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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71450C433EF for ; Thu, 12 May 2022 13:03:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354079AbiELNDF convert rfc822-to-8bit (ORCPT ); Thu, 12 May 2022 09:03:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354077AbiELNDB (ORCPT ); Thu, 12 May 2022 09:03:01 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 3534162201 for ; Thu, 12 May 2022 06:02:59 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-273-FQdGDavxPjSQABZUDFCotQ-1; Thu, 12 May 2022 14:02:56 +0100 X-MC-Unique: FQdGDavxPjSQABZUDFCotQ-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.32; Thu, 12 May 2022 14:02:55 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.033; Thu, 12 May 2022 14:02:55 +0100 From: David Laight To: "'Kirill A. Shutemov'" , Dave Hansen , Andy Lutomirski , "Peter Zijlstra" CC: "x86@kernel.org" , Andrey Ryabinin , Alexander Potapenko , "Dmitry Vyukov" , "H . J . Lu" , Andi Kleen , Rick Edgecombe , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Subject: RE: [RFCv2 06/10] x86/uaccess: Remove tags from the address before checking Thread-Topic: [RFCv2 06/10] x86/uaccess: Remove tags from the address before checking Thread-Index: AQHYZN8hTSKv+xBtAEiDWI98RCjTSK0bNyYw Date: Thu, 12 May 2022 13:02:55 +0000 Message-ID: References: <20220511022751.65540-1-kirill.shutemov@linux.intel.com> <20220511022751.65540-8-kirill.shutemov@linux.intel.com> In-Reply-To: <20220511022751.65540-8-kirill.shutemov@linux.intel.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kirill A. Shutemov > Sent: 11 May 2022 03:28 > > The tags must not be included into check whether it's okay to access the > userspace address. > > Strip tags in access_ok(). Why? Just change the test to check the buffer doesn't cross 1u << 63. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)