Re: [PATCH] usb: dwc3: gadget: fix crash in dwc3_gadget_giveback()

[Mattijs Korpershoek <mkorpershoek@baylibre.com>]

Hi Neil,

Thank you for the patch.

On mar., mai 28, 2024 at 10:35, Neil Armstrong <neil.armstrong@linaro.org> wrote:

> If the ep0 stalls or request are dequeued when gagdet is stopped,
> the request dma may not be mapped yet and dwc3_flush_cache() may be
> called with a NULL pointer.
>
> Check req->request.dma before calling dwc3_flush_cache() and later
> the usb_gadget_unmap_request() functions since it means that
> usb_gadget_map_request() hasn't been called yet.
>
> Fixes: fd15b58c1a9 ("dwc3: flush cache only if there is a buffer attached to a request")
> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>

Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>

> ---
>  drivers/usb/dwc3/gadget.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index fab32575647..92c7c6d08b7 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -248,7 +248,7 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
>  
>  	list_del(&req->list);
>  	req->trb = NULL;
> -	if (req->request.length)
> +	if (req->request.dma && req->request.length)
>  		dwc3_flush_cache((uintptr_t)req->request.dma, req->request.length);
>  
>  	if (req->request.status == -EINPROGRESS)
> @@ -256,7 +256,7 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
>  
>  	if (dwc->ep0_bounced && dep->number == 0)
>  		dwc->ep0_bounced = false;
> -	else
> +	else if (req->request.dma)
>  		usb_gadget_unmap_request(&dwc->gadget, &req->request,
>  				req->direction);
>  
>
> ---
> base-commit: 7e52d6ccfb76e2afc2d183b357abe2a2e2f948cf
> change-id: 20240528-topic-sm8x50-dwc3-gadget-crash-fix-fa0404ffce33
>
> Best regards,
> -- 
> Neil Armstrong <neil.armstrong@linaro.org>