From 6b2baa49c8396e2cfdae9a9aab2790c554ea086f Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 11 Oct 2022 09:01:46 +0200 Subject: [PATCH] ALSA: rawmidi: Drop register_mutex in snd_rawmidi_free() 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+gWor7UdkiwPczmL7pn91xx8xpzOA@mail.gmail.com Cc: Link: https://lore.kernel.org/r/20221011070147.7611-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/rawmidi.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c index 481c1ad1db57..db283e5d9a41 100644 --- a/sound/core/rawmidi.c +++ b/sound/core/rawmidi.c @@ -1633,10 +1633,8 @@ static int snd_rawmidi_free(struct snd_rawmidi *rmidi) 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]);