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 86595CA0ED1 for ; Mon, 18 Aug 2025 15:48:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 266AD8E0022; Mon, 18 Aug 2025 11:48:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 23DD18E000F; Mon, 18 Aug 2025 11:48:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 105FC8E0022; Mon, 18 Aug 2025 11:48:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id EE61F8E000F for ; Mon, 18 Aug 2025 11:48:30 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id A0C151A09C3 for ; Mon, 18 Aug 2025 15:48:30 +0000 (UTC) X-FDA: 83790310380.23.A174AC2 Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by imf07.hostedemail.com (Postfix) with ESMTP id 573BF4000A for ; Mon, 18 Aug 2025 15:48:27 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=fNf+6wpr; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=phL+G95k; dmarc=pass (policy=reject) header.from=oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf07.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=1755532107; 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=SxRj91lb2oYh1vFFXmWnFIpuX8F51KuTE9WQ8jOhrhg=; b=qzVLoikFYCp6TkqFHMnMX2h5c8QZz2gHX/OvYgrekI+aJyIyWdB2WdF2H8bTWoMv+VMjG7 k+DYzxyXTTpFB81eAy+4utFF7aqXcZMeFPxY0WTuufeDwcKjrh2WARZWCdLZtL11Pc4sS2 TYbHzXxEq4B767qDs/XRITSBfVCRrGo= ARC-Authentication-Results: i=2; imf07.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=fNf+6wpr; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=phL+G95k; dmarc=pass (policy=reject) header.from=oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf07.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=1755532107; a=rsa-sha256; cv=pass; b=kTYZk0ONqjcloGC9hybuWBtmWeu15b1IwZCxUPWT0d17Z+s2pX8NplygaSPZIu/5mMoQRV Ltbx0ehEnWUrcgJ/D8GNiQLlDmgwDrtEYjw1hqF2UeALoYo1hcmQzWBoLjfRN5RyEHyP/E 28iSh7zhJL/f2Cl4FtUZbU/nYbMfYG8= 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 57IEtnXU020147; Mon, 18 Aug 2025 15:48:13 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=corp-2025-04-25; bh=SxRj91lb2oYh1vFFXm WnFIpuX8F51KuTE9WQ8jOhrhg=; b=fNf+6wprkkuCIEpG0zzBqZ1U+jgZoc08bp Kf38HASgvTrLwSR4NmuFrES1rCaKLXq9J1u5U9fS+4YPBflYJ6raJcpwFK4hRA+p NhrtB9lLLiQfKQh5D80cxvqqmrdx6jCgkdtnvTEyozu/bqxMZQN3/HvaIDDqrnaN Um5rEh4gJTBJNomIruRsXfovSv/1vpzPn5nitFST53jHFSKf1CIeXrWAxD5Ra8FL j8NxIBYORqbSkmg+wEIWEY9s89v5U+Tg8A7sybj3cIxO/+RIKBAKzJp3IaV1sC14 mJIBT+Ncia5Xvbxf2n+48R9n47iv9AfKjrZErsbNREAsNqriJ1AQ== Received: from iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta03.appoci.oracle.com [130.35.103.27]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 48jhkuuccy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 18 Aug 2025 15:48:12 +0000 (GMT) Received: from pps.filterd (iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 57IEqaku011367; Mon, 18 Aug 2025 15:48:12 GMT Received: from nam02-sn1-obe.outbound.protection.outlook.com (mail-sn1nam02on2079.outbound.protection.outlook.com [40.107.96.79]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 48jge9ejnm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 