On Fri, 06 Apr 2018 02:02:02 +0200,
syzbot wrote:
>
> WARNING: CPU: 0 PID: 4468 at sound/core/pcm_native.c:620
> snd_pcm_hw_params_choose sound/core/pcm_native.c:620 [inline]
This is a WARN_ON() to catch the inconsistent hw_params call.
This shouldn't happen in theory, but the reality looks weirder.
The necessary "fix" is just to get rid of snd_BUG_ON(), but still
wonder which condition it hits. If it's an empty parameter, the
previous snd_pcm_hw_refine() should have caught and returned the error
beforehand...
In anyway this can't be a real crash, let's remove the warning to stop
the chorus of syzbot birds.
thanks,
Takashi
-- 8< --
From: Takashi Iwai <ti...@suse.de>
Subject: [PATCH] ALSA: pcm: Remove WARN_ON() at snd_pcm_hw_params() error
snd_pcm_hw_params() may hit WARN_ON() when an inconsistent parameter
set is passed. Although this should have been caught by the former
snd_pcm_hw_refine() and returned the error, syzkaller succeeded to
pass through and hit the WARN_ON(), which in turn made it panic
unnecessarily.
For reducing this kind of noise, let's drop snd_BUG_ON() check.
Reported-by: syzbot+803e0047ac3a3096b...@syzkaller.appspotmail.com
Signed-off-by: Takashi Iwai <ti...@suse.de>
---
sound/core/pcm_native.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index b84554893fab..35ffccea94c3 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -617,7 +617,7 @@ static int snd_pcm_hw_params_choose(struct
snd_pcm_substream *pcm,
changed = snd_pcm_hw_param_first(pcm, params, *v, NULL);
else
changed = snd_pcm_hw_param_last(pcm, params, *v, NULL);
- if (snd_BUG_ON(changed < 0))
+ if (changed < 0)
return changed;
if (changed == 0)
continue;
--
2.16.3
