From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B52773B3C11; Fri, 3 Jul 2026 11:43:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783078986; cv=none; b=VVNx3qKIVhlNenb2g6k8nlBYOwFlZfkFTrahAc4l7aMC2tz9Ga2x2KXuylsc6yQ+gUjx0Sl1r7WZ0otbSqPamNYSrnwo4xobgw9CJXgiJPbHX2njOymQT/tIWictKPX9rUXTpXEgWTTWQDMwK0KVtvITLPx1o6Venn0LSFzBPlk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783078986; c=relaxed/simple; bh=QibAWbZw4adH0rQMvhQv9lcIr1WFPi662truFhm4Ubw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ihfw1W/gB1sjvppmwDXzM86UijnC2D9av1oiJpJkgllW9B4zgTKjo8hhv2ZtaV3d/QsgBJ5M7UV/8GVnvxfxGoC55rA1yXR0oSig4OKOdczC7bCBkVCmy60xbzQTmna35D59iaEBXIq/JuOwoe7fvP0hyKpeb8Fu65LXJuo7MHE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=uKpG9QTS; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="uKpG9QTS" 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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