deadlock and use correct static
branch API]
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Reviewed-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
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cpuset modifies partitions, including isolated, while holding the cpuset
mutex.
This means that holding the cpuset mutex is safe to synchronize against
housekeeping cpumask changes.
Provide a lockdep check to validate that.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
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boot_hk_cpus is an ad-hoc copy of HK_TYPE_DOMAIN_BOOT. Remove it and use
the official version.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Reviewed-by: Chen Ridong <chenridong@huawei.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
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|
An UAF issue was observed:
BUG: KASAN: slab-use-after-free in page_counter_uncharge+0x65/0x150
Write of size 8 at addr ffff888106715440 by task insmod/527
CPU: 4 UID: 0 PID: 527 Comm: insmod 6.19.0-rc7-next-20260129+ #11
Tainted: [O]=OOT_MODULE
Call Trace:
<TASK>
dump_stack_lvl+0x82/0xd0
kasan_report+0xca/0x100
kasan_check_range+0x39/0x1c0
page_counter_uncharge+0x65/0x150
dmem_cgroup_uncharge+0x1f/0x260
Allocated by task 527:
Freed by task 0:
The buggy address belongs to the object at ffff888106715400
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 64 bytes inside of
freed 512-byte region [ffff888106715400, ffff888106715600)
The buggy address belongs to the physical page:
Memory state around the buggy address:
ffff888106715300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888106715380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888106715400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888106715480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888106715500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
The issue occurs because a pool can still be held by a caller after its
associated memory region is unregistered. The current implementation frees
the pool even if users still hold references to it (e.g., before uncharge
operations complete).
This patch adds a reference counter to each pool, ensuring that a pool is
only freed when its reference count drops to zero.
Fixes: b168ed458dde ("kernel/cgroup: Add "dmem" memory accounting cgroup")
Cc: stable@vger.kernel.org # v6.14+
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
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A warnning was detected:
WARNING: suspicious RCU usage
6.19.0-rc7-next-20260129+ #1101 Tainted: G O
kernel/cgroup/dmem.c:456 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
1 lock held by insmod/532:
#0: ffffffff85e78b38 (dmemcg_lock){+.+.}-dmem_cgroup_unregister_region+
stack backtrace:
CPU: 2 UID: 0 PID: 532 Comm: insmod Tainted: 6.19.0-rc7-next-
Tainted: [O]=OOT_MODULE
Call Trace:
<TASK>
dump_stack_lvl+0xb0/0xd0
lockdep_rcu_suspicious+0x151/0x1c0
dmem_cgroup_unregister_region+0x1e2/0x380
? __pfx_dmem_test_init+0x10/0x10 [dmem_uaf]
dmem_test_init+0x65/0xff0 [dmem_uaf]
do_one_initcall+0xbb/0x3a0
The macro list_for_each_rcu() must be used within an RCU read-side critical
section (between rcu_read_lock() and rcu_read_unlock()). Using it outside
that context, as seen in dmem_cgroup_unregister_region(), triggers the
lockdep warning because the RCU protection is not guaranteed.
Replace list_for_each_rcu() with list_for_each_entry_safe(), which is
appropriate for traversal under spinlock protection where nodes may be
deleted.
Fixes: b168ed458dde ("kernel/cgroup: Add "dmem" memory accounting cgroup")
Cc: stable@vger.kernel.org # v6.14+
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
An issue was triggered:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP NOPTI
CPU: 15 UID: 0 PID: 658 Comm: bash Tainted: 6.19.0-rc6-next-2026012
Tainted: [O]=OOT_MODULE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
RIP: 0010:strcmp+0x10/0x30
RSP: 0018:ffffc900017f7dc0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888107cd4358
RDX: 0000000019f73907 RSI: ffffffff82cc381a RDI: 0000000000000000
RBP: ffff8881016bef0d R08: 000000006c0e7145 R09: 0000000056c0e714
R10: 0000000000000001 R11: ffff888107cd4358 R12: 0007ffffffffffff
R13: ffff888101399200 R14: ffff888100fcb360 R15: 0007ffffffffffff
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000105c79000 CR4: 00000000000006f0
Call Trace:
<TASK>
dmemcg_limit_write.constprop.0+0x16d/0x390
? __pfx_set_resource_max+0x10/0x10
kernfs_fop_write_iter+0x14e/0x200
vfs_write+0x367/0x510
ksys_write+0x66/0xe0
do_syscall_64+0x6b/0x390
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f42697e1887
It was trriggered setting max without limitation, the command is like:
"echo test/region0 > dmem.max". To fix this issue, add check whether
options is valid after parsing the region_name.
