From: Zi Yan <ziy@nvidia.com>
To: Usama Arif <usama.arif@linux.dev>
Cc: Andrew Morton <akpm@linux-foundation.org>,
david@kernel.org, chrisl@kernel.org, kasong@tencent.com,
ljs@kernel.org, ying.huang@linux.alibaba.com,
Baoquan He <baoquan.he@linux.dev>,
willy@infradead.org, youngjun.park@lge.com, hannes@cmpxchg.org,
riel@surriel.com, shakeel.butt@linux.dev, alex@ghiti.fr,
kas@kernel.org, baohua@kernel.org, dev.jain@arm.com,
baolin.wang@linux.alibaba.com, npache@redhat.com,
"Liam R. Howlett" <liam@infradead.org>,
ryan.roberts@arm.com, Vlastimil Babka <vbabka@kernel.org>,
lance.yang@linux.dev, linux-kernel@vger.kernel.org,
nphamcs@gmail.com, shikemeng@huaweicloud.com,
kernel-team@meta.com
Subject: Re: [v2 04/16] mm/huge_memory: move softleaf_to_folio() inside migration branch
Date: Sat, 13 Jun 2026 15:02:49 -0400 [thread overview]
Message-ID: <B173CCAF-FDBD-4FCF-AACD-5137EB79F3B6@nvidia.com> (raw)
In-Reply-To: <20260602142537.198755-5-usama.arif@linux.dev>
On 2 Jun 2026, at 10:24, Usama Arif wrote:
> change_non_present_huge_pmd() calls softleaf_to_folio() unconditionally
> at the top of the function. softleaf_to_folio() extracts a PFN from
> the entry and converts it to a folio pointer, which is only meaningful
> for migration and device_private entries that encode a real PFN.
>
> A swap entry encodes a swap offset instead, so softleaf_to_folio()
> would produce a bogus pointer and crash on mprotect() when a PMD swap
> entry is present.
>
> Move the call into the migration_write branch where the folio is
> actually used, so the function is safe for any non-present PMD type.
>
> Acked-by: David Hildenbrand (Arm) <david@kernel.org>
> Reviewed-by: Dev Jain <dev.jain@arm.com>
> Signed-off-by: Usama Arif <usama.arif@linux.dev>
> ---
> mm/huge_memory.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
LGTM.
Reviewed-by: Zi Yan <ziy@nvidia.com>
--
Best Regards,
Yan, Zi
next prev parent reply other threads:[~2026-06-13 19:02 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-02 14:24 [v2 00/16] mm: PMD-level swap entries for anonymous THPs Usama Arif
2026-06-02 14:24 ` [v2 01/16] mm: add softleaf_to_pmd() and convert existing callers Usama Arif
2026-06-13 18:52 ` Zi Yan
2026-06-02 14:24 ` [v2 02/16] mm: extract mm_prepare_for_swap_entries() helper Usama Arif
2026-06-13 18:53 ` Zi Yan
2026-06-02 14:24 ` [v2 03/16] fs/proc: use softleaf_has_pfn() in pagemap PMD walker Usama Arif
2026-06-13 19:01 ` Zi Yan
2026-06-02 14:24 ` [v2 04/16] mm/huge_memory: move softleaf_to_folio() inside migration branch Usama Arif
2026-06-13 19:02 ` Zi Yan [this message]
2026-06-02 14:24 ` [v2 05/16] mm/migrate_device: move softleaf_to_folio() inside device-private branch Usama Arif
2026-06-13 19:24 ` Zi Yan
2026-06-02 14:24 ` [v2 06/16] mm: rename ARCH_ENABLE_THP_MIGRATION to ARCH_SUPPORTS_PMD_SOFTLEAF Usama Arif
2026-06-13 19:26 ` Zi Yan
2026-06-02 14:24 ` [v2 07/16] mm: add PMD swap entry detection support Usama Arif
2026-06-02 14:24 ` [v2 08/16] mm: add PMD swap entry splitting support Usama Arif
2026-06-02 14:24 ` [v2 09/16] mm: handle PMD swap entries in fork path Usama Arif
2026-06-02 14:24 ` [v2 10/16] mm: swap in PMD swap entries as whole THPs during swapoff Usama Arif
2026-06-02 14:24 ` [v2 11/16] mm: handle PMD swap entries in non-present PMD walkers Usama Arif
2026-06-12 6:45 ` Lance Yang
2026-06-12 15:05 ` Usama Arif
2026-06-12 15:21 ` Lance Yang
2026-06-02 14:24 ` [v2 12/16] mm: handle PMD swap entries in MADV_WILLNEED Usama Arif
2026-06-02 14:24 ` [v2 13/16] mm: handle PMD swap entries in UFFDIO_MOVE Usama Arif
2026-06-12 8:50 ` Lance Yang
2026-06-02 14:24 ` [v2 14/16] mm: handle PMD swap entry faults on swap-in Usama Arif
2026-06-02 14:24 ` [v2 15/16] mm: install PMD swap entries on swap-out Usama Arif
2026-06-12 14:21 ` Lance Yang
2026-06-22 13:50 ` Alexandre Ghiti
2026-06-22 16:53 ` Usama Arif
2026-06-02 14:24 ` [v2 16/16] selftests/mm: add PMD swap entry tests Usama Arif
2026-06-09 14:29 ` [v2 00/16] mm: PMD-level swap entries for anonymous THPs Usama Arif
2026-06-10 12:24 ` David Hildenbrand (Arm)
2026-06-10 13:01 ` Lance Yang
2026-06-10 13:48 ` David Hildenbrand (Arm)
2026-06-10 14:44 ` Usama Arif
2026-06-13 4:22 ` Lance Yang
2026-06-13 19:18 ` Usama Arif
2026-06-14 17:32 ` Kairui Song
2026-06-13 19:27 ` Zi Yan
2026-06-13 19:34 ` Usama Arif
2026-06-13 19:48 ` Usama Arif
2026-06-14 1:48 ` Lance Yang
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