* Peng Zhang zhangpeng.00@bytedance.com [230411 00:10]:
In mas_alloc_nodes(), "node->node_count = 0" means to initialize the node_count field of the new node, but the node may not be a new node. It may be a node that existed before and node_count has a value, setting it to 0 will cause a memory leak. At this time, mas->alloc->total will be greater than the actual number of nodes in the linked list, which may cause many other errors. For example, out-of-bounds access in mas_pop_node(), and mas_pop_node() may return addresses that should not be used. Fix it by initializing node_count only for new nodes.
Also, by the way, an if-else statement was removed to simplify the code.
Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Peng Zhang zhangpeng.00@bytedance.com Cc: stable@vger.kernel.org
Reviewed-by: Liam R. Howlett Liam.Howlett@oracle.com
lib/maple_tree.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-)
diff --git a/lib/maple_tree.c b/lib/maple_tree.c index dd1a114d9e2b..938634bea2d6 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -1303,26 +1303,21 @@ static inline void mas_alloc_nodes(struct ma_state *mas, gfp_t gfp) node = mas->alloc; node->request_count = 0; while (requested) {
max_req = MAPLE_ALLOC_SLOTS;if (node->node_count) {unsigned int offset = node->node_count;slots = (void **)&node->slot[offset];max_req -= offset;} else {slots = (void **)&node->slot;}
max_req = MAPLE_ALLOC_SLOTS - node->node_count;slots = (void **)&node->slot[node->node_count];
if (node->node_count == 0) {node->slot[0]->node_count = 0;node->slot[0]->request_count = 0;}- node->node_count += count; allocated += count; node = node->slot[0];
node->node_count = 0;node->request_count = 0;-- 2.20.1