Thread (8 messages) 8 messages, 2 authors, 2014-12-29

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

From: Wu, Songjun <hidden>
Date: 2014-12-24 01:15:14
Also in: lkml

? 12/24/2014 00:24, Felipe Balbi ??:
On Mon, Dec 22, 2014 at 05:26:14PM +0800, Songjun Wu wrote:
quoted
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.
have you triggered the NULL pointer oops ? Care to add it to the commit
log.
Executing the 'insmod g_hid.ko', then executing the 'rmmod g_hid.ko', 
the NULL pointer oops will be triggered.
Also, which commit is this fixing ? Does this need to be backported ?
When was the bug introduced ?
quoted
Signed-off-by: Songjun Wu <redacted>
---
  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
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