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 X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F2F1C433E7 for ; Wed, 2 Sep 2020 13:24:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7AB6E207D3 for ; Wed, 2 Sep 2020 13:24:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726310AbgIBNXw convert rfc822-to-8bit (ORCPT ); Wed, 2 Sep 2020 09:23:52 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([207.82.80.151]:55759 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726990AbgIBNNu (ORCPT ); Wed, 2 Sep 2020 09:13:50 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-164-H07lfWV_NS6c2T74vCbBog-1; Wed, 02 Sep 2020 14:13:23 +0100 X-MC-Unique: H07lfWV_NS6c2T74vCbBog-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Wed, 2 Sep 2020 14:13:22 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Wed, 2 Sep 2020 14:13:22 +0100 From: David Laight To: 'Christoph Hellwig' , Christophe Leroy CC: Linus Torvalds , Al Viro , Michael Ellerman , "x86@kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-arch@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , Kees Cook , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH 10/10] powerpc: remove address space overrides using set_fs() Thread-Topic: [PATCH 10/10] powerpc: remove address space overrides using set_fs() Thread-Index: AQHWgSXGxcHfrrTX9UCmYjSyVg3SwKlVUsKA Date: Wed, 2 Sep 2020 13:13:22 +0000 Message-ID: <61b9a880a6424a34b841cf3dddb463ad@AcuMS.aculab.com> References: <20200827150030.282762-1-hch@lst.de> <20200827150030.282762-11-hch@lst.de> <8974838a-a0b1-1806-4a3a-e983deda67ca@csgroup.eu> <20200902123646.GA31184@lst.de> In-Reply-To: <20200902123646.GA31184@lst.de> 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: 0.001 X-Mimecast-Originator: aculab.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Content-Language: en-US Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Christoph Hellwig > Sent: 02 September 2020 13:37 > > On Wed, Sep 02, 2020 at 08:15:12AM +0200, Christophe Leroy wrote: > >> - return 0; > >> - return (size == 0 || size - 1 <= seg.seg - addr); > >> + if (addr >= TASK_SIZE_MAX) > >> + return false; > >> + if (size == 0) > >> + return false; > > > > __access_ok() was returning true when size == 0 up to now. Any reason to > > return false now ? > > No, this is accidental and broken. Can you re-run your benchmark with > this fixed? Is TASK_SIZE_MASK defined such that you can do: return (addr | size) < TASK_SIZE_MAX) || !size; David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)