diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9be3cf8..0e3fdbd 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1485,7 +1485,8 @@
 		SetPageCgroupFileMapped(pc);
 	} else {
 		__this_cpu_dec(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
-		ClearPageCgroupFileMapped(pc);
+		if (!page_mapped(page)) /* for race between dec->inc counter */
+			ClearPageCgroupFileMapped(pc);
 	}
 
 done: