linux-kernel - [PATCH next] ALSA: mixer: fix deadlock in snd_mixer_oss_set

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Date:   Sun, 24 Oct 2021 17:03:15 +0300
From:   Pavel Skripkin <paskripkin@...il.com>
To:     perex@...ex.cz, tiwai@...e.com, broonie@...nel.org,
        joe@...ches.com, lars@...afoo.de
Cc:     alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        Pavel Skripkin <paskripkin@...il.com>,
        syzbot+ace149a75a9a0a399ac7@...kaller.appspotmail.com
Subject: [PATCH next] ALSA: mixer: fix deadlock in snd_mixer_oss_set_volume

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@...kaller.appspotmail.com
Fixes: 411cef6adfb3 ("ALSA: mixer: oss: Fix racy access to slots")
Signed-off-by: Pavel Skripkin <paskripkin@...il.com>
---
 sound/core/oss/mixer_oss.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/core/oss/mixer_oss.c b/sound/core/oss/mixer_oss.c
index d5ddc154a735..9620115cfdc0 100644
--- a/sound/core/oss/mixer_oss.c
+++ b/sound/core/oss/mixer_oss.c
@@ -313,7 +313,7 @@ static int snd_mixer_oss_set_volume(struct snd_mixer_oss_file *fmixer,
 	pslot->volume[1] = right;
 	result = (left & 0xff) | ((right & 0xff) << 8);
  unlock:
-	mutex_lock(&mixer->reg_mutex);
+	mutex_unlock(&mixer->reg_mutex);
 	return result;
 }
 
-- 
2.33.1