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 73A68C35FE4 for ; Sun, 15 Sep 2024 13:26:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D806E6B007B; Sun, 15 Sep 2024 09:26:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D2EAD6B0082; Sun, 15 Sep 2024 09:26:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BA8A16B0083; Sun, 15 Sep 2024 09:26:17 -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 9C1D56B007B for ; Sun, 15 Sep 2024 09:26:17 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 45894802FD for ; Sun, 15 Sep 2024 13:26:17 +0000 (UTC) X-FDA: 82567046394.19.1C6ACF2 Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by imf24.hostedemail.com (Postfix) with ESMTP id 89654180007 for ; Sun, 15 Sep 2024 13:26:13 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=VO036574; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=Do+EgWJL; dmarc=pass (policy=reject) header.from=oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf24.hostedemail.com: domain of lorenzo.stoakes@oracle.com designates 205.220.177.32 as permitted sender) smtp.mailfrom=lorenzo.stoakes@oracle.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1726406766; a=rsa-sha256; cv=pass; b=Lz6JyrV7wOfsV6OInwHTCFHbz0npQippJgftw5Ax+26t68Qd8UZsB1ucPYk4FmVvtzvDMc vlywK0DrWsWHjDEAXnF23geT3tWX39e2lw4SA0RF5Xzw2GN6dLT+hcn/1PKm2ZyfV8t77X ZWsH1sSCqy1wmacXR8X1EvJE7qAINME= ARC-Authentication-Results: i=2; imf24.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=VO036574; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=Do+EgWJL; dmarc=pass (policy=reject) header.from=oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf24.hostedemail.com: domain of lorenzo.stoakes@oracle.com designates 205.220.177.32 as permitted sender) smtp.mailfrom=lorenzo.stoakes@oracle.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1726406766; 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=Dt+UqbXF1qRWaS1zhKnv9GuwJYoZm1XlZMA7rCUNhg0=; b=bJNEbaQGKwryglnP5xZCAbzjYStv8NRrLgPsPyauHYz8uX6kSI6aJ2WO3Y+GddWGttwmZA Z73kO9boLh8raANzPtusfA6gjJ6rP2O1ocezIY2eJ8ZT4UhfeEZmz7eE7ks+64uFhsYSR7 imYaLG7UZJR1ZdsAaJ3L+2c7tWP+SAw= Received: from pps.filterd (m0246632.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 48F4tEAv026591; Sun, 15 Sep 2024 13:26:10 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h= date:from:to:cc:subject:message-id:references:content-type :in-reply-to:mime-version; s=corp-2023-11-20; bh=Dt+UqbXF1qRWaS1 zhKnv9GuwJYoZm1XlZMA7rCUNhg0=; b=VO0365742IalVMCwrzN0lromW9jkOOn GlzzN0LPpMciOoSMSC3Eo0G+/alIUTJKDH9yQ/BKXEzwqTdF6J46N8tLqZlltASg 3wPD0qHdZV5YxvcPovgA4e2B+0rggevMWrzrNWH2Zz9W+heXhRMLpnXOnl3uODh7 B5uDjO0VwWdkvUGJGcda97nKiqtX2sBONc+WIXGxhsLyJLHJyfJoZkqnWPqytleI t8xJX2ObXS2boqgRbQsOvpPE1J517hl0HeCtE6PnNxvmuKo6BXEaLu6BRYg4md3m N5mnXJ/KNUYUpFgKv1TQSfoGl6+Tc4imZSa/cnjEgTLa7lgWVT8I8eQ== Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.appoci.oracle.com [147.154.18.20]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 