LinuxLists.cc - [PATCH] RDMA/mlx5: Fix memory leak

2022-03-11 22:55:54

Subject: [PATCH] RDMA/mlx5: Fix memory leak

[why]
xa_insert is failed, so caller of subscribe_event_xa_alloc
cannot call other function to free obj_event. Therefore,
Resource release is needed on the error handling path to
prevent memory leak.

[how]
Fix this by adding kfree on the error handling path.

Fixes: 7597385 ("IB/mlx5: Enable subscription for device events over DEVX")

Signed-off-by: Yongzhi Liu <[email protected]>
---
drivers/infiniband/hw/mlx5/devx.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c
index 08b7f6b..15c0884 100644
--- a/drivers/infiniband/hw/mlx5/devx.c
+++ b/drivers/infiniband/hw/mlx5/devx.c
@@ -1886,8 +1886,10 @@ subscribe_event_xa_alloc(struct mlx5_devx_event_table *devx_event_table,
key_level2,
obj_event,
GFP_KERNEL);
- if (err)
+ if (err) {
+ kfree(obj_event);
return err;
+ }
INIT_LIST_HEAD(&obj_event->obj_sub_list);
}

--
2.7.4

2022-03-14 12:25:59

by Leon Romanovsky

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Subject: Re: [PATCH] RDMA/mlx5: Fix memory leak

On Fri, Mar 11, 2022 at 09:06:01AM -0800, Yongzhi Liu wrote:
> [why]
> xa_insert is failed, so caller of subscribe_event_xa_alloc
> cannot call other function to free obj_event. Therefore,
> Resource release is needed on the error handling path to
> prevent memory leak.
>
> [how]
> Fix this by adding kfree on the error handling path.
>
> Fixes: 7597385 ("IB/mlx5: Enable subscription for device events over DEVX")
>
> Signed-off-by: Yongzhi Liu <[email protected]>
> ---
> drivers/infiniband/hw/mlx5/devx.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)

The change itself is correct one, but commit message needs to be improved.
Something like that:

------------------------------------------------------------------
[PATCH] RDMA/mlx5: Fix memory leak in error subscribe event routine

In case second xa_insert() fails, the obj_event is not released.
Fix the error unwind flow to free that memory to avoid memory leak.

Fixes: 7597385 ("IB/mlx5: Enable subscription for device events over DEVX")
Signed-off-by: Yongzhi Liu <[email protected]>
-------------------------------------------------------------------

>
> diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c
> index 08b7f6b..15c0884 100644
> --- a/drivers/infiniband/hw/mlx5/devx.c
> +++ b/drivers/infiniband/hw/mlx5/devx.c
> @@ -1886,8 +1886,10 @@ subscribe_event_xa_alloc(struct mlx5_devx_event_table *devx_event_table,
> key_level2,
> obj_event,
> GFP_KERNEL);
> - if (err)
> + if (err) {
> + kfree(obj_event);
> return err;
> + }
> INIT_LIST_HEAD(&obj_event->obj_sub_list);
> }
>
> --
> 2.7.4
>

2022-03-17 06:23:20

by Jason Gunthorpe

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