[PATCH v1 net-next 2/4] net: Hold __rtnl_net_lock() in (un)?register_netdevice_notifier().

[Kuniyuki Iwashima <kuniyu@amazon.com>]

(un)?register_netdevice_notifier() hold pernet_ops_rwsem and RTNL,
iterate all netns, and trigger the notifier for all netdev.

Let's hold __rtnl_net_lock() before triggering the notifier.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/core/dev.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 404f5bda821b..7d49b4018ea2 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1776,7 +1776,9 @@ int register_netdevice_notifier(struct notifier_block *nb)
 	if (dev_boot_phase)
 		goto unlock;
 	for_each_net(net) {
+		__rtnl_net_lock(net);
 		err = call_netdevice_register_net_notifiers(nb, net);
+		__rtnl_net_unlock(net);
 		if (err)
 			goto rollback;
 	}
@@ -1787,8 +1789,11 @@ int register_netdevice_notifier(struct notifier_block *nb)
 	return err;
 
 rollback:
-	for_each_net_continue_reverse(net)
+	for_each_net_continue_reverse(net) {
+		__rtnl_net_lock(net);
 		call_netdevice_unregister_net_notifiers(nb, net);
+		__rtnl_net_unlock(net);
+	}
 
 	blocking_notifier_chain_unregister(&netdev_chain, nb);
 	goto unlock;
@@ -1821,8 +1826,11 @@ int unregister_netdevice_notifier(struct notifier_block *nb)
 	if (err)
 		goto unlock;
 
-	for_each_net(net)
+	for_each_net(net) {
+		__rtnl_net_lock(net);
 		call_netdevice_unregister_net_notifiers(nb, net);
+		__rtnl_net_unlock(net);
+	}
 
 unlock:
 	rtnl_unlock();
-- 
2.39.5 (Apple Git-154)