diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index ee1ff0c59fd7..8f68582451c4 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1699,6 +1699,7 @@ static inline void mas_adopt_children(struct ma_state *mas,
 	do {
 		child = mas_slot_locked(mas, slots, offset);
 		mas_set_parent(mas, child, parent, offset);
+		smp_wmb(); /* Needed for RCU */
 	} while (offset--);
 }