FAILED: patch "[PATCH] usb: dwc3: gadget: Fix list_del corruption in dwc3_ep_dequeue" failed to apply to 4.14-stable tree

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: Mayank Rana <[email protected]>
Date: Fri, 23 Mar 2018 10:05:33 -0700
Subject: [PATCH] usb: dwc3: gadget: Fix list_del corruption in dwc3_ep_dequeue

dwc3_ep_dequeue() waits for completion of End Transfer command using wait_event_lock_irq(), which will release the dwc3->lock while waiting and reacquire after completion. This allows a potential race condition with ep_disable() which also removes all requests from started_list and pending_list.

The check for NULL r->trb should catch this but currently it exits to the wrong 'out1' label which calls dwc3_gadget_giveback(). Since its list entry was already removed, if CONFIG_DEBUG_LIST is enabled a 'list_del corruption' bug is thrown since its next/prev pointers are already LIST_POISON1/2. If r->trb is NULL it should simply exit to 'out0'.

index eeb30133878e..69bf137aab37 100644
@@ -1395,7 +1395,7 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
 					dwc->lock);
 
 			if (!r->trb)
-				goto out1;
+				goto out0;
 
 			if (r->num_pending_sgs) {
 				struct dwc3_trb *trb;