On 11/14/2016 03:25 AM, Takashi Iwai wrote:
On Sat, 12 Nov 2016 00:34:38 +0100, Shuah Khan wrote:
Hi Takashi,
I am seeing the following use-after-free error when I disconnect an USB speaker. I saw this on 4.9-rc4 and 4.8.7. There might be race condition between the disconnect and pcm close perhaps.
Thanks, this looks like a new discovery. Could you check whether the patch below works?
Takashi
diff --git a/sound/usb/card.c b/sound/usb/card.c index 9e5276d6dda0..2ddc034673a8 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -315,7 +315,8 @@ static int snd_usb_audio_free(struct snd_usb_audio *chip) snd_usb_endpoint_free(ep);
mutex_destroy(&chip->mutex);
- dev_set_drvdata(&chip->dev->dev, NULL);
- if (!atomic_read(&chip->shutdown))
dev_set_drvdata(&chip->dev->dev, NULL);}
Hi Takashi,
The patch fixed the problem on 4.9-rc4. Didn't get a chance to test it on 4.8.7.
thanks, -- Shuah