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![]() A slave timer instance might be still accessible in a racy way while operating the master instance as it lacks of locking. Since the master operation is mostly protected with timer->lock, we should cope with it while changing the slave instance, too. Also, some linked lists (active_list and ack_list) of slave instances aren't unlinked immediately at stopping or closing, and this may lead to unexpected accesses. This patch tries to address these issues. It adds spin lock of timer->lock (either from master or slave, which is equivalent) in a few places. For avoiding a deadlock, we ensure that the global slave_active_lock is always locked at first before each timer lock. Also, ack and active_list of slave instances are properly unlinked at snd_timer_stop() and snd_timer_close(). Last but not least, remove the superfluous call of _snd_timer_stop() at removing slave links. This is a noop, and calling it may confuse readers wrt locking. Further cleanup will follow in a later patch. Actually we've got reports of use-after-free by syzkaller fuzzer, and this hopefully fixes these issues. Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de> |
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.. | ||
oss | ||
seq | ||
compress_offload.c | ||
control.c | ||
control_compat.c | ||
ctljack.c | ||
device.c | ||
hrtimer.c | ||
hwdep.c | ||
hwdep_compat.c | ||
info.c | ||
info_oss.c | ||
init.c | ||
isadma.c | ||
jack.c | ||
Kconfig | ||
Makefile | ||
memalloc.c | ||
memory.c | ||
misc.c | ||
pcm.c | ||
pcm_compat.c | ||
pcm_dmaengine.c | ||
pcm_drm_eld.c | ||
pcm_iec958.c | ||
pcm_lib.c | ||
pcm_memory.c | ||
pcm_misc.c | ||
pcm_native.c | ||
pcm_timer.c | ||
pcm_trace.h | ||
rawmidi.c | ||
rawmidi_compat.c | ||
rtctimer.c | ||
sgbuf.c | ||
sound.c | ||
sound_oss.c | ||
timer.c | ||
timer_compat.c | ||
vmaster.c |