Re: [PATCH] net: ipv6: xfrm6_state: remove VLA usage

[Mathias Krause]

On 9 March 2018 at 13:21, Andreas Christoforou
<andreaschristofo@xxxxxxxxx> wrote:
> The kernel would like to have all stack VLA usage removed[1].
>
> Signed-off-by: Andreas Christoforou <andreaschristofo@xxxxxxxxx>
> ---
>  net/ipv6/xfrm6_state.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/net/ipv6/xfrm6_state.c b/net/ipv6/xfrm6_state.c
> index b15075a..45c0d98 100644
> --- a/net/ipv6/xfrm6_state.c
> +++ b/net/ipv6/xfrm6_state.c
> @@ -62,7 +62,12 @@ __xfrm6_sort(void **dst, void **src, int n, int (*cmp)(void *p), int maxclass)
>  {
>         int i;
>         int class[XFRM_MAX_DEPTH];
> -       int count[maxclass];
> +       int *count;
> +
> +       count = kcalloc(maxclass + 1, sizeof(*count), GFP_KERNEL);
> +
> +       if (!count)
> +               return -ENOMEM;
>
>         memset(count, 0, sizeof(count));
>
> @@ -80,6 +85,7 @@ __xfrm6_sort(void **dst, void **src, int n, int (*cmp)(void *p), int maxclass)
>                 src[i] = NULL;
>         }
>
> +       kfree(count);
>         return 0;
>  }

Instead of dynamically allocating and freeing memory here, shouldn't
we just get rid of the maxclass parameter and use XFRM_MAX_DEPTH as
size for the count[] array, too?

Cheers,
Mathias