Patch "ALSA: au88x0: avoid theoretical uninitialized access" 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: au88x0: avoid theoretical uninitialized access

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-au88x0-avoid-theoretical-uninitialized-access.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: Arnd Bergmann <[email protected]>
Date: Thu, 23 Mar 2017 16:15:55 +0100
Subject: ALSA: au88x0: avoid theoretical uninitialized access

From: Arnd Bergmann <[email protected]>

commit 13f99ebdd602ebdafb909e15ec6ffb1e34690167 upstream.

The latest gcc-7.0.1 snapshot points out that we if nr_ch is zero, we never initialize some variables:

sound/pci/au88x0/au88x0_core.c: In function 'vortex_adb_allocroute':
sound/pci/au88x0/au88x0_core.c:2304:68: error: 'mix[0]' may be used uninitialized in this function [-Werror=maybe-uninitialized] sound/pci/au88x0/au88x0_core.c:2305:58: error: 'src[0]' may be used uninitialized in this function [-Werror=maybe-uninitialized]

I assume this can never happen in practice, but adding a check here doesn't hurt either and avoids the warning. The code has been unchanged since the start of git history.

---
 sound/pci/au88x0/au88x0_core.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -2279,6 +2279,9 @@ vortex_adb_allocroute(vortex_t *vortex,
 	} else {
 		int src[2], mix[2];
 
+		if (nr_ch < 1)
+			return -EINVAL;
+
 		/* Get SRC and MIXER hardware resources. */
 		for (i = 0; i < nr_ch; i++) {
 			if ((mix[i] =

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

queue-4.9/arm-remove-duplicate-const-annotations.patch queue-4.9/ttpci-address-stringop-overflow-warning.patch queue-4.9/ib-qib-fix-false-postive-maybe-uninitialized-warning.patch queue-4.9/asoc-rt5514-fix-gcc-7-warning.patch queue-4.9/mips-lantiq-fix-another-request_mem_region-return-code-check.patch queue-4.9/alsa-au88x0-avoid-theoretical-uninitialized-access.patch queue-4.9/asoc-rt5659-drop-double-const.patch