From 6bd0405bb4196b44f1acb7a58f11382cdaf6f7f0 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Thu, 5 Jul 2012 15:42:10 +0200 Subject: [PATCH] netfilter: nf_ct_ecache: fix crash with multiple containers, one shutting down Hans reports that he's still hitting: BUG: unable to handle kernel NULL pointer dereference at 000000000000027c IP: [] netlink_has_listeners+0xb/0x60 PGD 0 Oops: 0000 [#3] PREEMPT SMP CPU 0 It happens when adding a number of containers with do: nfct_query(h, NFCT_Q_CREATE, ct); and most likely one namespace shuts down. this problem was supposed to be fixed by: 70e9942 netfilter: nf_conntrack: make event callback registration per-netns Still, it was missing one rcu_access_pointer to check if the callback is set or not. Reported-by: Hans Schillstrom Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack_ecache.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/netfilter/nf_conntrack_ecache.h b/include/net/netfilter/nf_conntrack_ecache.h index a88fb6939387..e1ce1048fe5f 100644 --- a/include/net/netfilter/nf_conntrack_ecache.h +++ b/include/net/netfilter/nf_conntrack_ecache.h @@ -78,7 +78,7 @@ nf_conntrack_event_cache(enum ip_conntrack_events event, struct nf_conn *ct) struct net *net = nf_ct_net(ct); struct nf_conntrack_ecache *e; - if (net->ct.nf_conntrack_event_cb == NULL) + if (!rcu_access_pointer(net->ct.nf_conntrack_event_cb)) return; e = nf_ct_ecache_find(ct); -- 2.20.1