dect
/
linux-2.6
Archived
13
0
Fork 0
Code Releases Activity

ALSA: usb-audio: Fix NULL dereference by access to non-existing substream 

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>
This commit is contained in:
Takashi Iwai 2013-01-10 14:06:38 +01:00
parent c18ab0bac4
commit 31be5425d7
1 changed files with 10 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
sound/usb/pcm.c
View 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,