linux-kernel - [PATCH 6/8] mm: page_alloc: fix move_freepages

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:   Mon, 21 Aug 2023 14:33:38 -0400
From:   Johannes Weiner <hannes@...xchg.org>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Vlastimil Babka <vbabka@...e.cz>,
        Mel Gorman <mgorman@...hsingularity.net>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 6/8] mm: page_alloc: fix move_freepages_block() range error

When a block is partially outside the zone of the cursor page, the
function cuts the range to the pivot page instead of the zone
start. This can leave large parts of the block behind, which
encourages incompatible page mixing down the line (ask for one type,
get another), and thus long-term fragmentation.

Signed-off-by: Johannes Weiner <hannes@...xchg.org>
---
 mm/page_alloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6a4004f07123..6fcda8e96f16 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1697,7 +1697,7 @@ int move_freepages_block(struct zone *zone, struct page *page,
 
 	/* Do not cross zone boundaries */
 	if (!zone_spans_pfn(zone, start_pfn))
-		start_pfn = pfn;
+		start_pfn = zone->zone_start_pfn;
 	if (!zone_spans_pfn(zone, end_pfn))
 		return 0;
 
-- 
2.41.0