linux-stable.git/kernel/time/posix-timers.c, branch linux-rolling-stable Linux kernel stable tree posix-timers: Expand timer_[re]arm() callbacks with a boolean return value 2026-07-24T14:21:26+00:00 Thomas Gleixner tglx@kernel.org 2026-04-08T11:53:56+00:00 60325bf5e2c155e807270ed788c7610fd39bdbe9 commit 6fdb2677a594ab38eade927919bbd4d9688bfa1c upstream. In order to catch expiry times which are already in the past the timer_arm() and timer_rearm() callbacks need to be able to report back to the caller whether the timer has been queued or not. Change the function signature and let all implementations return true for now. While at it simplify posix_cpu_timer_rearm(). No functional change intended. Signed-off-by: Thomas Gleixner <tglx@kernel.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: John Stultz <jstultz@google.com> Link: https://patch.msgid.link/20260408114952.130222296@kernel.org Signed-off-by: Salvatore Bonaccorso <carnil@debian.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 6fdb2677a594ab38eade927919bbd4d9688bfa1c upstream.

In order to catch expiry times which are already in the past the
timer_arm() and timer_rearm() callbacks need to be able to report back to
the caller whether the timer has been queued or not.

Change the function signature and let all implementations return true for
now. While at it simplify posix_cpu_timer_rearm().

No functional change intended.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/20260408114952.130222296@kernel.org
Signed-off-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
posix-timers: Fix stale function name in comment 2026-03-28T13:18:13+00:00 Zhan Xusheng zhanxusheng1024@gmail.com 2026-03-26T14:22:10+00:00 e9fb60a780fe7eae6a5d73e647208b2a7d3e3b54 The comment in exit_itimers() still refers to itimer_delete(), which was replaced by posix_timer_delete(). Update the comment accordingly. Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260326142210.98632-1-zhanxusheng@xiaomi.com 
The comment in exit_itimers() still refers to itimer_delete(),
which was replaced by posix_timer_delete(). Update the comment
accordingly.

Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260326142210.98632-1-zhanxusheng@xiaomi.com
compiler-context-analysis: Remove __cond_lock() function-like helper 2026-01-05T15:43:33+00:00 Marco Elver elver@google.com 2025-12-19T15:40:13+00:00 e4588c25c9d122b5847b88e18b184404b6959160 As discussed in [1], removing __cond_lock() will improve the readability of trylock code. Now that Sparse context tracking support has been removed, we can also remove __cond_lock(). Change existing APIs to either drop __cond_lock() completely, or make use of the __cond_acquires() function attribute instead. In particular, spinlock and rwlock implementations required switching over to inline helpers rather than statement-expressions for their trylock_* variants. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/all/20250207082832.GU7145@noisy.programming.kicks-ass.net/ [1] Link: https://patch.msgid.link/20251219154418.3592607-25-elver@google.com 
As discussed in [1], removing __cond_lock() will improve the readability
of trylock code. Now that Sparse context tracking support has been
removed, we can also remove __cond_lock().

Change existing APIs to either drop __cond_lock() completely, or make
use of the __cond_acquires() function attribute instead.

