can: usb_8dev: unregister netdev before free()ing

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@pengutronix.de>
Reviewed-by: Bernd Krumboeck <krumboeck@universalnet.at>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/net/can/usb/usb_8dev.c b/drivers/net/can/usb/usb_8dev.c
index 6e15ef08f301..cbd388eea682 100644
--- 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_interface *intf,
         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_interface *intf,
 
         return 0;
 
+cleanup_unregister_candev:
+        unregister_netdev(priv->netdev);
+
 cleanup_cmd_msg_buffer:
         kfree(priv->cmd_msg_buffer);