ALSA: au88x0: avoid theoretical uninitialized access
authorArnd Bergmann <arnd@arndb.de>
Thu, 23 Mar 2017 15:15:55 +0000 (16:15 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 8 Oct 2017 08:26:12 +0000 (10:26 +0200)
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.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sound/pci/au88x0/au88x0_core.c

index e1af24f..c308a4f 100644 (file)
@@ -2279,6 +2279,9 @@ vortex_adb_allocroute(vortex_t *vortex, int dma, int nr_ch, int dir,
        } 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] =