The quilt patch titled
Subject: maple_tree: fix a potential memory leak, OOB access, or other unpredictable bug
has been removed from the -mm tree. Its filename was
maple_tree-fix-a-potential-memory-leak-oob-access-or-other-unpredictable-bug.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
From: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx>
Subject: maple_tree: fix a potential memory leak, OOB access, or other unpredictable bug
Date: Fri, 7 Apr 2023 12:07:18 +0800
In mas_alloc_nodes(), there is such a piece of code:
while (requested) {
...
node->node_count = 0;
...
}
"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.
Link: https://lkml.kernel.org/r/20230407040718.99064-2-zhangpeng.00@xxxxxxxxxxxxx
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx>
Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/maple_tree.c | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)
--- a/lib/maple_tree.c~maple_tree-fix-a-potential-memory-leak-oob-access-or-other-unpredictable-bug
+++ a/lib/maple_tree.c
@@ -1303,26 +1303,18 @@ static inline void mas_alloc_nodes(struc
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];
max_req = min(requested, max_req);
count = mt_alloc_bulk(gfp, max_req, slots);
if (!count)
goto nomem_bulk;
+ if (node->node_count == 0)
+ node->slot[0]->node_count = 0;
node->node_count += count;
allocated += count;
node = node->slot[0];
- node->node_count = 0;
- node->request_count = 0;
requested -= count;
}
mas->alloc->total = allocated;
_
Patches currently in -mm which might be from zhangpeng.00@xxxxxxxxxxxxx are
maple_tree-use-correct-variable-type-in-sizeof.patch
mm-kfence-improve-the-performance-of-__kfence_alloc-and-__kfence_free.patch
maple_tree-simplify-mas_wr_node_walk.patch
maple_tree-add-a-test-case-to-check-maple_alloc.patch
