[PATCH 5/5] mm, memcg: always call __mod_node_page_state() with preempt disabled

Miaohe Lin
2021-07-29T12:57:55Z

We should always ensure __mod_node_page_state() is called with preempt
disabled or percpu ops may manipulate the wrong cpu when preempt happened.

Fixes: b4e0b68fbd9d ("mm: memcontrol: use obj_cgroup APIs to charge kmem pages")
Signed-off-by: Miaohe Lin <linmiaohe-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---
mm/memcontrol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 70a32174e7c4..616d1a72ece3 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -697,8 +697,8 @@ void __mod_lruvec_page_state(struct page *page, enum node_stat_item idx,
memcg = page_memcg(head);
/* Untracked pages have no memcg, no lruvec. Update only the node */
if (!memcg) {
- rcu_read_unlock();
__mod_node_page_state(pgdat, idx, val);
+ rcu_read_unlock();
return;
}

--
2.23.0