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 <[email protected]> Acked-by: Christoph Lameter <[email protected]> Cc: Gautham R Shenoy <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
mgowda · May 13, 2008 · b5be113 · b5be113
1 parent 78f508a
commit b5be113
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/mm/vmstat.c b/mm/vmstat.c
@@ -41,7 +41,9 @@ static void sum_vm_events(unsigned long *ret, cpumask_t *cpumask)
 */
 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);