ALSA: seq: Fix race during FIFO resize
authorTakashi Iwai <tiwai@suse.de>
Fri, 24 Mar 2017 16:07:57 +0000 (17:07 +0100)
committerTakashi Iwai <tiwai@suse.de>
Fri, 24 Mar 2017 16:11:00 +0000 (17:11 +0100)
commit2d7d54002e396c180db0c800c1046f0a3c471597
tree69d989dd2752c6a076e74d3d2431aaf2129ebe53
parent3f307834e695f59dac4337a40316bdecfb9d0508
ALSA: seq: Fix race during FIFO resize

When a new event is queued while processing to resize the FIFO in
snd_seq_fifo_clear(), it may lead to a use-after-free, as the old pool
that is being queued gets removed.  For avoiding this race, we need to
close the pool to be deleted and sync its usage before actually
deleting it.

The issue was spotted by syzkaller.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
sound/core/seq/seq_fifo.c