Commit 88c54cdf authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: core: Fix unexpected error at replacing user TLV

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: 8aa9b586

 ("[ALSA] Control API - more robust TLV implementation")
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 07b3b5e9
......@@ -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;
......
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