18 Aug 2025 15:48:12 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=NAxFpN7xaxUl3tJPyYtRd7FbJfBXi1oZQFezzeyHIYxsRZVm2+KVMJJMlzEgw6jvDRRhY9c7v1k/gG4N30PMHob8J4jyHqpeWxrRGVgLUW8GFAge/0rqveTpWcjDLKylaKPnm8MZ61DkTEdjRhcx1C8dAclariRX3rvLi2sPqLPcqcxIJYvqggvIvAdhYHwnLe7NXhUWj7meB3yEM98zBqbpZf1mlTkatN2EBn/4KRHX4DZ3Kr2HlHJjr0cJ8f5+o1EONL93Q+fncS2dwi7/UgdoHhjeaXcQCPuKjBmDN3Sx3va03uPgCK+dGevzWqpK6ck0WVDNuF2TyNqouuKZCQ== 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=SxRj91lb2oYh1vFFXmWnFIpuX8F51KuTE9WQ8jOhrhg=; b=X9dpYH6sPhmwZ5HY2aYGDqslvZW13T+pvp7warcn0EBca7hax/IOmeZyX+PzDC0+lRxQ+nhepibFKageUBa8rA7nZAKhdNW6c8mwyVEMG4zz9QSq+Yt3mM18kRIlXix7ebdL7ARtq9/FXfjrppPi3Ahf7LcwhJQZrG8jjnpxC7xTyVZQoE4t1/0A9UEXaXgdRZWRojpYqKD9d1SDitmXi7ZQGS4kPpGwQesfEq9O+fI7iaXd788HqYHUXjuhDDWT7+oPbnqxY5KLe/KITRMLDSwPI9j6UI5X2Ej6L9wL2TumFUIld8L0EmvCj+cAmA0VlZ339U14h7Y3XLOsreodFw== 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=SxRj91lb2oYh1vFFXmWnFIpuX8F51KuTE9WQ8jOhrhg=; b=phL+G95knwVZZxc61Gdx3TtsUupmMMCPI/vte/Lhd5jHQoFnLMMwfWLgCsY3FgunPIxueyIoyEsyH9RbYPQj/cdosQ935Q7jFzh/6Ru2bYG76GDUKhIO9PxwaHFKkCZlJZipaTWnPdBZM1lm48aW9gPkvKQpXey0kPFqdVq6KCU= Received: from DM4PR10MB8218.namprd10.prod.outlook.com (2603:10b6:8:1cc::16) by PH3PPF67E073224.namprd10.prod.outlook.com (2603:10b6:518:1::7aa) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9031.23; Mon, 18 Aug 2025 15:48:02 +0000 Received: from DM4PR10MB8218.namprd10.prod.outlook.com ([fe80::2650:55cf:2816:5f2]) by DM4PR10MB8218.namprd10.prod.outlook.com ([fe80::2650:55cf:2816:5f2%5]) with mapi id 15.20.9031.023; Mon, 18 Aug 2025 15:48:01 +0000 Date: Mon, 18 Aug 2025 16:47:58 +0100 From: Lorenzo Stoakes To: David Hildenbrand Cc: "Liam R. Howlett" , maple-tree@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Andrew Morton , Jann Horn , Pedro Falcato , Charan Teja Kalla , shikemeng@huaweicloud.com, kasong@tencent.com, nphamcs@gmail.com, bhe@redhat.com, baohua@kernel.org, chrisl@kernel.org, Matthew Wilcox Subject: Re: [RFC PATCH 0/6] Remove XA_ZERO from error recovery of Message-ID: <1e26e895-cad6-4920-a9df-21619777d25a@lucifer.local> References: <20250815191031.3769540-1-Liam.Howlett@oracle.com> <3970cd97-2e9e-403f-867a-3addfbe399dc@redhat.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3970cd97-2e9e-403f-867a-3addfbe399dc@redhat.com> X-ClientProxiedBy: LO4P123CA0180.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:18a::23) To DM4PR10MB8218.namprd10.prod.outlook.com (2603:10b6:8:1cc::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM4PR10MB8218:EE_|PH3PPF67E073224:EE_ X-MS-Office365-Filtering-Correlation-Id: 297973a7-2baf-4c57-a8a1-08ddde6e9cff X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|1800799024|366016; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?mRYscFMXA+W5gGwXGAKCybNk/tkZY0nJzZ6MVJbavE5TPYj+haCrGxyf8Uqh?= =?us-ascii?Q?DNqL/gMNExbCXMPaayER4K3HZ+q80CRoJUxoL1s3nfFqjX+EHbQH0ATKXGFi?= =?us-ascii?Q?Z7p6iVaHah3S4VWQNpEPjCPUmT4+QOiYnVL68plMcXNkx8WmEg6mMplO36Tj?= =?us-ascii?Q?xlNt6udr+EZIk9IQv4pnwIuQavvAz5oq5baeV4p4k1o0tgR1qi13dQ33SF2q?