Commit d7f910bf authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: timer: Wrap with spinlock for queue access 



For accessing the snd_timer_user queue indices, we take tu->qlock.
But it's forgotten in a couple of places.

The one in snd_timer_user_params() should be safe without the
spinlock as the timer is already stopped.  But it's better for
consistency.

The one in poll is just a read-out, so it's not inevitably needed, but
it'd be good to make the result consistent, too.

Tested-by: default avatarAlexander Potapenko <glider@google.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 890e2cb5

sound/core/timer.c

+4 −0
Original line number Diff line number Diff line
@@ -1755,6 +1755,7 @@ static int snd_timer_user_params(struct file *file, 
		if (err < 0)

			goto _end;

	}

	spin_lock_irq(&tu->qlock);

	tu->qhead = tu->qtail = tu->qused = 0;

	if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {

		if (tu->tread) {
@@ -1775,6 +1776,7 @@ static int snd_timer_user_params(struct file *file, 
	}

	tu->filter = params.filter;

	tu->ticks = params.ticks;

	spin_unlock_irq(&tu->qlock);

	err = 0;

 _end:

	if (copy_to_user(_params, &params, sizeof(params)))
@@ -2022,10 +2024,12 @@ static unsigned int snd_timer_user_poll(struct file *file, poll_table * wait) 
        poll_wait(file, &tu->qchange_sleep, wait);



	mask = 0;

	spin_lock_irq(&tu->qlock);

	if (tu->qused)

		mask |= POLLIN | POLLRDNORM;

	if (tu->disconnected)

		mask |= POLLERR;

	spin_unlock_irq(&tu->qlock);



	return mask;

}