From: Vincent Guittot Date: Thu, 21 Feb 2019 07:59:02 +0000 (+0100) Subject: PM-runtime: Fix deadlock when canceling hrtimer X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=74fb44863084275b952f21ec6a024af0e2e75cb8;p=openwrt%2Fstaging%2Fblogic.git PM-runtime: Fix deadlock when canceling hrtimer When rpm_resume() desactivates the autosuspend timer, it should only try to cancel hrtimer but not wait for the handler to finish, because both rpm_resume() and pm_suspend_timer_fn() take the power.lock. A deadlock is possible as follows: CPU0 CPU1 rpm_resume() spin_lock_irqsave pm_suspend_timer_fn() spin_lock_irqsave pm_runtime_deactivate_timer() hrtimer_cancel() It is sufficient to call hrtimer_try_to_cancel() from pm_runtime_deactivate_timer(), because dev->power.timer_expires reset to 0 by it, so use that function instead of hrtimer_cancel(). Fixes: 8234f6734c5d ("PM-runtime: Switch autosuspend over to using hrtimers") Reported-by: Sunzhaosheng Sun(Zhaosheng) Signed-off-by: Vincent Guittot [ rjw: Changelog ] Signed-off-by: Rafael J. Wysocki --- diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 0ea2139c50d8..ccd296dbb95c 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -95,7 +95,7 @@ static void __update_runtime_status(struct device *dev, enum rpm_status status) static void pm_runtime_deactivate_timer(struct device *dev) { if (dev->power.timer_expires > 0) { - hrtimer_cancel(&dev->power.suspend_timer); + hrtimer_try_to_cancel(&dev->power.suspend_timer); dev->power.timer_expires = 0; } }