[patch 41/45] ALSA: Fix a deadlock in snd-rtctimer

[Greg KH]

-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Takashi Iwai <tiwai@xxxxxxx>

[PATCH] ALSA: Fix a deadlock in snd-rtctimer

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

Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Jaroslav Kysela <perex@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 sound/core/timer.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- linux-2.6.17.6.orig/sound/core/timer.c
+++ linux-2.6.17.6/sound/core/timer.c
@@ -628,8 +628,9 @@ static void snd_timer_tasklet(unsigned l
 	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 l
 		spin_lock(&timer->lock);
 		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
 	}
-	spin_unlock(&timer->lock);
+	spin_unlock_irqrestore(&timer->lock, flags);
 }
 
 /*

--
-
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