From: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Date: Thu, 20 Jul 2017 02:41:34 -0700
Subject: tun/tap: Add the missed return value check of
 register_netdevice_notifier
Patch-mainline: v4.13-rc4
Git-commit: 5edfbd3c0697e643f179dba819a7c09375b42543
References: bsc#1109837

There is some codes of tun/tap module which did not check the return
value of register_netdevice_notifier. Add the check now.

Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/tun.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -2601,8 +2601,16 @@ static int __init tun_init(void)
 		goto err_misc;
 	}
 
-	register_netdevice_notifier(&tun_notifier_block);
+	ret = register_netdevice_notifier(&tun_notifier_block);
+	if (ret) {
+		pr_err("Can't register netdevice notifier\n");
+		goto err_notifier;
+	}
+
 	return  0;
+
+err_notifier:
+	misc_deregister(&tun_miscdev);
 err_misc:
 	rtnl_link_unregister(&tun_link_ops);
 err_linkops: