linux-kernel - [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]

Date:   Fri,  8 May 2020 14:30:48 -0400
From:   Johannes Weiner <hannes@...xchg.org>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     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: [PATCH 01/19] mm: fix NUMA node file count error in replace_page_cache()

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);
-- 
2.26.2