4.9-stable review patch. If anyone has any objections, please let me know.
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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; }