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From: Muchun Song In-Reply-To: <20260625112955.3254283-4-dev.jain@arm.com> Date: Fri, 26 Jun 2026 11:32:03 +0800 Cc: osalvador@suse.de, akpm@linux-foundation.org, ljs@kernel.org, david@kernel.org, liam@infradead.org, 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, mel@csn.ul.ie, nao.horiguchi@gmail.com, ak@linux.intel.com, j-nomura@ce.jp.nec.com, pfalcato@suse.de, dave.hansen@intel.com, tglx@kernel.org, jpoimboe@kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com, stable@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: <7E9EBE58-C2D0-44F4-8797-D8077E26AFEC@linux.dev> References: <20260625112955.3254283-1-dev.jain@arm.com> <20260625112955.3254283-4-dev.jain@arm.com> To: Dev Jain X-Migadu-Flow: FLOW_OUT X-Stat-Signature: gd5puii5ggk3i9pufijr8y4rtfkca45w X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 197CA160006 X-HE-Tag: 1782444817-826989 X-HE-Meta: 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 2zL66GOf VHT80/GOp2wwnHjA5PFLl2kDHpyYsnLgkPPeDHKxT5mwPIV+fD9T8Ei0/YTt11trkPe6Ti31dbzpvNz7mkPVb2+OhmIsGsSVGipJLG5hPuOrm7fdDEyePR6+pvn+BgiV3KZVc7EhNNkhROqJRZ0+sDm8VWeGDsVEb/2gZfS3r5Wo+RkP56/tiNRYdMfZySJ3onNtzcQoMJRfSEk1Nik9U+sXDAeNGx3XjpzNiisfk77t+K6/Myh+VokYjgh8NJMjZOtOt9JOIh+MRSZixo6mCAsDSxNwmJ9KLhSV1Qz4l2Tq3pvbyNzO9F/llnE/g+jokuWD4j2l6ZUvekAjY3+UbPt1VQdgxwPplBe9hQitKm5+K6L03DbKncA2w9oMYiCQRzyxs3iLLSHufvHUgbwGHmMXrmk/SflwaS1VnHWuuIN5mwhl/hufwSIIsO97cWOYn2mVR Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: > On Jun 25, 2026, at 19:29, Dev Jain wrote: >=20 > 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(). >=20 > 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. >=20 > It is not clear whether this has a trivially visible effect to = userspace. We are dealing with migration entries here, so the issue mentioned = shouldn't be a problem with any of the architectures. Semantically speaking, we = definitely should fix this. >=20 > Use huge_ptep_get() to dereference a huge pte pointer. >=20 > Fixes: 290408d4a250 ("hugetlb: hugepage migration core") > Cc: stable@vger.kernel.org > Signed-off-by: Dev Jain Acked-by: Muchun Song Thanks