From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Dev Jain <dev.jain@arm.com>,
muchun.song@linux.dev, osalvador@suse.de,
akpm@linux-foundation.org, ljs@kernel.org, liam@infradead.org
Cc: riel@surriel.com, vbabka@kernel.org, harry@kernel.org,
jannh@google.com, lance.yang@linux.dev, kas@kernel.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
rcampbell@nvidia.com, apopple@nvidia.com, ziy@nvidia.com,
matthew.brost@intel.com, joshua.hahnjy@gmail.com,
rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net,
ying.huang@linux.alibaba.com, j-nomura@ce.jp.nec.com,
nao.horiguchi@gmail.com, ak@linux.intel.com, mel@csn.ul.ie,
pfalcato@suse.de, jpoimboe@kernel.org, dave.hansen@intel.com,
tglx@kernel.org, catalin.marinas@arm.com, will@kernel.org,
linux-arm-kernel@lists.infradead.org, ryan.roberts@arm.com,
anshuman.khandual@arm.com, stable@vger.kernel.org
Subject: Re: [PATCH v2 4/6] mm/migrate: use huge_ptep_get() in remove_migration_pte()
Date: Thu, 2 Jul 2026 17:44:20 +0200 [thread overview]
Message-ID: <e552da60-3d44-4812-9522-19df8470c495@kernel.org> (raw)
In-Reply-To: <20260702051341.126509-5-dev.jain@arm.com>
On 7/2/26 07:13, Dev Jain wrote:
> remove_migration_pte() converts migration entries back to present PTEs
> after folio migration completes. For hugetlb folios,
> page_vma_mapped_walk() returns the pte pointer to the hugetlb folio in
> pvmw.pte, but the code reads it with ptep_get().
>
> On arches which provide their own huge_ptep_get() to dereference a huge
> pte pointer, accessing via ptep_get() would cause pte_pfn(),
> pte_present() etc to misbehave.
>
> It is not clear whether this has a trivially visible effect to userspace.
Right, for non-present entries it's even weirder. Fortunately your patch #1 also
handles that.
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
--
Cheers,
David
next prev parent reply other threads:[~2026-07-02 15:44 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-02 5:13 [PATCH v2 0/6] Fix incorrect access of hugetlb pte entries Dev Jain
2026-07-02 5:13 ` [PATCH v2 1/6] arm64: make huge_ptep_get handled unaligned addresses Dev Jain
2026-07-02 15:28 ` David Hildenbrand (Arm)
2026-07-02 5:13 ` [PATCH v2 2/6] mm/rmap: use huge_ptep_get() in try_to_unmap_one() Dev Jain
2026-07-02 8:47 ` Muchun Song
2026-07-02 9:08 ` Dev Jain
2026-07-02 9:35 ` Muchun Song
2026-07-02 15:30 ` David Hildenbrand (Arm)
2026-07-02 15:32 ` David Hildenbrand (Arm)
2026-07-03 5:30 ` Dev Jain
2026-07-03 7:06 ` David Hildenbrand (Arm)
2026-07-02 5:13 ` [PATCH v2 3/6] mm/rmap: use huge_ptep_get() in try_to_migrate_one() Dev Jain
2026-07-02 15:34 ` David Hildenbrand (Arm)
2026-07-02 5:13 ` [PATCH v2 4/6] mm/migrate: use huge_ptep_get() in remove_migration_pte() Dev Jain
2026-07-02 15:44 ` David Hildenbrand (Arm) [this message]
2026-07-02 5:13 ` [PATCH v2 5/6] mm/page_vma_mapped: use huge_ptep_get() for hugetlb Dev Jain
2026-07-02 8:33 ` Muchun Song
2026-07-02 15:44 ` David Hildenbrand (Arm)
2026-07-02 5:13 ` [PATCH v2 6/6] mm/mprotect: " Dev Jain
2026-07-02 5:18 ` Dev Jain
2026-07-02 8:29 ` Muchun Song
2026-07-02 8:30 ` Muchun Song
2026-07-02 15:47 ` David Hildenbrand (Arm)
2026-07-03 5:30 ` Dev Jain
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