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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8DF0FC6FA82 for ; Fri, 23 Sep 2022 07:34:37 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CE72580008; Fri, 23 Sep 2022 03:34:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C963180007; Fri, 23 Sep 2022 03:34:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AE8C380008; Fri, 23 Sep 2022 03:34:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 9D2DC80007 for ; Fri, 23 Sep 2022 03:34:36 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 74AFDA0F1B for ; Fri, 23 Sep 2022 07:34:36 +0000 (UTC) X-FDA: 79942537752.01.DFF1822 Received: from EUR04-DB3-obe.outbound.protection.outlook.com (mail-eopbgr60133.outbound.protection.outlook.com [40.107.6.133]) by imf05.hostedemail.com (Postfix) with ESMTP id BF15D100017 for ; Fri, 23 Sep 2022 07:34:35 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=dAHuuhZgSs1oRlHwhqbcqPH8N3aBWsAsziyjdl7Mzlncy/xwv2XtDwnY+eA3fnh5ehbIIBdT+IfBHvdqj0qqGx7VgiuBNeUUMZzCVWMahxsdWXUGF5OM1rJZSEPBmgSawhFc96rwAb/92oXGMgJZIHD4ciz4jlofR34JMseAD0Z1hJnbBzdkEhAuOAMa8yM34bDmQS2ezDVR08g1AVU2w2R4qQ2+ExyX6cJhBhfAErEulV9/ewOXS3TjJg3LmfqUsu5L4NP2sSiliw9JjjTlG60zAQAwE7Lz7/Ffls4UsvHYjX94AKBnu6408D/OtOqjGx8o84fzz/3jZyhBaqXPkg== 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-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=fjOYn/4k09qNOyxi88hh7BxnKaKDN3zBNvOmPFWhqjo=; b=gXZ9WlF8F4rR6diMs2t0KomNmOJyZP4ZjC4uCCZGv8nhnRxv7mB3vEtTNk82pfKJx3cI1tmzMdxX5Y7DigHj43HaQJt4YgYPyDdX4WoCYnwIr3lepZvkThSsWoHUyG+x4OgRB/m/3J+R9G9vX1EMEOj4en4WWgvcwr4X7eqgVco4nO/ZtAIi2lECAI+gZ9rHIYeQb+DYyl27FjGb3t/JUzlbQOHnFI4H2Gb7ip5TfQU0pM7FAlL5I/om5gQZfF/gy3HMqjK/U2tuhEKx2uZcN8ax/LjLmoZc8JsQkDwXTobwGo9bACrEr+qiG/ebMFfckm0ncFtTp9OCKSFpOdvkVw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=virtuozzo.com; dmarc=pass action=none header.from=virtuozzo.com; dkim=pass header.d=virtuozzo.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=virtuozzo.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=fjOYn/4k09qNOyxi88hh7BxnKaKDN3zBNvOmPFWhqjo=; b=Y2pDOSHKlJIC5k+qk/8fQc7UEIJay/t+ixY0BMxNyUfjxok8caMSznWqL3iMtk1ElRXG2JBxtOb0sm5Rw6b+4zbmwfDtMYWxYRzg1lZP31NACvNj9IkOEwWs3q/97QWKN4McURWhYfy4ew0SRXu3O1XwG/SCnSn+WL4OIIhEtP7EnZKXouuWmen/G11iQdUl0/xtXEVOGjpiWOVHWfCdnhwIqDfJ1uX+AOhn07Ob9pS+j4vsV9YBfqpvLw4OcEnj8rO7k9IeUF2yDxyBRTFM3P74P52lbjOhdFiK0X1CcfC2i3VWAXzoicqVYBTsNwwaqccgOiCAA0ZzJjl53d7CWg== Received: from VE1PR08MB4765.eurprd08.prod.outlook.com (2603:10a6:802:a5::16) by GV1PR08MB7803.eurprd08.prod.outlook.com (2603:10a6:150:5a::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5654.18; Fri, 23 Sep 2022 