Revision 382225e62bdb8059b7f915b133426425516dd300 authored by Takashi Iwai on 22 February 2011, 09:21:18 UTC, committed by Takashi Iwai on 23 February 2011, 07:15:43 UTC
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>
1 parent 3064967
lcm.h
#ifndef _LCM_H
#define _LCM_H
#include <linux/compiler.h>
unsigned long lcm(unsigned long a, unsigned long b) __attribute_const__;
#endif /* _LCM_H */
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