When user tries to replace the user-defined control TLV, the kernel checks the change of its content via memcmp(). The problem is that the kernel passes the return value from memcmp() as is. memcmp() gives a non-zero negative value depending on the comparison result, and this shall be recognized as an error code.

The patch covers that corner-case, return 1 properly for the changed TLV.

Fixes: 8aa9b586e420 ("[ALSA] Control API - more robust TLV implementation") Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/core/control.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/core/control.c b/sound/core/control.c index 3c6be1452e35..4525e127afd9 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -1137,7 +1137,7 @@ static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol, mutex_lock(&ue->card->user_ctl_lock); change = ue->tlv_data_size != size; if (!change) - change = memcmp(ue->tlv_data, new_data, size); + change = memcmp(ue->tlv_data, new_data, size) != 0; kfree(ue->tlv_data); ue->tlv_data = new_data; ue->tlv_data_size = size;