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timers: Fix warning condition in __run_timers()
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When the timer base is empty, base::next_expiry is set to base::clk +
NEXT_TIMER_MAX_DELTA and base::next_expiry_recalc is false. When no timer
is queued until jiffies reaches base::next_expiry value, the warning for
not finding any expired timer and base::next_expiry_recalc is false in
__run_timers() triggers.

To prevent triggering the warning in this valid scenario
base::timers_pending needs to be added to the warning condition.

Fixes: 31cd0e1 ("timers: Recalculate next timer interrupt only when necessary")
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20220405191732.7438-3-anna-maria@linutronix.de
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Anna-Maria Behnsen authored and Thomas Gleixner committed Apr 9, 2022
1 parent 3123109 commit c54bc0f
Showing 1 changed file with 7 additions and 4 deletions.
11 changes: 7 additions & 4 deletions kernel/time/timer.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);

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