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 A75FCC3DA61 for ; Wed, 24 Jul 2024 07:11:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1CDDC6B0082; Wed, 24 Jul 2024 03:11:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 17DBE6B0085; Wed, 24 Jul 2024 03:11:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F39206B0088; Wed, 24 Jul 2024 03:11:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id CF3A36B0082 for ; Wed, 24 Jul 2024 03:11:02 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 82C83A2DAC for ; Wed, 24 Jul 2024 07:11:02 +0000 (UTC) X-FDA: 82373774364.17.7EE55FC Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) by imf05.hostedemail.com (Postfix) with ESMTP id 8FFEE10000C for ; Wed, 24 Jul 2024 07:10:58 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Jf8PSfCU; arc=reject ("signature check failed: fail, {[1] = sig:microsoft.com:reject}"); spf=pass (imf05.hostedemail.com: domain of oliver.sang@intel.com designates 198.175.65.9 as permitted sender) smtp.mailfrom=oliver.sang@intel.com; dmarc=pass (policy=none) header.from=intel.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1721805011; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=t2WW+nfgFyVihHqWDMgz9+SJdIAhfKT0P1djoybtBEw=; b=xLcMD/k6rnljEWgSOV1pV40S4eWH+v3e8TTcROS4o28LV4/3Cpu6mdIw7wGN+1RrE4XBD5 jwgGdCntbCxRqZDUku51ufWHEkHoAUD7ifVp7YUQgwc6WZXblMa7l061y1X9zoaLSBs4cI 8sY3tB6abZ/55e6fjPAuV7pIwQadfKY= ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1721805011; a=rsa-sha256; cv=fail; b=qJohPS1t1Ghk5idy8Iu0B26+IDOTM8kWra8yF9j/L4iLFe02qL/Mfv32k7hwXGtNABs043 QlCq4RzuzQ6A8MNhgF9iG68PZA8V3epR1I3n24plLAIZeXLEXOdbV+ZQX8qvxiv+p+U8lG 55qaF2trZZi4yYF0BlP3E/xMaMyP64Y= ARC-Authentication-Results: i=2; imf05.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Jf8PSfCU; arc=reject ("signature check failed: fail, {[1] = sig:microsoft.com:reject}"); spf=pass (imf05.hostedemail.com: domain of oliver.sang@intel.com designates 198.175.65.9 as permitted sender) smtp.mailfrom=oliver.sang@intel.com; dmarc=pass (policy=none) header.from=intel.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1721805059; x=1753341059; h=date:from:to:cc:subject:message-id:references: in-reply-to:mime-version; bh=HnkD6SssZ9tSfkbybBxoWaIOJko+A0jcBtdlZUYQc7Y=; b=Jf8PSfCUlw3ra2INgRzTaNEwUYLh5BdNDRjRNLGI4UCchprP0I9/VjEO Bgf5ng/ZqqmnqJOKFualS76lghwA41wwvhUoUd2iT12kqiCuuQLd8XU0/ CexV0UgHo12SJpo4EJFtrjwnuyq7szK3jiivfzV+e3CCXQjdV6YyAVwGv VKAbwL4BMp/A+yytxQxSrSQv/kNp8+NrIwpxd+WD7AnH45UVqmx6pbU7s 5EseUtliVJmEigJi3eCYYf56UZkwvoJEwa9OpgjmlsJpaygf8aJLYh75W Q/Zm2XoPqMqxU0Pfzz5riLP57ZQiGepyckTyehKScuksdoyV/E4xldupC g==; X-CSE-ConnectionGUID: wI5PrRuCTL28RNiYS/jRuA== X-CSE-MsgGUID: siR1YAozQJ+GG/99oqq1cg== X-IronPort-AV: E=McAfee;i="6700,10204,11142"; a="41991307" X-IronPort-AV: