From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9833DC43458 for ; Fri, 3 Jul 2026 11:43:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=rhmPAyPji4IiYnAgpKt2XVKFZNBHGXgCXYcf2whmneI=; b=EIQvgzEK2XSvG0olPUBfS0jYtJ siwi97aWr7UmDjrI0Mjfk/DLJLthms/pdEWXzeNaJmz0fHqL08DetjgDwya65guahb0CLTtou+WGD e91ZdLzX5k0gU17Ge4sCD7iQqInmuIT4vDKzS2XWUg7IclowhO+wVYcoqMskBz2pj9AtIqQgBi8Dt TjxD96RSSauIqEUAVs9+J0Ksxgeuff/BbmaoKYqfLe16K2mNdEAbS2DckP0TCelbpZRAOv2P9TDNi yAOk/kzU1W1mdjInogk0+C662+Jf/7okb4uDpas1d19E4LmbxqswY7jyfHHU5POCdvI9/dNDGfh7w STmo23Qw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wfcIW-00000006pi7-0gtk; Fri, 03 Jul 2026 11:43:08 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wfcIT-00000006pfs-0cPA for linux-arm-kernel@lists.infradead.org; Fri, 03 Jul 2026 11:43:07 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C3E4535C8; Fri, 3 Jul 2026 04:42:59 -0700 (PDT) Received: from cesw-amp-gbt-1s-m12830-01.blr.arm.com (cesw-amp-gbt-1s-m12830-01.blr.arm.com [10.164.195.31]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id A11603F673; Fri, 3 Jul 2026 04:42:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1783078984; 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-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260703_044305_229529_ABD39169 X-CRM114-Status: UNSURE ( 9.85 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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