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=-8.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 4E5CFC432BE for ; Wed, 25 Aug 2021 00:08:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E8EA6138B for ; Wed, 25 Aug 2021 00:08:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235907AbhHYAJf (ORCPT ); Tue, 24 Aug 2021 20:09:35 -0400 Received: from esa16.fujitsucc.c3s2.iphmx.com ([216.71.158.33]:27576 "EHLO esa16.fujitsucc.c3s2.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235388AbhHYAJd (ORCPT ); Tue, 24 Aug 2021 20:09:33 -0400 X-Greylist: delayed 428 seconds by postgrey-1.27 at vger.kernel.org; Tue, 24 Aug 2021 20:09:32 EDT DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=fujitsu.com; i=@fujitsu.com; q=dns/txt; s=fj1; t=1629850129; x=1661386129; h=from:to:cc:subject:date:message-id:references: in-reply-to:content-transfer-encoding:mime-version; bh=IaZq/mVsjwWtv0XkFPBO9ZZKlUhZWHBskSs69xPsRnY=; b=uGaqYLMbwSOOUkK07WB8MJluBNvohNYgTxR/A1OvMcavXeLX2LhPVWt7 zW5BH0zS3PF5PsVeyDvwhFVWS681XWmfLFN/FCC4+qkncZJeG7gxyZyzJ 6+alwxo3Gke54EKyxte1RdYWNb/ozfjHLgQBQ+KRGXHopHMQgiu2AIXC4 oveJK42+RKVZgvaNNE/Zg3uMRkRAdVLAME0EfxFd1TbyAyRC9g3tdjkQk dchO4dKTHxp7rQVs0c3sSy8GdM6vt2sjL9EK7I3wT9xPGu9zwBjwJLmKr 9i+U0qpJib+SLpkB73ReZXt7TbOsKyZgF+RhHgBzqyi9WSg6fLXQG4B9h Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10086"; a="37629090" X-IronPort-AV: E=Sophos;i="5.84,348,1620658800"; d="scan'208";a="37629090" Received: from mail-os2jpn01lp2055.outbound.protection.outlook.com (HELO JPN01-OS2-obe.outbound.protection.outlook.com) ([104.47.92.55]) by ob1.fujitsucc.c3s2.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2021 09:01:20 +0900 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=fdglCKYyZBXBqps9OzW9elXz7P0tZ/zIY1xa+gndjqMTCqLtATKq+7Uohnu+jy5x/FGB2o3/xWUI/k6h3k+DIEW8upk4AVnrRka501xVrerNbsUdAvqlPNw2m888py/QCtT0fuOxnkgApQfultQvXmcxV35NWCwIM1H85ZMrZNTaJMUdB/grOtfvU/04vMqHLV2tZJniG/3SjVwixxG629LXYksNYG/BwmJ2myEMEidmkeAtqOmZkecwVFk2dgH++YDRj++iYgTaLeUa+Rjd6g0Wt2sslCVr128f/3mRp8v/kEZePe5yXGE1gseSJ5/4uk5wkGX7U/NonuUi4+mipA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=y/NgoPTXm5Hb9++7/11h93nf63eMPbp0a3zwBifbx3g=; b=NpD8QlxrTr7ycf+ItxWRE7d1vnaCmBGXoJvirF3GjE34T5moBU38EtRRXjARw8eBPAuhSPz1robjl0Z6h2fCHxs0FtPodYbjC0FNJxOrJOUF5LeVNNrTSz+fRN5b1T5hHQP56Agy8Ej5Px8lEf9l3bLBtCMl0cNMxV5kiX6GDzC3Eve3DYSzAJjSh3YzqiWQr1049WnnthYucEv3bxKPs+GPZ82NdzpWfEHzFWN3aVq5Q+lNiR+G6McSYWNo2cmloO5gKDHnaPrX4NXe1u6mt34J5y6/TUrNSS/RSm05ePR4472m1CLLSnHjqYebnwk2MTwvn0ij8RFUi4yeXCL2zg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=fujitsu.com; dmarc=pass action=none header.from=fujitsu.com; dkim=pass header.d=fujitsu.