ALSA: usb-audio - Avoid Oops after disconnect

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>

diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index 4963defee18a210632ea8a8fd7c2b1e2d54f5476..9edef4684978f43285bd6e076532ab795cfb9ccb 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;
        }