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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 6DC3FC3A5A3 for ; Tue, 27 Aug 2019 06:40:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3F7EF206BB for ; Tue, 27 Aug 2019 06:40:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727528AbfH0GkF (ORCPT ); Tue, 27 Aug 2019 02:40:05 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:54602 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725943AbfH0GkF (ORCPT ); Tue, 27 Aug 2019 02:40:05 -0400 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x7R6bEF3028513 for ; Tue, 27 Aug 2019 02:40:04 -0400 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 2umxgv1u3q-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 27 Aug 2019 02:40:04 -0400 Received: from localhost by e06smtp02.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 27 Aug 2019 07:39:59 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x7R6dwpE25035018 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 27 Aug 2019 06:39:58 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5B845A4053; Tue, 27 Aug 2019 06:39:58 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 090EDA404D; Tue, 27 Aug 2019 06:39:58 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 27 Aug 2019 06:39:57 +0000 (GMT) Received: from adsilva.ozlabs.ibm.com (haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id 85C73A022E; Tue, 27 Aug 2019 16:39:56 +1000 (AEST) Subject: Re: [PATCH] powerpc: Perform a bounds check in arch_add_memory From: "Alastair D'Silva" To: Michal Hocko Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Christophe Leroy , Andrew Morton , David Hildenbrand , Mike Rapoport , "Aneesh Kumar K.V" , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Date: Tue, 27 Aug 2019 16:39:56 +1000 In-Reply-To: <20190827062844.GQ7538@dhcp22.suse.cz> References: <20190827052047.31547-1-alastair@au1.ibm.com> <20190827062844.GQ7538@dhcp22.suse.cz> Organization: IBM Australia Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.32.2 (3.32.2-1.fc30) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 19082706-0008-0000-0000-0000030DBCC0 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19082706-0009-0000-0000-00004A2BF765 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-26_08:,, 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=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908270073 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2019-08-27 at 08:28 +0200, Michal Hocko wrote: > On Tue 27-08-19 15:20:46, Alastair D'Silva wrote: > > From: Alastair D'Silva > > > > It is possible for firmware to allocate memory ranges outside > > the range of physical memory that we support (MAX_PHYSMEM_BITS). > > Doesn't that count as a FW bug? Do you have any evidence of that in > the > field? Just wondering... > Not outside our lab, but OpenCAPI attached LPC memory is assigned addresses based on the slot/NPU it is connected to. These addresses prior to: 4ffe713b7587 ("powerpc/mm: Increase the max addressable memory to 2PB") were inaccessible and resulted in bogus sections - see our discussion on 'mm: Trigger bug on if a section is not found in __section_nr'. Doing this check here was your suggestion :) It's entirely possible that a similar problem will occur in the future, and it's cheap to guard against, which is why I've added this. -- Alastair D'Silva Open Source Developer Linux Technology Centre, IBM Australia mob: 0423 762 819