Re: [PATCH 1/5] mm, swap: Fix memory leak in setup_clusters() error path

[Kairui Song <ryncsn@gmail.com>]

On Wed, Oct 29, 2025 at 8:44 PM Youngjun Park <youngjun.park@lge.com> wrote:
>
> Some error path neglects to free the allocated 'cluster_info',
> causing a memory leak.
>
> Change the error jumps to the 'err_free' label to ensure proper
> cleanup.
>
> Fixes: 07adc4cf1ecd ("mm, swap: implement dynamic allocation of swap table")
> Signed-off-by: Youngjun Park <youngjun.park@lge.com>
> ---
>  mm/swapfile.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index c35bb8593f50..6dc0e7a738bc 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -3339,7 +3339,7 @@ static struct swap_cluster_info *setup_clusters(struct swap_info_struct *si,
>          */
>         err = swap_cluster_setup_bad_slot(cluster_info, 0);
>         if (err)
> -               goto err;
> +               goto err_free;
>         for (i = 0; i < swap_header->info.nr_badpages; i++) {
>                 unsigned int page_nr = swap_header->info.badpages[i];
>
> @@ -3347,12 +3347,12 @@ static struct swap_cluster_info *setup_clusters(struct swap_info_struct *si,
>                         continue;
>                 err = swap_cluster_setup_bad_slot(cluster_info, page_nr);
>                 if (err)
> -                       goto err;
> +                       goto err_free;
>         }
>         for (i = maxpages; i < round_up(maxpages, SWAPFILE_CLUSTER); i++) {
>                 err = swap_cluster_setup_bad_slot(cluster_info, i);
>                 if (err)
> -                       goto err;
> +                       goto err_free;
>         }
>
>         INIT_LIST_HEAD(&si->free_clusters);
> --
> 2.34.1
>
>

Nice catch.

Maybe it's better to just move free_cluster_info under "err:"? That
might help to avoid more issues like this. free_cluster_info checks if
cluster_info is null already, we just need to initialize *cluster_info
with "= NULL".

Just a nit pick, I'm fine either way.

Reviewed-by: Kairui Song <kasong@tencent.com>