Merge tag 'timers-urgent-2022-04-17' of git://git.kernel.org/pub/scm/linux/kernel...

Pull timer fixes from Thomas Gleixner:
 "A small set of fixes for the timers core:

   - Fix the warning condition in __run_timers() which does not take
     into account that a CPU base (especially the deferrable base) never
     has a timer armed on it and therefore the next_expiry value can
     become stale.

   - Replace a WARN_ON() in the NOHZ code with a WARN_ON_ONCE() to
     prevent endless spam in dmesg.

   - Remove the double star from a comment which is not meant to be in
     kernel-doc format"

* tag 'timers-urgent-2022-04-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick/sched: Fix non-kernel-doc comment
  tick/nohz: Use WARN_ON_ONCE() to prevent console saturation
  timers: Fix warning condition in __run_timers()

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 2d76c91b85de428aac7bd6627533170f6697ad56..d257721c68b8fc74d85601b713cded1bffded8d7 100644 (file)
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -188,7 +188,7 @@ static void tick_sched_do_timer(struct tick_sched *ts, ktime_t now)
         */
        if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE)) {
 #ifdef CONFIG_NO_HZ_FULL
-               WARN_ON(tick_nohz_full_running);
+               WARN_ON_ONCE(tick_nohz_full_running);
 #endif
                tick_do_timer_cpu = cpu;
        }
@@ -1538,7 +1538,7 @@ void tick_cancel_sched_timer(int cpu)
 }
 #endif
 
-/**
+/*
  * Async notification about clocksource changes
  */
 void tick_clock_notify(void)
@@ -1559,7 +1559,7 @@ void tick_oneshot_notify(void)
        set_bit(0, &ts->check_clocks);
 }
 
-/**
+/*
  * Check, if a change happened, which makes oneshot possible.
  *
  * Called cyclic from the hrtimer softirq (driven by the timer

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 85f1021ad45955026eba845727e53c87693ed2db..9dd2a39cb3b0058e4756ea129cd968195010c00e 100644 (file)
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1722,11 +1722,14 @@ static inline void __run_timers(struct timer_base *base)
               time_after_eq(jiffies, base->next_expiry)) {
                levels = collect_expired_timers(base, heads);
                /*
-                * The only possible reason for not finding any expired
-                * timer at this clk is that all matching timers have been
-                * dequeued.
+                * The two possible reasons for not finding any expired
+                * timer at this clk are that all matching timers have been
+                * dequeued or no timer has been queued since
+                * base::next_expiry was set to base::clk +
+                * NEXT_TIMER_MAX_DELTA.
                 */
-               WARN_ON_ONCE(!levels && !base->next_expiry_recalc);
+               WARN_ON_ONCE(!levels && !base->next_expiry_recalc
+                            && base->timers_pending);
                base->clk++;
                base->next_expiry = __next_timer_interrupt(base);