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[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>
This commit is contained in:
Patrick McHardy 2007-02-12 11:13:14 -08:00 committed by David S. Miller
parent 923f4902fe
commit abbaccda4c
2 changed files with 13 additions and 7 deletions
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6
include/linux/netfilter_ipv4/ip_conntrack.h
View File

@ -301,6 +301,12 @@ extern unsigned int ip_conntrack_htable_size;
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>

14
net/ipv4/netfilter/ip_conntrack_core.c
View File

@ -538,7 +538,7 @@ static int early_drop(struct list_head *chain)
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 @@ unsigned int ip_conntrack_in(unsigned int hooknum,
/* 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 @@ unsigned int ip_conntrack_in(unsigned int hooknum,
* 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 @@ unsigned int ip_conntrack_in(unsigned int hooknum,
* 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;
}