Patch "ALSA: line6: Fix NULL dereference at podhd_disconnect()" has been added to the 4.13-stable tree

[<gregkh@linuxfoundation.org>]

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

    ALSA: line6: Fix NULL dereference at podhd_disconnect()

to the 4.13-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-line6-fix-null-dereference-at-podhd_disconnect.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 54a4b2b45817ea2365b40c923c098a26af0c0dbb Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Mon, 9 Oct 2017 14:26:27 +0200
Subject: ALSA: line6: Fix NULL dereference at podhd_disconnect()

From: Takashi Iwai <tiwai@suse.de>

commit 54a4b2b45817ea2365b40c923c098a26af0c0dbb upstream.

When podhd_init() failed with the acquiring a ctrl i/f, the line6
helper still calls the disconnect callback that eventually calls again
usb_driver_release_interface() with the NULL intf.

Put the proper NULL check before calling it for avoiding an Oops.

Fixes: fc90172ba283 ("ALSA: line6: Claim pod x3 usb data interface")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 sound/usb/line6/podhd.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/sound/usb/line6/podhd.c
+++ b/sound/usb/line6/podhd.c
@@ -301,7 +301,8 @@ static void podhd_disconnect(struct usb_
 
 		intf = usb_ifnum_to_if(line6->usbdev,
 					pod->line6.properties->ctrl_if);
-		usb_driver_release_interface(&podhd_driver, intf);
+		if (intf)
+			usb_driver_release_interface(&podhd_driver, intf);
 	}
 }
 


Patches currently in stable-queue which might be from tiwai@suse.de are

queue-4.13/alsa-line6-fix-null-dereference-at-podhd_disconnect.patch
queue-4.13/alsa-line6-fix-missing-initialization-before-error-path.patch
queue-4.13/alsa-caiaq-fix-stray-urb-at-probe-error-path.patch
queue-4.13/alsa-seq-fix-copy_from_user-call-inside-lock.patch
queue-4.13/alsa-seq-fix-use-after-free-at-creating-a-port.patch
queue-4.13/alsa-line6-fix-leftover-urb-at-error-path-during-probe.patch
queue-4.13/alsa-usb-audio-kill-stray-urb-at-exiting.patch