ALSA: timer: Fix double unlink of active_list
authorTakashi Iwai <tiwai@suse.de>
Wed, 13 Jan 2016 20:35:06 +0000 (21:35 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 31 Jan 2016 19:28:56 +0000 (11:28 -0800)
commit3c0e535fee2e67d06220e676cbf7b69099d741ce
tree13170e010529ad46d10e879f1965be456d8af97a
parentd87622a1662af5782c94b88a613c09de0bde5288
ALSA: timer: Fix double unlink of active_list

commit ee8413b01045c74340aa13ad5bdf905de32be736 upstream.

ALSA timer instance object has a couple of linked lists and they are
unlinked unconditionally at snd_timer_stop().  Meanwhile
snd_timer_interrupt() unlinks it, but it calls list_del() which leaves
the element list itself unchanged.  This ends up with unlinking twice,
and it was caught by syzkaller fuzzer.

The fix is to use list_del_init() variant properly there, too.

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sound/core/timer.c