From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754052AbdJSUl1 (ORCPT ); Thu, 19 Oct 2017 16:41:27 -0400 Received: from esa1.hgst.iphmx.com ([68.232.141.245]:33940 "EHLO esa1.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753047AbdJSUl0 (ORCPT ); Thu, 19 Oct 2017 16:41:26 -0400 X-IronPort-AV: E=Sophos;i="5.43,403,1503331200"; d="scan'208";a="161318714" From: Bart Van Assche To: "willy@infradead.org" CC: "tglx@linutronix.de" , "mingo@kernel.org" , "linux-kernel@vger.kernel.org" , "peterz@infradead.org" , "byungchul.park@lge.com" , "linux-mm@kvack.org" , "kernel-team@lge.com" Subject: Re: [PATCH v2 2/3] lockdep: Remove BROKEN flag of LOCKDEP_CROSSRELEASE Thread-Topic: [PATCH v2 2/3] lockdep: Remove BROKEN flag of LOCKDEP_CROSSRELEASE Thread-Index: AQHTSJ7m0UDqA3q6tkapniLX+oGlRqLrRiaAgAAIIwCAAAN6gIAANxSAgAACMgCAABOJgIAAAyiAgAACRoA= Date: Thu, 19 Oct 2017 20:41:23 +0000 Message-ID: <1508445681.2429.61.camel@wdc.com> References: <1508392531-11284-1-git-send-email-byungchul.park@lge.com> <1508392531-11284-3-git-send-email-byungchul.park@lge.com> <1508425527.2429.11.camel@wdc.com> <1508428021.2429.22.camel@wdc.com> <1508444515.2429.55.camel@wdc.com> <20171019203313.GA10538@bombadil.infradead.org> In-Reply-To: <20171019203313.GA10538@bombadil.infradead.org> 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=Bart.VanAssche@wdc.com; x-originating-ip: [63.163.107.100] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;CY1PR0401MB1533;20:I0lNH1v91RxpiN7Tdc0k0dRvabn2ZVOe5rIei1auOWLR4ojg4VN3MuCNMoD8TGPdy0RjGvozqoZb4v8oNPldI4e78NrQTjjX4LH1W7K8S+B+CtYhRmPrrgpH5ZhMGl9v9Z8B97HO56Vljv50BgIZw5CNtJIjLvgEY3pzoEPhDtw= x-ms-exchange-antispam-srfa-diagnostics: SSOS; x-ms-office365-filtering-correlation-id: a54d0721-4ead-4ede-1fb9-08d51731c2f9 x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(22001)(2017030254172)(4534020)(4602075)(4627075)(201703031133081)(201702281549075)(48565401081)(2017052603199)(201703131423095);SRVR:CY1PR0401MB1533; x-ms-traffictypediagnostic: CY1PR0401MB1533: wdcipoutbound: EOP-TRUE x-exchange-antispam-report-test: UriScan:; x-microsoft-antispam-prvs: x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(100000700101)(100105000095)(100000701101)(100105300095)(100000702101)(100105100095)(6040450)(2401047)(5005006)(8121501046)(10201501046)(100000703101)(100105400095)(3002001)(93006095)(93001095)(6055026)(6041248)(20161123555025)(20161123558100)(201703131423075)(201702281528075)(201703061421075)(201703061406153)(20161123562025)(20161123560025)(20161123564025)(6072148)(201708071742011)(100000704101)(100105200095)(100000705101)(100105500095);SRVR:CY1PR0401MB1533;BCL:0;PCL:0;RULEID:(100000800101)(100110000095)(100000801101)(100110300095)(100000802101)(100110100095)(100000803101)(100110400095)(100000804101)(100110200095)(100000805101)(100110500095);SRVR:CY1PR0401MB1533; x-forefront-prvs: 0465429B7F x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(6009001)(346002)(39860400002)(376002)(199003)(24454002)(377424004)(189002)(93886005)(53936002)(7736002)(305945005)(2501003)(6486002)(77096006)(5660300001)(229853002)(68736007)(5640700003)(2950100002)(6916009)(8676002)(6512007)(478600001)(4326008)(316002)(81166006)(99286003)(81156014)(14454004)(8936002)(102836003)(6116002)(25786009)(72206003)(3846002)(1730700003)(6246003)(54906003)(4001150100001)(97736004)(103116003)(3660700001)(36756003)(189998001)(86362001)(66066001)(3280700002)(76176999)(2900100001)(105586002)(6506006)(33646002)(50986999)(54356999)(2351001)(2906002)(106356001)(6436002)(101416001);DIR:OUT;SFP:1102;SCL:1;SRVR:CY1PR0401MB1533;H:CY1PR0401MB1536.namprd04.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: <5669043A0A1EFD49A4B7E512BF71109B@namprd04.prod.outlook.com> MIME-Version: 1.0 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-originalarrivaltime: 19 Oct 2017 20:41:23.3798 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY1PR0401MB1533 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 nfs id v9JKfV5v010009 On Thu, 2017-10-19 at 13:33 -0700, Matthew Wilcox wrote: > For example, the page lock is not annotatable with lockdep -- we return > to userspace with it held, for heaven's sake! So it is quite easy for > someone not familiar with the MM locking hierarchy to inadvertently > introduce an ABBA deadlock against the page lock. (ie me. I did that.) > Right now, that has to be caught by a human reviewer; if cross-release > checking can catch that, then it's worth having. Hello Matthew, Although I agree that enabling lock inversion checking for page locks is useful, I think my questions still apply to other locking objects than page locks. Thanks, Bart.