Hi Laurent,
Thanks for the review!
On Fri, Jun 17, 2022 at 03:51:08PM +0300, Laurent Pinchart wrote:
> Hi Dan,
>
> Thank you for the patch.
>
> On Wed, Jun 15, 2022 at 10:09:15PM -0500, Dan Vacura wrote:
> > A panic can occur if the endpoint becomes disabled and the
> > uvcg_video_pump adds the request back to the req_free list after it has
> > already been queued to the endpoint. The endpoint complete will add the
> > request back to the req_free list. Invalidate the local request handle
> > once it's been queued.
>
> Good catch !
>
> > <6>[ 246.796704][T13726] configfs-gadget gadget: uvc: uvc_function_set_alt(1, 0)
> > <3>[ 246.797078][ T26] list_add double add: new=ffffff878bee5c40, prev=ffffff878bee5c40, next=ffffff878b0f0a90.
> > <6>[ 246.797213][ T26] ------------[ cut here ]------------
> > <2>[ 246.797224][ T26] kernel BUG at lib/list_debug.c:31!
> > <6>[ 246.807073][ T26] Call trace:
> > <6>[ 246.807180][ T26] uvcg_video_pump+0x364/0x38c
> > <6>[ 246.807366][ T26] process_one_work+0x2a4/0x544
> > <6>[ 246.807394][ T26] worker_thread+0x350/0x784
> > <6>[ 246.807442][ T26] kthread+0x2ac/0x320
> >
> > Fixes: f9897ec0f6d3 ("usb: gadget: uvc: only pump video data if necessary")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Dan Vacura <w36195@xxxxxxxxxxxx>
> > ---
> > drivers/usb/gadget/function/uvc_video.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
> > index 93f42c7f800d..59e2f51b53a5 100644
> > --- a/drivers/usb/gadget/function/uvc_video.c
> > +++ b/drivers/usb/gadget/function/uvc_video.c
> > @@ -427,6 +427,9 @@ static void uvcg_video_pump(struct work_struct *work)
> > if (ret < 0) {
> > uvcg_queue_cancel(queue, 0);
> > break;
> > + } else {
> > + /* Endpoint now owns the request */
> > + req = NULL;
> > }
> > video->req_int_count++;
>
> I'd write it as
>
> if (ret < 0) {
> uvcg_queue_cancel(queue, 0);
> break;
> }
>
> /* Endpoint now owns the request. */
> req = NULL;
> video->req_int_count++;
This is cleaner. I'll send a v2 with this suggestion.
>
> Apart from that,
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>
> > }
>
> --
> Regards,
>
> Laurent Pinchart
