staging: hv: re-order the code in netvsc_probe()

Re-order the code in netvsc_probe() to prevent a guest crash caused by
packets possibly received from NetVSP before call to register_netdev().

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/hv/netvsc_drv.c

@@ -348,19 +348,6 @@ static int netvsc_probe(struct hv_device *dev)
 	dev_set_drvdata(&dev->device, net);
 	INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_send_garp);
 
-	/* Notify the netvsc driver of the new device */
-	device_info.ring_size = ring_size;
-	ret = rndis_filter_device_add(dev, &device_info);
-	if (ret != 0) {
-		free_netdev(net);
-		dev_set_drvdata(&dev->device, NULL);
-		return ret;
-	}
-
-	netif_carrier_on(net);
-
-	memcpy(net->dev_addr, device_info.mac_adr, ETH_ALEN);
-
 	net->netdev_ops = &device_ops;
 
 	/* TODO: Add GSO and Checksum offload */
@@ -372,11 +359,26 @@ static int netvsc_probe(struct hv_device *dev)
 
 	ret = register_netdev(net);
 	if (ret != 0) {
-		/* Remove the device and release the resource */
-		rndis_filter_device_remove(dev);
+		pr_err("Unable to register netdev.\n");
 		free_netdev(net);
+		goto out;
 	}
 
+	/* Notify the netvsc driver of the new device */
+	device_info.ring_size = ring_size;
+	ret = rndis_filter_device_add(dev, &device_info);
+	if (ret != 0) {
+		netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
+		unregister_netdev(net);
+		free_netdev(net);
+		dev_set_drvdata(&dev->device, NULL);
+		return ret;
+	}
+	memcpy(net->dev_addr, device_info.mac_adr, ETH_ALEN);
+
+	netif_carrier_on(net);
+
+out:
 	return ret;
 }