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 42C51C4828D for ; Mon, 5 Feb 2024 22:00:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C9FC66B0080; Mon, 5 Feb 2024 17:00:53 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C28566B0081; Mon, 5 Feb 2024 17:00:53 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A53D36B0082; Mon, 5 Feb 2024 17:00:53 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 907C36B0080 for ; Mon, 5 Feb 2024 17:00:53 -0500 (EST) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 54199160858 for ; Mon, 5 Feb 2024 22:00:53 +0000 (UTC) X-FDA: 81759120786.20.9B2FDF5 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by imf04.hostedemail.com (Postfix) with ESMTP id D16BA4000A for ; Mon, 5 Feb 2024 22:00:49 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=cZCx6byt; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=v6YZPlQz; dmarc=pass (policy=none) header.from=oracle.com; spf=pass (imf04.hostedemail.com: domain of liam.howlett@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=liam.howlett@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=1707170450; 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=OaqiXpnE3hJQ8Uhe+f11uybriOk1/Ut/hFx0SzYTaJ0=; b=dFT/Xw5XDgnrQgyNDebtBotJh2osE/0IPZWIfphIAE+EerHHFgLDJd0wLwvwRwpe5JbOK7 RL4Y1YXgQ4nbMahoR4wBsHyjVyAeiQVASnPDDBrcHJEKAA48y3N7+GcUjP8s16a2JZ5w/G qwX9sjDsV3BUo4HuirlZCQDfxcDYNw4= ARC-Authentication-Results: i=2; imf04.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=cZCx6byt; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=v6YZPlQz; dmarc=pass (policy=none) header.from=oracle.com; spf=pass (imf04.hostedemail.com: domain of liam.howlett@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=liam.howlett@oracle.com; arc=pass ("microsoft.com:s=arcselector9901:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1707170450; a=rsa-sha256; cv=pass; b=kLfaG+LsYhFr/CmPdXcarVG0WUNZx6COFzw23AcUssAIDAdwEciuhavBjYMDQldFFP5gsH Xmr+6XmjgYP8aRpr6q6i3WYMT3Z1HC3UmdJ68bXyh5FZS0lCd+zNKSHoSI2PeLHvdqMVrZ e26rWCl7hN+o3EJGXPcwM9vvsX0Q9mk= Received: from pps.filterd (m0246627.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 415LFk1s024993; Mon, 5 Feb 2024 22:00:29 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=OaqiXpnE3hJQ8Uhe+f11uybriOk1/Ut/hFx0SzYTaJ0=; b=cZCx6bytMRHgjxabtkIu2mi3slCZNA1UJsIq/3P2mwSAtzu8VSzJQ5cEccDpR6cn9Aro C8+WGeRyzt0pzHxXTwiV9DfkaXYGKfXkcJL8Yv2mwC1jU6RMui3QpX9DAxUt3mxcKZF7 /TOcnTOAzyuLGvWEKD6H0ylt+2n7VOOSuykDpGLCnGokDqrRiWu9sosOPoWPn/4SFUtc 4fSE7IN+42zzvgmGbEtMUDRP1WlEz5o38Qqd6APNtL/cetQfz8kInIAtSvYe9GFb11Fj VyQ3M/FsF3xAdcACPAVmrh0U11MLExKatWSD72vIh71ChUtJE8EqeXYCRMGpEK41B8jt 7A== Received: from phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta03.appoci.oracle.com [138.1.37.129]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3w1c32n8ve-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 05 Feb 2024 22:00:29 +0000 Received: from pps.filterd (phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com (8.17.1.19/8.17.1.19) with