07:34:31 +0000 Received: from VE1PR08MB4765.eurprd08.prod.outlook.com ([fe80::2846:1df0:88bb:451f]) by VE1PR08MB4765.eurprd08.prod.outlook.com ([fe80::2846:1df0:88bb:451f%3]) with mapi id 15.20.5654.020; Fri, 23 Sep 2022 07:34:31 +0000 Message-ID: <30063d97-69f0-bea2-9d59-108140995bfc@virtuozzo.com> Date: Fri, 23 Sep 2022 10:34:28 +0300 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: Re: [PATCH v2] mm: Make failslab writable again To: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Jonathan Corbet , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka , Roman Gushchin , kernel@openvz.org, Kees Cook , Roman Gushchin , Jann Horn , Vijayanand Jitta , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20220920121111.1792905-1-alexander.atanasov@virtuozzo.com> From: Alexander Atanasov In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: VI1PR07CA0252.eurprd07.prod.outlook.com (2603:10a6:803:b4::19) To VE1PR08MB4765.eurprd08.prod.outlook.com (2603:10a6:802:a5::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: VE1PR08MB4765:EE_|GV1PR08MB7803:EE_ X-MS-Office365-Filtering-Correlation-Id: 50ff07b1-44c9-47fc-f308-08da9d360d91 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:VE1PR08MB4765.eurprd08.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(4636009)(396003)(39850400004)(136003)(346002)(366004)(376002)(451199015)(478600001)(54906003)(6916009)(316002)(66476007)(8676002)(66556008)(31686004)(6486002)(4326008)(66946007)(38350700002)(6666004)(41300700001)(5660300002)(53546011)(6506007)(52116002)(6512007)(44832011)(26005)(186003)(36756003)(2906002)(2616005)(8936002)(86362001)(31696002)(7416002)(83380400001)(38100700002)(45980500001)(43740500002);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?TGxES0g3dURVNzZPK05OUWxhdkUvc04wTHdpTkRycmNHT1lYeHFsd08rdlgx?= =?utf-8?B?WlB0Mkk1OVFTQStOT2x3U0ZGek85cWdBRGN2eHJDUFlBS0x3ZTgxSDZzdVA0?= =?utf-8?B?UGw0WGErMjcyaTRqUWRKRSsyMHBVT3pTZ2JVSzg2TVFmWkwrOXZBQm9UWWpK?= =?utf-8?B?aEYyb0pWbVBobXBzQi9ONmtDR2NlQXAvRVAwYnpWbVlRTVFFcGZxbE9lT0w2?= =?utf-8?B?SDkyUm1ZemVKaVFyQlN2Vk1EY3BzOHYyR3M1aklqSHNDUkR4RHlQT3VkU3NN?= =?utf-8?B?TEhzdDYxZGZtdkVzbHQwUmxvNFhOelBtQUt6dm9JdEx3R3RqSXZ0UkhGTitl?= =?utf-8?B?SUhFMmZpbFo5Z1ZPQTFlUWxsQUt4NnpnNnFYdjdMY0E5YktIV1Bxc3BxQkpn?= =?utf-8?B?QVVyODl3YnlYMHhEZG1SMHRGM2lJRFRkbHpHRDZzZ0lLdXNqV3ZGM1YvQzRs?= =?utf-8?B?S1k1Zlc1TFZ0RmlHQXNjdWtXRUwyZkRPOGZvUkdSQjlHTnlqazNaVlVSSnE4?= =?utf-8?B?cXNTd3c2eW1sbkVvQjZJVjl6ZVdWQVlqMEJIUkVWL2Y4YUtSUVJQM2MxTHF6?= =?utf-8?B?NmI5QU5iREU5Rk1NMzBrdGZ0UGtKdzZybUFoSTFjTkJ1QmtjYTZxOHFiRkN6?= =?utf-8?B?ZVo4dytDTGF5Rm9qVjI5NzBuNTdHQnlQZ0pqUG9wM0JoTklLTzc3S1NjajJ0?