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bh=QibAWbZw4adH0rQMvhQv9lcIr1WFPi662truFhm4Ubw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uKpG9QTSOi87p1LOsj3dnWli+GqrppjCjNWMmEgZLXCJtd57TsRx7GWJ98w1ZVOAZ 20yIQYe4WsOHi148Hhyqepvl/DlVJN4MyKKvI5WdispsFnQlQaD+7fhvc0UOsbtErU ReX/Pnc7lJHNnbHM3HH3YQyfDO/tChOi9OHrBpu4= 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, apopple@nvidia.com, rcampbell@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, ak@linux.intel.com, nao.horiguchi@gmail.com, mel@csn.ul.ie, j-nomura@ce.jp.nec.com, pfalcato@suse.de, tglx@kernel.org, dave.hansen@intel.com, jpoimboe@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: [PATCH v3 4/6] mm/migrate: use huge_ptep_get() in remove_migration_pte() Date: Fri, 3 Jul 2026 11:41:57 +0000 Message-ID: <20260703114202.365553-5-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260703114202.365553-1-dev.jain@arm.com> References: <20260703114202.365553-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam11 X-Rspam-User: X-Stat-Signature: 1h9xwx8t4ftywxj5zbdxiwp8nqpusxpo X-Rspamd-Queue-Id: E6ABB4000B X-HE-Tag: 1783078984-681740 X-HE-Meta: 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 kaD4qI+n OUGLB4WPh/AcDLIGldFCOUE7N+ErWN7jThwaCxGMsAs3Ann8aEIpW0COY1hUUCXY7eHeA+sn9erqm+CjXmioOGaJ2QjcAZGUHNMGJ0ixyJzQk55vyQVecU3No2nknAZ9RmOKSzEBwUPlYrX7GoP3mL/DSfj52fS43094cUVHERpqJHk0VtGEmKpfBriFwCdEzVhwGYxDs7Wsnuq80A16DlxisxDG+RSEI7tDtRMTEuKS41C3ySA5a+9l39IpA7DvkkRhH5CE3alphbTDWtzM48JRAWl1eU7CpsGIPp0Rz9kWB7wgV9z11C4bt015MhJC6VwOjuJsNBN7FusYuKcY6HFQAuD0+jZBY0fc77iApB+3qIQEWJwckZwbAJvQT6MYeA2F5nAEEMe5JVeY= 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 Acked-by: Muchun Song Acked-by: David Hildenbrand (Arm) 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