Hi Oliver,
Thank you for the patch.
On Thursday 10 January 2013 11:04:55 Oliver Neukum wrote:
> Ming Lei reported:
> IMO, there is a minor fault in the error handling path of
> uvc_status_start() inside uvc_v4l2_open(), and the 'users' count
> should have been decreased before usb_autopm_put_interface().
> In theory, the warning can be triggered when the device is
> opened just between usb_autopm_put_interface() and
> atomic_dec(&stream->dev->users).
> The fix is trivial.
>
> Signed-off-by:Oliver Neukum <oneukum@xxxxxxx>
I've slightly modified the commit message with more details about the warning:
uvcvideo: Fix race of open and suspend in error case
Ming Lei reported:
IMO, there is a minor fault in the error handling path of
uvc_status_start() inside uvc_v4l2_open(), and the 'users' count should
have been decreased before usb_autopm_put_interface(). In theory, a [URB
resubmission] warning can be triggered when the device is opened just
between usb_autopm_put_interface() and atomic_dec(&stream->dev->users).
The fix is trivial.
Reported-by: Ming Lei <tom.leiming@xxxxxxxxx>
Signed-off-by: Oliver Neukum <oneukum@xxxxxxx>
Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
The patch is in my tree, I'll push it to v3.9.
> ---
> drivers/media/usb/uvc/uvc_v4l2.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c
> b/drivers/media/usb/uvc/uvc_v4l2.c index f2ee8c6..74937b7 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -501,8 +501,8 @@ static int uvc_v4l2_open(struct file *file)
> if (atomic_inc_return(&stream->dev->users) == 1) {
> ret = uvc_status_start(stream->dev);
> if (ret < 0) {
> - usb_autopm_put_interface(stream->dev->intf);
> atomic_dec(&stream->dev->users);
> + usb_autopm_put_interface(stream->dev->intf);
> kfree(handle);
> return ret;
> }
--
Regards,
Laurent Pinchart
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