Commit 61ca6c78 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'timers-urgent-2024-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull timer fixes from Thomas Gleixner:
 "Two fixes for the timer/clocksource code:

   - The recent fix to make the take over of the broadcast timer more
     reliable retrieves a per CPU pointer in preemptible context.

     This went unnoticed in testing as some compilers hoist the access
     into the non-preemotible section where the pointer is actually
     used, but obviously compilers can rightfully invoke it where the
     code put it.

     Move it into the non-preemptible section right to the actual usage
     side to cure it.

   - The clocksource watchdog is supposed to emit a warning when the
     retry count is greater than one and the number of retries reaches
     the limit.

     The condition is backwards and warns always when the count is
     greater than one. Fixup the condition to prevent spamming dmesg"

* tag 'timers-urgent-2024-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource: Fix brown-bag boolean thinko in cs_watchdog_read()
  tick/broadcast: Move per CPU pointer access into the atomic section
parents 6cc82dc2 f2655ac2

kernel/time/clocksource.c

+1 −1
Original line number Diff line number Diff line
@@ -246,7 +246,7 @@ static enum wd_read_status cs_watchdog_read(struct clocksource *cs, u64 *csnow, 


		wd_delay = cycles_to_nsec_safe(watchdog, *wdnow, wd_end);

		if (wd_delay <= WATCHDOG_MAX_SKEW) {

			if (nretries > 1 || nretries >= max_retries) {

			if (nretries > 1 && nretries >= max_retries) {

				pr_warn("timekeeping watchdog on CPU%d: %s retried %d times before success\n",

					smp_processor_id(), watchdog->name, nretries);

			}

kernel/time/tick-broadcast.c

+2 −1
Original line number Diff line number Diff line
@@ -1141,7 +1141,6 @@ void tick_broadcast_switch_to_oneshot(void) 
#ifdef CONFIG_HOTPLUG_CPU

void hotplug_cpu__broadcast_tick_pull(int deadcpu)

{

	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);

	struct clock_event_device *bc;

	unsigned long flags;
@@ -1167,6 +1166,8 @@ void hotplug_cpu__broadcast_tick_pull(int deadcpu) 
		 * device to avoid the starvation.

		 */

		if (tick_check_broadcast_expired()) {

			struct tick_device *td = this_cpu_ptr(&tick_cpu_device);



			cpumask_clear_cpu(smp_processor_id(), tick_broadcast_force_mask);

			tick_program_event(td->evtdev->next_event, 1);

		}