[PATCH] USB: gadget: udc: atmel: fix possible oops when unloading module

[Songjun Wu]

When unloading the module, the urb request will be dequeued
and the completion routine will be excuted.
If no urb packet, the urb request will not be added to the endpoint queue
and the completion routine pointer in urb request is NULL.
Accessing to the NULL function pointer will cause the oops issue.
Add the code to check the urb request is in the endpoint queue or not.
If the urb request is not in the endpoint queue, a negative error code
will be returned.

Signed-off-by: Songjun Wu <songjun.wu at atmel.com>
---
 drivers/usb/gadget/udc/atmel_usba_udc.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/udc/atmel_usba_udc.c b/drivers/usb/gadget/udc/atmel_usba_udc.c
index ce88237..48629cc 100644
--- a/drivers/usb/gadget/udc/atmel_usba_udc.c
+++ b/drivers/usb/gadget/udc/atmel_usba_udc.c
@@ -828,7 +828,7 @@ static int usba_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
 {
 	struct usba_ep *ep = to_usba_ep(_ep);
 	struct usba_udc *udc = ep->udc;
-	struct usba_request *req = to_usba_req(_req);
+	struct usba_request *req;
 	unsigned long flags;
 	u32 status;
 
@@ -837,6 +837,16 @@ static int usba_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
 
 	spin_lock_irqsave(&udc->lock, flags);
 
+	list_for_each_entry(req, &ep->queue, queue) {
+		if (&req->req == _req)
+			break;
+	}
+
+	if (&req->req != _req) {
+		spin_unlock_irqrestore(&udc->lock, flags);
+		return -EINVAL;
+	}
+
 	if (req->using_dma) {
 		/*
 		 * If this request is currently being transferred,
-- 
1.7.9.5