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 7BEC2C4708C for ; Mon, 5 Dec 2022 23:34:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 175338E0002; Mon, 5 Dec 2022 18:34:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0FE138E0001; Mon, 5 Dec 2022 18:34:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E6B4D8E0002; Mon, 5 Dec 2022 18:34:17 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id D05AF8E0001 for ; Mon, 5 Dec 2022 18:34:17 -0500 (EST) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id AAD71A0C9F for ; Mon, 5 Dec 2022 23:34:17 +0000 (UTC) X-FDA: 80209858554.06.8208B41 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by imf29.hostedemail.com (Postfix) with ESMTP id 1A169120008 for ; Mon, 5 Dec 2022 23:34:16 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2022-7-12 header.b=OM80RKNO; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=YeEG0CGl; dmarc=pass (policy=none) header.from=oracle.com; spf=pass (imf29.hostedemail.com: domain of mike.kravetz@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=mike.kravetz@oracle.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=1670283257; 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=w8aDRmCLx2RPaPfEJWmJ7hQbmO9zpKZvqnn8mcQa77k=; b=D7zJ9nF2Xy65ySzn6TfNilgfUncCksn6/v7BsK08VaAoa6tKSy1a3decHAVnOclQL8tak1 uOQdvLLXp37MCYpbaAlUy1xZbR7mzFfkIqiz38QlydfSw/MuqknNOwLzzpwCb/auKXXJ6l AxEcUX2qHwh5zIDWXyAefFL4JQw3nH8= ARC-Authentication-Results: i=2; imf29.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2022-7-12 header.b=OM80RKNO; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=YeEG0CGl; dmarc=pass (policy=none) header.from=oracle.com; spf=pass (imf29.hostedemail.com: domain of mike.kravetz@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=mike.kravetz@oracle.com; arc=pass ("microsoft.com:s=arcselector9901:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1670283257; a=rsa-sha256; cv=pass; b=1UN+FoVLcYBzPpFjsiu+WK4/Y36bcpJskVnlh2nfhWwNZNuGVzXel9Ryhx9UYcVdos/O1q ZdT7zuP0EnjQmGjBM9sfR+gbb2Fx3rRBjsDVBfC9XWohPOKQYpJGP74SBYyfkDvTXi/aJF ue3q482cCi7tuX3K69oozG1hbB/95s0= Received: from pps.filterd (m0246629.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 2B5KOVfc021673; Mon, 5 Dec 2022 23:34:06 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-2022-7-12; bh=w8aDRmCLx2RPaPfEJWmJ7hQbmO9zpKZvqnn8mcQa77k=; b=OM80RKNO8VX/kTqkYGrPbdboUJ0Y2SJynPEp91roizpHapmomLaLpnuttSWXlBilN/O6 BFtzcSxHRA3hoANzfXjj+dtjCxVmTgvhVxLUmQ2CF27PEiP4PRqVs0LwqU0ikPi48eE8 y84DT9UjO9N02wHDFKS1oo4WEcqs6AFI4HUUQWBM6pbun10yVWs5qe4+cKZbPIgsT3YL