From 43a3542870328601be02fcc9d27b09db467336ef Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 30 Nov 2017 10:08:28 +0100
Subject: [PATCH] ALSA: seq: Remove spurious WARN_ON() at timer check
Git-commit: 43a3542870328601be02fcc9d27b09db467336ef
Patch-mainline: v4.15-rc3
References: bsc#1051510
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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/core/seq/seq_timer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/core/seq/seq_timer.c b/sound/core/seq/seq_timer.c
index 37d9cfbc29f9..b80985fbc334 100644
--- a/sound/core/seq/seq_timer.c
+++ b/sound/core/seq/seq_timer.c
@@ -355,7 +355,7 @@ static int initialize_timer(struct snd_seq_timer *tmr)
unsigned long freq;
t = tmr->timeri->timer;
- if (snd_BUG_ON(!t))
+ if (!t)
return -EINVAL;
freq = tmr->preferred_resolution;
--
2.15.1