1 files changed, 37 insertions, 15 deletions

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 57be71dd6a9e..220c4b4af4cf 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -89,17 +89,14 @@ struct fib_table *fib_new_table(struct net *net, u32 id)
 
 	switch (id) {
 	case RT_TABLE_LOCAL:
-		net->ipv4.fib_local = tb;
+		rcu_assign_pointer(net->ipv4.fib_local, tb);
 		break;
-
 	case RT_TABLE_MAIN:
-		net->ipv4.fib_main = tb;
+		rcu_assign_pointer(net->ipv4.fib_main, tb);
 		break;
-
 	case RT_TABLE_DEFAULT:
-		net->ipv4.fib_default = tb;
+		rcu_assign_pointer(net->ipv4.fib_default, tb);
 		break;
-
 	default:
 		break;
 	}
@@ -132,13 +129,14 @@ struct fib_table *fib_get_table(struct net *net, u32 id)
 static void fib_flush(struct net *net)
 {
 	int flushed = 0;
-	struct fib_table *tb;
-	struct hlist_head *head;
 	unsigned int h;
 
 	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
-		head = &net->ipv4.fib_table_hash[h];
-		hlist_for_each_entry(tb, head, tb_hlist)
+		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
+		struct hlist_node *tmp;
+		struct fib_table *tb;
+
+		hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
 			flushed += fib_table_flush(tb);
 	}
 
@@ -665,10 +663,12 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 	s_h = cb->args[0];
 	s_e = cb->args[1];
 
+	rcu_read_lock();
+
 	for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
 		e = 0;
 		head = &net->ipv4.fib_table_hash[h];
-		hlist_for_each_entry(tb, head, tb_hlist) {
+		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
 			if (e < s_e)
 				goto next;
 			if (dumped)
@@ -682,6 +682,8 @@ next:
 		}
 	}
 out:
+	rcu_read_unlock();
+
 	cb->args[1] = e;
 	cb->args[0] = h;
 
@@ -1117,14 +1119,34 @@ static void ip_fib_net_exit(struct net *net)
 
 	rtnl_lock();
 	for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
-		struct fib_table *tb;
-		struct hlist_head *head;
+		struct hlist_head *head = &net->ipv4.fib_table_hash[i];
 		struct hlist_node *tmp;
+		struct fib_table *tb;
+
+		/* this is done in two passes as flushing the table could
+		 * cause it to be reallocated in order to accommodate new
+		 * tnodes at the root as the table shrinks.
+		 */
+		hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
+			fib_table_flush(tb);
 
-		head = &net->ipv4.fib_table_hash[i];
 		hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
+#ifdef CONFIG_IP_MULTIPLE_TABLES
+			switch (tb->tb_id) {
+			case RT_TABLE_LOCAL:
+				RCU_INIT_POINTER(net->ipv4.fib_local, NULL);
+				break;
+			case RT_TABLE_MAIN:
+				RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
+				break;
+			case RT_TABLE_DEFAULT:
+				RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
+				break;
+			default:
+				break;
+			}
+#endif
 			hlist_del(&tb->tb_hlist);
-			fib_table_flush(tb);
 			fib_free_table(tb);
 		}
 	}