From 82d9b8c85b7e4bd85c679ac2da26b57224c4999d Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Tue, 4 Jul 2023 19:18:23 +0800 Subject: [PATCH] mm: page_alloc: avoid false page outside zone error info 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. [akpm@linux-foundation.org: code simplification, per Matthew] Link: https://lkml.kernel.org/r/20230704111823.940331-1-linmiaohe@huawei.com Fixes: bdc8cb984576 ("[PATCH] memory hotplug locking: zone span seqlock") Signed-off-by: Miaohe Lin Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- mm/page_alloc.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index b51bbc4..1eb3864 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -459,7 +459,7 @@ void set_pageblock_migratetype(struct page *page, int migratetype) #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; @@ -468,8 +468,7 @@ static int page_outside_zone_boundaries(struct zone *zone, struct page *page) seq = zone_span_seqbegin(zone); start_pfn = zone->zone_start_pfn; sp = zone->spanned_pages; - if (!zone_spans_pfn(zone, pfn)) - ret = 1; + ret = !zone_spans_pfn(zone, pfn); } while (zone_span_seqretry(zone, seq)); if (ret) -- 2.7.4