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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: Alexander Potapenko <glider@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2017-06-02 17:35:30 +02:00
parent 890e2cb5d1
commit d7f910bfed
1 changed files with 4 additions and 0 deletions
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4
sound/core/timer.c
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@ -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;
}