= =?us-ascii?Q?2V4GjPqbRqMV+EG2Js7W2g6VD9kjtPFBSinHXP/CYYyoHKEUrs60QzZGRyds?= =?us-ascii?Q?2soPbmaUivR4PH64QF3Q+gPqqnZAjTGNkelcJRY9U4Q71KWdVplgsKi5KGYZ?= =?us-ascii?Q?CWGfyS/DzseMY9OCE09B2Esf7fKOPc/ie6XNX3P0zM91YI1+OrCkbtG0qKAn?= =?us-ascii?Q?324XCKUTV0yVVdH/lpj0eEHt62M4IadjBsTJ2xBnAVIbqz9u9o/YtkZRbxA1?= =?us-ascii?Q?Y5hSDuEuAVd98cOSbK1rLygM3J+26TuGtObMoSjHV7io26vzUY8hiDOwNR8E?= =?us-ascii?Q?1bRSUA/M67HxpMXBlpPjt+CSIjWmh0rONwkMShkyN8uqP9lcXG9XiJlhECi+?= =?us-ascii?Q?bBUc07UFleVkeIX23uXPv5aTHjX3ohsjz/CsQl2MEqNrOJUCixX51rd1JCXP?= =?us-ascii?Q?7XICT2C7EAJRrf+6m1Sqn0pAWq2TPSjJt0U1anGPJf+O/i27dIgMqKJSKcQ7?= =?us-ascii?Q?TSFaF3AR0B0P5wOHda07scyvOw1J4AxprZl8+zWpUVpaOhVPKmoH6j01grf1?= =?us-ascii?Q?wC0UaLSYtNUMRCtYNh1/abh6fWRVdYVttYkVBBYbDZvccE6kBdMRRKCiKf+7?= =?us-ascii?Q?CUE9OLf80W5OJoGHG5AZ14FQsFyviH6bjry/xCzHSCpRVwHJh1xn8/MO+Mai?= =?us-ascii?Q?0IV6BLJjPGdwVBZFXaavJIgxz7ywVRH+VmwfU4xTaQlIvqGGfBP6rQGbZKa2?= =?us-ascii?Q?9Q+J3abodxRNWLib8y4/64eoOzdv87SP1RgrzJlAVMj3ImtW3DiOWEiJrt9I?= =?us-ascii?Q?eqKyzn+2mS/kz4GsgwTmRW6WcmlBnsRzkGwbReEffqmR4skzTytvPf9skcOK?= =?us-ascii?Q?7Gu4GDHjWZi89TQ8MRxIiuRMJ9+c9dkpOMLyLk5OaSUwspQ4muw5cfzXVULy?= =?us-ascii?Q?EBKp7aj6t+V5qRLZ3ucgn4Uzf9+5FKJaWNjzkS5S4cU2SvKueq9aatlnDRm+?= =?us-ascii?Q?yB2c7FrJeIX9fEQWb0GchywrBBhrWT6RKFQGUxJ26BrjbBJ2NibOYE8Zipuk?= =?us-ascii?Q?J+kkKa+syRilnXO70Qmr6mwDI2Y4DjsINcNA6CgT61q4dr10IcU49fIaFaV1?= =?us-ascii?Q?DUeLkz/5CN6ksFrkWztRjLp91OLUkp9VsZHblHHURvaNX8mHNNB9bEzVTwJZ?= =?us-ascii?Q?TK39NnI=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM4PR10MB8218.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(1800799024)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?uq8M/xBqWlRfID5n2KVRfttr2Bed2dZ8+7PEiad0PX/aYk3CD3N9jJ/V2JKQ?= =?us-ascii?Q?XQGZiw1dy1mMEg/F5BRyXnSQqOXFJ26nwsFgJ6EyBmdvQfOjxsyFVbMxbF/w?= =?us-ascii?Q?sV+tgVXjJVgbR3g3awLuYZ2j4huAuw1s/pOxEnwTzAw1xae+wNbAEb1u0uFz?= =?us-ascii?Q?yjmi7K4JNzQw5GHy1YEDWWcID52v1FyaMBDDJCKY5HNjPvjELogYxe6lEsLU?= =?us-ascii?Q?gYzFO+ElEypbNc6pCJtGHZzWTbo1DDeWDFOvYcpPdYNHVJilSzAahMhD5veX?= =?us-ascii?Q?sm5NCE0WT+XLrG3EuIzFffG7mOwKfkHsnU8HPyJW5lf4R2hfCHLX1zNj9Pny?= =?us-ascii?Q?1HIh2+oS/G9RbYb0NJIL6QuByFPZtveqO/x+SHdUr+oEcjwLbFmysgNYeiGP?= =?us-ascii?Q?T8dGNoDo55RaDBAJVucYMk6B1IihGkNJ7Q5gJK14LHcgFQ6BtUq1NfgAK4wY?= =?us-ascii?Q?lR6sKINSga6mwj7xn5DPEZsgDiQElGAZZR1TmlR7+Lk8pMgyDR7uMbnM4Fng?= =?us-ascii?Q?fDkdRU62NK4dDLVxh5htVDi/iYycxqVDob9MltMWuIoH84jknn3nWhGrbvd/?= =?us-ascii?Q?T0MpLWDiDA3vQzGrT18ssKXDLlCPtHKbp4ozewewExPBFlle3n0SAOw/w6yU?= =?us-ascii?Q?s1hbhrd2i9xQYT45g6k2j2bD8RRmmkJp9dziYzz5GHZKCcBIiV2lOIjY+CII?= =?us-ascii?Q?1d9mkmM5cvkInbw7QBq4FC2JYR/nCCwGshYIpCV4Nj0iK39+BanGzkm2J2UA?= =?us-ascii?Q?84V+dpcQ1kIEEK4uanEN7qlvfs2ezzQjGQWne14ITy3vjZc/4E0Wdjv1B2NN?= =?us-ascii?Q?470oLtPNujRUO1vMW405f9u7cYbZE+vWIE8n7HJASTMNieyAJVrlGBa30Ylw?= =?us-ascii?Q?FbOKX1WJrAcpNET/oe7OosFNFPrlpNt3F09hgbAPHwYnX9SDY5HJ+CpDJtj+?= =?us-ascii?Q?Ge+ij19Ark3C/wdUezTV7LpkGjC9RE9SrQDheQw9ssQJliLTJlxeDw6QQQMM?= =?us-ascii?Q?1hqxPawzoKltS6ZjJYWJYhNTO0GLe0vgi45dfjY23w7sfVrxlkKSNgoJop3u?