Re: [PATCH net-next v3 01/23] net: page_pool: sanitise allocation order

[Pavel Begunkov <asml.silence@gmail.com>]

On 8/19/25 00:33, Mina Almasry wrote:
> On Mon, Aug 18, 2025 at 6:56 AM Pavel Begunkov <asml.silence@gmail.com> wrote:
>>
>> We're going to give more control over rx buffer sizes to user space, and
>> since we can't always rely on driver validation, let's sanitise it in
>> page_pool_init() as well. Note that we only need to reject over
>> MAX_PAGE_ORDER allocations for normal page pools, as current memory
>> providers don't need to use the buddy allocator and must check the order
>> on init.
>>
>> Suggested-by: Stanislav Fomichev <stfomichev@gmail.com>
>> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
> 
> Reviewed-by: Mina Almasry <almasrymina@google.com>
> 
> I think I noticed an unrelated bug in this code and we need this fix?

Good catch

> 
> ```
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index 343a6cac21e3..ba70569bd4b0 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -287,8 +287,10 @@ static int page_pool_init(struct page_pool *pool,
>          }
> 
>          if (pool->mp_ops) {
> -               if (!pool->dma_map || !pool->dma_sync)
> -                       return -EOPNOTSUPP;
> +               if (!pool->dma_map || !pool->dma_sync) {
> +                       err = -EOPNOTSUPP;
> +                       goto free_ptr_ring;
> +               }
> 
>                  if (WARN_ON(!is_kernel_rodata((unsigned long)pool->mp_ops))) {
>                          err = -EFAULT;
> ```


-- 
Pavel Begunkov