From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932433AbeCIUAm (ORCPT ); Fri, 9 Mar 2018 15:00:42 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:44864 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932221AbeCIUAk (ORCPT ); Fri, 9 Mar 2018 15:00:40 -0500 Date: Fri, 9 Mar 2018 12:00:17 -0800 From: Ram Pai To: Florian Weimer Cc: mpe@ellerman.id.au, mingo@redhat.com, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, dave.hansen@intel.com, benh@kernel.crashing.org, paulus@samba.org, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org, bauerman@linux.vnet.ibm.com, ebiederm@xmission.com, corbet@lwn.net, arnd@arndb.de, msuchanek@suse.com, Ulrich.Weigand@de.ibm.com Subject: Re: [PATCH] x86, powerpc : pkey-mprotect must allow pkey-0 Reply-To: Ram Pai References: <1520583161-11741-1-git-send-email-linuxram@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-12-10) X-TM-AS-GCONF: 00 x-cbid: 18030920-0040-0000-0000-0000041CFD8D X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18030920-0041-0000-0000-000026201D84 Message-Id: <20180309200017.GR1060@ram.oc3035372033.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-03-09_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1803090239 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 09, 2018 at 12:04:49PM +0100, Florian Weimer wrote: > On 03/09/2018 09:12 AM, Ram Pai wrote: > >Once an address range is associated with an allocated pkey, it cannot be > >reverted back to key-0. There is no valid reason for the above behavior. > > mprotect without a key does not necessarily use key 0, e.g. if > protection keys are used to emulate page protection flag combination > which is not directly supported by the hardware. > > Therefore, it seems to me that filtering out non-allocated keys is > the right thing to do. I am not sure, what you mean. Do you agree with the patch or otherwise? RP