= =?utf-8?B?cmZSRWN4K0xtNFVNUnZ2c21kc0hCL0pOV2o0SzBCMXZFNEhOZkp3S2hxRFZx?= =?utf-8?B?Y0piS3VLa3JPQlRNVitmTkE2R1dkcjNkcTljWFN1SzZEblJaUFo3N1dhV093?= =?utf-8?B?ZHZFL0hkQVdXTVkxY1JZOGdPbGVFVXNGbjlIbVlzTEZQdE0vZThLaWVOaDU0?= =?utf-8?B?RFhDNHhrNDgrWEQ2SHpJQVpkWlNHT01lUCttRG16ZHB5MFhCeGg5T21qRXl6?= =?utf-8?B?ajhZb2lMVGM5Y002Lzc5TWZPUmcxZVE0OHhHbzM0SUZNREVJczRGMktObEJx?= =?utf-8?B?TWJFNVpuNlhlbWxKNWt4bDNURU1MNFRJQWJIRVhoWUxSUGVOY0pyLzJyZzd4?= =?utf-8?B?dFFQU1dXdHUrcUlmWGpZL3NOd1JIOUZ3QVBPWWNGMmRpSG0zS1ZSMVk1TW1u?= =?utf-8?B?OG92cVJINEk0aHhPcTdrOGNNTW50MVBDck9nNThxQWNSL0M0Q1FLTVl2akV0?= =?utf-8?B?bzJRTXBMUzNlUTFsSHQxa2FJTHNwVXVJRnM5LzVjNGFvVG1sU2Z3eVpFdVJU?= =?utf-8?B?RWVGakdMTVNibGlHN08rQWlHbWw3VEhPUDliWDJmNlVzT2xJSnl3RGd3SEgz?= =?utf-8?B?TzJ3NkFmTlhSNzJvdVVyRW1hb013Ni9McWFpTno4UXJtaWJBblVtZnRxL1hX?= =?utf-8?B?bmRIbG1IU01FQk0rcSs2TzhIbXlGeVFncnRZLzhZS1BGMnEycW02bWczb0pR?= =?utf-8?B?Nk1JVTFaOW9CUnVTMXVCQ2QrMDR3NE9ZZ3dqQVZqVVFBYTcvUTFGMC9tS2U5?= =?utf-8?B?QkJydkRZeEkvbUxuUklHVytkSUZiSXo4SnIxMEVkVEI5Q1ZaYzJLb0RzOFNZ?= =?utf-8?B?QjFwTVBoNHNLc21yU1g1MHBRcmtrdGs3ZjdJRDNNM3Q0aGRIR0hwNytWd29q?= =?utf-8?B?UkozNkY3UTRLMENWZlJwdEk4UzFDYUdKMjhUYWl5MVBob2duaUdTSDdYNDlN?= =?utf-8?B?SGtrbjV0RHlWTXdQS0J0c1UyamdnMWtaV3VZME56RkpzbU5uRkZ0ZFVmZHcv?= =?utf-8?B?NTR5U3dGUWtySjVZVzI0aGlTSUs4OTQrN1dVa3BYWURxSmxIZmxSM3BYVisr?= =?utf-8?B?R2kyYmE1djRiVUNIR2dseTBPaGd6Y0NsSXRRVW01Sk9VS21pVHcwYmRkeE5M?= =?utf-8?B?QWo4SGdZK0s5SUx0N21ndmtIcmlQSkI3TVZVem9ZQmdrc2tERzRVZGlTSnJw?= =?utf-8?B?QmhsaXgvSTNGejFUcGFqYlY3UDVEdzg0UHNUNXFXUy9NY2MraDF5cXRSUGpJ?= =?utf-8?B?OWV2S0wzdUVvRGhKWER2TVkyTURGY1UwTzE1aW9pZFZpazA1MEdjTkJyeGNN?= =?utf-8?B?K3Y5UWNvTGk4SkZVRW5WTWxPS2wxREJIQnRZR0gzUEFUamtXc0ZsV3lMWjgr?= =?utf-8?B?SXhpYTRxSkVvSWY2cE1qMnlUb3ZDS1lndmxoU3lZSEgrOWZBbjVMNlNVS2Ft?= =?utf-8?B?UlE9PQ==?= X-OriginatorOrg: virtuozzo.com X-MS-Exchange-CrossTenant-Network-Message-Id: 50ff07b1-44c9-47fc-f308-08da9d360d91 X-MS-Exchange-CrossTenant-AuthSource: VE1PR08MB4765.eurprd08.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Sep 2022 07:34:30.9841 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 0bc7f26d-0264-416e-a6fc-8352af79c58f X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Q09N7xg7jKPnKr+SUdHmor3JCvEg1obW04n+BOMsy22/8Ge+c/oOwZ6zjvxocalz1eikbTws5oTpuje3ow6rAjanpMeoH7kC58fPY2aToh5yACVQMbZC/g5eVgJTauDO X-MS-Exchange-Transport-CrossTenantHeadersStamped: GV1PR08MB7803 ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1663918476; a=rsa-sha256; cv=pass; b=v6qNsof7/+FwfjNwVjv6BLlasFF1qzDIBE/RJ/70GilRfdOKe+V0uozS94j9pc9TU489Iq DFBF1+SvrL6pSv9gPLRQfbneUcxcHWB+Fkj5fLPQE0vy0jmurCES/jbyjcBYPmoLgrlKJ/ k8NfZsEGwuR+KKQwyw8aZVkk5pNtt9g= ARC-Authentication-Results: