make vmstat cpu-unplug safe
When accessing cpu_online_map, we should prevent dynamic changing
of cpu_online_map by get_online_cpus().
Unfortunately, all_vm_events() doesn't do that.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 1a32130..db9eabb 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -41,7 +41,9 @@
*/
void all_vm_events(unsigned long *ret)
{
+ get_online_cpus();
sum_vm_events(ret, &cpu_online_map);
+ put_online_cpus();
}
EXPORT_SYMBOL_GPL(all_vm_events);