[ALSA] Fix a deadlock in snd-rtctimer

Fix a occasional deadlock occuring with snd-rtctimer driver,
added irqsave to the lock in tasklet (ALSA bug#952).

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 3 insertions, 2 deletions

diff --git a/sound/core/timer.c b/sound/core/timer.c
index 78199f58b93a..0a984e881c10 100644
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -628,8 +628,9 @@ static void snd_timer_tasklet(unsigned long arg)
         struct snd_timer_instance *ti;
         struct list_head *p;
         unsigned long resolution, ticks;
+        unsigned long flags;
 
-        spin_lock(&timer->lock);
+        spin_lock_irqsave(&timer->lock, flags);
         /* now process all callbacks */
         while (!list_empty(&timer->sack_list_head)) {
                 p = timer->sack_list_head.next;         /* get first item */
@@ -649,7 +650,7 @@ static void snd_timer_tasklet(unsigned long arg)
                 spin_lock(&timer->lock);
                 ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
         }
-        spin_unlock(&timer->lock);
+        spin_unlock_irqrestore(&timer->lock, flags);
 }
 
 /*