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Commit 474e941b authored by Richard Larocque's avatar Richard Larocque Committed by John Stultz
Browse files

alarmtimer: Lock k_itimer during timer callback 



Locks the k_itimer's it_lock member when handling the alarm timer's
expiry callback.

The regular posix timers defined in posix-timers.c have this lock held
during timout processing because their callbacks are routed through
posix_timer_fn().  The alarm timers follow a different path, so they
ought to grab the lock somewhere else.

Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: default avatarRichard Larocque <rlarocque@google.com>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent 265b81d2

kernel/time/alarmtimer.c

+8 −2
Original line number Diff line number Diff line
@@ -464,8 +464,12 @@ static enum alarmtimer_type clock2alarm(clockid_t clockid) 
static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,

							ktime_t now)

{

	unsigned long flags;

	struct k_itimer *ptr = container_of(alarm, struct k_itimer,

						it.alarm.alarmtimer);

	enum alarmtimer_restart result = ALARMTIMER_NORESTART;



	spin_lock_irqsave(&ptr->it_lock, flags);

	if ((ptr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) {

		if (posix_timer_event(ptr, 0) != 0)

			ptr->it_overrun++;
@@ -475,9 +479,11 @@ static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm, 
	if (ptr->it.alarm.interval.tv64) {

		ptr->it_overrun += alarm_forward(alarm, now,

						ptr->it.alarm.interval);

		return ALARMTIMER_RESTART;

		result = ALARMTIMER_RESTART;

	}

	return ALARMTIMER_NORESTART;

	spin_unlock_irqrestore(&ptr->it_lock, flags);



	return result;

}



/**