Patch "ALSA: core: Fix unexpected error at replacing user TLV" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

ALSA: core: Fix unexpected error at replacing user TLV

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
alsa-core-fix-unexpected-error-at-replacing-user-tlv.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Takashi Iwai <[email protected]>
Date: Tue, 22 Aug 2017 08:15:13 +0200
Subject: ALSA: core: Fix unexpected error at replacing user TLV

From: Takashi Iwai <[email protected]>

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.

---
 sound/core/control.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -1156,7 +1156,7 @@ static int snd_ctl_elem_user_tlv(struct
 		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;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/alsa-hda-add-stereo-mic-quirk-for-lenovo-g50-70-17aa-3978.patch queue-4.9/input-alps-fix-two-finger-scroll-breakage-in-right-side-on-alps-touchpad.patch queue-4.9/alsa-usb-audio-add-delay-quirk-for-h650e-jabra-550a-usb-headsets.patch queue-4.9/alsa-core-fix-unexpected-error-at-replacing-user-tlv.patch queue-4.9/alsa-firewire-fix-null-pointer-dereference-when-releasing-uninitialized-data-of-iso-resource.patch