i=2; imf05.hostedemail.com; dkim=pass header.d=virtuozzo.com header.s=selector2 header.b=Y2pDOSHK; dmarc=pass (policy=quarantine) header.from=virtuozzo.com; spf=pass (imf05.hostedemail.com: domain of alexander.atanasov@virtuozzo.com designates 40.107.6.133 as permitted sender) smtp.mailfrom=alexander.atanasov@virtuozzo.com; arc=pass ("microsoft.com:s=arcselector9901:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1663918476; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=fjOYn/4k09qNOyxi88hh7BxnKaKDN3zBNvOmPFWhqjo=; b=quxkmNVnTTX4t3LnXlgZrumTSsuZP7u7xjQh58BcdAEFpXx3+STwhzRHHRi+PyA2+3U79j 97YxgOXs+YBZJc7l0I5xwE4TiUqeeONReUVU4MSR1he/n4Ciovz/uFaGZxpeegX8uliVN8 p00MYCuUdyDmetRrHsDzOAzMTonwPlQ= X-Rspamd-Server: rspam04 X-Rspam-User: X-Rspamd-Queue-Id: BF15D100017 Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=virtuozzo.com header.s=selector2 header.b=Y2pDOSHK; dmarc=pass (policy=quarantine) header.from=virtuozzo.com; spf=pass (imf05.hostedemail.com: domain of alexander.atanasov@virtuozzo.com designates 40.107.6.133 as permitted sender) smtp.mailfrom=alexander.atanasov@virtuozzo.com; arc=pass ("microsoft.com:s=arcselector9901:i=1") X-Stat-Signature: cyroud9r9orgnsp95rd7koyd9aacrunk X-HE-Tag: 1663918475-76775 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hello, On 21.09.22 14:30, Hyeonggon Yoo wrote: > On Tue, Sep 20, 2022 at 03:11:11PM +0300, Alexander Atanasov wrote: >> In (060807f841ac mm, slub: make remaining slub_debug related attributes >> read-only) failslab was made read-only. >> I think it became a collateral victim to the two other options for which >> the reasons are perfectly valid. >> Here is why: >> - sanity_checks and trace are slab internal debug options, >> failslab is used for fault injection. >> - for fault injections, which by presumption are random, it >> does not matter if it is not set atomically. And you need to >> set atleast one more option to trigger fault injection. >> - in a testing scenario you may need to change it at runtime >> example: module loading - you test all allocations limited >> by the space option. Then you move to test only your module's >> own slabs. >> - when set by command line flags it effectively disables all >> cache merges. > > Maybe we can make failslab= boot parameter to consider cache filtering? > > With that, just pass something like this: > failslab=X,X,X,X,cache_filter slub_debug=A,> > Users should pass slub_debug=A, anyway to prevent cache merging. It will be good to have this in case you want to test cache that is used early. But why push something to command line option only when it can be changed at runtime? -- Regards, Alexander Atanasov