= =?us-ascii?Q?2YmVNXCdewg9pL/bNihPxEN/VLJMjLdts/CGQ1LFX9CyOD5Kju6UomU4T3Sh?= =?us-ascii?Q?9r660m1ndQjI1fF2z0hKKy6IKrELb8bRD/IvOCAqJqhNlxh56ruzvDpfdk89?= =?us-ascii?Q?ld4jt+u2qz8d8VxAqrsFcwtriN3hjusivGVTwab3PsDZ8JdbuZrlQmm6dXw+?= =?us-ascii?Q?PTYvaKe7Wrjuk6xVJqbHl+F9Sx7NO+rVJlg4Z7qASWSi0LiWtdXJDQxVrL95?= =?us-ascii?Q?hZczt5OVw8QaX9agA645XM2MAP2LDB0gv3QpP2FT4EH+0Nr+3JPj7u/PD+xw?= =?us-ascii?Q?LWv8EcJR/aExyI6zM/fDAvX1N+TJaqHBbLHL1LZ+bPx3FL5sEEjvT3Bw8sFJ?= =?us-ascii?Q?AXdHBUtA4OIkh07LUNxPasWTS+BwD8Jwl+/BIYI03NvEF2xwpsmmAscpYhG2?= =?us-ascii?Q?Y44xQToibABZ/5kPHF0CVTwMfXNMyL2Gu/+TtNPM0vYUrQi2MpygY7cYAado?= =?us-ascii?Q?c7WnpJi0PxpYl3BrThjHUn1hCkytML2bMTluH/ArwVhkz3C7cjLHnwfXF+14?= =?us-ascii?Q?4g=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: 297973a7-2baf-4c57-a8a1-08ddde6e9cff X-MS-Exchange-CrossTenant-AuthSource: DM4PR10MB8218.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Aug 2025 15:48:01.8900 (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: XaG2t1tcdhaX6jU668E6cH8pqm3Q0/SkF0I8PLtDK6dxe6A56nIoslIBCflqAv8ek4YYcNVfsOw2maSeajMFxN0/6wiSjv2e4vfzfE6heg4= X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH3PPF67E073224 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-08-18_05,2025-08-14_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 mlxlogscore=999 adultscore=0 phishscore=0 bulkscore=0 mlxscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2507300000 definitions=main-2508180148 X-Proofpoint-GUID: LAFjyK_4w-bm6RmskUVEEoFgPIVjCLcr X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwODE4MDE0OCBTYWx0ZWRfX29O8WXjHiuY5 TUFf7izpBpKbPwOQwVeNm5U9W9/w6gxlNA+gqGbReDVn2ZIywIfXUL0xwGUhfJZ5Z7IVn6EYhNE JDpuslq4GP0hfKN7aDEE6Vf+yeXFG3Va2QVgB76GagAfRXRI5dSHtTwwiTS199Wcoio8vBXllYj Dp30uERKARUIVLD3/vl8fuO6OchoF5E5S6rHcOtZUR/lEospBvO8UV8w91H/77ZY6zVLiUvOcvC tO60K3lsGIXPFSl/q/bn+wRFIFLZ7BheZHwS3Y9Vw+892h9j/fnA9gGijwko2X3sEaqt8zyQhQc bZ/F+bE4gWU742vnmBJYXNCFnkD+Y1jnEbMkWTN2W7Vo+G0TTgB3fwRBNUnBq+NJpByiuB08L48 ZhUaUFXRL3sya5UJiAiEvn6Wh06HX0uFhhFk2sR0HkH6NSRRGgXGw3IFI/wDYpBjZLqfVfJU X-Proofpoint-ORIG-GUID: LAFjyK_4w-bm6RmskUVEEoFgPIVjCLcr X-Authority-Analysis: v=2.4 cv=HKzDFptv c=1 sm=1 tr=0 ts=68a34b3c b=1 cx=c_pps a=qoll8+KPOyaMroiJ2sR5sw==:117 a=qoll8+KPOyaMroiJ2sR5sw==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=wKuvFiaSGQ0qltdbU6+NXLB8nM8=:19 a=Ol13hO9ccFRV9qXi2t6ftBPywas=:19 a=xqWC_Br6kY4A:10 a=kj9zAlcOel0A:10 a=2OwXVqhp2XgA:10 a=GoEa3M9JfhUA:10 a=VwQbUJbxAAAA:8 a=COk6AnOGAAAA:8 a=xPrUTxJFcWhoDamw8IkA:9 a=CjuIK1q_8ugA:10 a=TjNXssC_j7lpFel5tvFf:22 cc=ntf awl=host:12070 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 573BF4000A X-Stat-Signature: em8yyof9xypa7cqm8cxhq1xd61zgjw8a X-Rspam-User: X-HE-Tag: 1755532107-27456 X-HE-Meta: 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 u3+r+kq5 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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: On Mon, Aug 18, 2025 at 11:44:16AM +0200, David Hildenbrand wrote: > On 15.08.25 21:10, Liam R. Howlett wrote: > > Before you read on, please take a moment to acknowledge that David > > Hildenbrand