Hi,
changbin.du@xxxxxxxxx writes:
> From: "Du, Changbin" <changbin.du@xxxxxxxxx>
>
> Queue a request to disabled ep doesn't make sense, and induce caller
> make mistakes.
>
> Here is a example for the android mtp gadget function driver. A mem
> corruption can happen on below senario.
> 1) On disconnect, mtp driver disable its EPs,
> 2) During send_file_work and receive_file_work, mtp queues a request
> to ep. (The mtp driver need improve its synchronization logic!)
> 3) mtp_function_unbind is invoked and all mtp requests are freed.
> 4) when udc process the request queued on step 2, will cause kernel
> NULL pointer dereference exception.
>
> Signed-off-by: Du, Changbin <changbin.du@xxxxxxxxx>
> ---
> This patch is seprated from below patches because gadget layer has
> added the 'enabled' flag in v4.4. so abandon it and submit new one.
> [PATCH 0/2] Two fix for dwc2 gadget driver
> usb: dwc2: add ep enabled flag to avoid double enable/disable
> usb: dwc2: forbid queuing request to a disabled ep
>
> ---
> include/linux/usb/gadget.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> index 3d583a1..d813bd2 100644
> --- a/include/linux/usb/gadget.h
> +++ b/include/linux/usb/gadget.h
> @@ -402,6 +402,9 @@ static inline void usb_ep_free_request(struct usb_ep *ep,
> static inline int usb_ep_queue(struct usb_ep *ep,
> struct usb_request *req, gfp_t gfp_flags)
> {
> + if (!ep->enabled)
> + return -ESHUTDOWN;
same warn here:
if (WARN_ON_ONCE(!ep->enabled))
return -ESHUTDOWN;
> +
> return ep->ops->queue(ep, req, gfp_flags);
> }
>
> --
> 2.5.0
>
--
balbi
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