[NETFILTER]: ip_conntrack: fix invalid conntrack statistics RCU assumption
CONNTRACK_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 ip_conntrack_lock.
Add CONNTRACK_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>
diff --git a/include/linux/netfilter_ipv4/ip_conntrack.h b/include/linux/netfilter_ipv4/ip_conntrack.h
index 33581c1..da9274e 100644
--- a/include/linux/netfilter_ipv4/ip_conntrack.h
+++ b/include/linux/netfilter_ipv4/ip_conntrack.h
@@ -301,6 +301,12 @@
extern int ip_conntrack_checksum;
#define CONNTRACK_STAT_INC(count) (__get_cpu_var(ip_conntrack_stat).count++)
+#define CONNTRACK_STAT_INC_ATOMIC(count) \
+do { \
+ local_bh_disable(); \
+ __get_cpu_var(ip_conntrack_stat).count++; \
+ local_bh_enable(); \
+} while (0)
#ifdef CONFIG_IP_NF_CONNTRACK_EVENTS
#include <linux/notifier.h>
diff --git a/net/ipv4/netfilter/ip_conntrack_core.c b/net/ipv4/netfilter/ip_conntrack_core.c
index e7de6d3..a7e34d0 100644
--- a/net/ipv4/netfilter/ip_conntrack_core.c
+++ b/net/ipv4/netfilter/ip_conntrack_core.c
@@ -538,7 +538,7 @@
if (del_timer(&ct->timeout)) {
death_by_timeout((unsigned long)ct);
dropped = 1;
- CONNTRACK_STAT_INC(early_drop);
+ CONNTRACK_STAT_INC_ATOMIC(early_drop);
}
ip_conntrack_put(ct);
return dropped;
@@ -804,7 +804,7 @@
/* Previously seen (loopback or untracked)? Ignore. */
if ((*pskb)->nfct) {
- CONNTRACK_STAT_INC(ignore);
+ CONNTRACK_STAT_INC_ATOMIC(ignore);
return NF_ACCEPT;
}
@@ -840,20 +840,20 @@
* core what to do with the packet. */
if (proto->error != NULL
&& (ret = proto->error(*pskb, &ctinfo, hooknum)) <= 0) {
- CONNTRACK_STAT_INC(error);
- CONNTRACK_STAT_INC(invalid);
+ CONNTRACK_STAT_INC_ATOMIC(error);
+ CONNTRACK_STAT_INC_ATOMIC(invalid);
return -ret;
}
if (!(ct = resolve_normal_ct(*pskb, proto,&set_reply,hooknum,&ctinfo))) {
/* Not valid part of a connection */
- CONNTRACK_STAT_INC(invalid);
+ CONNTRACK_STAT_INC_ATOMIC(invalid);
return NF_ACCEPT;
}
if (IS_ERR(ct)) {
/* Too stressed to deal. */
- CONNTRACK_STAT_INC(drop);
+ CONNTRACK_STAT_INC_ATOMIC(drop);
return NF_DROP;
}
@@ -865,7 +865,7 @@
* the netfilter core what to do*/
nf_conntrack_put((*pskb)->nfct);
(*pskb)->nfct = NULL;
- CONNTRACK_STAT_INC(invalid);
+ CONNTRACK_STAT_INC_ATOMIC(invalid);
return -ret;
}