[PATCH 4.4 23/53] ALSA: pcm: Remove yet superfluous WARN_ON()

Greg Kroah-Hartman
2018-01-22T08:40:15Z

From: Takashi Iwai <tiwai@suse.de>

commit 23b19b7b50fe1867da8d431eea9cd3e4b6328c2c upstream.

muldiv32() contains a snd_BUG_ON() (which is morphed as WARN_ON() with
debug option) for checking the case of 0 / 0. This would be helpful
if this happens only as a logical error; however, since the hw refine
is performed with any data set provided by user, the inconsistent
values that can trigger such a condition might be passed easily.
Actually, syzbot caught this by passing some zero'ed old hw_params
ioctl.

So, having snd_BUG_ON() there is simply superfluous and rather
harmful to give unnecessary confusions. Let's get rid of it.

Reported-by: syzbot+7e6ee55011deeebce15d@syzkaller.appspotmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
sound/core/pcm_lib.c | 1 -
1 file changed, 1 deletion(-)

--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -578,7 +578,6 @@ static inline unsigned int muldiv32(unsi
{
u_int64_t n = (u_int64_t) a * b;
if (c == 0) {
- snd_BUG_ON(!n);
*r = 0;
return UINT_MAX;
}