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fujitsu.onmicrosoft.com; s=selector2-fujitsu-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=y/NgoPTXm5Hb9++7/11h93nf63eMPbp0a3zwBifbx3g=; b=i0Sp4NxFqo3IoM1J7DJJu4sTumrtRc7Mys52LWDU7+LeciXLAyeijQeVREKHxJKgcbVOzXlnLfrneO86J//Bq/pHoeNhuHEEMPqfXu2dFAMOFGbqZknrJ+ZcqHhxuJ0/l0qI5+YGwzsfJU+7Wsz3HEmPO7AYte7QMeCUFbHBOoY= Received: from TY2PR01MB5257.jpnprd01.prod.outlook.com (2603:1096:404:11a::10) by TYAPR01MB4718.jpnprd01.prod.outlook.com (2603:1096:404:12c::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4457.17; Wed, 25 Aug 2021 00:01:17 +0000 Received: from TY2PR01MB5257.jpnprd01.prod.outlook.com ([fe80::d0f9:bb55:deb4:88bf]) by TY2PR01MB5257.jpnprd01.prod.outlook.com ([fe80::d0f9:bb55:deb4:88bf%5]) with mapi id 15.20.4436.025; Wed, 25 Aug 2021 00:01:17 +0000 From: "nobuta.keiya@fujitsu.com" To: "'Madhavan T. Venkataraman'" CC: "mark.rutland@arm.com" , "broonie@kernel.org" , "jpoimboe@redhat.com" , "ardb@kernel.org" , "sjitindarsingh@gmail.com" , "catalin.marinas@arm.com" , "will@kernel.org" , "jmorris@namei.org" , "pasha.tatashin@soleen.com" , "jthierry@redhat.com" , "linux-arm-kernel@lists.infradead.org" , "live-patching@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: RE: [RFC PATCH v8 3/4] arm64: Introduce stack trace reliability checks in the unwinder Thread-Topic: [RFC PATCH v8 3/4] arm64: Introduce stack trace reliability checks in the unwinder Thread-Index: AQHXj60kVJNMm5FzxU6EDROYO/rEjquAuwsQgAHqSACAAMNBkA== Date: Wed, 25 Aug 2021 00:01:16 +0000 Message-ID: References: <20210812190603.25326-1-madvenka@linux.microsoft.com> <20210812190603.25326-4-madvenka@linux.microsoft.com> <62d8969d-8ba1-4554-16b4-1c0bd4f8d9e7@linux.microsoft.com> In-Reply-To: <62d8969d-8ba1-4554-16b4-1c0bd4f8d9e7@linux.microsoft.com> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-shieldmailcheckermailid: 919e81a8178d48a1a67d7e32ee3d5163 x-securitypolicycheck: OK by SHieldMailChecker v2.6.3 msip_labels: MSIP_Label_a7295cc1-d279-42ac-ab4d-3b0f4fece050_Enabled=true; MSIP_Label_a7295cc1-d279-42ac-ab4d-3b0f4fece050_SetDate=2021-08-24T23:58:43Z; MSIP_Label_a7295cc1-d279-42ac-ab4d-3b0f4fece050_Method=Standard; MSIP_Label_a7295cc1-d279-42ac-ab4d-3b0f4fece050_Name=FUJITSU-RESTRICTED?; MSIP_Label_a7295cc1-d279-42ac-ab4d-3b0f4fece050_SiteId=a19f121d-81e1-4858-a9d8-736e267fd4c7; MSIP_Label_a7295cc1-d279-42ac-ab4d-3b0f4fece050_ActionId=0f27c542-3268-48e8-b71c-69fdb8c504c2; MSIP_Label_a7295cc1-d279-42ac-ab4d-3b0f4fece050_ContentBits=0 authentication-results: linux.microsoft.com; dkim=none (message not signed) header.d=none;linux.microsoft.com; dmarc=none action=none header.from=fujitsu.com; x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 292f493e-fafa-4201-0843-08d9675b7623 x-ms-traffictypediagnostic: TYAPR01MB4718: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:10000; x-ms-exchange-senderadcheck: 1 x-ms-exchange-antispam-relay: 0 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: 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 x-forefront-antispam-report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:TY2PR01MB5257.jpnprd01.