Re: [PATCH 1/8] mm: memory-failure: fix potential permanently locked hpage

From: Naoya Horiguchi
Date: Mon Jul 10 2023 - 03:56:34 EST


On Sat, Jul 08, 2023 at 04:57:37PM +0800, Miaohe Lin wrote:
> If hpage isn't Hugetlb page, MF_DELAYED is returned without unlock hpage
> leading to hpage permanently locked. But this shouldn't trigger in the
> real world because this PageHuge() check is just for potential problems.

Right, so this if-block is dead code, how about simply removing it?

Thanks,
Naoya Horiguchi

>
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> ---
> mm/memory-failure.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index a6221a4bc5ea..d21ee27ad412 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1187,8 +1187,10 @@ static int me_huge_page(struct page_state *ps, struct page *p)
> struct address_space *mapping;
> bool extra_pins = false;
>
> - if (!PageHuge(hpage))
> + if (!PageHuge(hpage)) {
> + unlock_page(hpage);
> return MF_DELAYED;
> + }
>
> mapping = page_mapping(hpage);
> if (mapping) {
> --
> 2.33.0
>
>
>