From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756468AbcHXOkN (ORCPT ); Wed, 24 Aug 2016 10:40:13 -0400 Received: from mail-co1nam03on0101.outbound.protection.outlook.com ([104.47.40.101]:13829 "EHLO NAM03-CO1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754065AbcHXOkL (ORCPT ); Wed, 24 Aug 2016 10:40:11 -0400 X-Greylist: delayed 56374 seconds by postgrey-1.27 at vger.kernel.org; Wed, 24 Aug 2016 10:40:11 EDT From: "Kani, Toshimitsu" To: "dan.j.williams@intel.com" CC: "Mulumudi, Abhilash Kumar" , "linux-nvdimm@lists.01.org" , "ard.biesheuvel@linaro.org" , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , "brian.starkey@arm.com" Subject: Re: [PATCH] memremap: Fix NULL pointer BUG in get_zone_device_page() Thread-Topic: [PATCH] memremap: Fix NULL pointer BUG in get_zone_device_page() Thread-Index: AQHR/W5ZePHh0bI7qkGTM3px2vEum6BXIayAgAAUw4CAAA1fgIAADk3AgAAYaQCAABIWAIAABjvwgAAHv4CAAKU0AA== Date: Wed, 24 Aug 2016 14:40:07 +0000 Message-ID: <1472049570.1532.10.camel@hpe.com> References: <1471977800-12688-1-git-send-email-toshi.kani@hpe.com> <1471996023.1532.6.camel@hpe.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=toshi.kani@hpe.com; x-originating-ip: [15.219.163.2] x-ms-office365-filtering-correlation-id: c6c6133b-d852-4f6f-6762-08d3cc2c8b6a x-microsoft-exchange-diagnostics: 1;CS1PR84MB0005;6:UP1/UlQbyDfhV+YLwfvWTmDJ8yoq+/Cy/cNfNhbTu7v/IZlB9EHuhxdK/JykWm+Jl5PAPW+v4j/cMWgGDe3bz222HIFVyTJZcZlBinCodZt7apoHZ9ruXhxdHR6Oxq2t2FmMz6I49qJrVddeciYDg8r/wbK1yYD8+C+I7VkdPYprP+C0CL947iaHk70YRsDntm2CcUds6DPs1dk9ugGvqbyinAMLPsISVYfig3GCyG92i9RYudQwaNnbB5OExoWvAeDz2icRfizPqB4aD9KDl5VoE+Tr9AwwvO31zQL3DbplsJuWy/VM7KBMkAr+deDecUUkZoZRcsIO7w+dytWM0Q==;5:bYf6LRg19geZF+MUC8BQOy1eyZoG8C0PzDurj5nyBwAeiXf8gsw5ry9oFcJUK9rR513RlOVPRl0uQjCo4jueDUy+WTtjMsctEAKuru+uT/d6WBpZe/nKDYyN6qOBRpmu0hq5CbBFHXo0Eiaq9LjFcQ==;24:djCNRxtSFtTjTzLo2yidXo/zvi/9SJ/A+uxL3+Dmq7xmAKBLvEQCoZwtgyqlozLG4Sm0So4s6S0gOeTwKitCCISVgtP2Y13+Kz3ZDp89+tM=;7:2vlIO1Ksy2sHm1hWJp7MqZgMWJ4nUPRR+XJoDVvvhGVFoPoiBUqZ44ZNmGxgjB/8keE9VuSvDMZQB5KUTutR0i04YG5t0zZvBUQmuojNsQK7crZcNHbYKmGyjpa6srpFjtHGfn2Dxp8Sswuc4lJbhJg/MtZpbaBRbFjLO57rhDrvRwpvLJ2WBMMVfIMpor8sdiImng7hykRSVaJsgfwGVfxfqbJVYIy8nzUVXNjJc7dFa1FXkPcVIR+0dmt90SCE x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:CS1PR84MB0005; x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:(227479698468861); x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(6040176)(601004)(2401047)(8121501046)(5005006)(10201501046)(3002001)(6055026);SRVR:CS1PR84MB0005;BCL:0;PCL:0;RULEID:;SRVR:CS1PR84MB0005; x-forefront-prvs: 0044C17179 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(6009001)(7916002)(377454003)(377424004)(199003)(24454002)(189002)(103116003)(305945005)(586003)(102836003)(6116002)(33646002)(77096005)(99286002)(105586002)(7736002)(7846002)(2501003)(106116001)(3846002)(86362001)(2906002)(68736007)(5660300001)(106356001)(4326007)(5640700001)(2351001)(3660700001)(3280700002)(66066001)(101416001)(122556002)(97736004)(8676002)(81156014)(110136002)(81166006)(189998001)(93886004)(54356999)(76176999)(50986999)(19580405001)(36756003)(5002640100001)(92566002)(10400500002)(87936001)(8936002)(19580395003)(2900100001)(2950100001);DIR:OUT;SFP:1102;SCL:1;SRVR:CS1PR84MB0005;H:CS1PR84MB0005.NAMPRD84.PROD.OUTLOOK.COM;FPR:;SPF:None;PTR:InfoNoRecords;A:1;MX:1;LANG:en; spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="utf-8" Content-ID: <0F2EE656D522D64CB12B35C04D1633E6@NAMPRD84.PROD.OUTLOOK.COM> MIME-Version: 1.0 X-OriginatorOrg: hpe.com X-MS-Exchange-CrossTenant-originalarrivaltime: 24 Aug 2016 14:40:07.6663 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 105b2061-b669-4b31-92ac-24d304d195dc X-MS-Exchange-Transport-CrossTenantHeadersStamped: CS1PR84MB0005 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id u7OEeIAM031131 On Tue, 2016-08-23 at 21:48 -0700, Dan Williams wrote: > On Tue, Aug 23, 2016 at 9:28 PM, Kani, Toshimitsu > > > BTW, why does devm_memremap_pages() put a whole range to > > pgmap_radix as device memory, but only initialize page->pgmap for > > its data range?  Is there particular reason for this inconsistency? > > The radix tree is indexed by section number, but we don't always > initialize a full section.  The cases when we don't use a full > section is when it overlaps device metadata, or if a platform > multiplexes the device memory range with another resource within the > same section. I see, but I still feel odd about making get_dev_pagemap() to work for metadata, but get_page() -> get_zone_device_page() to crash like this.  follow_devmap_pmd() assumes get_page() to work when get_dev_pagemap() returns a valid pgmap... Thanks, -Toshi