From: Baolin Wang <baolin.wang@linux.alibaba.com>
To: "David Hildenbrand (Arm)" <david@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
"Liam R. Howlett" <liam@infradead.org>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Xu <peterx@redhat.com>,
Lokesh Gidra <lokeshgidra@google.com>,
Barry Song <baohua@kernel.org>, Rik van Riel <riel@surriel.com>,
Harry Yoo <harry@kernel.org>, Jann Horn <jannh@google.com>,
Lance Yang <lance.yang@linux.dev>,
Ryan Roberts <ryan.roberts@arm.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, Chris Mason <mason@kernel.org>
Subject: Re: [PATCH 2/3] mm/rmap: fix PTE table overruns during batched unmap
Date: Thu, 12 Nov 2026 15:16:31 +0800 [thread overview]
Message-ID: <08ae2f1d-964e-4f20-a66c-d2ce3460220b@linux.alibaba.com> (raw)
In-Reply-To: <20261111-pte_table_clamped_end-v1-2-2dbe339c487a@kernel.org>
On 11/12/26 6:00 AM, David Hildenbrand (Arm) wrote:
> With a folded PMD, pmd_addr_end() simply returns the supplied end.
> folio_unmap_pte_batch() can therefore walk past the PTE table when
> unmapping a large folio.
>
> Folded PMDs are uncommon, but can occur even on arm64, for example
> with 64K pages and a 42-bit virtual address space.
>
> Use pte_table_clamped_end() to clamp the range to the PTE table and
> VMA boundaries.
>
> Fixes: 354dffd29575 ("mm: support batched unmap for lazyfree large folios during reclamation")
> Cc: stable@vger.kernel.org
> Reported-by: Chris Mason <mason@kernel.org>
> Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
> ---
LGTM.
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
next prev parent reply other threads:[~2026-11-12 7:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-11 21:59 [PATCH 0/3] mm: fix PTE table overruns with folded PMDs David Hildenbrand (Arm)
2026-11-11 21:59 ` [PATCH 1/3] mm/userfaultfd: fix PTE table overruns in UFFDIO_MOVE David Hildenbrand (Arm)
2026-11-12 7:15 ` Baolin Wang
2026-11-11 22:00 ` [PATCH 2/3] mm/rmap: fix PTE table overruns during batched unmap David Hildenbrand (Arm)
2026-11-12 7:16 ` Baolin Wang [this message]
2026-11-11 22:00 ` [PATCH 3/3] mm/rmap: fix PTE table overruns during batched reference checks David Hildenbrand (Arm)
2026-11-12 7:25 ` Baolin Wang
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