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Message-Id: <20220418121207.873707302@linuxfoundation.org>
Date: Mon, 18 Apr 2022 14:13:15 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Johannes Berg <johannes@...solutions.net>,
Anna-Maria Behnsen <anna-maria@...utronix.de>,
Thomas Gleixner <tglx@...utronix.de>,
Frederic Weisbecker <frederic@...nel.org>
Subject: [PATCH 5.15 175/189] timers: Fix warning condition in __run_timers()
From: Anna-Maria Behnsen <anna-maria@...utronix.de>
commit c54bc0fc84214b203f7a0ebfd1bd308ce2abe920 upstream.
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: 31cd0e119d50 ("timers: Recalculate next timer interrupt only when necessary")
Reported-by: Johannes Berg <johannes@...solutions.net>
Signed-off-by: Anna-Maria Behnsen <anna-maria@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Frederic Weisbecker <frederic@...nel.org>
Link: https://lore.kernel.org/r/20220405191732.7438-3-anna-maria@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
kernel/time/timer.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1722,11 +1722,14 @@ static inline void __run_timers(struct t
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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