[PATCH] net: get ops lock under dev valid

[Edward Adam Davis]

Make sure that dev is not NULL before locking ops. 

Fixes: 8965c160b8f7 ("net: use netif_disable_lro in ipv6_add_dev")
Reported-by: syzbot+10d145ea96fc91185445@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
---
 net/ipv6/addrconf.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 2cffb8f4a2bc..5d9fd01e6265 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3154,12 +3154,13 @@ int addrconf_add_ifaddr(struct net *net, void __user *arg)
 
 	rtnl_net_lock(net);
 	dev = __dev_get_by_index(net, ireq.ifr6_ifindex);
-	netdev_lock_ops(dev);
-	if (dev)
+	if (dev) {
+		netdev_lock_ops(dev);
 		err = inet6_addr_add(net, dev, &cfg, 0, 0, NULL);
+		netdev_unlock_ops(dev);
+	}
 	else
 		err = -ENODEV;
-	netdev_unlock_ops(dev);
 	rtnl_net_unlock(net);
 	return err;
 }
-- 
2.43.0