Fixes: b168ed458dde ("kernel/cgroup: Add "dmem" memory accounting cgroup")
Cc: stable@vger.kernel.org # v6.14+
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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A warning was detect:
WARNING: kernel/cgroup/cpuset.c:825 at rebuild_sched_domains_locked
Modules linked in:
CPU: 12 UID: 0 PID: 681 Comm: rmdir 6.19.0-rc6-next-20260121+
RIP: 0010:rebuild_sched_domains_locked+0x309/0x4b0
RSP: 0018:ffffc900019bbd28 EFLAGS: 00000202
RAX: ffff888104413508 RBX: 0000000000000008 RCX: ffff888104413510
RDX: ffff888109b5f400 RSI: 000000000000ffcf RDI: 0000000000000001
RBP: 0000000000000002 R08: ffff888104413508 R09: 0000000000000002
R10: ffff888104413508 R11: 0000000000000001 R12: ffff888104413500
R13: 0000000000000002 R14: ffffc900019bbd78 R15: 0000000000000000
FS: 00007fe274b8d740(0000) GS:ffff8881b6b3c000(0000) knlGS:
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe274c98b50 CR3: 00000001047a9000 CR4: 00000000000006f0
Call Trace:
<TASK>
update_prstate+0x1c7/0x580
cpuset_css_killed+0x2f/0x50
kill_css+0x32/0x180
cgroup_destroy_locked+0xa7/0x200
cgroup_rmdir+0x28/0x100
kernfs_iop_rmdir+0x4c/0x80
vfs_rmdir+0x12c/0x280
filename_rmdir+0x19e/0x200
__x64_sys_rmdir+0x23/0x40
do_syscall_64+0x6b/0x390
It can be reproduced by steps:
# cd /sys/fs/cgroup/
# mkdir A1
# mkdir B1
# mkdir C1
# echo 1-3 > A1/cpuset.cpus
# echo root > A1/cpuset.cpus.partition
# echo 3-5 > B1/cpuset.cpus
# echo root > B1/cpuset.cpus.partition
# echo 6 > C1/cpuset.cpus
# echo root > C1/cpuset.cpus.partition
# rmdir A1/
# rmdir C1/
Both A1 and B1 were initially configured with CPU 3, which was exclusively
assigned to A1's partition. When A1 was removed, CPU 3 was returned to the
root pool. However, B1 incorrectly regained access to CPU 3 when
update_cpumasks_hier was triggered during C1's removal, which also updated
sibling configurations.
The update_sibling_cpumasks function was called to synchronize siblings'
effective CPUs due to changes in their parent's effective CPUs. However,
parent effective CPU changes should not affect partition-effective CPUs.
To fix this issue, update_cpumasks_hier should only be invoked when the
sibling is not a valid partition in the update_sibling_cpumasks.
Fixes: 2a3602030d80 ("cgroup/cpuset: Don't invalidate sibling partitions on cpuset.cpus conflict")
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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The current cgroup subsystem limit of 16 is insufficient, as the number of
existing subsystems has already reached this limit. When adding a new
subsystem that is not yet in the mainline kernel, building with
`make allmodconfig` requires first bypassing the
`BUILD_BUG_ON(CGROUP_SUBSYS_COUNT > 16)` restriction to allow compilation
to succeed. However, the kernel still fails to boot afterward.
This patch increases the maximum number of supported cgroup subsystems from
16 to 32, providing enough room for future subsystem additions.
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Acked-by: Waiman Long <longman@redhat.com>
Tested-by: JP Kobryn <inwardvessel@gmail.com>
Acked-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Now that nodes_and() returns true if the result nodemask is not empty,
drop useless nodes_intersects() in guarantee_online_mems() and
nodes_empty() in update_nodemasks_hier(), which both are O(N).
Link: https://lkml.kernel.org/r/20260114172217.861204-4-ynorov@nvidia.com
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add an appropriate SPDX-License-Identifier line to the file,
and remove the GNU boilerplate text.
Signed-off-by: Tim Bird <tim.bird@sony.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Add GPL-2.0 SPDX license id lines to a few old
files, replacing the reference to the COPYING file.
The COPYING file at the time of creation of these files
(2007 and 2005) was GPL-v2.0, with an additional clause
indicating that only v2 applied.
Signed-off-by: Tim Bird <tim.bird@sony.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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lockdep_assert_cpuset_lock_held()
We already added lockdep_assert_cpuset_lock_held(), use this new function
to keep consistency.
Signed-off-by: Zhao Mengmeng <zhaomengmeng@kylinos.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>
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As stated in commit 1c09b195d37f ("cpuset: fix a regression in validating
config change"), it is not allowed to clear masks of a cpuset if
there're tasks in it. This is specific to v1 since empty "cpuset.cpus"
or "cpuset.mems" will cause the v2 cpuset to inherit the effective CPUs
or memory nodes from its parent. So it is OK to have empty cpus or mems
even if there are tasks in the cpuset.
Move this empty cpus/mems check in validate_change() to
cpuset1_validate_change() to allow more flexibility in setting
cpus or mems in v2. cpuset_is_populated() needs to be moved into
cpuset-internal.h as it is needed by the empty cpus/mems checking code.
Also add a test case to test_cpuset_prs.sh to verify that.
Reported-by: Chen Ridong <chenridong@huaweicloud.com>
Closes: https://lore.kernel.org/lkml/7a3ec392-2e86-4693-aa9f-1e668a668b9c@huaweicloud.com/
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
|