E=Sophos;i="6.09,232,1716274800"; d="scan'208";a="41991307" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jul 2024 00:10:57 -0700 X-CSE-ConnectionGUID: Jaqs2gdwSwmsriONlt9YZQ== X-CSE-MsgGUID: U0qnBYbpS2acQfFWl3f2JQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.09,232,1716274800"; d="scan'208";a="57313532" Received: from fmsmsx601.amr.corp.intel.com ([10.18.126.81]) by orviesa003.jf.intel.com with ESMTP/TLS/AES256-GCM-SHA384; 24 Jul 2024 00:10:56 -0700 Received: from fmsmsx603.amr.corp.intel.com (10.18.126.83) by fmsmsx601.amr.corp.intel.com (10.18.126.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Wed, 24 Jul 2024 00:10:55 -0700 Received: from FMSEDG603.ED.cps.intel.com (10.1.192.133) by fmsmsx603.amr.corp.intel.com (10.18.126.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39 via Frontend Transport; Wed, 24 Jul 2024 00:10:55 -0700 Received: from NAM10-BN7-obe.outbound.protection.outlook.com (104.47.70.42) by edgegateway.intel.com (192.55.55.68) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Wed, 24 Jul 2024 00:10:54 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=iW3cw+YLtPjdXj6X6MHN+vSrs1yPvUwjvvXtMadyD2m4jabfyKAIV92gNKab2yzqkHJSULBAN+qujhit4JIlaISdQ6xvrSXiZl+HZf4K/Zu1Q371uFOBEzRZjMPg/ZFHbBAzDXFOpxgj7noVy5DGzVOfo/JqyVvybxdqzHrTtqLAbSFAf/BRvfTd3BBqZa8AMiQcIbTvrr0+OtB64u2NC3PngCKGXjYZwUjxSYUJwBD9HBCsGvcHXaypbM9RqVDJO5SXzp+Lf3LDwvLaPhTnKR6/njkAneAeVC7CtlB5vkwIpQSt7dUGPEzt/2Y7u+cQU5qtXFlo79ZoWEhF1nI42g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; 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=t2WW+nfgFyVihHqWDMgz9+SJdIAhfKT0P1djoybtBEw=; b=jBYMcGPiWNv8pLM2VdTUGB6b3m3k/MqiVSBwBaCZMsO95vrjPn5rfyvjhpYMAdkUCfyA5KXeNiCFcINp+wg5LGZjlxci/pWhoEbKmYqhGk27hKDugbB7hLZK9RH0/ElBlz7YgKq7z5+CbpGH48EwAyoy6VJJ/jmGKAryorGP0l6CKIilrK7plAU+SBVSDYUxZSR9rAb57AXHKMZZ1UxKQkcADJRW7P08mbtLSwesF154ETZHKsmf5hU5RM2C4TGdFt2IEg1Kl+bULAI+PYy9V7rA6Mq8rRQpxjEMLSmFReDkSjRcm+aqF2yRJmEwn1ue7w5M3Sn+5og3cKL7bviptw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Received: from LV3PR11MB8603.namprd11.prod.outlook.com (2603:10b6:408:1b6::9) by MW5PR11MB5882.namprd11.prod.outlook.com (2603:10b6:303:19e::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7784.14; Wed, 24 Jul 2024 07:10:52 +0000 Received: from LV3PR11MB8603.namprd11.prod.outlook.com ([fe80::4622:29cf:32b:7e5c]) by LV3PR11MB8603.namprd11.prod.outlook.com ([fe80::4622:29cf:32b:7e5c%5]) with mapi id 15.20.7762.027; Wed, 24 Jul 2024 07:10:52 +0000 Date: Wed, 24 Jul 2024 15:10:36 +0800 From: Oliver Sang To: Dennis Zhou CC: Boqun Feng , Tejun Heo , "Suren Baghdasaryan" , , , , Andrew Morton , Kent Overstreet , Kees Cook , Alexander Viro , "Alex Gaynor" , Alice Ryhl , "Andreas Hindborg" , Benno Lossin , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , "Christoph Lameter" , Gary Guo , Miguel Ojeda , Pasha Tatashin , "Peter Zijlstra" , Vlastimil Babka , "Wedson Almeida Filho" , , , Subject: Re: [linus:master] [mm] 24e44cc22a: BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_block_update_hint_alloc Message-ID: References: <202407191651.f24e499d-oliver.sang@intel.