iLXfI9hd8Yv+rgGKDarathp2CnEjfQCKeZbvtETGQ/Hu7kGY2VZeixgSTsxoaKYgrGh0 vnysBONvXFqsoDJpdxRkqKntcmjCy2FvaTo629B354XKoEZ9wLX0/ZFflctF8urtigtY 6g== Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.appoci.oracle.com [130.35.100.223]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3m7ycf5r7g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 05 Dec 2022 23:34:05 +0000 Received: from pps.filterd (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (8.17.1.5/8.17.1.5) with ESMTP id 2B5LWjrX009377; Mon, 5 Dec 2022 23:34:04 GMT Received: from nam10-mw2-obe.outbound.protection.outlook.com (mail-mw2nam10lp2105.outbound.protection.outlook.com [104.47.55.105]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 3m8ugeyhnf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 05 Dec 2022 23:34:04 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=ZI7wtvkWXNAI8uRFx0jGkmhwnojza4jbt81foyhC9TVR82ikziyTpDWekTOAfHhtGqNffP764Mla9tG+zhjbdhQRtkEO86tDFHhgK7un+MUUtjFF2Y7CtowaiYznkIuYaTXUxl21US+2/3XlCi1ATksl71J07unPzBWKIW6W6D8QF+gYPAtO47IdbypkToJsJGgvF+T+cP2UNva4i2otRDSQtCt6J0yJT5U6BAbluq3E4rmuob1DOiOBk8Kbu/QANrjsVahKSAHxjPUmaW6cQh6ny8/V+8IQ4erdhSn8er826mdIkTTyj99JCVsmu9sfC4ITuT5MOzAzA29d/txHpQ== 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=w8aDRmCLx2RPaPfEJWmJ7hQbmO9zpKZvqnn8mcQa77k=; b=HQhd+6auNqj2P/Ece5E+415nay+0T0IDDFKE+GLIPVuhfbAtmQpLL10cXQdN/xn2t4BHp9k9ruHKNbYW09W+FPpymAaaLkFVGLSLaBp67f0MVQWM3FkP5X+PQuPHJzP13PY3DJVpvMcaY5WUoI8TIIHjLn15/n/yldvRiv64PTAam59h8EGCdBDol6141U0DlnhV6dY7y/kx/xDXZMH+MO/hirwUGmpX5eoBKD/TdYPEZ7Vd04/Kxgfitdluevqinga/xEVIA2hZ4jzZw1OJrQc73/cjtEA8s2rE4pWxVGpbYcVPjygspR52N7JBnpOLoWk3un2o/tK+5WAXM3zhNw== 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=w8aDRmCLx2RPaPfEJWmJ7hQbmO9zpKZvqnn8mcQa77k=; b=YeEG0CGlU//BnBclIzu1El1xgfNwiGV/1nyIMt/0wI8UHajAWETLFE3dq7q0HIdcn/qlPMk1uIi0ASyb3vJcEv1pXR8u6nypXMZmoQTyK8F73R700FyooacCcSNGxvVveJG0tSyfNG0d3Ah7oyv0t850cws5IIA/Ml4h3T8jUcM= Received: from BY5PR10MB4196.namprd10.prod.outlook.com (2603:10b6:a03:20d::23) by IA0PR10MB6745.namprd10.prod.outlook.com (2603:10b6:208:43f::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5880.13; Mon, 5 Dec 2022 23:34:01 +0000 Received: from BY5PR10MB4196.namprd10.prod.outlook.com ([fe80::8d67:8c42:d124:3721]) by BY5PR10MB4196.namprd10.prod.outlook.com ([fe80::8d67:8c42:d124:3721%4]) with mapi id 15.20.5880.014; Mon, 5 Dec 2022 23:34:01 +0000 Date: Mon, 5 Dec 2022 15:33:57 -0800 From: Mike Kravetz To: Peter Xu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, James Houghton , Jann Horn , Andrew Morton , Andrea Arcangeli , Rik van Riel , Nadav Amit , Miaohe Lin , Muchun Song , David Hildenbrand Subject: Re: [PATCH 08/10] mm/hugetlb: Make walk_hugetlb_range() safe to pmd unshare Message-ID: References: <20221129193526.3588187-1-peterx@redhat.com> <20221129193526.3588187-9-peterx@redhat.