ESMTP id 415LNAWM007103; Mon, 5 Feb 2024 22:00:28 GMT Received: from nam12-bn8-obe.outbound.protection.outlook.com (mail-bn8nam12lp2169.outbound.protection.outlook.com [104.47.55.169]) by phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 3w1bx6jcqb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 05 Feb 2024 22:00:28 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=m5SMoGeXvsLkKwkKmXKNpNk+QNaP/2/1hx4vEirKdM2a+jmjZe95qJYubnEHpEf6pSXfepuA2aOtWnmH0vRSuxjPDtdLyoIMt8KQ/0dsZgfqSgctWT4r3/O25kL1v796pZiw4AvzSlh5CcdRJMuPDruuuGo38pO/j9PA2QpHjA6faWkg0a22PJ0ojEfUzeds2WJk974hRbPuznJ2imeqcNDIK/uiygoZV/NVAfz4aQYsacjQPA4Etzym4QugetE9a2JILVqN0W01c+i//KDOXwv7Y22Evvc6UfKMZ9NCCxLc+BcLClq8dBRZxxz1/Yxa50M8ipajZlny65MzBc3yTw== 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=OaqiXpnE3hJQ8Uhe+f11uybriOk1/Ut/hFx0SzYTaJ0=; b=kG55E1wbxbgLv652zxOEWwwtcIjdbGwmV6kHKMdMuN4kkRAN2ItlpttV4bjEJtVQgqhSoZwi8EKpCcZTJuOXODkWstz0CMQ49JtGDqao2v8XZsCD3ikMQP9E9A0ZvHSgZOdfXc9shZCeLwGzaJIl3b2jh/lv7qO+rMXongujUnmCPEcMcmhFZQLuZRW7gAi1mXwg4AIpn5F9b6zC+gWONfTvR5DtSysrCDXTG1OfbJ1El9iqfH+UOhxJWYZqJZPcr+e5+Un1+MVDZ5T4HGRFD+szkc8yPEFfPGOgqJ1MLakTByzqeYSH8ic34mCHxtmqoXEKvOwT27q+5EEAyuXmYQ== 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=OaqiXpnE3hJQ8Uhe+f11uybriOk1/Ut/hFx0SzYTaJ0=; b=v6YZPlQzYYdTTx9cb2q72fwkKZNq/l6IRfBv3mtJzy9NbPX8Y5gHkp5QAvoE/kcveqG7BCUtq8u/vG2F7oUSg8ABHEKSCSDL/f1fxtX2ke0CR9Xhqvk76q7Uj8/9uX27mYok9X8JMX5SBnJEy08r02vL3+LWyG27hGbjlQHTYyU= Received: from DS0PR10MB7933.namprd10.prod.outlook.com (2603:10b6:8:1b8::15) by SA1PR10MB6448.namprd10.prod.outlook.com (2603:10b6:806:29e::19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7249.34; Mon, 5 Feb 2024 22:00:25 +0000 Received: from DS0PR10MB7933.namprd10.prod.outlook.com ([fe80::20c8:7efa:f9a8:7606]) by DS0PR10MB7933.namprd10.prod.outlook.com ([fe80::20c8:7efa:f9a8:7606%4]) with mapi id 15.20.7249.032; Mon, 5 Feb 2024 22:00:24 +0000 Date: Mon, 5 Feb 2024 17:00:22 -0500 From: "Liam R. Howlett" To: Lokesh Gidra Cc: Suren Baghdasaryan , akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, selinux@vger.kernel.org, kernel-team@android.com, aarcange@redhat.com, peterx@redhat.com, david@redhat.com, axelrasmussen@google.com, bgeffon@google.com, willy@infradead.org, jannh@google.com, kaleshsingh@google.com, ngeoffray@google.com, timmurray@google.com, rppt@kernel.org Subject: Re: [PATCH v2 3/3] userfaultfd: use per-vma locks in userfaultfd operations Message-ID: <20240205220022.a4qy7xlv6jpcsnh7@revolver> Mail-Followup-To: "Liam R. Howlett" , Lokesh Gidra , Suren Baghdasaryan , akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, selinux@vger.kernel.org, kernel-team@android.com, aarcange@redhat.com, peterx@redhat.com, david@redhat.com, axelrasmussen@google.com, bgeffon@google.com, willy@infradead.org, jannh@google.com, kaleshsingh@google.com, ngeoffray@google.com, timmurray@google.com, rppt@kernel.org References: <20240129193512.123145-1-lokeshgidra@google.com> <20240129193512.123145-4-lokeshgidra@google.com> <20240129203626.uq5tdic4z5qua5qy@revolver> <20240130025803.2go3xekza5qubxgz@revolver> <20240131214104.rgw3x5vuap43xubi@revolver> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20220429 X-ClientProxiedBy: YT3PR01CA0108.