Re: [PATCH v2] USB: core: WARN if pipe direction != setup packet direction

[Johan Hovold <johan@kernel.org>]

On Fri, May 21, 2021 at 10:16:23PM -0400, Alan Stern wrote:
> When a control URB is submitted, the direction indicated by URB's pipe
> member is supposed to match the direction indicated by the setup
> packet's bRequestType member.  A mismatch could lead to trouble,
> depending on which field the host controller drivers use for
> determining the actual direction.
> 
> This shouldn't ever happen; it would represent a careless bug in a
> kernel driver somewhere.  This patch adds a dev_WARN_ONCE to let
> people know about the potential problem.
> 
> Suggested-by: "Geoffrey D. Bennett" <g@b4.vu>
> Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
> ---
> 
> v2: Use dev_WARN_ONCE instead of dev_WARN

Reviewed-by: Johan Hovold <johan@kernel.org>

>  drivers/usb/core/urb.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> Index: usb-devel/drivers/usb/core/urb.c
> ===================================================================
> --- usb-devel.orig/drivers/usb/core/urb.c
> +++ usb-devel/drivers/usb/core/urb.c
> @@ -407,6 +407,9 @@ int usb_submit_urb(struct urb *urb, gfp_
>  			return -ENOEXEC;
>  		is_out = !(setup->bRequestType & USB_DIR_IN) ||
>  				!setup->wLength;
> +		dev_WARN_ONCE(&dev->dev, (usb_pipeout(urb->pipe) != is_out),
> +				"BOGUS control dir, pipe %x doesn't match bRequestType %x\n",
> +				urb->pipe, setup->bRequestType);
>  	} else {
>  		is_out = usb_endpoint_dir_out(&ep->desc);
>  	}

Johan