[PATCH 3.2 42/61] ipv6: fix memory leak with multiple tables during netns destruction

From: Ben Hutchings
Date: Tue Nov 21 2017 - 21:55:17 EST

3.2.96-rc1 review patch. If anyone has any objections, please let me know.


From: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>

commit ba1cc08d9488c94cb8d94f545305688b72a2a300 upstream.

fib6_net_exit only frees the main and local tables. If another table was
created with fib6_alloc_table, we leak it when the netns is destroyed.

Fix this in the same way ip_fib_net_exit cleans up tables, by walking
through the whole hashtable of fib6_table's. We can get rid of the
special cases for local and main, since they're also part of the

ip netns add x
ip -net x -6 rule add from 6003:1::/64 table 100
ip netns del x

Reported-by: Jianlin Shi <jishi@xxxxxxxxxx>
Fixes: 58f09b78b730 ("[NETNS][IPV6] ip6_fib - make it per network namespace")
Signed-off-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[bwh: Backported to 3.2:
- No need to call inetpeer_invalidate_tree()
- Add the extra iterator variable needed by hlist_for_each_entry_safe()]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1577,13 +1577,22 @@ out_timer:

static void fib6_net_exit(struct net *net)
+ unsigned int i;
rt6_ifdown(net, NULL);

- kfree(net->ipv6.fib6_local_tbl);
- kfree(net->ipv6.fib6_main_tbl);
+ for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
+ struct hlist_head *head = &net->ipv6.fib_table_hash[i];
+ struct hlist_node *node, *tmp;
+ struct fib6_table *tb;
+ hlist_for_each_entry_safe(tb, node, tmp, head, tb6_hlist) {
+ hlist_del(&tb->tb6_hlist);
+ kfree(tb);
+ }
+ }