41n3rjskc5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 15 Sep 2024 13:26:09 +0000 (GMT) Received: from pps.filterd (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 48FCI07k008173; Sun, 15 Sep 2024 13:26:09 GMT Received: from nam02-bn1-obe.outbound.protection.outlook.com (mail-bn1nam02lp2049.outbound.protection.outlook.com [104.47.51.49]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 41nyf9rtw1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 15 Sep 2024 13:26:08 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=RSOQKMrIJDuoCYshnNvA65qq1/6ogF5rQRPYyl3ZpCzSoNWM61LxBIhliUsC74v8ydnC566G2FfWWth22D8S19AiLxj4IwdrjrcXXBy2piE92V50/JM4DTDQySeUvXWNLUkmHjaZkF2KfjwzO2D+aeM1NATfyFe8PTAfoHINRwL46KFtRZfBrsZjgDeo4Rn7ywaBbz/r3x5O2ytypVVci/gn7PQixOG8ON/PnXpmTRs7d7oQQkQ6euyV5saeDsm6x/ErRk6cwDSi9EstRdUNrgJADSSWIUCmRrukXjeMMTmhOPRQbOfM4SzW9GAUdd0l/NE97SFcDRZL4H5Uvm+Iyg== 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=Dt+UqbXF1qRWaS1zhKnv9GuwJYoZm1XlZMA7rCUNhg0=; b=UC94Op6drneXZlOM43XDiHPtU7gyiG1hoDrWbgXXZEaJ37sIoOkxeUJjxgStDplR0uB+2Ng4i2VbNtW8LgwW8pBhgs/fNadgvJ02GFdJ/oKVuBEEBrUabR6mNsFsaxEx/n9/lSyScUPPsdxhe27oGGhUY5RJ3h6WLfhX+8BT8ibUOChDarrpQDY9hNCo5u/2/OcBKl/JFNv4nzFDCOE7WK53ocoKYcSozpy+ZTqlgyei57OIjPzDGi7C4xfe6J0QbQKt5WvkSVGaokIbFIPHvAZVzA+uL8DJdRqhMQLTx1NOOVmrRrgjCp8o+haEKJOTJYsBrZP1LyGuwzHfYq6lvQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=Dt+UqbXF1qRWaS1zhKnv9GuwJYoZm1XlZMA7rCUNhg0=; b=Do+EgWJLSd1MS9sRAXSDNf8XkfNYsUSSVUJKdotOxH1yJxV/UkaEBaXZdWDUbY5Ee/LNQtuDHRMFDYBu05itJjyhTDmn6q66CQuKIkYoaPn4dFcxLMJneWoJ3JatCNGMRFjV2coGz0QCFGQuu9/G+HMP3O6BN8Y73uqPKPyxopo= Received: from SJ0PR10MB5613.namprd10.prod.outlook.com (2603:10b6:a03:3d0::5) by SJ0PR10MB4750.namprd10.prod.outlook.com (2603:10b6:a03:2d5::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7982.14; Sun, 15 Sep 2024 13:26:07 +0000 Received: from SJ0PR10MB5613.namprd10.prod.outlook.com ([fe80::4239:cf6f:9caa:940e]) by SJ0PR10MB5613.namprd10.prod.outlook.com ([fe80::4239:cf6f:9caa:940e%5]) with mapi id 15.20.7982.011; Sun, 15 Sep 2024 13:26:06 +0000 Date: Sun, 15 Sep 2024 14:26:03 +0100 From: Lorenzo Stoakes To: Dan Carpenter Cc: Linus Torvalds , linux-mm@kvack.org, Dimitri Sivanich , Arnd Bergmann , Greg Kroah-Hartman , linux-kernel@vger.kernel.org Subject: Re: [bug report] mm: avoid leaving partial pfn mappings around in error case Message-ID: References: <8e3ffaf2-358f-479c-8de6-46e1b0bb0c5f@stanley.mountain> <68590155-fd3c-4ce4-9a1f-d314efada198@lucifer.local> <5a2f4219-e863-413a-96b9-ad2002f5b35d@stanley.mountain> <998b7c12-19a5-4213-8df6-154f50cd5dee@lucifer.local> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: LO4P123CA0670.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:351::16) To SJ0PR10MB5613.namprd10.prod.outlook.com (2603:10b6:a03:3d0::5) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ0PR10MB5613:EE_|SJ0PR10MB4750:EE_ X-MS-Office365-Filtering-Correlation-Id: 96893210-6270-4d3d-fa00-08dcd589f479 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|366016; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?8/MsB4/mhKoxXbNJqj0GbBqUVLEu24XtIhml/RSJYYAvNdINxlpbs/7j6BPK?