From: Anna-Maria Behnsen <anna-maria@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <frederic@kernel.org>,
Johannes Berg <johannes@sipsolutions.net>
Subject: [PATCH 2/2] timers: Fix warning in __run_timers()
Date: Tue, 5 Apr 2022 21:17:32 +0200 [thread overview]
Message-ID: <20220405191732.7438-3-anna-maria@linutronix.de> (raw)
In-Reply-To: <20220405191732.7438-1-anna-maria@linutronix.de>
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@sipsolutions.net>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
---
kernel/time/timer.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 4af98e77cd78..204d6cd83d0e 100644
--- 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);
--
2.20.1
next prev parent reply other threads:[~2022-04-05 21:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-05 19:17 [PATCH 0/2] timers: Small fixes Anna-Maria Behnsen
2022-04-05 19:17 ` [PATCH 1/2] timers: Initialize base::next_expiry_recalc during prepare cpu Anna-Maria Behnsen
2022-04-05 21:51 ` Frederic Weisbecker
2022-04-09 20:22 ` [tip: timers/core] timers: Initialize base::next_expiry_recalc in timers_prepare_cpu() tip-bot2 for Anna-Maria Behnsen
2022-04-05 19:17 ` Anna-Maria Behnsen [this message]
2022-04-05 21:43 ` [PATCH 2/2] timers: Fix warning in __run_timers() Frederic Weisbecker
2022-04-09 20:22 ` [tip: timers/core] timers: Fix warning condition " tip-bot2 for Anna-Maria Behnsen
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