linux-rng/kernel/time, branch master

Merge tag 'timers-urgent-2026-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-11-01T17:19:12Z

Pull timer fixes from Ingo Molnar: - Fix on-stack hrtimer cleanup in play_idle_precise(), and add the hrtimer_on_stack cleanup class to facilitate the fix (Hui Su) - Fix clock_getres() system call's handling of NULL output pointer in the !CONFIG_POSIX_TIMERS case (Hungyu Lin) - Fix get_cpu_itimer() to return TICK_NSEC when the sampled CPU time is exactly equal to the nonzero expiry (Hungyu Lin) - Fix do_timens_ktime_to_host() time offset subtraction underflow check (Hungyu Lin) - Report zero remaining time for disarmed SIGEV_NONE posix timers, and add a self-test to detect this bug in the future (Hung-Jui Lin) - Fix NOHZ 'full kick' handling bug that can cause missed tick updates (Peng Wang) - Fix field access bug in the vdso/gettimeofday code that works only by accident (Thomas Weißschuh) - Fix & prevent immediate clocksource watchdog rerun after a delay (Karl Mehltretter) * tag 'timers-urgent-2026-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clocksource: Prevent immediate watchdog rerun after a delay vdso/gettimeofday: Correct the read of tz_minuteswest and tz_dsttime tick/nohz: Reevaluate the tick for kicks flushed outside hardirq selftests: timers: Add a test for disarmed SIGEV_NONE timers posix-timers: Report zero remaining time for disarmed SIGEV_NONE timers time/namespace: Fix overflow when converting absolute deadlines timers/itimer: Keep a nonzero value at CPU timer expiry posix-timers: Accept NULL clock_getres() output in stubs sched/idle: Use hrtimer cleanup class in play_idle_precise() hrtimer: Add cleanup class for on-stack timers

clocksource: Prevent immediate watchdog rerun after a delay

2026-10-27T20:26:16Z

The watchdog rewrite made the clocksource check handle long intervals between two measurements, but missed that the timer expiry needs to be rebased after such a delay. When a watchdog invocation is delayed by more than one interval, adding WATCHDOG_INTERVAL to the previous expiry leaves the timer expiry in the past. That causes an immediate second invocation. The resulting short measurement interval can mark a clocksource unstable. Cure this by rearming the timer based on jiffies, which places the next expiry one full watchdog interval into the future. Fixes: 763aacf86f1b ("clocksource: Rewrite watchdog code completely") Signed-off-by: Karl Mehltretter Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20261026010200.96371-1-kmehltretter@gmail.com Closes: https://lore.kernel.org/r/20261010065509.72916-1-kmehltretter@gmail.com/

Merge tag 'timers-urgent-2026-10-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-10-26T03:54:02Z

Pull timer fixes from Ingo Molnar: - Clear timer_base::pending_map on CPU hot-unplug, that can cause temporal timeout processing anomalous on the next hot-replug (Liang Hao) - Fix PID refcount leak in the posix-cpu-timers do_cpu_nanosleep() signal path (Cen Zhang) - Require (CAP_SYS_TIME) permission to set auxiliary clocks via aux_clock_set() (Daehyeon Ko) - Update offsets on sequence counter retry in ktime_get_update_offsets_now() (Thomas Weißschuh) * tag 'timers-urgent-2026-10-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timekeeping: Update offsets on sequence counter retry in ktime_get_update_offsets_now() timekeeping: Require permission to set auxiliary clocks posix-cpu-timers: Fix pid refcount leak in do_cpu_nanosleep() signal path timers: Clear pending_map on CPU hotplug

tick/nohz: Reevaluate the tick for kicks flushed outside hardirq

2026-10-25T21:43:19Z

The nohz full kick relies on interrupt exit to reevaluate the tick. However, a remote kick can also be flushed from task context without an interrupt exit guaranteed to follow. If a tick dependency is set or an earlier timer is queued after the idle-exit reevaluation, the required tick update can be delayed until another interrupt. Reevaluate the tick directly from the callback outside hardirq context. Keep the existing interrupt exit handling for hardirq callbacks. The offline flush remains harmless because tick_sched_timer_dying() has already cleared TS_FLAG_NOHZ. Fixes: 4b44a21dd640 ("irq_work, smp: Allow irq_work on call_single_queue") Fixes: a5183862e76f ("tick/nohz: Conditionally restart tick on idle exit") Suggested-by: Frederic Weisbecker Co-developed-by: He Rongguang Signed-off-by: He Rongguang Signed-off-by: Peng Wang Signed-off-by: Thomas Gleixner Reviewed-by: Frederic Weisbecker Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20261023145101.8217-1-peng_wang@linux.alibaba.com

