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Groups > linux.kernel > #1290821

[PATCH v2] usb: gadget: forbid queuing request to a disabled ep

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From: "Du, Changbin" <changbin.du@intel.com>

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>
---
change from v1: add WARN_ON_ONCE message.

---
 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..b566a4b 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 (WARN_ON_ONCE(!ep->enabled))
+		return -ESHUTDOWN;
+
 	return ep->ops->queue(ep, req, gfp_flags);
 }
 
-- 
2.5.0

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[PATCH v2] usb: gadget: forbid queuing request to a disabled ep changbin.du@intel.com - 2015-12-14 05:00 +0100
  RE: [PATCH v2] usb: gadget: forbid queuing request to a disabled ep "Du, Changbin" <changbin.du@intel.com> - 2015-12-14 11:30 +0100
    RE: [PATCH v2] usb: gadget: forbid queuing request to a disabled ep Felipe Balbi <balbi@ti.com> - 2015-12-16 18:00 +0100
      RE: [PATCH v2] usb: gadget: forbid queuing request to a disabled ep "Du, Changbin" <changbin.du@intel.com> - 2015-12-17 10:40 +0100
      [PATCH v3] usb: gadget: forbid queuing request to a disabled ep changbin.du@intel.com - 2015-12-17 11:10 +0100
        Re: [PATCH v3] usb: gadget: forbid queuing request to a disabled ep Felipe Balbi <balbi@ti.com> - 2015-12-17 16:30 +0100
          RE: [PATCH v3] usb: gadget: forbid queuing request to a disabled ep "Du, Changbin" <changbin.du@intel.com> - 2015-12-18 08:40 +0100
          [PATCH v4] usb: gadget: forbid queuing request to a disabled ep changbin.du@intel.com - 2015-12-18 08:50 +0100

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