[NETFILTER]: nf_conntrack: fix invalid conntrack statistics RCU assumption

NF_CT_STAT_INC assumes rcu_read_lock in nf_hook_slow disables
preemption as well, making it legal to use __get_cpu_var without
disabling preemption manually. The assumption is not correct anymore
with preemptable RCU, additionally we need to protect against softirqs
when not holding nf_conntrack_lock.

Add NF_CT_STAT_INC_ATOMIC macro, which disables local softirqs,
and use where necessary.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
index a2353edf4ebc..4b7be4bb4d03 100644
--- a/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
+++ b/net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
@@ -154,8 +154,8 @@ ipv6_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff,
          */
         if ((protoff < 0) || (protoff > (*pskb)->len)) {
                 DEBUGP("ip6_conntrack_core: can't find proto in pkt\n");
-                NF_CT_STAT_INC(error);
-                NF_CT_STAT_INC(invalid);
+                NF_CT_STAT_INC_ATOMIC(error);
+                NF_CT_STAT_INC_ATOMIC(invalid);
                 return -NF_ACCEPT;
         }