commit 3567eb6af6 upstream.
ALSA sequencer code has an open race between the timer setup ioctl and
the close of the client. This was triggered by syzkaller fuzzer, and
a use-after-free was caught there as a result.
This patch papers over it by adding a proper queue->timer_mutex lock
around the timer-related calls in the relevant code path.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Willy Tarreau <w@1wt.eu>
af6387516d