]> git.openfabrics.org - ~shefty/rdma-dev.git/commitdiff
ALSA: usb-audio: Fix NULL dereference by access to non-existing substream
authorTakashi Iwai <tiwai@suse.de>
Thu, 10 Jan 2013 13:06:38 +0000 (14:06 +0100)
committerTakashi Iwai <tiwai@suse.de>
Fri, 11 Jan 2013 10:12:17 +0000 (11:12 +0100)
The commit [0d9741c0: ALSA: usb-audio: sync ep init fix for
audioformat mismatch] introduced the correction of parameters to be
set for sync EP.  But since the new code assumes that the sync EP is
always paired with the data EP of another direction, it triggers Oops
when a device only with a single direction is used.

This patch adds a proper check of sync EP type and the presence of the
paired substream for avoiding the crash.

Reported-and-tested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
sound/usb/pcm.c

index c6593101c049b88ca6e5661f8765b3f3df0b4d33..d82e378d37cbb7202aaa487b6003b6b171b79eab 100644 (file)
@@ -511,6 +511,16 @@ static int configure_sync_endpoint(struct snd_usb_substream *subs)
        struct snd_usb_substream *sync_subs =
                &subs->stream->substream[subs->direction ^ 1];
 
+       if (subs->sync_endpoint->type != SND_USB_ENDPOINT_TYPE_DATA ||
+           !subs->stream)
+               return snd_usb_endpoint_set_params(subs->sync_endpoint,
+                                                  subs->pcm_format,
+                                                  subs->channels,
+                                                  subs->period_bytes,
+                                                  subs->cur_rate,
+                                                  subs->cur_audiofmt,
+                                                  NULL);
+
        /* Try to find the best matching audioformat. */
        list_for_each_entry(fp, &sync_subs->fmt_list, list) {
                int score = match_endpoint_audioformats(fp, subs->cur_audiofmt,