The debug patch which detects the use of smp_processor_id() in preempt-enabled
regions is triggering due to CONNTRACK_STAT_INC.
And it does need to be preempt-safe, becuase even if the compiler takes a copy
of the per-cpu data's address into a register, preemption between the read and
the write could cause us to lose counts.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/include/linux/netfilter_ipv4/ip_conntrack.h | 6 +++++-
1 files changed, 5 insertions(+), 1 deletion(-)
diff -puN include/linux/netfilter_ipv4/ip_conntrack.h~conntrack-preempt-safety include/linux/netfilter_ipv4/ip_conntrack.h
--- 25/include/linux/netfilter_ipv4/ip_conntrack.h~conntrack-preempt-safety 2004-10-03 10:59:55.814603384 -0700
+++ 25-akpm/include/linux/netfilter_ipv4/ip_conntrack.h 2004-10-03 11:01:36.554288624 -0700
@@ -311,7 +311,11 @@ struct ip_conntrack_stat
unsigned int expect_delete;
};
-#define CONNTRACK_STAT_INC(count) (__get_cpu_var(ip_conntrack_stat).count++)
+#define CONNTRACK_STAT_INC(count) \
+ do { \
+ per_cpu(ip_conntrack_stat, get_cpu()).count++; \
+ put_cpu(); \
+ } while (0)
/* eg. PROVIDES_CONNTRACK(ftp); */
#define PROVIDES_CONNTRACK(name) \
_