In particular, spinlock and rwlock implementations required switching
over to inline helpers rather than statement-expressions for their
trylock_* variants.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250207082832.GU7145@noisy.programming.kicks-ass.net/ [1]
Link: https://patch.msgid.link/20251219154418.3592607-25-elver@google.com
Merge tag 'timers-core-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2025-12-02T17:58:33+00:00 Linus Torvalds torvalds@linux-foundation.org 2025-12-02T17:58:33+00:00 d42e504a555d0da2a10001e697f0c8a7f633fb05 Pull timer core updates from Thomas Gleixner: - Prevent a thundering herd problem when the timekeeper CPU is delayed and a large number of CPUs compete to acquire jiffies_lock to do the update. Limit it to one CPU with a separate "uncontended" atomic variable. - A set of improvements for the timer migration mechanism: - Support imbalanced NUMA trees correctly - Support dynamic exclusion of CPUs from the migrator duty to allow the cpuset/isolation mechanism to exclude them from handling timers of remote idle CPUs - The usual small updates, cleanups and enhancements * tag 'timers-core-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timers/migration: Exclude isolated cpus from hierarchy cpumask: Add initialiser to use cleanup helpers sched/isolation: Force housekeeping if isolcpus and nohz_full don't leave any cgroup/cpuset: Rename update_unbound_workqueue_cpumask() to update_isolation_cpumasks() timers/migration: Use scoped_guard on available flag set/clear timers/migration: Add mask for CPUs available in the hierarchy timers/migration: Rename 'online' bit to 'available' selftests/timers/nanosleep: Add tests for return of remaining time selftests/timers: Clean up kernel version check in posix_timers time: Fix a few typos in time[r] related code comments time: tick-oneshot: Add missing Return and parameter descriptions to kernel-doc hrtimer: Store time as ktime_t in restart block timers/migration: Remove dead code handling idle CPU checking for remote timers timers/migration: Remove unused "cpu" parameter from tmigr_get_group() timers/migration: Assert that hotplug preparing CPU is part of stable active hierarchy timers/migration: Fix imbalanced NUMA trees timers/migration: Remove locking on group connection timers/migration: Convert "while" loops to use "for" tick/sched: Limit non-timekeeper CPUs calling jiffies update 
Pull timer core updates from Thomas Gleixner:

 - Prevent a thundering herd problem when the timekeeper CPU is delayed
   and a large number of CPUs compete to acquire jiffies_lock to do the
   update. Limit it to one CPU with a separate "uncontended" atomic
   variable.

 - A set of improvements for the timer migration mechanism:

     - Support imbalanced NUMA trees correctly

     - Support dynamic exclusion of CPUs from the migrator duty to allow
       the cpuset/isolation mechanism to exclude them from handling
       timers of remote idle CPUs

 - The usual small updates, cleanups and enhancements

* tag 'timers-core-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timers/migration: Exclude isolated cpus from hierarchy
  cpumask: Add initialiser to use cleanup helpers
  sched/isolation: Force housekeeping if isolcpus and nohz_full don't leave any
  cgroup/cpuset: Rename update_unbound_workqueue_cpumask() to update_isolation_cpumasks()
  timers/migration: Use scoped_guard on available flag set/clear
  timers/migration: Add mask for CPUs available in the hierarchy
  timers/migration: Rename 'online' bit to 'available'
  selftests/timers/nanosleep: Add tests for return of remaining time
  selftests/timers: Clean up kernel version check in posix_timers
  time: Fix a few typos in time[r] related code comments
  time: tick-oneshot: Add missing Return and parameter descriptions to kernel-doc
  hrtimer: Store time as ktime_t in restart block
  timers/migration: Remove dead code handling idle CPU checking for remote timers
  timers/migration: Remove unused "cpu" parameter from tmigr_get_group()
  timers/migration: Assert that hotplug preparing CPU is part of stable active hierarchy
  timers/migration: Fix imbalanced NUMA trees
  timers/migration: Remove locking on group connection
  timers/migration: Convert "while" loops to use "for"
  tick/sched: Limit non-timekeeper CPUs calling jiffies update
time: Fix a few typos in time[r] related code comments 2025-11-14T19:34:50+00:00 Jianyun Gao jianyungao89@gmail.com 2025-09-27T09:34:10+00:00 4518767be9089ea4f54754ad27364d6134fc46e2 Signed-off-by: Jianyun Gao <jianyungao89@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://patch.msgid.link/20250927093411.1509275-1-jianyungao89@gmail.com 
Signed-off-by: Jianyun Gao <jianyungao89@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20250927093411.1509275-1-jianyungao89@gmail.com
posix-timers: Plug potential memory leak in do_timer_create() 2025-11-14T15:58:31+00:00 Eslam Khafagy eslam.medhat1993@gmail.com 2025-11-14T12:27:39+00:00 e0fd4d42e27f761e9cc82801b3f183e658dc749d When posix timer creation is set to allocate a given timer ID and the access to the user space value faults, the function terminates without freeing the already allocated posix timer structure. Move the allocation after the user space access to cure that. [ tglx: Massaged change log ] Fixes: ec2d0c04624b3 ("posix-timers: Provide a mechanism to allocate a given timer ID") Reported-by: syzbot+9c47ad18f978d4394986@syzkaller.appspotmail.com Suggested-by: Cyrill Gorcunov <gorcunov@gmail.com> Signed-off-by: Eslam Khafagy <eslam.medhat1993@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Link: https://patch.msgid.link/20251114122739.994326-1-eslam.medhat1993@gmail.com Closes: https://lore.kernel.org/all/69155df4.a70a0220.3124cb.0017.GAE@google.com/T/ 
When posix timer creation is set to allocate a given timer ID and the
access to the user space value faults, the function terminates without
freeing the already allocated posix timer structure.

