[alsa-devel] [PATCH] ak4117: Do not free priv until timer handler hasn't actually stopped using it

Kirill Tkhai ktkhai at parallels.com
Fri Feb 14 12:47:57 CET 2014

Function del_timer() does not guarantee that timer was really deleted.
If the timer handler is beeing executed at the moment, the function
does nothing. So, it's possible to use already freed memory in the handler:

[ref: Documentation/DocBook/kernel-locking.tmpl]

This was found using grep and compile-tested only.

Signed-off-by: Kirill Tkhai <ktkhai at parallels.com>
CC: Jaroslav Kysela <perex at perex.cz>
CC: Takashi Iwai <tiwai at suse.de>
 sound/i2c/other/ak4117.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/i2c/other/ak4117.c b/sound/i2c/other/ak4117.c
index 40e33c9..88452e8 100644
--- a/sound/i2c/other/ak4117.c
+++ b/sound/i2c/other/ak4117.c
@@ -62,7 +62,7 @@ static void reg_dump(struct ak4117 *ak4117)
 static void snd_ak4117_free(struct ak4117 *chip)
-	del_timer(&chip->timer);
+	del_timer_sync(&chip->timer);

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