From: Takashi Iwai tiwai@suse.de
commit a70aef7982b012e86dfd39fbb235e76a21ae778a upstream.
The register_mutex taken around the dev_unregister callback call in snd_rawmidi_free() may potentially lead to a mutex deadlock, when OSS emulation and a hot unplug are involved.
Since the mutex doesn't protect the actual race (as the registration itself is already protected by another means), let's drop it.
Link: https://lore.kernel.org/r/CAB7eexJP7w1B0mVgDF0dQ+gWor7UdkiwPczmL7pn91xx8xpzO... Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20221011070147.7611-1-tiwai@suse.de Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- sound/core/rawmidi.c | 2 -- 1 file changed, 2 deletions(-)
--- a/sound/core/rawmidi.c +++ b/sound/core/rawmidi.c @@ -1736,10 +1736,8 @@ static int snd_rawmidi_free(struct snd_r
snd_info_free_entry(rmidi->proc_entry); rmidi->proc_entry = NULL; - mutex_lock(®ister_mutex); if (rmidi->ops && rmidi->ops->dev_unregister) rmidi->ops->dev_unregister(rmidi); - mutex_unlock(®ister_mutex);
snd_rawmidi_free_substreams(&rmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT]); snd_rawmidi_free_substreams(&rmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT]);