Move the allocation after the user space access to cure that.

[ tglx: Massaged change log ]

Fixes: ec2d0c04624b3 ("posix-timers: Provide a mechanism to allocate a given timer ID")
Reported-by: syzbot+9c47ad18f978d4394986@syzkaller.appspotmail.com
Suggested-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Eslam Khafagy <eslam.medhat1993@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://patch.msgid.link/20251114122739.994326-1-eslam.medhat1993@gmail.com
Closes: https://lore.kernel.org/all/69155df4.a70a0220.3124cb.0017.GAE@google.com/T/
time: Fix spelling mistakes in comments 2025-09-21T08:02:02+00:00 Haofeng Li lihaofeng@kylinos.cn 2025-09-10T09:37:03+00:00 391253b25f078d2fe5657a1dedd360396d186407 Correct several typos found in comments across various files in the kernel/time directory. No functional changes are introduced by these corrections. Signed-off-by: Haofeng Li <lihaofeng@kylinos.cn> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> 
Correct several typos found in comments across various files in the
kernel/time directory.

No functional changes are introduced by these corrections.

Signed-off-by: Haofeng Li <lihaofeng@kylinos.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
posix-timers: Avoid direct access to hrtimer clockbase 2025-09-09T10:27:17+00:00 Thomas Weißschuh thomas.weissschuh@linutronix.de 2025-08-21T13:28:08+00:00 24fb08dcc40f52cf5f95d2cdaa0c26e33a2f4285 The field timer->base->get_time is a private implementation detail and should not be accessed outside of the hrtimer core. Switch to the equivalent helpers. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/all/20250821-hrtimer-cleanup-get_time-v2-1-3ae822e5bfbd@linutronix.de 
The field timer->base->get_time is a private implementation detail and
should not be accessed outside of the hrtimer core.

Switch to the equivalent helpers.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250821-hrtimer-cleanup-get_time-v2-1-3ae822e5bfbd@linutronix.de
timekeeping: Add minimal posix-timers support for auxiliary clocks 2025-06-27T18:13:12+00:00 Thomas Gleixner tglx@linutronix.de 2025-06-25T18:38:32+00:00 606424bf4ffd9d27865c45b5707c1edac6b187ed Provide clock_getres(2) and clock_gettime(2) for auxiliary clocks. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <jstultz@google.com> Link: https://lore.kernel.org/all/20250625183757.932220594@linutronix.de 
Provide clock_getres(2) and clock_gettime(2) for auxiliary clocks.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/all/20250625183757.932220594@linutronix.de
posix-timers: Initialize cache early and move pointer into __timer_data 2025-04-09T19:21:36+00:00 Eric Dumazet edumazet@google.com 2025-04-02T13:31:14+00:00 0df6db767a535472a46aeea93c280de067784a9f Move posix_timers_cache initialization to posixtimer_init(). At that point the memory subsystem is already up and running. Also move the cache pointer to the __timer_data variable to avoid potential false sharing, since it never was marked as __ro_after_init. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20250402133114.253901-1-edumazet@google.com 
Move posix_timers_cache initialization to posixtimer_init(). At that point
the memory subsystem is already up and running.

Also move the cache pointer to the __timer_data variable to avoid
potential false sharing, since it never was marked as __ro_after_init.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250402133114.253901-1-edumazet@google.com