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:85::25) To DS0PR10MB7933.namprd10.prod.outlook.com (2603:10b6:8:1b8::15) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS0PR10MB7933:EE_|SA1PR10MB6448:EE_ X-MS-Office365-Filtering-Correlation-Id: 44f7aa36-8781-4f1d-e583-08dc2695db07 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:DS0PR10MB7933.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(7916004)(136003)(366004)(396003)(376002)(346002)(39860400002)(230922051799003)(1800799012)(186009)(64100799003)(451199024)(7416002)(5660300002)(8936002)(4326008)(8676002)(2906002)(316002)(66946007)(66556008)(6916009)(66476007)(6486002)(6512007)(478600001)(9686003)(6506007)(1076003)(33716001)(38100700002)(86362001)(83380400001)(41300700001)(26005);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?OZOctOBkKXbNNStD+aQHaOvbH4CKxn0bTYwFT2zDgqk3O43v8lL8jHLrysRD?= =?us-ascii?Q?Rq6WR3pmxWzhVusCZK8G4Vk8GaHEMzwaP5uNY6u238oJZ8UDsjgx9AgSLsjK?= =?us-ascii?Q?hZtfS2fGVmdXE/uqb4ANBN68lsDplFzzorh2FvSW3Yrwd5+8PfH+wLll+UIJ?= =?us-ascii?Q?l0sYKXJwaRqSrXfgls+qHby7baMwsWiTv2nPZF6ljO1RCfIiykj4lpTnrCuw?= =?us-ascii?Q?Rhavthc5Njgao73SNTzTQJyiOZVoop3GPGIO2p7Ly98dcROFdYOU1ii6aEMZ?= =?us-ascii?Q?brlAOH3SeuYz2lJEGN0QOhVA1fCkylV6jD7fZJAHE4WU1+see3BK1PoaBwM6?= =?us-ascii?Q?+D7IaJt8ODj6jn3w+spjn5+9d6ozinJug35gP2k1oM6HuHJaaG8cWMjzVYf6?= =?us-ascii?Q?JqEuBsZ7MszwXB6YhLZwK+oMpQIP/c0ymzbO8Xk6BfihGfaIFLPE2Z+rHoOT?= =?us-ascii?Q?EVCu3FIGNFlpytlIIX61mTAoDXVHLZ4KY/0oDkB8pSeW07hWBKOKQigkUp33?= =?us-ascii?Q?+S/WrE+QmYl3zSK1dxazgaGMkS7cZzGA5oHvayKKXEtx9uNA60LWL1iNPMkK?= =?us-ascii?Q?DBc8cVAi5/UQMCA0KIWuLHn34rHQpaT/Jy95byvLA6hEixJX0wsevN5VQl5q?= =?us-ascii?Q?xSdPu3UwU9/m1kaR/ZkvZV1sRHDGhgn5ceOgcF6TJrPcICVzATPFXvXUnMJx?= =?us-ascii?Q?gZNt0H6Uwsqjf1p6p+H6hZEBvFzNaslqu5jhs3BiOJlApvq0N5U41PsUIH5j?= =?us-ascii?Q?ws16qib8H6nmHJYjiAhZ1iVmf7RyyPYvhicRtkFZuyZA9WAuHQeoG0VgJMMb?= =?us-ascii?Q?FkbNRaUV83FI4Jqve3RSWIUrRQI7BTCId97Q9+kRs61iHJJaCN1qv5BSA7lH?= =?us-ascii?Q?aJi/hGDkDilqdJML491uuj9/8EOvwmVesCXtsosChEeKw2zRJw3j1tKCjOR8?= =?us-ascii?Q?s1PLhDoHppLInnw7g8u+CyV6Q0RnRNEkilg8xvj9XkrfeEu7Z96/DmBt4COP?= =?us-ascii?Q?NQaapgAInL4xZOTZGh1hox3/5x6HuQMttsaNPnAo3worv+2RdhdI1fzMeFkW?= =?us-ascii?Q?vMbQlZSEvOTFWLNRlm1O6HkUxDQtKrNLVGV99HLjk+6/LFwMY49cJsaUinZS?= =?us-ascii?Q?ySktf0SV47WEHjDW7omy21lNSuIlQNHN5JFLdcbPrRSmpCBBOKhSlsnvFQAB?= =?us-ascii?Q?XEetBr5uYYKZhfZgTfNPSyEDpWo81jB+lMWM6ZwpACnGeTBNrhkhwTl5+eBh?= =?us-ascii?Q?L2+7JCGYR7N5PZyB1FRTxQZRqCI3g2/Ch1s2ibmk2tdsjkODYl540JePn1oa?= =?us-ascii?Q?SpA4I/4+uX7l6+4UWl4SLJTZ17E8+n08sjbx9QQwaaZBU9tQKcq8CCtyMs9E?= =?us-ascii?Q?ZK2pg/0Q0KQr5gIEzygxwzz5HsHxAjVf1zDlicqU+jbzl3SKINxonfabyrVQ?= =?us-ascii?Q?eb+qfgz11Ec22/AyXE0ZiRG6XbGX3QFsG0lK0Rb10uWdvHfmgJ4ktwieR0AB?= =?us-ascii?Q?G4y2VWNmpVyNLd80w7rr4iaBqLb7tAP0trxoP2K3xn+WQm9kiMnYNmNUG/Tg?