linux-kernel - Re: [PATCH 2/2] mm: shmem: fix the update of 'shmem_falloc->nr

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

Message-ID: <7d087c20-91f2-4c38-9ad8-7cd45a0906b6@redhat.com>
Date: Thu, 19 Dec 2024 16:36:46 +0100
From: David Hildenbrand <david@...hat.com>
To: Baolin Wang <baolin.wang@...ux.alibaba.com>, akpm@...ux-foundation.org,
 hughd@...gle.com
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] mm: shmem: fix the update of
 'shmem_falloc->nr_unswapped'

On 19.12.24 08:30, Baolin Wang wrote:
> The 'shmem_falloc->nr_unswapped' is used to record how many writepage
> refused to swap out because fallocate() is allocating, but after shmem
> supports large folio swap out, the update of 'shmem_falloc->nr_unswapped'
> does not use the correct number of pages in the large folio, which may
> lead to fallocate() not exiting as soon as possible.
> 
> Anyway, this is found through code inspection, and I am not sure whether
> it would actually cause serious issues.
> 
> Fixes: 809bc86517cc ("mm: shmem: support large folio swap out")
> Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
> ---
>   mm/shmem.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/shmem.c b/mm/shmem.c
> index dec659e84562..ac58d4fb2e6f 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -1535,7 +1535,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
>   			    !shmem_falloc->waitq &&
>   			    index >= shmem_falloc->start &&
>   			    index < shmem_falloc->next)
> -				shmem_falloc->nr_unswapped++;
> +				shmem_falloc->nr_unswapped += nr_pages;
>   			else
>   				shmem_falloc = NULL;
>   			spin_unlock(&inode->i_lock);

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


-- 
Cheers,

David / dhildenb