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 <[email protected]> Cc: Thomas Graf <[email protected]> Signed-off-by: Cong Wang <[email protected]> Signed-off-by: David S. Miller <[email protected]>
ambv · Apr 3, 2015 · 419df12 · 419df12
1 parent ed78530
commit 419df12
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Showing 6 changed files with 8 additions and 5 deletions.
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
@@ -175,9 +175,9 @@ void fib_rules_unregister(struct fib_rules_ops *ops)
 
 	spin_lock(&net->rules_mod_lock);
 	list_del_rcu(&ops->list);
-	fib_rules_cleanup_ops(ops);
 	spin_unlock(&net->rules_mod_lock);
 
+	fib_rules_cleanup_ops(ops);
 	call_rcu(&ops->rcu, fib_rules_put_rcu);
 }
 EXPORT_SYMBOL_GPL(fib_rules_unregister);

diff --git a/net/decnet/dn_rules.c b/net/decnet/dn_rules.c
@@ -248,7 +248,9 @@ void __init dn_fib_rules_init(void)
 
 void __exit dn_fib_rules_cleanup(void)
 {
+	rtnl_lock();
 	fib_rules_unregister(dn_fib_rules_ops);
+	rtnl_unlock();
 	rcu_barrier();
 }
 

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
@@ -1111,11 +1111,10 @@ static void ip_fib_net_exit(struct net *net)
 {
 	unsigned int i;
 
+	rtnl_lock();
 #ifdef CONFIG_IP_MULTIPLE_TABLES
 	fib4_rules_exit(net);
 #endif
-
-	rtnl_lock();
 	for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
 		struct fib_table *tb;
 		struct hlist_head *head;

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
@@ -283,8 +283,8 @@ static void __net_exit ipmr_rules_exit(struct net *net)
 		list_del(&mrt->list);
 		ipmr_free_table(mrt);
 	}
-	rtnl_unlock();
 	fib_rules_unregister(net->ipv4.mr_rules_ops);
+	rtnl_unlock();
 }
 #else
 #define ipmr_for_each_table(mrt, net) \

diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
@@ -322,7 +322,9 @@ static int __net_init fib6_rules_net_init(struct net *net)
 
 static void __net_exit fib6_rules_net_exit(struct net *net)
 {
+	rtnl_lock();
 	fib_rules_unregister(net->ipv6.fib6_rules_ops);
+	rtnl_unlock();
 }
 
 static struct pernet_operations fib6_rules_net_ops = {

diff --git 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) \