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(39860400002)(346002)(396003)(376002)(136003)(366004)(6916009)(4326008)(54906003)(33656002)(38100700002)(186003)(26005)(122000001)(7416002)(55016002)(7696005)(86362001)(478600001)(85182001)(6506007)(64756008)(76116006)(9686003)(2906002)(66946007)(52536014)(66476007)(8676002)(66446008)(66556008)(8936002)(5660300002)(71200400001)(316002)(38070700005);DIR:OUT;SFP:1101; x-ms-exchange-antispam-messagedata-chunkcount: 1 x-ms-exchange-antispam-messagedata-0: =?iso-2022-jp?B?dGRpdEZBZFNTSEZsVGZLM1QvNDdIM0lGTzdLbG9hY3gzeGc2SldKRVp0?= =?iso-2022-jp?B?ZVQ1MVljdHUxTmVybldIWkpsayt2Wi8rN0Z4S1o0SlVEejM0dnptZXIr?= =?iso-2022-jp?B?eS8zbmtTM2RYUUdydzkzTmQwL25TNWlBeWZsQUVZYTZQYVVnRE0rODhi?= =?iso-2022-jp?B?UHJRak8zZUdXSVFKSWd5T2NZS1NYQUlGTDh4b3djMWJNUjAyR3ZrWlli?= =?iso-2022-jp?B?cGVUUjhTR3hCdHJrWjI5K2EwNE8xZnljWEg3Nk9CbzJFUHlKRG1YOWd4?= =?iso-2022-jp?B?TlF5QU9IcTN1a3BlMUZzMzBMdjBUSnlieG1NUWlzTENHN2xwY0hQSWgv?= =?iso-2022-jp?B?ZzNPcnhjWVMvMVRnL2hKNmRZWThnQ1dxZ0RWOVdpUEFHeGU0d3ByY0E3?= =?iso-2022-jp?B?MlZHam1DOE5jYjliQUtjZjZCTGE5S0ZPMGxxTklhWWN5a1ZzSUV3Q2d2?= =?iso-2022-jp?B?TGFvcG1uZWZxK25OeFFFMkQ1OHpUZDllT2w0cHgrZm1QR3pPL3Iva2J6?= =?iso-2022-jp?B?OUlvSUdOQnkxVit5S0pjSzhjeWlkaXBUejZXd2JGck1EVlRGbUpSendS?= =?iso-2022-jp?B?SjBjdEhMOTZuRnJkSUFNL1lucWVYYkdDTzZiYVJoOWdyZWVvR05VTU5T?= =?iso-2022-jp?B?MGtUS2hBZEU3N0k2eGNsMW9BQyt2SExIV3BwSk9RdDM5NlZ5MHM0MEU2?= =?iso-2022-jp?B?ak9xb0xaVzVUbmxNM3pKcllKeCtZdUppMEVsMExwbkdrMXZJYnZvOHVq?= =?iso-2022-jp?B?QzdNdHl6Q1pKbTZlTmN3YzQ1UUNSM2lCU1dtbjZHZXYrSGFJWGwrYitK?= =?iso-2022-jp?B?bkQ3bnorVlV2OEpxMU9KVWh5K0h1cTRQK0dnd0JnN2dwNnRFMCtid2VO?= =?iso-2022-jp?B?VGJTT2gvK0hBdnZoRlVkd1VoUXB5WjVOcUxRZ2JLQXg5RlpBZU1VWVI3?= =?iso-2022-jp?B?dUMzSEhqU2M1Zkk4SC9SOXdkSFdNODY1YUNUMmRZQit3WlZKR2tOaDh3?= =?iso-2022-jp?B?dlNmZ051YU9iQ1dqZWk3L29FZW1GOWcrdlgvTVZ2ZVFuRnZYWVNONmZF?= =?iso-2022-jp?B?SUxvSG10MTVlTCtVNEo2VGFzc2R5aXVqME9vTVQwZGcxNUtEem5oK1dK?= =?iso-2022-jp?B?RFZCYjdtcjlWQmF6WUJJUGpnd1RVaDl1aWhBUEFGMzg3Qm9ub2lBZGt1?= =?iso-2022-jp?B?RVpKdVpWRWZldGI5eStEd25GR1h6K2E5YWRjdWJmZDluK3gxc0o4Tkoy?= =?iso-2022-jp?B?N3M2cFNYdXhYNlI2RG9yTzBQSldaZnZvQTh0VWwzWGYvT3JxWndMRXVz?= =?iso-2022-jp?B?OHR0bGwzQVAyOTBPUnVkZG9UYVp0c0pPZDlnTTA0aTBSWnpjU0l0NDJr?= =?iso-2022-jp?B?N2E0RHQ3a1ZndlVBUkNOeGNmMkFTbDF0czZ4Njk4UEhDMU9qZW4zOXRz?= =?iso-2022-jp?B?M05OWTlmbUpQZjRRbkl5V0J3NytKWGdyTEpua3ltbVYxd1psRmtlSStU?= =?iso-2022-jp?B?ZXRURGU2Qmg1ZWs3bGUrdW9HVzMyM281R0N1MnVTeUdVQldzQllQc2Vw?