Commit cd738246 authored Mar 08, 2019 by Viresh Kumar Committed by Greg Kroah-Hartman Mar 23, 2019

PM / wakeup: Rework wakeup source timer cancellation



commit 1fad17fb1bbcd73159c2b992668a6957ecc5af8a upstream.

If wakeup_source_add() is called right after wakeup_source_remove()
for the same wakeup source, timer_setup() may be called for a
potentially scheduled timer which is incorrect.

To avoid that, move the wakeup source timer cancellation from
wakeup_source_drop() to wakeup_source_remove().

Moreover, make wakeup_source_remove() clear the timer function after
canceling the timer to let wakeup_source_not_registered() treat
unregistered wakeup sources in the same way as the ones that have
never been registered.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.4+ <stable@vger.kernel.org> # 4.4+
[ rjw: Subject, changelog, merged two patches together ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 43bceddc

drivers/base/power/wakeup.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -118,7 +118,6 @@ void wakeup_source_drop(struct wakeup_source *ws)
		if (!ws)
		return;

		del_timer_sync(&ws->timer);
		__pm_relax(ws);
		}
		EXPORT_SYMBOL_GPL(wakeup_source_drop);
		@@ -205,6 +204,13 @@ void wakeup_source_remove(struct wakeup_source *ws)
		list_del_rcu(&ws->entry);
		raw_spin_unlock_irqrestore(&events_lock, flags);
		synchronize_srcu(&wakeup_srcu);

		del_timer_sync(&ws->timer);
		/*
		* Clear timer.function to make wakeup_source_not_registered() treat
		* this wakeup source as not registered.
		*/
		ws->timer.function = NULL;
		}
		EXPORT_SYMBOL_GPL(wakeup_source_remove);