![]() The recent change for USB-audio disconnection race fixes introduced a mutex deadlock again. There is a circular dependency between chip->shutdown_rwsem and pcm->open_mutex, depicted like below, when a device is opened during the disconnection operation: A. snd_usb_audio_disconnect() -> card.c::register_mutex -> chip->shutdown_rwsem (write) -> snd_card_disconnect() -> pcm.c::register_mutex -> pcm->open_mutex B. snd_pcm_open() -> pcm->open_mutex -> snd_usb_pcm_open() -> chip->shutdown_rwsem (read) Since the chip->shutdown_rwsem protection in the case A is required only for turning on the chip->shutdown flag and it doesn't have to be taken for the whole operation, we can reduce its window in snd_usb_audio_disconnect(). Reported-by: Jiri Slaby <jslaby@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de> |
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aoa | ||
arm | ||
atmel | ||
core | ||
drivers | ||
firewire | ||
i2c | ||
isa | ||
mips | ||
oss | ||
parisc | ||
pci | ||
pcmcia | ||
ppc | ||
sh | ||
soc | ||
sparc | ||
spi | ||
synth | ||
usb | ||
ac97_bus.c | ||
Kconfig | ||
last.c | ||
Makefile | ||
sound_core.c | ||
sound_firmware.c |