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author | Takashi Iwai <tiwai@suse.de> | 2015-04-28 17:11:44 +0200 |
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committer | Takashi Iwai <tiwai@suse.de> | 2015-04-28 17:45:45 +0200 |
commit | 1c94e65c668f44d2c69ae7e7fc268ab3268fba3e (patch) | |
tree | 14e8a5875c542973577f789d47a1f7d9419ed6fa /include | |
parent | ALSA: hda - Fix missing va_end() call in snd_hda_codec_pcm_new() (diff) | |
download | linux-1c94e65c668f44d2c69ae7e7fc268ab3268fba3e.tar.xz linux-1c94e65c668f44d2c69ae7e7fc268ab3268fba3e.zip |
ALSA: emux: Fix mutex deadlock in OSS emulation
The OSS emulation in synth-emux helper has a potential AB/BA deadlock
at the simultaneous closing and opening:
close ->
snd_seq_release() ->
sne_seq_free_client() ->
snd_seq_delete_all_ports(): takes client->ports_mutex ->
port_delete() ->
snd_emux_unuse(): takes emux->register_mutex
open ->
snd_seq_oss_open() ->
snd_emux_open_seq_oss(): takes emux->register_mutex ->
snd_seq_event_port_attach() ->
snd_seq_create_port(): takes client->ports_mutex
This patch addresses the deadlock by reducing the rance taking
emux->register_mutex in snd_emux_open_seq_oss(). The lock is needed
for the refcount handling, so move it locally. The calls in
emux_seq.c are already with the mutex, thus they are replaced with the
version without mutex lock/unlock.
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'include')
0 files changed, 0 insertions, 0 deletions