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: SI2PR01CA0019.apcprd01.prod.exchangelabs.com (2603:1096:4:192::12) To LV3PR11MB8603.namprd11.prod.outlook.com (2603:10b6:408:1b6::9) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV3PR11MB8603:EE_|MW5PR11MB5882:EE_ X-MS-Office365-Filtering-Correlation-Id: 588ad149-77ae-415b-3238-08dcabafc097 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|376014|7416014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?9IcMisVKV28I8BAeP40S3fpUVdHL1B+yJcNhG4lDD755Cqqw3f1BtDvixXQx?= =?us-ascii?Q?nEivLai5AN4+/cW66iqCmyYyCFwd/oX35tPR+iQaGKVbyJ/VUpCxsOS+n+BL?= =?us-ascii?Q?E3JDvDfoEjOJU2fj7M5yPWm+VdsobQdGyJa7Ahv9427Zm2zey/3U/0Htgfka?= =?us-ascii?Q?SBd4++EhqM/hw6qtTBE94rJ7dkNdxYVQT5AlYXGDXDGf8bW/iO3Z13N5qEf7?= =?us-ascii?Q?KxFUncrQsyl9hkWrQh2tnyj7obGqAOGcUHuEfSasc7gpzbgTDP3RRxP68XoG?= =?us-ascii?Q?muLZcfNopqBrUpH2S+QNfgmhKh65bucY+6WQgJYv+c7Gy8jdQ/Uj/2BTrBWi?= =?us-ascii?Q?t4bnLkjTHJcjIBFEn8V0eTxc6SwL9Zk1AEcnE17DiSMb4DNdO6R5qQZ+VdB8?= =?us-ascii?Q?f9sxzJKTMWOzzDphP4qjcC7RHKmykWD6PGvbV4DuTfpZdehzZEnheEP0lk5I?= =?us-ascii?Q?FAGO3Lgddz+IpxRMW1jeQ2TRYsVItQ4NFzk8wdp1Li5K+JMT86jW2yRQ7vgM?= =?us-ascii?Q?vn2J7s8fgsDCOxaNwS1n4IPvlGUGzYnlrzYETkwYB4JK6eE5TXLNhd0o9+HU?= =?us-ascii?Q?LqALYuwypkzNqSGHk+rphKsW+fMykX+ptRzsdXL418fn2mPMiVCu9rFvAnr9?= =?us-ascii?Q?SEbxXZRdhmgmOehPEKsMjVGQSYIOP/EEG7velvNdLaT4o1z0fM8yRguh1825?= =?us-ascii?Q?/3GVOiLkT4YxmyA0D8brclc3iAaiGCdXWqOcbH4A8NeFmZ3+SvBjh+hlfaY4?= =?us-ascii?Q?ZVRGEl8PcLMoo3+yDpAlNYFIxs7Eesw6JlFymtuQ0N5++9ICvXVb6BbLhkv3?= =?us-ascii?Q?OEsbMqTW5HX4vkt5MxSz/o0fumROs7xclmecMNJyGo9HxbarWj0lk8pCazSI?= =?us-ascii?Q?FAIJsZdWoLrk62zEQi0RaKoWc8lATXgLXCbgeqoQNCsJlQUsxY9vWEHAI+Np?= =?us-ascii?Q?TbrF4QlGRqte40Ar9gYgPQUle0diE3f7EY2XzmS9tc60pKnHAWNeF47k+8oa?= =?us-ascii?Q?SqcNP+mnlzYBjKOSeCRqxQzlTHWWS/iAJaq61MnZqjVVM6YpVgco/+HinFPb?= =?us-ascii?Q?iOcJckaU9L3sBDbqVD3+6bWiMFhDOlmP7AgFvyEmDyotPGNBszNzI5VRqsri?= =?us-ascii?Q?OgIELbgoxMpvbajqWRMAwMY9dtzGoz+PbvYfuTG+SqAWQdahiWQ2fT5G83Q3?= =?us-ascii?Q?etQMdtdgNXWzaBtsLagAYI+43an5iZfJntPQ3yV+Ke7FSgsGIJ566AF7rJkK?= =?us-ascii?Q?CsO9RMztbBZfFeHIhvIZr9O4jOswINei6Si2bKrhgVLNfE3PWQRra2gcu2g0?= =?us-ascii?Q?ljHBtwdnOgsH4C9jOTbnhKHAQGg3T7SUyRtaWnl66tEodA=3D=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LV3PR11MB8603.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(376014)(7416014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?5tXMQOW1qCtIJgIx5Nx74ITKiIrtSe/lGI2D4x4YqLxYVzaDQn3CWiilyKum?= =?us-ascii?Q?eVUew2e4RynP4vKvZw+efLU9zHg6BPFu+OMvGAXrRgTid7jRMB1DCyByEC22?