= =?iso-2022-jp?B?dEhWdlZEU1Y5YnNqMjRuTXRCY01XVjFybHhFaHBOY2pmVFdxcjlJZjE1?= =?iso-2022-jp?B?VS9EK0hIam1sdTNNNDhIL3dtSnZnT1ROZ0xxVlRvU3NoNjdHNTVkSElw?= =?iso-2022-jp?B?cmdkRFVxbWVTUTV6NWFIbVovdXVwK0RiMzQ3V1pLWVJOdkxRRDdjVzVm?= =?iso-2022-jp?B?U2I5ekhodUZZVmhqSGtza25ydUJEdGhKYVVxbHl5Ym01cDNQY0Q0RWNX?= =?iso-2022-jp?B?Z1owTU56QTlYNjlrWFZJMU1kZG9iRERUVmZQRDZWc2hsWFV3RDkveFBK?= =?iso-2022-jp?B?S0VpeEpwSHJyQTJUc3A1VHpzVWx4WHZ0b1RkY2ZpQnZ3enpia3EyK3BN?= x-ms-exchange-transport-forked: True Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: fujitsu.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: TY2PR01MB5257.jpnprd01.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 292f493e-fafa-4201-0843-08d9675b7623 X-MS-Exchange-CrossTenant-originalarrivaltime: 25 Aug 2021 00:01:17.0508 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: a19f121d-81e1-4858-a9d8-736e267fd4c7 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: 1yZ3TdVokMWnKwrItSFmW2vQ1wzvtCsnkl0/TMl/I1q4AjkkhFz9xGVgVhJ/LNDR4niKdKVwjuMqZqvw/mtqJnY6Va45pClGRzZgSSR7ZgI= X-MS-Exchange-Transport-CrossTenantHeadersStamped: TYAPR01MB4718 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Hi Madhavan, > > > >> @@ -245,7 +271,36 @@ noinline notrace void arch_stack_walk(stack_trace= _consume_fn consume_entry, > >> fp =3D thread_saved_fp(task); > >> pc =3D thread_saved_pc(task); > >> } > >> - unwind(consume_entry, cookie, task, fp, pc); > >> + unwind(consume_entry, cookie, task, fp, pc, false); } > >> + > >> +/* > >> + * arch_stack_walk_reliable() may not be used for livepatch until > >> +all of > >> + * the reliability checks are in place in unwind_consume(). However, > >> + * debug and test code can choose to use it even if all the checks > >> +are not > >> + * in place. > >> + */ > > > > I'm glad to see the long-awaited function :) > > > > Does the above comment mean that this comment will be removed by > > another patch series that about live patch enablement, instead of [PATC= H 4/4]? > > > > It seems to take time... But I start thinking about test code. > > >=20 > Yes. This comment will be removed when livepatch will be enabled eventual= ly. > So, AFAICT, there are 4 pieces that are needed: >=20 > - Reliable stack trace in the kernel. I am trying to address that with my= patch > series. >=20 > - Mark Rutland's work for making patching safe on ARM64. >=20 > - Objtool (or alternative method) for stack validation. >=20 > - Suraj Jitindar Singh's patch for miscellaneous things needed to enable = live patch. >=20 > Once all of these pieces are in place, livepatch can be enabled. >=20 > That said, arch_stack_walk_reliable() can be used for test and debug purp= oses anytime once this patch series gets accepted. >=20 > Thanks. >=20 > Madhavan Thank you for the information. Keiya