posix-timers: Report zero remaining time for disarmed SIGEV_NONE timers

2026-10-25T21:43:19Z

SIGEV_NONE timers are never queued. common_timer_get() emulates their expiry by computing the remaining time from the stored expiry value. Because an armed SIGEV_NONE oneshot timer is not queued, its it_status stays POSIX_TIMER_DISARMED. So common_timer_get() cannot use it_status to skip a disarmed SIGEV_NONE timer and evaluates the stored expiry value for all SIGEV_NONE timers. Disarming a timer with timer_settime() and a zero it_value cancels the timer and sets it_status to POSIX_TIMER_DISARMED, but leaves the expiry value unchanged. As a consequence, timer_gettime() on a disarmed SIGEV_NONE timer reports the remaining time of the previous arming until that time has passed, instead of zero as POSIX requires for a disarmed timer. Example with a CLOCK_MONOTONIC timer armed with it_value = 10ms and it_interval = 100ms, then disarmed with an all-zero itimerspec: armed: it_value = 0.009999000 it_interval = 0.100000000 disarmed: it_value = 0.008700792 it_interval = 0.000000000 SIGEV_SIGNAL timers and SIGEV_NONE CPU timers report zero in the same situation. All clocks which use common_timer_get() are affected, including the alarm timer clocks. Mark SIGEV_NONE timers as POSIX_TIMER_ARMED when they are armed, so that common_timer_get() returns early for every disarmed timer. Forward SIGEV_NONE interval timers in common_timer_get() regardless of it_status, as they are never queued and therefore never forwarded by the expiry code. After the change the disarmed timer above reports zero. Armed SIGEV_NONE oneshot and interval timers on CLOCK_MONOTONIC, CLOCK_REALTIME, CLOCK_BOOTTIME and CLOCK_BOOTTIME_ALARM still report their remaining time, and the posix_timers selftest passes. Fixes: becf8b5d00f4 ("[PATCH] hrtimer: convert posix timers completely") Signed-off-by: Hung-Jui Lin Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20261023151411.28685-1-alex.lin.programmer@gmail.com

time/namespace: Fix overflow when converting absolute deadlines

2026-10-25T21:43:19Z

do_timens_ktime_to_host() subtracts the namespace offset from an absolute deadline and clamps the result to [0, KTIME_MAX]. A negative offset can make a large deadline overflow to a negative value. Since ktime_t is signed and KTIME_MAX is its maximum value, the subsequent comparison against KTIME_MAX can never detect this overflow. For example, with a -1 second boottime offset, an absolute CLOCK_BOOTTIME timerfd deadline of KTIME_MAX can expire immediately. An absolute clock_nanosleep() using the same clock and deadline can also return immediately instead of waiting. The earlier tim < offset check already handles the lower bound. A negative subtraction result in the remaining branch therefore indicates overflow. Detect that result and clamp it to KTIME_MAX. Fixes: 89dd8eecfe961 ("time: Add do_timens_ktime_to_host() helper") Signed-off-by: Hungyu Lin Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20261020233433.20997-1-dennylin0707@gmail.com

timers/itimer: Keep a nonzero value at CPU timer expiry

2026-10-25T21:43:19Z

get_cpu_itimer() returns a zero remaining time when the sampled CPU time is exactly equal to the nonzero expiry. This makes an armed ITIMER_VIRTUAL or ITIMER_PROF timer appear disarmed. The cputime cleanup replaced cputime_le(), which implements <=, with <. Restore the inclusive comparison so the equality case returns TICK_NSEC, like the overdue case and set_process_cpu_timer(). Fixes: 648616343cdb ("[S390] cputime: add sparse checking and cleanup") Signed-off-by: Hungyu Lin Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20261020223957.87842-1-dennylin0707@gmail.com

posix-timers: Accept NULL clock_getres() output in stubs

2026-10-25T21:43:19Z

With CONFIG_POSIX_TIMERS disabled, clock_getres() returns -EFAULT for a supported clock when the result pointer is NULL. POSIX permits a NULL result pointer to suppress returning the clock resolution. Only copy the result when a destination is provided, in both the native and time32 stubs. This matches the full POSIX timer implementation and preserves clock ID validation. Fixes: baa73d9e478f ("posix-timers: Make them configurable") Fixes: d822cdcce43f ("posix-timers: Move compat versions of clock_gettime/settime/getres") Signed-off-by: Hungyu Lin Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20261020161121.85042-1-dennylin0707@gmail.com

hrtimer: Add cleanup class for on-stack timers

2026-10-25T21:43:19Z

hrtimer_setup_on_stack() requires callers to destroy the timer before its backing stack storage goes out of scope, but the setup interface does not encode the required teardown pairing. Add an hrtimer_on_stack cleanup class that pairs on-stack setup with destroy_hrtimer_on_stack(). Document the existing setup API's lifetime requirement. The cleanup class provides debug-object teardown, not timer cancellation. Callers must ensure that no hrtimer operation can still access the timer before the scope ends; in particular, the timer must no longer be queued and any running callback must have completed. Signed-off-by: Hui Su Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/5f48c32490d19f51035e4209174f9cfe44472c71.1792083743.git.sh_def@163.com

timekeeping: Update offsets on sequence counter retry in ktime_get_update_offsets_now()

2026-10-23T19:52:01Z

The sequence counter of the cwsseq target is modified during the sequence counter loop. If the loop retries, cwsseq will now match but the offsets contain the values from the previous loop iteration. These are not guaranteed to be consistent in themselves or with the current loops "now. Save the target's original sequence counter value so that the update also happens on loop retries. Fixes: 868a3e915f7f ("hrtimer: Make offset update smarter") Signed-off-by: Thomas Weißschuh (Schneider Electric) Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20261023-timekeeping-clock_was_set_seq-v1-1-61c4c53d031c@linutronix.de