Like the previous fix (commit c0317c0e8709 "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@xxxxxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
v1->v2: return -EBUSY again if the instance isn't running
sound/core/timer.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/sound/core/timer.c b/sound/core/timer.c
index 4f9bab931951..b3214baa8919 100644
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -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;
}
/*
--
2.26.2