= =?us-ascii?Q?12gX0SIAHqhNFFX+dn6AiTT3FfB+MuKvGTYk9M1p/r3ghiLOg637ulSnwPU+?= =?us-ascii?Q?APNuGdo3upoy650cMfxgALHhfQAVDG2AXQc8MNKN7FxDfvPxjZ+89fLHW2Hd?= =?us-ascii?Q?WbePWqSE5FsbTzS/kJP6yC22q+ehHtwHvNyxHzmg8R96TMJHQdZpLHgZSCU2?= =?us-ascii?Q?NMECqBkuX3bQGZ9/NDpa0bB8P3eqkckvuF/BCoPN25hjekE22ciRYbIZYM0o?= =?us-ascii?Q?NF3EcrenNRviG4b+trHqE2NNOq6gVmmgswz1GH6HhY/r8fMzx8anj+Ai1geC?= =?us-ascii?Q?L9zDgB3oE7l95SMj3jcfqDODHx62qWPHl91ZJYVcxAWnS/KkAxr74aQJzW1C?= =?us-ascii?Q?3PyJvHXtH6uJPEwnOJkjiyi78PWWWh4rLTSPoWTIOdDL/2NoZG6tTJEOqXNq?= =?us-ascii?Q?SCbOrtwIthHEUhkx2SkCTS8TUQ5ugf5DZJe/WZmA+9uCga7ydwrdqxfxWiVe?= =?us-ascii?Q?+S+hWB2La+FsDdxMIMoHdeZil/A8qE6i8HRGOEVa/HE/+RLg3eHn9kf6zOD/?= =?us-ascii?Q?UCekYsrQiG4u22hAmRSsAsTmaG3jyPFAftSahjF073Xk2/lrp443t/ht+Dwu?= =?us-ascii?Q?idf+YQVc9HtzkpSm/I4TnRelYgfWdPA9BXZLzW7xTd9BdkPwuJRsQxWsAOpK?= =?us-ascii?Q?06sQNZMdOcVkavwIgLnxfGX3gx3rCI6Uc7AXcLsDnpwLoyf9lFfbgGoorVT9?= =?us-ascii?Q?3KovujvH3uR3KxgtO8ug7M61nsbASK2uLrdw8KGI2AtRbrdPG6ZUHmw2Bql+?= =?us-ascii?Q?bZA5JqUvzbzlzyyuGMgg+Ndi6ni95qOzqnTBVppg8Q/5yCF0gvDAKkeEtW/Z?= =?us-ascii?Q?QRaCo2IOTWJHXkcsbNQux6gHlDfC57nmlEYM/wzbVrLMXDe1CNbpPyJqC7jn?= =?us-ascii?Q?lN4LNJjdzpOUfYidoNXAzmjFzNH26eZJHBcOOtGc8SqLr66MDgb+JDgQ7Cua?= =?us-ascii?Q?9ziTuduJqPbge1XoopxB5t8Afn6GoBnAAmcTS4wgdnTdYWHgIEN5wq4ZJjZR?= =?us-ascii?Q?S4SFem9CRMS7ttOWk0XTILnghr6b4jiZLumzCVv/3zHR/OM2JtDvBAqer5kP?= =?us-ascii?Q?8HcdeTYkmq7tG4PmwP8n47vGnlhl7UjM0gw1sxnhjfpK/7dh+kDnawpxPSY+?= =?us-ascii?Q?sqGxT4yZpm0L7OjaRhoFrNliHl5H7LqJc9ynOz6Eagocchb/RrNUqnm+rhG8?= =?us-ascii?Q?E9i/RUVMxXYBBq7K9yoPkUBbIK3RyQaKYCk8R/CoCx96xweSHEutQmwrTk0P?= =?us-ascii?Q?5pPcEa9s9qSyMWL45iyXhiOnIDTpz2DznrGa+S3NPiy+sw51BWyCwjf44r3V?= =?us-ascii?Q?vu3hpVzoWzwCwD4iV9YIx3r4jAWdLZlsL6n4k4Jy44tjNEyFcsLNHdrehulG?= =?us-ascii?Q?PbRi6YA4Z2Yn9VmuJjScWEd8TdUKIXYLor/Aau2ETVUqDrCZbo+jimhnsdq2?= =?us-ascii?Q?5u7FAZFYbMWIjrZ//7z3SDPfo5wDyPcT0HdFBJ9J?= X-MS-Exchange-CrossTenant-Network-Message-Id: 588ad149-77ae-415b-3238-08dcabafc097 X-MS-Exchange-CrossTenant-AuthSource: LV3PR11MB8603.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Jul 2024 07:10:52.1950 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: p6p5VLEIO1zA/hjFhj0pI9sjWUkYxP9wasql24eTHI8YTty4ph/KAU8jqit0NYJWxObYKdHZeqDSH9ID8nQCMg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW5PR11MB5882 X-OriginatorOrg: intel.com X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 8FFEE10000C X-Stat-Signature: sd4ek3hkgo6omf5ywrgstpd11kmadnmk X-HE-Tag: 1721805058-834104 X-HE-Meta: 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 xAQHh3o1 