Re: Patch "mm: Fix is_zero_page() usage in try_grab_page()" has been added to the 6.1-stable tree

[David Hildenbrand <david@redhat.com>]

On 22.04.25 10:05, gregkh@linuxfoundation.org wrote:
> 
> This is a note to let you know that I've just added the patch titled
> 
>      mm: Fix is_zero_page() usage in try_grab_page()
> 
> to the 6.1-stable tree which can be found at:
>      http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>       mm-fix-is_zero_page-usage-in-try_grab_page.patch
> and it can be found in the queue-6.1 subdirectory.
> 
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@vger.kernel.org> know about it.
> 
> 
>  From alex.williamson@redhat.com  Tue Apr 22 10:00:53 2025
> From: Alex Williamson <alex.williamson@redhat.com>
> Date: Wed, 16 Apr 2025 14:24:39 -0600
> Subject: mm: Fix is_zero_page() usage in try_grab_page()
> Cc: Alex Williamson <alex.williamson@redhat.com>, Salvatore Bonaccorso <carnil@debian.org>, Milan Broz <gmazyland@gmail.com>, stable@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Sasha Levin <sashal@kernel.org>
> Message-ID: <20250416202441.3911142-1-alex.williamson@redhat.com>
> 
> From: Alex Williamson <alex.williamson@redhat.com>
> 
> 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@debian.org>
> Reported-by: Milan Broz <gmazyland@gmail.com>
> Cc: stable@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-mm@kvack.org
> Cc: Sasha Levin <sashal@kernel.org>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>   mm/gup.c |    2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -232,7 +232,7 @@ bool __must_check try_grab_page(struct p
>   		 * 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*
> 
> 
> Patches currently in stable-queue which might be from alex.williamson@redhat.com are
> 
> queue-6.1/mm-fix-is_zero_page-usage-in-try_grab_page.patch
> queue-6.1/revert-pci-avoid-reset-when-disabled-via-sysfs.patch
> 

FWIW

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

-- 
Cheers,

David / dhildenb