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[PATCH 2/2] usb: dwc2: 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 dwc2 process the request queued on step 2, will cause kernel
   NULL pointer dereference exception.

Signed-off-by: Du, Changbin <changbin.du@intel.com>
---
 drivers/usb/dwc2/gadget.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 586bbcd..4d637ab 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -786,6 +786,12 @@ static int dwc2_hsotg_ep_queue(struct usb_ep *ep, struct usb_request *req,
 		ep->name, req, req->length, req->buf, req->no_interrupt,
 		req->zero, req->short_not_ok);
 
+	if (!hs_ep->enabled) {
+		dev_warn(hs->dev, "%s: cannot queue to disabled ep\n",
+				__func__);
+		return -ESHUTDOWN;
+	}
+
 	/* Prevent new request submission when controller is suspended */
 	if (hs->lx_state == DWC2_L2) {
 		dev_dbg(hs->dev, "%s: don't submit request while suspended\n",
-- 
2.5.0

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Thread

[PATCH 0/2] Two fix for dwc2 gadget driver changbin.du@intel.com - 2015-11-30 06:30 +0100
  [PATCH 2/2] usb: dwc2: forbid queuing request to a disabled ep changbin.du@intel.com - 2015-11-30 06:40 +0100
    Re: [PATCH 2/2] usb: dwc2: forbid queuing request to a disabled ep Felipe Balbi <balbi@ti.com> - 2015-12-10 18:30 +0100
  [PATCH 1/2] usb: dwc2: add ep enabled flag to avoid double enable/disable changbin.du@intel.com - 2015-11-30 06:40 +0100
    Re: [PATCH 1/2] usb: dwc2: add ep enabled flag to avoid double enable/disable Felipe Balbi <balbi@ti.com> - 2015-12-10 18:30 +0100
  Re: [PATCH 0/2] Two fix for dwc2 gadget driver John Youn <John.Youn@synopsys.com> - 2015-12-03 02:30 +0100
    RE: [PATCH 0/2] Two fix for dwc2 gadget driver "Du, Changbin" <changbin.du@intel.com> - 2015-12-03 05:30 +0100
      [PATCH] usb: gadget: forbid queuing request to a disabled ep changbin.du@intel.com - 2015-12-04 08:30 +0100
        Re: [PATCH] usb: gadget: forbid queuing request to a disabled ep Felipe Balbi <balbi@ti.com> - 2015-12-10 18:30 +0100

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