From: Andrew Morton <akpm@linux-foundation.org>
To: Wei Yang <richard.weiyang@gmail.com>
Cc: vbabka@suse.cz, surenb@google.com, mhocko@suse.com,
jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com,
david@redhat.com, lorenzo.stoakes@oracle.com,
Liam.Howlett@oracle.com, rppt@kernel.org, iamjoonsoo.kim@lge.com,
linux-mm@kvack.org
Subject: Re: [PATCH 0/2] mm/compaction: some fix for the range passed to pageblock_pfn_to_page()
Date: Tue, 7 Oct 2025 18:29:22 -0700 [thread overview]
Message-ID: <20251007182922.4a254daff78633b1452bdcc3@linux-foundation.org> (raw)
In-Reply-To: <20251002033140.24462-1-richard.weiyang@gmail.com>
On Thu, 2 Oct 2025 03:31:38 +0000 Wei Yang <richard.weiyang@gmail.com> wrote:
> During the code reading of isolate_migratepages_range(), first spot the range
> passed to pageblock_pfn_to_page() is different from that to
> isolate_migratepages_block().
>
> This implies there is a chance that pageblock_pfn_to_page() thinks the range
> is in the same zone, but isolate_migratepages_block() will isolate range in
> two different zones. This is not what we expect.
>
> Then I found pageblock_pfn_to_page() has an optimization if zone->contiguous,
> this means even the range is across two different zones, it will think the
> range is within the same zone.
>
> So introduce two patches to fix it:
What do you think might be the worst-case userspace-visible effects
of the bug?
Thanks.
next prev parent reply other threads:[~2025-10-08 1:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-02 3:31 Wei Yang
2025-10-02 3:31 ` [PATCH 1/2] mm/compaction: check the range to pageblock_pfn_to_page() is within the zone first Wei Yang
2025-10-08 10:14 ` David Hildenbrand
2025-10-09 2:08 ` Wei Yang
2025-10-09 7:19 ` David Hildenbrand
2025-10-02 3:31 ` [PATCH 2/2] mm/compaction: fix the range to pageblock_pfn_to_page() Wei Yang
2025-10-08 10:17 ` David Hildenbrand
2025-10-08 11:16 ` Michal Hocko
2025-10-09 3:39 ` Wei Yang
2025-10-08 1:29 ` Andrew Morton [this message]
2025-10-08 2:32 ` [PATCH 0/2] mm/compaction: some fix for the range passed " Wei Yang
2025-10-08 7:52 ` Michal Hocko
2025-10-08 9:13 ` Wei Yang
2025-10-08 9:55 ` David Hildenbrand
2025-11-11 23:32 ` Andrew Morton
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