= =?us-ascii?Q?vxHfHFQXefSMxCEX8/NxnDEbkEfztiNVPZhA1pTogMPGrZ2kVexfGpMloooI?= =?us-ascii?Q?Nx0H0a+/ye28yKJKZk+bYrb46YIH4Th7PKkH6X9jzXGkrEXXQnTCiCd4Eve3?= =?us-ascii?Q?+A/eoeWQ/OJwmip+8TX/lXa4DVllU0TXcEHPGG/GCTcsughWWeox15APx02V?= =?us-ascii?Q?CZgXF4DthrLczTIcpO9pVuqQy2NhmZy6nQs673uqnnZPGqaMsSOXTLftXgde?= =?us-ascii?Q?KUQcEfuBAML6AftyHTbDdmhztwraMxUvpwStT8L2/o98RTsl7reZzMJYJV95?= =?us-ascii?Q?EnFz6tglwE+S1mMCyKbqp2NB25VdPF1Uf9a1NbL5sPs1bBoGFQNdc1rrgF2c?= =?us-ascii?Q?u8JSHD5hocBw2U39V0f6OVJqW5uSNjn3MsXXAi1ZmsOsm8XYX3bvgFJjv8Hh?= =?us-ascii?Q?v/1gpXjNRTxiWpDeEzQAb5+ZLYJs6tQC6CWRo4PArttGhLLG6DmYN+Hjfpx3?= =?us-ascii?Q?TEN0XMVFFGBmYPRJlH6JmAakubcfnUz/5PSfTB4obs/57vhH9Taj2Y7oIWzV?= =?us-ascii?Q?wAesVekm8AyDvvdxcW+CUauv8ZeCwy5BRcw1XkTAe95Crfm2eR92hi3qdBJw?= =?us-ascii?Q?Icx6QdI5ZaZ7Eod/VG5vmAAF9uq/rJ3HMLcKYIDQ6vMb1bECsg4xkwoNnXWw?= =?us-ascii?Q?cZHSHCPGRWJMkwayxbu2F3GuIFUb4ieWKx6bSLCpEnCFIEnTNK8Po8czW+w7?= =?us-ascii?Q?EUNfSU9JNrgolAG3jKNESMJRHKtOESGV0QK+8XwqEG+RdUlgGwuWYgI147qV?= =?us-ascii?Q?rC8H3epJ3NGHpkAVhOfRrLjcFCH2SV1xdBOh+rUNqkrk2gQFqcmdLGkETzmZ?= =?us-ascii?Q?i74antIfsC431RDbhQn1Gt7kL5HFIdCPNs5U3em5DbnAKG5dE8tmdE7ImLd3?= =?us-ascii?Q?9h36tpzMQdzGnUah4zVyF3h55ievIBFcbChYKKaV/ryU2iWJJjN+2L03jWhD?= =?us-ascii?Q?GBkvSrsZUnPAAryqH1Qar0/+3iaHnFrmFzoMarghoYfozFPy+ziYvCf4UFdX?= =?us-ascii?Q?7Nn44XR0EEy8STvYuD8r5GbgzcEfZWWpIX1gl67Pa6P7uju74Rox7kOniT2v?= =?us-ascii?Q?SebKHeFsCXVVplDCTqfFbR5zk+ke9VHQvCCl3mtm5S4lw88OnxfUJjKZIto8?= =?us-ascii?Q?ky/v0ScHUWZ9Q0L5Tam4edmpdUJzzWjorq7SEgSidF2Sp2DPTQOG2U3kJ69W?= =?us-ascii?Q?mZsBqawwqoGP7XFTkMw2xEd8crBL/4cHw3Fben+jtOONWRz7crXCw6vaeIa/?= =?us-ascii?Q?ClSxcnapYhq/2DuG02sCaVQOG5NuBBx3N2cueVyEj21XZQ=3D=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SJ0PR10MB5613.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(376014)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?crSBBIuOvTlwAqsOwPwyLllEG0O8kMA9/5B7F7nQZ5qqESwYHoXQksjEJ/lu?= =?us-ascii?Q?a+qgqsgyv3HwEGnECaO301ZQyet2hw1pW9cV3v6bnI1kAg5QZ/8xP8GeEHkv?= =?us-ascii?Q?8q41vPFFVYCEBg8tPhnkB4QVYRGgb+/7J9wixuZFyu9MlKtpuyTxx9rbpWRe?= =?us-ascii?Q?hHd11Nm2ozbXL7bXbIyMCKcfi6qecD2H5PCSpSQaqowOCI5/sEGhq3G5m7HI?= =?us-ascii?Q?LjGcaUzz+DpF6REYQQmMMXBQnpGulTV48ZRcwOBhl1RDAVU3EiXX+509Qyft?= =?us-ascii?Q?7s5e/65ZVthyysvnzLQA/dto9c738MeC0AN3v5os5tjkAQuhzS9HmfXysZ6j?= =?us-ascii?Q?1xp7WGz+jEKhXP1MKyveq1oUWD/w5LzqVcEdAiHIq5MGByld9+5fCZcK4SE8?= =?us-ascii?Q?tWP40tFD48qRCJeC2VUrrsVYWEhbjJ805H0TEGIyTCTjbYiWe3pP/z+yA9pa?= =?us-ascii?Q?iT21QKMJJsjLp7R1SFCYW9kDXs1CO31E6nsbuBavsFUsIgKYIhJlHEZzlFlf?= =?us-ascii?Q?mZexRpvMzagVN6CoTkX0qvT1NRUBqP+1k0pcpCRrKIfa6eMTJl/eYezYg1Dm?= =?us-ascii?Q?XC6bI2jm6gjlamYyNOvUZfmJ3CoXbHmT9/0nWEm6fWPNJaVrQaKOBM2HAdFO?= =?us-ascii?Q?+DY0UG2Jd4LaxZNve6y/BGDNjHqSQpC2WqKUP4km4jyrjlYnEcR8ySZqZcm1?= =?us-ascii?Q?WVngvG85zBPdZbR/UwZhKG7lGOnmu0IbSD43q/M7ye/R3DUt5Jx0RlltQEoI?