3.16.50-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx> commit 3840538ad384fb7891adeeaf36624f870c51fc0e upstream. When we delete a netns with a CLUSTERIP rule, clusterip_net_exit() is called first, removing /proc/net/ipt_CLUSTERIP. Then clusterip_config_entry_put() is called from clusterip_tg_destroy(), and tries to remove its entry under /proc/net/ipt_CLUSTERIP/. Fix this by checking that the parent directory of the entry to remove hasn't already been deleted. The following triggers a KASAN splat (stealing the reproducer from 202f59afd441, thanks to Jianlin Shi and Xin Long): ip netns add test ip link add veth0_in type veth peer name veth0_out ip link set veth0_in netns test ip netns exec test ip link set lo up ip netns exec test ip link set veth0_in up ip netns exec test iptables -I INPUT -d 1.2.3.4 -i veth0_in -j \ CLUSTERIP --new --clustermac 89:d4:47:eb:9a:fa --total-nodes 3 \ --local-node 1 --hashmode sourceip-sourceport ip netns del test Fixes: ce4ff76c15a8 ("netfilter: ipt_CLUSTERIP: make proc directory per net namespace") Signed-off-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx> Reviewed-by: Xin Long <lucien.xin@xxxxxxxxx> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- net/ipv4/netfilter/ipt_CLUSTERIP.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/net/ipv4/netfilter/ipt_CLUSTERIP.c +++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c @@ -115,7 +115,8 @@ clusterip_config_entry_put(struct cluste * functions are also incrementing the refcount on their own, * so it's safe to remove the entry even if it's in use. */ #ifdef CONFIG_PROC_FS - proc_remove(c->pde); + if (cn->procdir) + proc_remove(c->pde); #endif return; } @@ -735,6 +736,7 @@ static void clusterip_net_exit(struct ne #ifdef CONFIG_PROC_FS struct clusterip_net *cn = net_generic(net, clusterip_net_id); proc_remove(cn->procdir); + cn->procdir = NULL; #endif }