[CVE-2016-2384][Precise][Trusty][LTS-Utopic][Vivid][Wily] ALSA: usb-audio: avoid freeing umidi object twice

[Luis Henriques]

From: Andrey Konovalov <andreyknvl at gmail.com>

The 'umidi' object will be free'd on the error path by snd_usbmidi_free()
when tearing down the rawmidi interface. So we shouldn't try to free it
in snd_usbmidi_create() after having registered the rawmidi interface.

Found by KASAN.

Signed-off-by: Andrey Konovalov <andreyknvl at gmail.com>
Acked-by: Clemens Ladisch <clemens at ladisch.de>
Cc: <stable at vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai at suse.de>
(cherry picked from commit 07d86ca93db7e5cdf4743564d98292042ec21af7)
CVE-2016-2384
BugLink: https://bugs.launchpad.net/bugs/1546177
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 sound/usb/midi.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index 075f32483769..7b8532453c4f 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -2289,7 +2289,6 @@ int snd_usbmidi_create(struct snd_card *card,
 	else
 		err = snd_usbmidi_create_endpoints(umidi, endpoints);
 	if (err < 0) {
-		snd_usbmidi_free(umidi);
 		return err;
 	}