1 files changed, 16 insertions, 1 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e2996b80601f..b66512771167 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -358,6 +358,10 @@ void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
                 return;
 
         pc = lookup_page_cgroup(page);
+        /*
+         * Used bit is set without atomic ops but after smp_wmb().
+         * For making pc->mem_cgroup visible, insert smp_rmb() here.
+         */
         smp_rmb();
         /* unused page is not rotated. */
         if (!PageCgroupUsed(pc))
@@ -374,7 +378,10 @@ void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
         if (mem_cgroup_disabled())
                 return;
         pc = lookup_page_cgroup(page);
-        /* barrier to sync with "charge" */
+        /*
+         * Used bit is set without atomic ops but after smp_wmb().
+         * For making pc->mem_cgroup visible, insert smp_rmb() here.
+         */
         smp_rmb();
         if (!PageCgroupUsed(pc))
                 return;
@@ -559,6 +566,14 @@ mem_cgroup_get_reclaim_stat_from_page(struct page *page)
                 return NULL;
 
         pc = lookup_page_cgroup(page);
+        /*
+         * Used bit is set without atomic ops but after smp_wmb().
+         * For making pc->mem_cgroup visible, insert smp_rmb() here.
+         */
+        smp_rmb();
+        if (!PageCgroupUsed(pc))
+                return NULL;
+
         mz = page_cgroup_zoneinfo(pc);
         if (!mz)
                 return NULL;