= =?us-ascii?Q?b4TpbivDS9sKfAVcn0lhL9GiivwfHBM+5ondQC3J?= 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: 44f7aa36-8781-4f1d-e583-08dc2695db07 X-MS-Exchange-CrossTenant-AuthSource: DS0PR10MB7933.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 05 Feb 2024 22:00:24.7632 (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: saE6E1REaNwbFJ+toGeu29MwRZ7uZy9NuIuyMUGxE+DSrP4XTImwWHuwWyYIJXXnW3GqNzEQ3F3HifB9/ooqwQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR10MB6448 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.1011,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2024-02-05_16,2024-01-31_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=0 mlxlogscore=742 bulkscore=0 mlxscore=0 adultscore=0 malwarescore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311290000 definitions=main-2402050165 X-Proofpoint-GUID: bOn994PU1eDCEWRZctnEuzcaOVDU3BYF X-Proofpoint-ORIG-GUID: bOn994PU1eDCEWRZctnEuzcaOVDU3BYF X-Rspamd-Queue-Id: D16BA4000A X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: of3efek6sjeip96ryypq51pqnaorrhkg X-HE-Tag: 1707170449-935644 X-HE-Meta: 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 /meUQm4q 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 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: * Lokesh Gidra [240205 16:55]: ... > > > > We can take care of anon_vma as well here right? I can take a bool > > > > parameter ('prepare_anon' or something) and then: > > > > > > > > if (vma) { > > > > if (prepare_anon && vma_is_anonymous(vma)) && > > > > !anon_vma_prepare(vma)) { > > > > vma = ERR_PTR(-ENOMEM); > > > > goto out_unlock; > > > > } > > > > > vma_aquire_read_lock(vma); > > > > } > > > > out_unlock: > > > > > mmap_read_unlock(mm); > > > > > return vma; > > > > > } > > > > > > Do you need this? I didn't think this was happening in the code as > > > written? If you need it I would suggest making it happen always and > > > ditch the flag until a user needs this variant, but document what's > > > going on in here or even have a better name. > > > > I think yes, you do need this. I can see calls to anon_vma_prepare() > > under mmap_read_lock() protection in both mfill_atomic_hugetlb() and > > in mfill_atomic(). This means, just like in the pagefault path, we > > modify vma->anon_vma under mmap_read_lock protection which guarantees > > that adjacent VMAs won't change. This is important because > > __anon_vma_prepare() uses find_mergeable_anon_vma() that needs the > > neighboring VMAs to be stable. Per-VMA lock guarantees stability of > > the VMA we locked but not of its neighbors, therefore holding per-VMA > > lock while calling anon_vma_prepare() is not enough. The solution > > Lokesh suggests would call anon_vma_prepare() under mmap_read_lock and > > therefore would avoid the issue. > > ... > anon_vma_prepare() is also called in validate_move_areas() via move_pages(). Probably worth doing it unconditionally and have a comment as to why it is necessary. Does this avoid your locking workaround? Thanks, Liam