Re: [PATCH 3/4] KFENCE: Deferring the assignment of the local variable addr

[Marco Elver <elver@google.com>]

On Wed, 19 Jul 2023 at 10:28, Enze Li <lienze@kylinos.cn> wrote:
>
> The LoongArch architecture is different from other architectures.
> It needs to update __kfence_pool during arch_kfence_init_pool.
>
> This patch modifies the assignment location of the local variable addr
> in the kfence_init_pool function to support the case of updating
> __kfence_pool in arch_kfence_init_pool.
>
> Signed-off-by: Enze Li <lienze@kylinos.cn>

I think it's fair to allow this use case.

However, please make sure that when your arch_kfence_init_pool()
fails, it is still possible to free the memblock allocated memory
properly.

Acked-by: Marco Elver <elver@google.com>

> ---
>  mm/kfence/core.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/mm/kfence/core.c b/mm/kfence/core.c
> index dad3c0eb70a0..e124ffff489f 100644
> --- a/mm/kfence/core.c
> +++ b/mm/kfence/core.c
> @@ -566,13 +566,14 @@ static void rcu_guarded_free(struct rcu_head *h)
>   */
>  static unsigned long kfence_init_pool(void)
>  {
> -       unsigned long addr = (unsigned long)__kfence_pool;
> +       unsigned long addr;
>         struct page *pages;
>         int i;
>
>         if (!arch_kfence_init_pool())
> -               return addr;
> +               return (unsigned long)__kfence_pool;
>
> +       addr = (unsigned long)__kfence_pool;
>         pages = virt_to_page(__kfence_pool);
>
>         /*
> --
> 2.34.1
>