From: Takashi Iwai Date: Tue, 22 Aug 2017 06:15:13 +0000 (+0200) Subject: ALSA: core: Fix unexpected error at replacing user TLV X-Git-Tag: v4.12.10~62 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ba6b08b62f0cc989a9b9465bf5bdca2b68ba43d4;p=thirdparty%2Fkernel%2Fstable.git ALSA: core: Fix unexpected error at replacing user TLV commit 88c54cdf61f508ebcf8da2d819f5dfc03e954d1d upstream. 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") Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- diff --git a/sound/core/control.c b/sound/core/control.c index c109b82eef4bd..7b43b0f74b842 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -1157,7 +1157,7 @@ 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;