maple_tree: Fix potential rcu issue

Ensure the node isn't dead after reading the node end.

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index f107920ca5ef2151c872ad9de8deb5a4d3f2d752..0da105a6d8a73708da607f97cee50825cb182658 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4651,13 +4651,13 @@ static inline void *mas_next_nentry(struct ma_state *mas,
        pivots = ma_pivots(node, type);
        slots = ma_slots(node, type);
        mas->index = mas_safe_min(mas, pivots, mas->offset);
+       count = ma_data_end(node, type, pivots, mas->max);
        if (ma_dead_node(node))
                return NULL;
 
        if (mas->index > max)
                return NULL;
 
-       count = ma_data_end(node, type, pivots, mas->max);
        if (mas->offset > count)
                return NULL;