The patch titled
Subject: mm: page_alloc: avoid false page outside zone error info
has been added to the -mm mm-unstable branch. Its filename is
mm-page_alloc-avoid-false-page-outside-zone-error-info.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_alloc-avoid-false-page-outside-zone-error-info.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm: page_alloc: avoid false page outside zone error info
Date: Tue, 4 Jul 2023 19:18:23 +0800
If pfn is outside zone boundaries in the first round, ret will be set to
1. But if pfn is changed to inside the zone boundaries in zone span
seqretry path, ret is still set to 1 leading to false page outside zone
error info.
This is from code inspection. The race window should be really small thus
hard to trigger in real world.
Link: https://lkml.kernel.org/r/20230704111823.940331-1-linmiaohe@xxxxxxxxxx
Fixes: bdc8cb984576 ("[PATCH] memory hotplug locking: zone span seqlock")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/mm/page_alloc.c~mm-page_alloc-avoid-false-page-outside-zone-error-info
+++ a/mm/page_alloc.c
@@ -459,7 +459,7 @@ void set_pageblock_migratetype(struct pa
#ifdef CONFIG_DEBUG_VM
static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
{
- int ret = 0;
+ int ret;
unsigned seq;
unsigned long pfn = page_to_pfn(page);
unsigned long sp, start_pfn;
@@ -470,6 +470,8 @@ static int page_outside_zone_boundaries(
sp = zone->spanned_pages;
if (!zone_spans_pfn(zone, pfn))
ret = 1;
+ else
+ ret = 0;
} while (zone_span_seqretry(zone, seq));
if (ret)
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-mm_initc-update-obsolete-comment-in-get_pfn_range_for_nid.patch
mm-memory-failure-fix-unexpected-return-value-in-soft_offline_page.patch
mm-memory-failure-fix-potential-page-refcnt-leak-in-memory_failure.patch
mm-memory-failure-remove-unneeded-page-state-check-in-shake_page.patch
memory-tier-use-helper-function-destroy_memory_type.patch
mm-memory-failure-remove-unneeded-inline-annotation.patch
mm-mm_initc-remove-obsolete-macro-hash_small.patch
mm-page_alloc-avoid-false-page-outside-zone-error-info.patch
