[PATCH 4.4 036/162] ALSA: mixer: fix deadlock in snd_mixer_oss_set_volume

Greg Kroah-Hartman
2021-11-24T12:02:04Z

From: Pavel Skripkin <paskripkin@gmail.com>

commit 3ab7992018455ac63c33e9b3eaa7264e293e40f4 upstream.

In commit 411cef6adfb3 ("ALSA: mixer: oss: Fix racy access to slots")
added mutex protection in snd_mixer_oss_set_volume(). Second
mutex_lock() in same function looks like typo, fix it.

Reported-by: syzbot+ace149a75a9a0a399ac7@syzkaller.appspotmail.com
Fixes: 411cef6adfb3 ("ALSA: mixer: oss: Fix racy access to slots")
Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Link: https://lore.kernel.org/r/20211024140315.16704-1-paskripkin@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
sound/core/oss/mixer_oss.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/sound/core/oss/mixer_oss.c
+++ b/sound/core/oss/mixer_oss.c
@@ -327,7 +327,7 @@ static int snd_mixer_oss_set_volume(stru
pslot->volume[1] = right;
result = (left & 0xff) | ((right & 0xff) << 8);
unlock:
- mutex_lock(&mixer->reg_mutex);
+ mutex_unlock(&mixer->reg_mutex);
return result;
}