linux-kernel - Re: [PATCH 01/19] mm: fix NUMA node file count error in replace_page

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: <20200518111850.GA107644@dev-dsk-sblbir-1c-a524888b.ap-northeast-1.amazon.com>
Date:   Mon, 18 May 2020 11:18:50 +0000
From:   Balbir Singh <bsingharora@...il.com>
To:     Johannes Weiner <hannes@...xchg.org>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Alex Shi <alex.shi@...ux.alibaba.com>,
        Joonsoo Kim <js1304@...il.com>,
        Shakeel Butt <shakeelb@...gle.com>,
        Hugh Dickins <hughd@...gle.com>,
        Michal Hocko <mhocko@...e.com>,
        "Kirill A. Shutemov" <kirill@...temov.name>,
        Roman Gushchin <guro@...com>, linux-mm@...ck.org,
        cgroups@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-team@...com
Subject: Re: [PATCH 01/19] mm: fix NUMA node file count error in
 replace_page_cache()

On Fri, May 08, 2020 at 02:30:48PM -0400, Johannes Weiner wrote:
> When replacing one page with another one in the cache, we have to
> decrease the file count of the old page's NUMA node and increase the
> one of the new NUMA node, otherwise the old node leaks the count and
> the new node eventually underflows its counter.
> 
> Fixes: 74d609585d8b ("page cache: Add and replace pages using the XArray")
> Signed-off-by: Johannes Weiner <hannes@...xchg.org>
> Reviewed-by: Alex Shi <alex.shi@...ux.alibaba.com>
> Reviewed-by: Shakeel Butt <shakeelb@...gle.com>
> Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@....com>
> ---
>  mm/filemap.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/filemap.c b/mm/filemap.c
> index af1c6adad5bd..2b057b0aa882 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -808,11 +808,11 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
>  	old->mapping = NULL;
>  	/* hugetlb pages do not participate in page cache accounting. */
>  	if (!PageHuge(old))
> -		__dec_node_page_state(new, NR_FILE_PAGES);
> +		__dec_node_page_state(old, NR_FILE_PAGES);
>  	if (!PageHuge(new))
>  		__inc_node_page_state(new, NR_FILE_PAGES);
>  	if (PageSwapBacked(old))
> -		__dec_node_page_state(new, NR_SHMEM);
> +		__dec_node_page_state(old, NR_SHMEM);
>  	if (PageSwapBacked(new))
>  		__inc_node_page_state(new, NR_SHMEM);
>  	xas_unlock_irqrestore(&xas, flags);


Reviewed-by: Balbir Singh <bsingharora@...il.com>