[IPV4]: Check fib4_rules_init failure.

This adds error paths into both versions of fib4_rules_init
(with/without CONFIG_IP_MULTIPLE_TABLES) and returns error code to the
caller.

Acked-by: Benjamin Thery <benjamin.thery@bull.net>
Acked-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index ac6238a..1bb956b 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -59,12 +59,24 @@
 #define FIB_TABLE_HASHSZ 1
 static struct hlist_head fib_table_hash[FIB_TABLE_HASHSZ];
 
-static void __init fib4_rules_init(void)
+static int __init fib4_rules_init(void)
 {
 	ip_fib_local_table = fib_hash_init(RT_TABLE_LOCAL);
-	hlist_add_head_rcu(&ip_fib_local_table->tb_hlist, &fib_table_hash[0]);
+	if (ip_fib_local_table == NULL)
+		return -ENOMEM;
+
 	ip_fib_main_table  = fib_hash_init(RT_TABLE_MAIN);
+	if (ip_fib_main_table == NULL)
+		goto fail;
+
+	hlist_add_head_rcu(&ip_fib_local_table->tb_hlist, &fib_table_hash[0]);
 	hlist_add_head_rcu(&ip_fib_main_table->tb_hlist, &fib_table_hash[0]);
+	return 0;
+
+fail:
+	kfree(ip_fib_local_table);
+	ip_fib_local_table = NULL;
+	return -ENOMEM;
 }
 #else
 
@@ -944,7 +956,7 @@
 	for (i = 0; i < FIB_TABLE_HASHSZ; i++)
 		INIT_HLIST_HEAD(&fib_table_hash[i]);
 
-	fib4_rules_init();
+	BUG_ON(fib4_rules_init());
 
 	register_netdevice_notifier(&fib_netdev_notifier);
 	register_inetaddr_notifier(&fib_inetaddr_notifier);