VUJQ3Im8xJkZ3D10aHL3o4ACg7AxpSVbf4bWHuIO/1uOC7n2oX6CdKhfR6CKHNENn6sTDcDvw2q2PPZEvWE8l5qEDxpvGJB1vn4XL0UkIkmoZhHIDHtmPbxE6dnY6Y35h6A17mzzZ9QUarJ2iaprXXU5SiKlI06+uY55OEqEE9YVXEz9qniwY5T1F682m1tw2Uset6y/YUfPHWOMr1UdymWpiGt/kl+8rLF2LYCfvnw/qpLEqTAoEDjKdq4LyUJqrw7Vmyk3UGqp4CfSLbJe4iLAA2ghO2w7fAZ2vddEjS96X+d0j2Hm2WK7eI2YTxl4QuQCOdAX7AQEwKtfNi83IBMtqRG6WzWqq4aOZ+t/3sjO0zrltjoiS1ECK2Eh5tTdXLgjQn5rh6A2VSU0awvQRviQmEpeU+YAoyQDNr/DDga/G2+61rwemlRHFl+XhlmmgSg5sNswTk621+4XQ0iUS0sa24amcJ0S5MYJnOkJq9hMlfp2tk0zqbNVmsjSWMC/IcajmW45triGXDa0= 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: List-Subscribe: List-Unsubscribe: hi, Dannis, On Mon, Jul 22, 2024 at 11:13:10PM -0700, Dennis Zhou wrote: > Hi Oliver, > > On Tue, Jul 23, 2024 at 02:09:38PM +0800, Oliver Sang wrote: > > hi, Dennis Zhou, > > > > On Mon, Jul 22, 2024 at 10:50:53PM -0700, Dennis Zhou wrote: > > > On Mon, Jul 22, 2024 at 01:53:52PM -0700, Boqun Feng wrote: > > > > On Mon, Jul 22, 2024 at 11:27:48AM -0700, Dennis Zhou wrote: > > > > > Hello, > > > > > > > > > > On Mon, Jul 22, 2024 at 11:03:00AM -0700, Boqun Feng wrote: > > > > > > On Mon, Jul 22, 2024 at 07:52:22AM -1000, Tejun Heo wrote: > > > > > > > On Mon, Jul 22, 2024 at 10:47:30AM -0700, Boqun Feng wrote: > > > > > > > > This looks like a data race because we read pcpu_nr_empty_pop_pages out > > > > > > > > of the lock for a best effort checking, @Tejun, maybe you could confirm > > > > > > > > on this? > > > > > > > > > > > > > > That does sound plausible. > > > > > > > > > > > > > > > - if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW) > > > > > > > > + /* > > > > > > > > + * Checks pcpu_nr_empty_pop_pages out of the pcpu_lock, data races may > > > > > > > > + * occur but this is just a best-effort checking, everything is synced > > > > > > > > + * in pcpu_balance_work. > > > > > > > > + */ > > > > > > > > + if (data_race(pcpu_nr_empty_pop_pages) < PCPU_EMPTY_POP_PAGES_LOW) > > > > > > > > pcpu_schedule_balance_work(); > > > > > > > > > > > > > > Would it be better to use READ/WRITE_ONCE() for the variable? > > > > > > > > > > > > > > > > > > > For READ/WRITE_ONCE(), we will need to replace all write accesses and > > > > > > all out-of-lock read accesses to pcpu_nr_empty_pop_pages, like below. > > > > > > It's better in the sense that it doesn't rely on compiler behaviors on > > > > > > data races, not sure about the performance impact though. > > > > > > > > > > > > > > > > I think a better alternative is we can move it up into the lock under > > > > > area_found. The value gets updated as part of pcpu_alloc_area() as the > > > > > code above populates percpu memory that is already allocated. > > > > > > > > > > > > > Not sure I followed what exactly you suggested here because I'm not > > > > familiar with the logic, but a simpler version would be: > > > > > > > > > > > > > > I believe that's the only naked access of pcpu_nr_empty_pop_pages. So > > > I was thinking this'll fix this problem. > > > > > > I also don't know how to rerun this CI tho.. > > > > we