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221129193526.3588187-9-peterx@redhat.com> X-ClientProxiedBy: MW4PR03CA0203.namprd03.prod.outlook.com (2603:10b6:303:b8::28) To BY5PR10MB4196.namprd10.prod.outlook.com (2603:10b6:a03:20d::23) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BY5PR10MB4196:EE_|IA0PR10MB6745:EE_ X-MS-Office365-Filtering-Correlation-Id: 6a6d9119-9353-41fe-95b0-08dad7192fc2 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:BY5PR10MB4196.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(7916004)(346002)(136003)(396003)(39860400002)(376002)(366004)(451199015)(86362001)(478600001)(6486002)(6506007)(53546011)(6666004)(9686003)(44832011)(4326008)(7416002)(5660300002)(2906002)(66556008)(66946007)(6916009)(54906003)(66476007)(316002)(41300700001)(8676002)(8936002)(6512007)(26005)(38100700002)(83380400001)(186003)(33716001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?gPph2o+PhE/zK3Xl42QRL6Q8+x8zgydNaxyEvr3ZXt8HxH7L93iOa3+JlrZ6?= =?us-ascii?Q?9vnXxt5svZZCiRlAOqA+Wkef2GfbFVBpKtZqvR+zvrNfeH+RZvf1Wv10/FuD?= =?us-ascii?Q?Z7KbjSIrkq7de6lsqt2yAgPOqr7UDsTQlpsGMpFjbH+6Jv1tOxswytxq7hAX?= =?us-ascii?Q?IttMly1hd8+r1WwGnyw6qzee6MHuBClM77iwPkgsJjjFT5QRpDJTDbwHmZP5?= =?us-ascii?Q?5LS/Y4Rd91TsihIib2xEl+NkcGNp/J4498R1dbV+Apj9eIa4ZRujt/DXWfOD?= =?us-ascii?Q?kWdSf/GohO1IljWfUiOm9nnh6LjXK4tust8SOX45XWPfnAScHIZAjv5c++Lm?= =?us-ascii?Q?5tFSJBYvLuSxMJiPP5VeTqtIsww5fifJxjHzxPmSpGomJrdLD1xJDR9q/AqS?= =?us-ascii?Q?4FFo95HqlkuWGbS+HYzT0lAGXVAJh1KrwYA9smMNRBq1bDTNk5ek7JS2jTOP?= =?us-ascii?Q?LMJPPf8yV6Ox7kbNCdhf0w00ZEahRxBtZl6TLTkLtruUuQXqjAM95kZbxhLx?= =?us-ascii?Q?t6EcZaNH1sWOpsKG3AHuCqoMX0q8Spk95E41IL2qkuJRBVI8qUqXOWsKQaqS?= =?us-ascii?Q?2VZ8jOVvVqc22mHvDHydk43s4UFh6WFKKgXl0EW9c9zAXLvjCQoveNyyPG50?= =?us-ascii?Q?Ibfeb2EHpNLgwSOsYWl6OzuXGJ622TzgiN899K9xw0EO/OJ/xEGtUDSKneFU?= =?us-ascii?Q?JNYlr9qC/cMxpBqj9FUtvvVwbd8MbIPwy2MvzGWCzVO9QqKQPgOxKnP3vFyf?= =?us-ascii?Q?mUkJ7dRl7UXaGpvw4DPCb2QgQ8ooA5yiyW6MX0w+HbYRt70syuirlqul2EuO?= =?us-ascii?Q?XMK+78CGGmDT90MB2QvBw50Di0Ooeual5Z5Xpy086sIoz0gSdSPL6FcqBmZO?= =?us-ascii?Q?pHzp/6F6uVUT4z2k5ITllzonunE9mbPn2J9JuMOVYMq1ErdGRchI2ZtJqRfg?= =?us-ascii?Q?WWbUoOKMYwrxp1x4aU9pd0V+YtCUnHgSLSIy9NcEBtUbNMd5OBNDcdhlTGYE?= =?us-ascii?Q?6rgLwxwWmD1QyMRJBXNoA2mVSxi/7XYd34TTSzTh/cUN23rxP3vNqLNXKVgM?= =?us-ascii?Q?uMozoitLmvrjnA25FynnR4WzbDy7ywAaLx1RshzurIYXSc9EVUYAaPkgf+01?