diff options
| author | Takashi Iwai <tiwai@suse.de> | 2015-04-27 14:50:39 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-05-13 05:15:41 -0700 |
| commit | c19e77907dc450c69028c03c4058e5a5688ab2a9 (patch) | |
| tree | 0a8e9812f3f03d918e6efb666c04ae71ecf8d3b4 /sound/synth | |
| parent | cf30cd6bbc0c82854e0b5551e57ee02d001e61db (diff) | |
| download | lwn-c19e77907dc450c69028c03c4058e5a5688ab2a9.tar.gz lwn-c19e77907dc450c69028c03c4058e5a5688ab2a9.zip | |
ALSA: emux: Fix mutex deadlock at unloading
commit 07b0e5d49d227e3950cb13a3e8caf248ef2a310e upstream.
The emux-synth driver has a possible AB/BA mutex deadlock at unloading
the emu10k1 driver:
snd_emux_free() ->
snd_emux_detach_seq(): mutex_lock(&emu->register_mutex) ->
snd_seq_delete_kernel_client() ->
snd_seq_free_client(): mutex_lock(®ister_mutex)
snd_seq_release() ->
snd_seq_free_client(): mutex_lock(®ister_mutex) ->
snd_seq_delete_all_ports() ->
snd_emux_unuse(): mutex_lock(&emu->register_mutex)
Basically snd_emux_detach_seq() doesn't need a protection of
emu->register_mutex as it's already being unregistered. So, we can
get rid of this for avoiding the deadlock.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'sound/synth')
| -rw-r--r-- | sound/synth/emux/emux_seq.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/sound/synth/emux/emux_seq.c b/sound/synth/emux/emux_seq.c index 7778b8e19782..188fda0effb0 100644 --- a/sound/synth/emux/emux_seq.c +++ b/sound/synth/emux/emux_seq.c @@ -124,12 +124,10 @@ snd_emux_detach_seq(struct snd_emux *emu) if (emu->voices) snd_emux_terminate_all(emu); - mutex_lock(&emu->register_mutex); if (emu->client >= 0) { snd_seq_delete_kernel_client(emu->client); emu->client = -1; } - mutex_unlock(&emu->register_mutex); } |