4.14-stable review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai tiwai@suse.de
commit 43a3542870328601be02fcc9d27b09db467336ef upstream.
The use of snd_BUG_ON() in ALSA sequencer timer may lead to a spurious WARN_ON() when a slave timer is deployed as its backend and a corresponding master timer stops meanwhile. The symptom was triggered by syzkaller spontaneously.
Since the NULL timer is valid there, rip off snd_BUG_ON().
Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- sound/core/seq/seq_timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/sound/core/seq/seq_timer.c +++ b/sound/core/seq/seq_timer.c @@ -355,7 +355,7 @@ static int initialize_timer(struct snd_s unsigned long freq;
t = tmr->timeri->timer; - if (snd_BUG_ON(!t)) + if (!t) return -EINVAL;
freq = tmr->preferred_resolution;