Commit 8a0859b6 authored Dec 18, 2015 by Changbin Du Committed by Felipe Balbi Dec 22, 2015

usb: gadget: forbid queuing request to a disabled ep



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@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

parent 6d76c92c

include/linux/usb/gadget.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -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 (WARN_ON_ONCE(!ep->enabled && ep->address))
		return -ESHUTDOWN;

		return ep->ops->queue(ep, req, gfp_flags);
		}