2022-07-12 02:12:05

by Liam R. Howlett

Subject: [PATCH] maple_tree: Fix mas_empty_area_rev() search exhaustion at root node

When the possibilities of finding a gap are exhausted at the root node,
the error code was not returned which results in returning a range that
is currently occupied. Add the necessary check for the error code and
return to the caller.

Reported-by: Alexander Gordeev <[email protected]>
Fixes: d0aac5e48048 (Maple Tree: add new data structure)
Signed-off-by: Liam R. Howlett <[email protected]>
---
lib/maple_tree.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 9dc4ffff18d0..14e9ab14c1da 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5287,6 +5287,9 @@ int mas_empty_area_rev(struct ma_state *mas, unsigned long min,
}
}

+ if (mas_is_err(mas))
+ return xa_err(mas->node);
+
if (unlikely(mas->offset == MAPLE_NODE_SLOTS))
return -EBUSY;

--
2.35.1

2022-07-12 11:57:36

by Alexander Gordeev

Subject: Re: [PATCH] maple_tree: Fix mas_empty_area_rev() search exhaustion at root node

On Tue, Jul 12, 2022 at 01:50:36AM +0000, Liam Howlett wrote:
> When the possibilities of finding a gap are exhausted at the root node,
> the error code was not returned which results in returning a range that
> is currently occupied. Add the necessary check for the error code and
> return to the caller.
>
> Reported-by: Alexander Gordeev <[email protected]>
> Fixes: d0aac5e48048 (Maple Tree: add new data structure)
> Signed-off-by: Liam R. Howlett <[email protected]>
> ---
> lib/maple_tree.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index 9dc4ffff18d0..14e9ab14c1da 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -5287,6 +5287,9 @@ int mas_empty_area_rev(struct ma_state *mas, unsigned long min,
> }
> }
>
> + if (mas_is_err(mas))
> + return xa_err(mas->node);
> +
> if (unlikely(mas->offset == MAPLE_NODE_SLOTS))
> return -EBUSY;

Tested-by: Alexander Gordeev <[email protected]>

Thanks!