Commit ba7863f4 authored Apr 28, 2016 by Eric Dumazet Committed by David S. Miller Apr 28, 2016

net: snmp: fix 64bit stats on 32bit arches



I accidentally replaced BH disabling by preemption disabling
in SNMP_ADD_STATS64() and SNMP_UPD_PO_STATS64() on 32bit builds.

For 64bit stats on 32bit arch, we really need to disable BH,
since the "struct u64_stats_sync syncp" might be manipulated
both from process and BH contexts.

Fixes: 6aef70a8 ("net: snmp: kill various STATS_USER() helpers")
Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Tested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 8be2748a

include/net/snmp.h

+4 −4

Original line number	Diff line number	Diff line
		@@ -166,9 +166,9 @@ struct linux_xfrm_mib {

		#define SNMP_ADD_STATS64(mib, field, addend) \
		do { \
		preempt_disable(); \
		local_bh_disable(); \
		__SNMP_ADD_STATS64(mib, field, addend); \
		preempt_enable(); \
		local_bh_enable(); \
		} while (0)

		#define __SNMP_INC_STATS64(mib, field) SNMP_ADD_STATS64(mib, field, 1)
		@@ -184,9 +184,9 @@ struct linux_xfrm_mib {
		} while (0)
		#define SNMP_UPD_PO_STATS64(mib, basefield, addend) \
		do { \
		preempt_disable(); \
		local_bh_disable(); \
		__SNMP_UPD_PO_STATS64(mib, basefield, addend); \
		preempt_enable(); \
		local_bh_enable(); \
		} while (0)
		#else
		#define __SNMP_INC_STATS64(mib, field) __SNMP_INC_STATS(mib, field)