[ 24/26] can: usb_8dev: unregister netdev before free()ing

[Greg Kroah-Hartman]

3.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>

commit 4afe2156eb639e563d6ef0c2706b66ea400348b2 upstream.

The usb_8dev hardware has problems on some xhci USB hosts. The driver fails to
read the firmware revision in the probe function. This leads to the following
Oops:

    [ 3356.635912] kernel BUG at net/core/dev.c:5701!

The driver tries to free the netdev, which has already been registered, without
unregistering it.

This patch fixes the problem by unregistering the netdev in the error path.

Reported-by: Michael Olbrich <m.olbrich@xxxxxxxxxxxxxx>
Reviewed-by: Bernd Krumboeck <krumboeck@xxxxxxxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Cc: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/net/can/usb/usb_8dev.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/net/can/usb/usb_8dev.c
+++ b/drivers/net/can/usb/usb_8dev.c
@@ -977,7 +977,7 @@ static int usb_8dev_probe(struct usb_int
 	err = usb_8dev_cmd_version(priv, &version);
 	if (err) {
 		netdev_err(netdev, "can't get firmware version\n");
-		goto cleanup_cmd_msg_buffer;
+		goto cleanup_unregister_candev;
 	} else {
 		netdev_info(netdev,
 			 "firmware: %d.%d, hardware: %d.%d\n",
@@ -989,6 +989,9 @@ static int usb_8dev_probe(struct usb_int
 
 	return 0;
 
+cleanup_unregister_candev:
+	unregister_netdev(priv->netdev);
+
 cleanup_cmd_msg_buffer:
 	kfree(priv->cmd_msg_buffer);
 


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