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 8803d9d93f842bb1f43299a39f20a402c0b49278..f26a1254b0bb595a1d3e260d694655e7ba662573 100644 (file)
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -1936,7 +1936,7 @@ 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;
        }