diff --git a/mm/vmstat.c b/mm/vmstat.c
index 6038ce593ce3..9c624595e904 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1827,12 +1827,13 @@ static bool need_update(int cpu)
 
 		/*
 		 * The fast way of checking if there are any vmstat diffs.
-		 * This works because the diffs are byte sized items.
 		 */
-		if (memchr_inv(p->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS))
+		if (memchr_inv(p->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS *
+			       sizeof(p->vm_stat_diff[0])))
 			return true;
 #ifdef CONFIG_NUMA
-		if (memchr_inv(p->vm_numa_stat_diff, 0, NR_VM_NUMA_STAT_ITEMS))
+		if (memchr_inv(p->vm_numa_stat_diff, 0, NR_VM_NUMA_STAT_ITEMS *
+			       sizeof(p->vm_numa_stat_diff[0])))
 			return true;
 #endif
 	}