could test this patch. what's the base? could we apply it directly upon > > 24e44cc22a? > > > > BTW, our bot is not so clever so far to auto test fix patches, so this is kind > > of manual effort. due to resource constraint, it will be hard for us to test > > each patch (we saw several patches in this thread already) or test very fast. > > > > Ah yeah that makes sense. If you don't mind testing the last one I sent, > the one below, that applies cleanly to 24e44cc22a. in our tests, you patch could solve the KCSAN issues. thanks ========================================================================================= compiler/group/kconfig/nr_groups/rootfs/runtime/tbox_group/testcase: gcc-13/group-04/x86_64-randconfig-013-20240713/5/debian-11.1-i386-20220923.cgz/300s/vm-snb/trinity commit: 60fa4a9e23231 ("mm: percpu: add codetag reference into pcpuobj_ext") 24e44cc22aa31 ("mm: percpu: enable per-cpu allocation tagging") dcfbb68202759 <--- your patch 60fa4a9e23231721 24e44cc22aa3112082f2ee23137 dcfbb6820275994e92a9dcf309e ---------------- --------------------------- --------------------------- fail:runs %reproduction fail:runs %reproduction fail:runs | | | | | 281:999 -28% :998 -28% :999 dmesg.BUG:KCSAN:data-race_in_pcpu_alloc/pcpu_block_update_hint_alloc 296:999 -30% :998 -30% :999 dmesg.BUG:KCSAN:data-race_in_pcpu_alloc/pcpu_block_update_hint_free 25:999 -3% :998 -3% :999 dmesg.BUG:KCSAN:data-race_in_pcpu_alloc/pcpu_chunk_populated :999 29% 292:998 0% :999 dmesg.BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_block_update_hint_alloc :999 27% 269:998 0% :999 dmesg.BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_block_update_hint_free :999 4% 44:998 0% :999 dmesg.BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_chunk_populated > > Thanks, > Dennis > > > > > > > --- > > > diff --git a/mm/percpu.c b/mm/percpu.c > > > index 20d91af8c033..325fb8412e90 100644 > > > --- a/mm/percpu.c > > > +++ b/mm/percpu.c > > > @@ -1864,6 +1864,10 @@ void __percpu *pcpu_alloc_noprof(size_t size, size_t align, bool reserved, > > > > > > area_found: > > > pcpu_stats_area_alloc(chunk, size); > > > + > > > + if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW) > > > + pcpu_schedule_balance_work(); > > > + > > > spin_unlock_irqrestore(&pcpu_lock, flags); > > > > > > /* populate if not all pages are already there */ > > > @@ -1891,9 +1895,6 @@ void __percpu *pcpu_alloc_noprof(size_t size, size_t align, bool reserved, > > > mutex_unlock(&pcpu_alloc_mutex); > > > } > > > > > > - if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW) > > > - pcpu_schedule_balance_work(); > > > - > > > /* clear the areas and return address relative to base address */ > > > for_each_possible_cpu(cpu) > > > memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);