= =?us-ascii?Q?Vev2/6sT1YY4MiNtJnVZ9RwyPEz0tvpLt57ZdhMQWHVnSaq0p6s0UPn4qrVB?= =?us-ascii?Q?Cdfu5NjQtVIyO+2l95p04Bku7BCVFxvn2ovVOwhXNgoHpzJwb7/q49jP6I6W?= =?us-ascii?Q?QfPOTldSuhgQhXhO4OK3/BX7UQfchwx8Pe6wa9s+l4vMXHp9U81pNz5rvfgI?= =?us-ascii?Q?6EpFfqul2xYQlaMsWAB1Rg20dqBurEOl49VogdzjyMTbEGVLO4t/WsRgutP/?= =?us-ascii?Q?woYjgQsd2ywSuRvbZ0a8/HSGN0BUgetP/zB7f5nx6uW6Dskf+Um66buL9A5a?= =?us-ascii?Q?QvbBisMyfmzEAYZmu63Kz3bT3TNEmoXMjutUX2WweHU+mAtuGasHMBkaSagX?= =?us-ascii?Q?scGgQJxFuTBM0Zy5h5/7wTzSUNEwWok6Po9Zq8wVmFKZ69F7ER9Zly5k3Vog?= =?us-ascii?Q?U+f1Gnqkd1WacBrSSpJnXkJeuKgcrYjKSYZ1bDP/UQzXOFq8uxWSncco0PB4?= =?us-ascii?Q?AWRBRCb9ZFZWBZvu2HPvCTqfsTURivowCtNA3megIkN6NogQD/klSx+c5ANm?= =?us-ascii?Q?arP/YgkmlZ2dty9OeQOmsHMIQ0lIrfViYXtSdBxWEA7FcC9iERvqMUi8ziRJ?= =?us-ascii?Q?sR188KJK9RuL0jfrOiEozIm6/NkxAKp5+oNgI6cdH4Y3wEVpVP6SYnppjJjF?= =?us-ascii?Q?AEu/2l4ALdm2w9Dhlacx/Y5k+mFZAsuCCauPoFr91WAonrpOqI1pKJ2b9tdT?= =?us-ascii?Q?0lNEU2vecPiG1GI0F75zEfjwdodsN0BmkLHipsnkD6/5HR0QtxU+aBqn/jMP?= =?us-ascii?Q?aVJyoRpSSKhw0JO4/fs2QZy4lK0BZdPaRXyZDsghHYuj8fyIhYfaLK5roEdF?= =?us-ascii?Q?5w=3D=3D?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 96893210-6270-4d3d-fa00-08dcd589f479 X-MS-Exchange-CrossTenant-AuthSource: SJ0PR10MB5613.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Sep 2024 13:26:06.9621 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: LUvKRicldct7WFtNg5EFFGAQdwkFV4/0HYhsObg9ZrwfjxaUH1wDwImQYA1O5FBGvO4cMrz6QApHw3MH3pN/VP9crLcUX5cEWU57cezlGSQ= X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR10MB4750 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.60.29 definitions=2024-09-15_05,2024-09-13_02,2024-09-02_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 mlxlogscore=851 malwarescore=0 suspectscore=0 mlxscore=0 phishscore=0 bulkscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2408220000 definitions=main-2409150102 X-Proofpoint-ORIG-GUID: NH5Cs_1UVCnzxsnXzKRJLKFsyR-r95D3 X-Proofpoint-GUID: NH5Cs_1UVCnzxsnXzKRJLKFsyR-r95D3 X-Rspam-User: X-Stat-Signature: 5tidssuxj1xin8bd39o3qskpzcc9izy4 X-Rspamd-Queue-Id: 89654180007 X-Rspamd-Server: rspam02 X-HE-Tag: 1726406773-58919 X-HE-Meta: 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 Gr+vfYzU Q/g/sd+ZH/QH4LcZgK7E+Ak0uA+QMlrTU8hLgIrdh9zKjP2ppFRS1EdcBh+YIA9Gkc1SHFgeYCDykUgP2EhfwaMTfXIrYbHFPxlZVu7cHiHpNNVYk8ScqOejyuOMXQkel09bqlar63BdQ3fgt7lAxpjkxxASi6Qu3TMvKo+xqFi7eulxlb/AH0LtaAp6Kbjr2ombbuZH/fzvDf51LrIC9uuJZ0NjejVt2Rs2XuMFJCji6nw6nDeLPoH/P7wJi8XTGzR56h56iNntn2mSW+xFk7d599xtzppb8BSYnz5WD7+9yI+4+lrZI0rX1To/NaOIAspnT3mW/EpmDj4nwMlUokMo87uQD+q/BLWVJ/0F2qLNyCG7EP83OTekhsYIimkcJeFSkHKPFYhbsPLI= 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: On Sun, Sep 15, 2024 at 04:14:21PM GMT, Dan Carpenter wrote: > On Sun, Sep 15, 2024 at 01:38:40PM +0100, Lorenzo Stoakes wrote: > > + get_maintainers.pl people for drivers/misc/sgi-gru/grumain.c > > > > On Sun, Sep 15, 2024 at 03:09:35PM GMT, Dan Carpenter wrote: > > > On Sun, Sep 15, 2024 at 01:01:43PM +0100, Lorenzo Stoakes wrote: > > > > On Sun, Sep 15, 