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ALSA: timer: Unconditionally unlink slave instances, too

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Like the previous fix (commit c0317c0e87 "ALSA: timer: Fix
use-after-free problem"), we have to unlink slave timer instances
immediately at snd_timer_stop(), too.  Otherwise it may leave a stale
entry in the list if the slave instance is freed before actually
running.

Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20211105091517.21733-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2021-11-05 10:15:17 +01:00
parent dce9446192
commit ffdd98277f
1 changed files with 6 additions and 7 deletions
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13
sound/core/timer.c
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@ -665,23 +665,22 @@ static int snd_timer_stop1(struct snd_timer_instance *timeri, bool stop)
static int snd_timer_stop_slave(struct snd_timer_instance *timeri, bool stop)
{
unsigned long flags;
bool running;
spin_lock_irqsave(&slave_active_lock, flags);
if (!(timeri->flags & SNDRV_TIMER_IFLG_RUNNING)) {
spin_unlock_irqrestore(&slave_active_lock, flags);
return -EBUSY;
}
running = timeri->flags & SNDRV_TIMER_IFLG_RUNNING;
timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
if (timeri->timer) {
spin_lock(&timeri->timer->lock);
list_del_init(&timeri->ack_list);
list_del_init(&timeri->active_list);
snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
SNDRV_TIMER_EVENT_PAUSE);
if (running)
snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
SNDRV_TIMER_EVENT_PAUSE);
spin_unlock(&timeri->timer->lock);
}
spin_unlock_irqrestore(&slave_active_lock, flags);
return 0;
return running ? 0 : -EBUSY;
}
/*