asked for this, so I'm blaming mostly him :) > > :) > > > > > It is possible that the dup_mmap() call fails on allocating or setting > > up a vma after the maple tree of the oldmm is copied. Today, that > > failure point is marked by inserting an XA_ZERO entry over the failure > > point so that the exact location does not need to be communicated > > through to exit_mmap(). > > > > However, a race exists in the tear down process because the dup_mmap() > > drops the mmap lock before exit_mmap() can remove the partially set up > > vma tree. This means that other tasks may get to the mm tree and find > > the invalid vma pointer (since it's an XA_ZERO entry), even though the > > mm is marked as MMF_OOM_SKIP and MMF_UNSTABLE. > > > > To remove the race fully, the tree must be cleaned up before dropping > > the lock. This is accomplished by extracting the vma cleanup in > > exit_mmap() and changing the required functions to pass through the vma > > search limit. > > > > This does run the risk of increasing the possibility of finding no vmas > > (which is already possible!) in code this isn't careful. > > Right, it would also happen if __mt_dup() fails I guess. > > > > > The passing of so many limits and variables was such a mess when the > > dup_mmap() was introduced that it was avoided in favour of the XA_ZERO > > entry marker, but since the swap case was the second time we've hit > > cases of walking an almost-dead mm, here's the alternative to checking > > MMF_UNSTABLE before wandering into other mm structs. > > Changes look fairly small and reasonable, so I really like this. > > I agree with Jann that doing a partial teardown might be even better, but > code-wise I suspect it might end up with a lot more churn and weird > allocation-corner-cases to handle. I've yet to review the series and see exactly what's proposed but on gut instinct (and based on past experience with the munmap gather/reattach stuff), some kind of a partial thing like this tends to end up a nightmare of weird-stuff-you-didn't-think-about. So I'm instincitively against this. However I'll take a proper look through this series shortly and hopefully have more intelligent things to say... An aside - I was working on a crazy anon idea over the weekend (I know, I know) and noticed that mm life cycle is just weird. I observed apparent duplicate calls of __mmdrop() for instance (I think the unwinding just broke), the delayed mmdrop is strange and the whole area seems rife with complexity. So I'm glad David talked you into doing this ;) this particular edge case was always strange and the fact we have now hid it twice (and this time more seriously - as it's due to a fatal signal which is much more likely to arise than an OOM scenario with too-small-to-fail allocations). BTW where are we with the hotfix for the swapoff case [0]? I think we agreed settng on MMF_UNSTABLE there and using that to decide not to proceed in unuse_mm() right? Cheers, Lorenzo [0]: https://lore.kernel.org/all/20250808092156.1918973-1-quic_charante@quicinc.com/