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Subject[PATCH 3.2 64/87] ALSA: control: Avoid kernel warnings from tlv ioctl with numid 0
3.2.77-rc1 review patch.  If anyone has any objections, please let me know.


From: Takashi Iwai <>

commit c0bcdbdff3ff73a54161fca3cb8b6cdbd0bb8762 upstream.

When a TLV ioctl with numid zero is handled, the driver may spew a
kernel warning with a stack trace at each call. The check was
intended obviously only for a kernel driver, but not for a user
interaction. Let's fix it.

This was spotted by syzkaller fuzzer.

Reported-by: Dmitry Vyukov <>
Signed-off-by: Takashi Iwai <>
Signed-off-by: Ben Hutchings <>
sound/core/control.c | 2 ++
1 file changed, 2 insertions(+)

--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -1321,6 +1321,8 @@ static int snd_ctl_tlv_ioctl(struct snd_
return -EFAULT;
if (tlv.length < sizeof(unsigned int) * 2)
return -EINVAL;
+ if (!tlv.numid)
+ return -EINVAL;
kctl = snd_ctl_find_numid(card, tlv.numid);
if (kctl == NULL) {
 \ /
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