Re: [net RFC v1 1/1] page_pool: fix NULL dereference crash

[Alexei Starovoitov]

On Fri, Jan 21, 2022 at 4:57 PM Colin Foster
<colin.foster@xxxxxxxxxxxxxxxx> wrote:
>
> Check for the existence of page pool params before dereferencing. This can
> cause crashes in certain conditions.

In what conditions?
Out of tree driver?

> Fixes: 35b2e549894b ("page_pool: Add callback to init pages when they are
> allocated")
>
> Signed-off-by: Colin Foster <colin.foster@xxxxxxxxxxxxxxxx>
> ---
>  net/core/page_pool.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index bd62c01a2ec3..641f849c95e7 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -213,7 +213,7 @@ static void page_pool_set_pp_info(struct page_pool *pool,
>  {
>         page->pp = pool;
>         page->pp_magic |= PP_SIGNATURE;
> -       if (pool->p.init_callback)
> +       if (pool->p && pool->p.init_callback)
>                 pool->p.init_callback(page, pool->p.init_arg);
>  }
>
> --
> 2.25.1
>