From: Xueyuan chen <xueyuan.chen21@gmail•com>
To: akpm@linux-foundation•org, linux-mm@kvack•org
Cc: linux-kernel@vger•kernel.org,
linux-arm-kernel@lists•infradead.org, x86@kernel•org,
catalin.marinas@arm•com, will@kernel•org, tglx@kernel•org,
mingo@redhat•com, bp@alien8•de, dave.hansen@linux•intel.com,
hpa@zytor•com, david@kernel•org, ljs@kernel•org, ziy@nvidia•com,
baolin.wang@linux•alibaba.com, ryan.roberts@arm•com,
dev.jain@arm•com, lance.yang@linux•dev,
yang@os•amperecomputing.com, jannh@google•com,
Xueyuan Chen <xueyuan.chen21@gmail•com>
Subject: [RFC PATCH 0/3] make persistent huge zero folio read-only
Date: Wed, 27 May 2026 11:56:04 +0800 [thread overview]
Message-ID: <20260527035607.14919-1-xueyuan.chen21@gmail.com> (raw)
From: Xueyuan Chen <xueyuan.chen21@gmail•com>
Hi all,
This series makes the persistent huge zero folio read-only in the direct
map.
The motivation comes from Jann Horn's read-only zero page work[1] and the
follow-up discussion[2] with Yang Shi. As Jann pointed out, the kernel has
had bugs, including security bugs, where pages taken with read-only
semantics were later written to. For the huge zero folio, making the direct
map read-only turns such writes into faults instead of silently corrupting
shared zero contents.
The permission change is best effort. If the architecture cannot safely
make the direct map read-only, the kernel keeps using the writable
persistent huge zero folio.
Patch 1 adds the generic support for making the persistent huge zero folio
read-only. Patches 2 and 3 add arm64 and x86 support.
[1] https://lore.kernel.org/linux-mm/20260508-ro-zeropage-v1-1-9808abc20b49@google.com/
[2] https://lore.kernel.org/linux-mm/CAHbLzkrXXe7r3n3jXgDKtwZhRqj=jDx9E6dLOULohnhBguvi9A@mail.gmail.com/
Xueyuan Chen (3):
mm: make persistent huge zero folio read-only
arm64/mm: make huge zero folio read-only in linear map
x86/mm: make huge zero folio read-only in direct map
arch/arm64/Kconfig | 1 +
arch/arm64/mm/pageattr.c | 16 ++++++++++++++++
arch/x86/Kconfig | 1 +
arch/x86/mm/init.c | 11 +++++++++++
include/linux/huge_mm.h | 5 +++++
mm/Kconfig | 17 +++++++++++++++++
mm/huge_memory.c | 25 ++++++++++++++++++++++++-
7 files changed, 75 insertions(+), 1 deletion(-)
--
2.47.3
next reply other threads:[~2026-05-27 3:56 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-27 3:56 Xueyuan chen [this message]
2026-05-27 3:56 ` [RFC PATCH 1/3] mm: make persistent huge zero folio read-only Xueyuan chen
2026-05-27 13:32 ` Dev Jain
2026-05-27 23:03 ` Xueyuan Chen
2026-05-27 15:55 ` Dave Hansen
2026-05-27 16:20 ` Jann Horn
2026-05-28 18:43 ` Yang Shi
2026-05-29 3:09 ` Lance Yang
2026-06-01 13:49 ` David Hildenbrand (Arm)
2026-06-01 15:43 ` Lance Yang
2026-06-01 15:46 ` David Hildenbrand (Arm)
2026-05-27 3:56 ` [RFC PATCH 2/3] arm64/mm: make huge zero folio read-only in linear map Xueyuan chen
2026-05-27 3:56 ` [RFC PATCH 3/3] x86/mm: make huge zero folio read-only in direct map Xueyuan chen
2026-05-27 15:58 ` [RFC PATCH 0/3] make persistent huge zero folio read-only Dave Hansen
2026-05-30 7:46 ` Lance Yang
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