| From | Kamal Mostafa <> | Subject | [PATCH 4.2.y-ckt 122/268] ALSA: timer: Fix double unlink of active_list | Date | Wed, 27 Jan 2016 12:33:03 -0800 |
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4.2.8-ckt3 -stable review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai <tiwai@suse.de>
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: Kamal Mostafa <kamal@canonical.com> --- sound/core/timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/core/timer.c b/sound/core/timer.c index 31f40f0..9241784df 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -694,7 +694,7 @@ void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left) } else { ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING; if (--timer->running) - list_del(&ti->active_list); + list_del_init(&ti->active_list); } if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) || (ti->flags & SNDRV_TIMER_IFLG_FAST)) -- 1.9.1
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