ALSA: usb-audio - Avoid Oops after disconnect

commit 78b8d5d2ee280c463908fd75f3bdf246bcb6ac8d upstream.

As the release of substreams may be done asynchronously from the
disconnection, close callback needs to check the shutdown flag before
actually accessing the usb interface.

Reference: Novell bnc#505027
	http://bugzilla.novell.com/show_bug.cgi?id=565027

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index b70527a92b01587aefb7ee59ac9e648b6203d7b4..8da53c56c4d280764c21daf0153200e508a2bd4b 100644 (file)
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -1934,7 +1934,7 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
        struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
        struct snd_usb_substream *subs = &as->substream[direction];
 
-       if (subs->interface >= 0) {
+       if (!as->chip->shutdown && subs->interface >= 0) {
                usb_set_interface(subs->dev, subs->interface, 0);
                subs->interface = -1;
        }