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bh=JOkyYoKGZVws+y2+vmN9YpBtKEwEn/j5yavI9jEFAmE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HRZxSSoCdsFKyHQSKFqPXzo5e1bfb1d0NEPHf3RMNJajp0QYStiKg/Vgbi2YEH6yW ZlKHPkn3b0tpmJUQ2jnPfVaAexLjTsDpyaSxTnzsHtlNzCSyzg7/zrcXoAXYy+aJy0 IYrPDR1Ax3981AssSUlNsanBGRqoHg66FQ/kJPuI= From: Dev Jain To: muchun.song@linux.dev, osalvador@suse.de, akpm@linux-foundation.org, ljs@kernel.org, david@kernel.org, liam@infradead.org Cc: Dev Jain , 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 Subject: [PATCH 3/5] mm/migrate: use huge_ptep_get() in remove_migration_pte() Date: Thu, 25 Jun 2026 11:29:52 +0000 Message-ID: <20260625112955.3254283-4-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260625112955.3254283-1-dev.jain@arm.com> References: <20260625112955.3254283-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: 9z1kwkiuz7o4jps3pw33g8zamhz93os4 X-Rspamd-Queue-Id: 9FF6D8000D X-Rspam-User: X-Rspamd-Server: rspam01 X-HE-Tag: 1782387039-813029 X-HE-Meta: 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 nHJvyvFB nLO6UrSePBKHOm9irhK3Emi3WjKJHIE1oU5ZeqRygVGHIPsRSRtEIDff+s8CstZf4o5NaXT894FaIS0E9zHkpHpxhMXpgphAE7EEWJkQy7addK/t5QUy/wtG6q0fQOUA873ANMvFsk/D29ydFeGBVsjmZXq1Ov1U2xQfqC/pHGCyks4NgeJ5y0cJlzY/95pJxHoQ37Afs7L0BHtBg1TIDyHJ/zV1IqZi0eCBL81nCDuHjMaUonf61W53XpGKTjOzuOUs2j6PTZUAKgGZpcGjBiGZV0zzrG5SlhtPqYGCMYcQ8Jiz+jehlv+kaUnkl4NyTWm712PmDRBXTKL9pkukOaCO4IKniV6KdruAAplNep3yyj/m9ui0+Ce0FOrGklzqqke25moFmHI7bSaU= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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. Use huge_ptep_get() to dereference a huge pte pointer. Fixes: 290408d4a250 ("hugetlb: hugepage migration core") Cc: stable@vger.kernel.org Signed-off-by: Dev Jain --- mm/migrate.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/migrate.c b/mm/migrate.c index d9b23909d716c..c65f0f43df7eb 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -371,7 +371,11 @@ static bool remove_migration_pte(struct folio *folio, continue; } #endif - old_pte = ptep_get(pvmw.pte); + if (folio_test_hugetlb(folio)) + old_pte = huge_ptep_get(vma->vm_mm, pvmw.address, + pvmw.pte); + else + old_pte = ptep_get(pvmw.pte); if (rmap_walk_arg->map_unused_to_zeropage && try_to_map_unused_to_zeropage(&pvmw, folio, old_pte, idx)) continue; -- 2.43.0