linux-kernel - Re: [PATCH stable 6.1] mm: Fix is_zero_page() usage in try_grab

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <1eb021d5-3472-4a47-8a3f-d5bae83b8391@redhat.com>
Date: Thu, 17 Apr 2025 09:12:18 +0200
From: David Hildenbrand <david@...hat.com>
To: Alex Williamson <alex.williamson@...hat.com>
Cc: Salvatore Bonaccorso <carnil@...ian.org>, Milan Broz
 <gmazyland@...il.com>, stable@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-mm@...ck.org, Sasha Levin <sashal@...nel.org>
Subject: Re: [PATCH stable 6.1] mm: Fix is_zero_page() usage in
 try_grab_page()

On 16.04.25 22:24, Alex Williamson wrote:
> The backport of upstream commit c8070b787519 ("mm: Don't pin ZERO_PAGE
> in pin_user_pages()") into v6.1.130 noted below in Fixes does not
> account for commit 0f0892356fa1 ("mm: allow multiple error returns in
> try_grab_page()"), which changed the return value of try_grab_page()
> from bool to int.  Therefore returning 0, success in the upstream
> version, becomes an error here.  Fix the return value.
> 
> Fixes: 476c1dfefab8 ("mm: Don't pin ZERO_PAGE in pin_user_pages()")
> Link: https://lore.kernel.org/all/Z_6uhLQjJ7SSzI13@eldamar.lan
> Reported-by: Salvatore Bonaccorso <carnil@...ian.org>
> Reported-by: Milan Broz <gmazyland@...il.com>
> Cc: stable@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> Cc: linux-mm@...ck.org
> Cc: Sasha Levin <sashal@...nel.org>
> Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
> ---
>   mm/gup.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/gup.c b/mm/gup.c
> index b1daaa9d89aa..76a2b0943e2d 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -232,7 +232,7 @@ bool __must_check try_grab_page(struct page *page, unsigned int flags)
>   		 * and it is used in a *lot* of places.
>   		 */
>   		if (is_zero_page(page))
> -			return 0;
> +			return true;
>   
>   		/*
>   		 * Similar to try_grab_folio(): be sure to *also*

Reviewed-by: David Hildenbrand <david@...hat.com>

-- 
Cheers,

David / dhildenb