2022-08-02 19:38:41

by Liam R. Howlett

Subject: [PATCH] maple_tree: Fix mas_alloc_nodes()

Use MAPLE_ALLOC_SLOTS, which differs on 32bit. This was causing an
out of bounds issue on 32bit bulk allocations

Fixes: 06b152b7980a (Maple Tree: add new data structure)
Signed-off-by: Liam R. Howlett <[email protected]>
---
lib/maple_tree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 4e41f3394114..032e7bb0d44f 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1242,7 +1242,7 @@ static inline void mas_alloc_nodes(struct ma_state *mas, gfp_t gfp)

node = mas->alloc;
while (requested) {
- max_req = MAPLE_NODE_SLOTS - 1;
+ max_req = MAPLE_ALLOC_SLOTS;
if (node->slot[0]) {
unsigned int offset = node->node_count + 1;

--
2.35.1

2022-08-06 15:22:22

by Dmitry Osipenko

Subject: Re: [PATCH] maple_tree: Fix mas_alloc_nodes()

02.08.2022 22:36, Liam Howlett пишет:
> Use MAPLE_ALLOC_SLOTS, which differs on 32bit. This was causing an
> out of bounds issue on 32bit bulk allocations
>
> Fixes: 06b152b7980a (Maple Tree: add new data structure)
> Signed-off-by: Liam R. Howlett <[email protected]>
> ---
> lib/maple_tree.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index 4e41f3394114..032e7bb0d44f 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -1242,7 +1242,7 @@ static inline void mas_alloc_nodes(struct ma_state *mas, gfp_t gfp)
>
> node = mas->alloc;
> while (requested) {
> - max_req = MAPLE_NODE_SLOTS - 1;
> + max_req = MAPLE_ALLOC_SLOTS;
> if (node->slot[0]) {
> unsigned int offset = node->node_count + 1;
>

Hello Liam,

This fixed the bug, thank you!

Tested-by: Dmitry Osipenko <[email protected]> # ARM32 Tegra