2024 at 01:08:27PM GMT, Dan Carpenter wrote: > > > > > Hi Linus, > > > > > > > > > > Commit 79a61cc3fc04 ("mm: avoid leaving partial pfn mappings around in > > > > > error case") from Sep 11, 2024 (linux-next), leads to the following > > > > > Smatch static checker warning: > > > > > > > > > > mm/memory.c:2709 remap_pfn_range_notrack() > > > > > warn: sleeping in atomic context > > > > > > > > > > mm/memory.c > > > > > 2696 int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr, > > > > > 2697 unsigned long pfn, unsigned long size, pgprot_t prot) > > > > > 2698 { > > > > > 2699 int error = remap_pfn_range_internal(vma, addr, pfn, size, prot); > > > > > 2700 > > > > > 2701 if (!error) > > > > > 2702 return 0; > > > > > 2703 > > > > > 2704 /* > > > > > 2705 * A partial pfn range mapping is dangerous: it does not > > > > > 2706 * maintain page reference counts, and callers may free > > > > > 2707 * pages due to the error. So zap it early. > > > > > 2708 */ > > > > > --> 2709 zap_page_range_single(vma, addr, size, NULL); > > > > > > > > > > The lru_add_drain() function at the start of zap_page_range_single() takes a > > > > > mutext. > > > > > > > > Hm does it? I see a local lock, and some folio batch locking which are > > > > local locks too? > > > > > > Ah... No it doesn't. It's the mmu_notifier_invalidate_range_start() which is > > > a might_sleep() function. Sorry for the confusion. > > > > OK so in conclusion it seems to be that Linus's commit introducing > > zap_page_range_single() accidentally had smatch hit a might_sleep() via > > mmu_notifier_invalidate_range_start(), but it should, in theory, have fired > > due to page table allocations invoking the page allocator that might sleep, > > but didn't, because smatch misses the below might_alloc() path... > > > > -> prepare_alloc_pages() > > -> might_alloc() > > -> might_sleep_if(gfpflags_allow_blocking(gfp_mask)) > > > > ...as a result of get_zeroed_page() tripping it up *breathes*. :) > > > > (please correct me if I am wrong here). > > That's an accurate summary... Thanks! > > > > > The preempt_disable() is introduced in commit fe5bb6b00c3a9 ("sgi-gru: misc > > GRU cleanup") from... 2009, but it fixed it from the far far more broken > > 'disable preemption before taking a mutex' situation that existed before. > > > > So fix seems to me to not invoke remap_pfn_range() with preemption disabled > > and a mutex held? gru_fault() maintainers added for input... > > Every time I get a response to this bug report I feel dumber. How did I not > see that this was a bug in drivers/misc/sgi-gru/? Here is another one from the > same driver: > > drivers/misc/sgi-gru/grukservices.c:262 gru_get_cpu_resources() warn: sleeping in atomic context Nothing to feel dumb about, this stuff is confounding by nature, if I had a penny for every time I felt dumb doing kernel work I'd be very rich by now! ;) > > regards, > dan carpenter Cheers for report! This means we can now get this thing fixed...