= =?us-ascii?Q?InKaC8JLMt+oCznTi8RloQyinyvQEuwYJn7QcIlFPuyjsO/Ys9rd6crv7Gwx?= =?us-ascii?Q?7sNgLNQ4fSqfq+DidYBMgDEWjvRILR9wxCDf3/fZKcpQP4iDxSoSHsKn0oIr?= =?us-ascii?Q?3QwhmSxSZ9qNAzdoMIGlWtq/rz3L03nYxbqOe6AS6ksqKL9wY7IqhZwiwqGS?= =?us-ascii?Q?Igw6mcr7B+RuMig7ae4cYELVGSpTfWZgmXdG0QsS3tgZE6fSXICxOIOx7SoX?= =?us-ascii?Q?ahDLEcX3dLwxtLOlCa/hI4Pp7LHowngxdLrWVow/eFinNSGY+v4rcyy4tbCI?= =?us-ascii?Q?r0lwk4k4h7xweuztc0s+t6PtyGQWUY6OMKyQgQaA8KjRFNXBhL6SWAL4jAiW?= =?us-ascii?Q?v97vJIqjElGPWtjNuDQ8UDmWTYGbHCuah3aj9LnUSjdJDvvivAmhUSh+GkaE?= =?us-ascii?Q?ilYNYg/Ba13BQ+XZz/EBzIILCLv/ENDWGt4feb+ywb8p70zNYeaSCalBfUjs?= =?us-ascii?Q?Kw=3D=3D?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: =?us-ascii?Q?2EAzZD20144210q81NgWFBDytzIDME9OvA64CTmUA0Ky93MuxjutiBhwRK0S?= =?us-ascii?Q?O3uwihHJGDu6eNlnHI64RigzKlpiSTYoYFUpbRsGJnNPITbMyAlsqN9t5Iyp?= =?us-ascii?Q?NBSdINjuT4jZKijeWOpXEkIpQWBkQ5de/mh2wpzXkHPYwhY4wVhb0moVJq1K?= =?us-ascii?Q?wmfERMozgdMJtquYDiByP+T1HCR34YFKINO/ZlX7w05ZAEvUldF1VmKy8gp9?= =?us-ascii?Q?yGCeEMPrBihYYn0sokTo9tA9BgKylxVdStnQvNhH/Dk6eEDd8yVLSwUfbc9Z?= =?us-ascii?Q?dTtRwHt8CS1MhoWjD3ib++CFhhQi3fto9SxHwKvpZXDAgdjhrHX3jaBBm3OP?= =?us-ascii?Q?bEEJ8IMF8jVNcCjtRtas3T3xNJ9aAZhjaEAaVKwANWWMkf+RtY3I1Glw+YyV?= =?us-ascii?Q?+JRTxVEfA928cIdiwGRDEKK2Azyv0nXfjdQwI4j2UDtVgZxIEnMgv9bZnxVQ?= =?us-ascii?Q?9l+8ng0cBj0jjjVxBMlzYhbtUYHf5mTOausOF9pVGXbJHcM1HH7Gi0OyAr64?= =?us-ascii?Q?J7WLV6gqR85kef8qMWfY1lTZ95kbeNFsR8oTSd3+DD2iAdnf2b07m5p/Z5QN?= =?us-ascii?Q?eePrvrez/pYiRvsX5MnNqbq6gPOoWiibfNVwE1G+VwAYq6MHgNK69XSIx0Sw?= =?us-ascii?Q?fKLLt+2l1DgM1h6wRrUjNXSL/VKBTRyZg6lILB0WYd3YrHlz9loryFh9lLk9?= =?us-ascii?Q?d0Y2Om9ufR0Kt1omGg2oqrRfztHtDI6Zmaog2DDVQU+5lTuEdmehLwkvetai?= =?us-ascii?Q?NT2x0dAdu+YIsET/Cb/j3VzccfLEaIzDMLiyQNtS/LlOLRREtx4RH8jGOvN8?= =?us-ascii?Q?PHKpz2XgqDh0MYzsWX4oPTHm4ENGIkQubsvekk9AcjhaLPofLYAT+L3WsOoV?= =?us-ascii?Q?ZYUMB0/n5zZ95AmaCDGCa/kvjVJZwLBBIj8LEaHdVke1BKVVMi8DMeNVLFoC?= =?us-ascii?Q?JolNH9QiKM8Pstu6r53WAbzomh+ILEc9VBmJG7ckjywdl5CDzlQyzgMCucdO?= =?us-ascii?Q?XziOhZpWq+aw2bg9OfAKZxG2IhRYcN29nx8l9vMbO9I40x/Bqd3Bzcy5WjGR?= =?us-ascii?Q?VFImWuOyWJJusCd5vpCimisDO7TsvZjlxoA4Lc1SkJ8cDOxbEUQ=3D?= X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 6a6d9119-9353-41fe-95b0-08dad7192fc2 X-MS-Exchange-CrossTenant-AuthSource: BY5PR10MB4196.