[PATCH] fix

[Lorenzo Stoakes]

---
 lib/maple_tree.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 37abf0fe380b..fc221a9f23f2 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -3527,6 +3527,7 @@ static bool mas_wr_walk(struct ma_wr_state *wr_mas)
 	return true;
 }

+// Return whether the node actually contains entries at or greater than wr_mas->mas->index.
 static bool mas_wr_walk_index(struct ma_wr_state *wr_mas)
 {
 	struct ma_state *mas = wr_mas->mas;
@@ -3696,6 +3697,7 @@ static noinline void mas_wr_spanning_store(struct ma_wr_state *wr_mas)
 	struct maple_big_node b_node;
 	struct ma_state *mas;
 	unsigned char height;
+	bool r_populated;

 	/* Left and Right side of spanning store */
 	MA_STATE(l_mas, NULL, 0, 0);
@@ -3737,7 +3739,7 @@ static noinline void mas_wr_spanning_store(struct ma_wr_state *wr_mas)
 		r_mas.last++;

 	r_mas.index = r_mas.last;
-	mas_wr_walk_index(&r_wr_mas);
+	r_populated = mas_wr_walk_index(&r_wr_mas);
 	r_mas.last = r_mas.index = mas->last;

 	/* Set up left side. */
@@ -3759,9 +3761,12 @@ static noinline void mas_wr_spanning_store(struct ma_wr_state *wr_mas)

 	memset(&b_node, 0, sizeof(struct maple_big_node));
 	/* Copy l_mas and store the value in b_node. */
+
 	mas_store_b_node(&l_wr_mas, &b_node, l_mas.end);
+
 	/* Copy r_mas into b_node. */
-	if (r_mas.offset <= r_mas.end)
+
+	if (r_populated && r_mas.offset <= r_mas.end)
 		mas_mab_cp(&r_mas, r_mas.offset, r_mas.end,
 			   &b_node, b_node.b_end + 1);
 	else
--
2.46.2