--- /dd/alsa-plugins/usb_stream/pcm_usb_stream.c	2008-11-21 18:08:16.000000000 -0500
+++ pcm_usb_stream.c	2009-12-30 12:57:13.779349630 -0500
@@ -256,7 +256,10 @@
 static int snd_pcm_us_stop(snd_pcm_ioplug_t *io)
 {
 	snd_pcm_us_t *us = io->private_data;
-	VDBG("%u", us->uus->s->periods_done);
 
+	if (!us->uus->s)
+	  return 0;
+
+	VDBG("%u", us->uus->s->periods_done);
 	if (io->stream == SND_PCM_STREAM_PLAYBACK)
 		memset(us->uus->write_area, 0, us->uus->s->write_size);