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authorTakashi Iwai <tiwai@suse.de>2022-10-11 09:01:46 +0200
committerTakashi Iwai <tiwai@suse.de>2022-10-11 09:02:32 +0200
commita70aef7982b012e86dfd39fbb235e76a21ae778a (patch)
treefdac27bfc2c9ddf247f01d7bcb4442ab1104701a
parent4f2e56a59b9947b3e698d3cabcb858765c12b1e8 (diff)
ALSA: rawmidi: Drop register_mutex in snd_rawmidi_free()
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: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20221011070147.7611-1-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--sound/core/rawmidi.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 6963d5a487b3..d8edb6055072 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -1899,10 +1899,8 @@ static int snd_rawmidi_free(struct snd_rawmidi *rmidi)
snd_info_free_entry(rmidi->proc_entry);
rmidi->proc_entry = NULL;
- mutex_lock(&register_mutex);
if (rmidi->ops && rmidi->ops->dev_unregister)
rmidi->ops->dev_unregister(rmidi);
- mutex_unlock(&register_mutex);
snd_rawmidi_free_substreams(&rmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT]);
snd_rawmidi_free_substreams(&rmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT]);