On Thu, 10 Jan 2013, Takashi Iwai wrote:
At Thu, 10 Jan 2013 13:49:22 +0100, Jens Axboe wrote:
Here it is, it's from the one introducing the audioformat lookup. Confirmed that 3.8-rc3 with this backed out works fine, too. So should be fairly confident in that result.
From: Takashi Iwai tiwai@suse.de Subject: [PATCH] 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.
Yes - sorry, I didn't consider this at all.
This patch adds a proper check of sync EP type and the presence of the paired substream for avoiding the crash.
Reported-by: Jens Axboe axboe@kernel.dk Signed-off-by: Takashi Iwai tiwai@suse.de
sound/usb/pcm.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c index c659310..21c0001 100644 --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -511,6 +511,17 @@ 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) {ret = snd_usb_endpoint_set_params(subs->sync_endpoint,subs->pcm_format,subs->channels,subs->period_bytes,subs->cur_rate,subs->cur_audiofmt,NULL);- }
I think you want to return here, no?
Jens, could you please send me the device's descriptors (lsusb -v)? I'd like to take a closer look at this.
Cheers, Eldad