net: move fib_rules_unregister() under rtnl lock

We have to hold rtnl lock for fib_rules_unregister()
otherwise the following race could happen:

fib_rules_unregister():	fib_nl_delrule():
...				...
...				ops = lookup_rules_ops();
list_del_rcu(&ops->list);
				list_for_each_entry(ops->rules) {
fib_rules_cleanup_ops(ops);	  ...
  list_del_rcu();		  list_del_rcu();
				}

Note, net->rules_mod_lock is actually not needed at all,
either upper layer netns code or rtnl lock guarantees
we are safe.

Cc: Alexander Duyck <alexander.h.duyck@redhat.com>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 52028f449a89..2f1fd9ffcb34 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -267,8 +267,8 @@ static void __net_exit ip6mr_rules_exit(struct net *net)
                 list_del(&mrt->list);
                 ip6mr_free_table(mrt);
         }
-        rtnl_unlock();
         fib_rules_unregister(net->ipv6.mr6_rules_ops);
+        rtnl_unlock();
 }
 #else
 #define ip6mr_for_each_table(mrt, net) \