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

From: Mathias Krause
Date: Fri Mar 09 2018 - 07:49:15 EST


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