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Frederic Weisbecker authored
When a timer is enqueued with a negative delta (ie: expiry is below base->clk), it gets added to the wheel as expiring now (base->clk). Yet the value that gets stored in base->next_expiry, while calling trigger_dyntick_cpu(), is the initial timer->expires value. The resulting state becomes: base->next_expiry < base->clk On the next timer enqueue, forward_timer_base() may accidentally rewind base->clk. As a possible outcome, timers may expire way too early, the worst case being that the highest wheel levels get spuriously processed again. To prevent from that, make sure that base->next_expiry doesn't get below base->clk. Fixes: a683f390 ("timers: Forward the wheel clock whenever possible") Signed-off-by:
Frederic Weisbecker <frederic@kernel.org> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Reviewed-by:
Anna-Maria Behnsen <anna-maria@linutronix.de> Tested-by:
Juri Lelli <juri.lelli@redhat.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200703010657.2302-1-frederic@kernel.org
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