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 05 Dec 2022 23:34:01.5540 (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: VEavrg9WSGu9hSiD0zR29+CyKluukxPH4iIAMWxjRwY11leP+a2A3W33uev2SrFCo20QJROWybJyxkRiCBYQFg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA0PR10MB6745 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.923,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-12-05_01,2022-12-05_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 adultscore=0 bulkscore=0 mlxlogscore=999 malwarescore=0 suspectscore=0 spamscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2210170000 definitions=main-2212050194 X-Proofpoint-ORIG-GUID: yZEX3FPl84t36iVnCmxXBsMhEIOLu168 X-Proofpoint-GUID: yZEX3FPl84t36iVnCmxXBsMhEIOLu168 X-Spamd-Result: default: False [-3.80 / 9.00]; BAYES_HAM(-4.90)[97.50%]; SUSPICIOUS_RECIPS(1.50)[]; SUBJECT_HAS_UNDERSCORES(1.00)[]; ARC_ALLOW(-1.00)[microsoft.com:s=arcselector9901:i=1]; DMARC_POLICY_ALLOW(-0.50)[oracle.com,none]; MID_RHS_NOT_FQDN(0.50)[]; R_DKIM_ALLOW(-0.20)[oracle.com:s=corp-2022-7-12,oracle.onmicrosoft.com:s=selector2-oracle-onmicrosoft-com]; R_SPF_ALLOW(-0.20)[+ip4:205.220.165.32]; RCVD_NO_TLS_LAST(0.10)[]; MIME_GOOD(-0.10)[text/plain]; MIME_TRACE(0.00)[0:+]; FROM_EQ_ENVFROM(0.00)[]; RCPT_COUNT_TWELVE(0.00)[12]; DKIM_TRACE(0.00)[oracle.com:+,oracle.onmicrosoft.com:+]; ARC_SIGNED(0.00)[hostedemail.com:s=arc-20220608:i=2]; FROM_HAS_DN(0.00)[]; RCVD_COUNT_SEVEN(0.00)[7]; TO_DN_SOME(0.00)[]; TAGGED_RCPT(0.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[] X-Rspamd-Queue-Id: 1A169120008 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: 1qmwn8ptq7csonzyym1a3ee3dj7kakeu X-HE-Tag: 1670283256-676622 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: On 11/29/22 14:35, Peter Xu wrote: > Since walk_hugetlb_range() walks the pgtable, it needs the vma lock > to make sure the pgtable page will not be freed concurrently. > > Signed-off-by: Peter Xu > --- > mm/pagewalk.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/pagewalk.c b/mm/pagewalk.c > index 7f1c9b274906..d98564a7be57 100644 > --- a/mm/pagewalk.c > +++ b/mm/pagewalk.c > @@ -302,6 +302,7 @@ static int walk_hugetlb_range(unsigned long addr, unsigned long end, > const struct mm_walk_ops *ops = walk->ops; > int err = 0; > > + hugetlb_vma_lock_read(vma); > do { > next = hugetlb_entry_end(h, addr, end); > pte = huge_pte_offset(walk->mm, addr & hmask, sz); For each found pte, we will be calling mm_walk_ops->hugetlb_entry() with the vma_lock held. I looked into the various hugetlb_entry routines, and I am not sure about hmm_vma_walk_hugetlb_entry. It seems like it could possibly call hmm_vma_fault -> handle_mm_fault -> hugetlb_fault. If this can happen, then we may have an issue as hugetlb_fault will also need to acquire the vma_lock in read mode. I do not know the hmm code well enough to know if this may be an actual issue? -- Mike Kravetz