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authorTakashi Iwai <tiwai@suse.de>2011-02-22 10:21:18 +0100
committerTakashi Iwai <tiwai@suse.de>2011-02-23 08:15:43 +0100
commit382225e62bdb8059b7f915b133426425516dd300 (patch)
tree25f85ecb38145f3ca1547685066b2bf9057e3c72 /sound/usb/usbaudio.h
parent306496761745942d8167e9193a738b559a7fb0b3 (diff)
downloadop-kernel-dev-382225e62bdb8059b7f915b133426425516dd300.zip
op-kernel-dev-382225e62bdb8059b7f915b133426425516dd300.tar.gz
ALSA: usb-audio: fix oops due to cleanup race when disconnecting
When a USB audio device is disconnected, snd_usb_audio_disconnect() kills all audio URBs. At the same time, the application, after being notified of the disconnection, might close the device, in which case ALSA calls the .hw_free callback, which should free the URBs too. Commit de1b8b93a0ba "[ALSA] Fix hang-up at disconnection of usb-audio" prevented snd_usb_hw_free() from freeing the URBs to avoid a hang that resulted from this race, but this introduced another race because the URB callbacks could now be executed after snd_usb_hw_free() has returned, and try to access already freed data. Fix the first race by introducing a mutex to serialize the disconnect callback and all PCM callbacks that manage URBs (hw_free and hw_params). Reported-and-tested-by: Pierre-Louis Bossart <pierre-louis.bossart@intel.com> Cc: <stable@kernel.org> [CL: also serialize hw_params callback] Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/usbaudio.h')
-rw-r--r--sound/usb/usbaudio.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index db3eb21..6e66fff 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -36,6 +36,7 @@ struct snd_usb_audio {
struct snd_card *card;
u32 usb_id;
int shutdown;
+ struct mutex shutdown_mutex;
unsigned int txfr_quirk:1; /* Subframe boundaries on transfers */
int num_interfaces;
int num_suspended_intf;
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