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 BAACCC83F03 for ; Wed, 9 Jul 2025 13:18:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 961B66B0103; Wed, 9 Jul 2025 09:18:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9118F6B0105; Wed, 9 Jul 2025 09:18:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7B25B6B0106; Wed, 9 Jul 2025 09:18:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 62C346B0103 for ; Wed, 9 Jul 2025 09:18:01 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 064671D81BE for ; Wed, 9 Jul 2025 13:18:01 +0000 (UTC) X-FDA: 83644779162.23.E27B6DC Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by imf19.hostedemail.com (Postfix) with ESMTP id A73B01A000D for ; Wed, 9 Jul 2025 13:17:57 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=ZAkodD1+; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=kyvVAS7x; spf=pass (imf19.hostedemail.com: domain of harry.yoo@oracle.com designates 205.220.177.32 as permitted sender) smtp.mailfrom=harry.yoo@oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); dmarc=pass (policy=reject) header.from=oracle.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1752067077; 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:content-transfer-encoding:in-reply-to: references:dkim-signature; bh=wNKnvunkDqROstJL+8Y2ThvLCZqsrxwOV2DK9R25mAs=; b=RuA3RtLqb6+vtr45CROYcIjgazk5jXkAjYv6NluICZ+u9JRmWNOgMtP9bCXJHB9FBEkfpG WCQGvS/tNNttajASibvbxlO8wFdX7U3vUwfoyFm2CQvGhXPS57EZmBA8KzluWfx4bXOmyj I06yQlVFBfqrk3O4CKnY+R0JcNassX0= ARC-Authentication-Results: i=2; imf19.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=ZAkodD1+; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=kyvVAS7x; spf=pass (imf19.hostedemail.com: domain of harry.yoo@oracle.com designates 205.220.177.32 as permitted sender) smtp.mailfrom=harry.yoo@oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); dmarc=pass (policy=reject) header.from=oracle.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1752067077; a=rsa-sha256; cv=pass; b=L+oXsGrlPxfWKNzCp2gPJN6r4hSrnn+OH7BNxq/Ej3RAUISy36qAC8JVsbhCGa75GUG8X4 1B0T6kg0LHl1nPR8MBylHQH27sQRwKwn0Av5T+n/cr97FJldZFM8JbD8MOTvQeyRJ8f1jm zib6YERRCP07AMSJReAwViPEOTh2x8s= Received: from pps.filterd (m0333520.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 5699jULP027207; Wed, 9 Jul 2025 13:17:31 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-transfer-encoding:content-type:date:from:message-id :mime-version:subject:to; s=corp-2025-04-25; bh=wNKnvunkDqROstJL +8Y2ThvLCZqsrxwOV2DK9R25mAs=; b=ZAkodD1+G1emAisngU6iqUdPl+hARyFn 5BzW6cQibTKAuziaM6ANt+dRthdF0bbEC74TFkHyoqN9kDBwmoZ1m1OdWDHdtFDK hty1eDg7PQGYpaaWkotyH8J4Ra6E+SpUnYU5NbEDL5HCeTWWkJOjyXn4o9QCr8xg XIIfzmtqhlp7xMEUmBM4Ao7GeoBFuJkNmA/KudB5j8KlhLER/bxACvphSVfaGAsO z3BhwctguX2Siqel3k7gdFbnbxXwv4wwVPauocX1CljcBUx5W1ufw5F/bikieXW8 MmbSFhGynfBcL7oXgE1cqVbmshO6YFdQ7y8cJg5zz6wG7SCnMJV+Kg== Received: from phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta02.appoci.oracle.com [147.154.114.232]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 47sp2rgbsq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 09 Jul 2025 13:17:30 +0000 (GMT) Received: from pps.filterd (phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 569D4Ren021505; Wed, 9 Jul 2025 13:17:29 GMT Received: from cy4pr05cu001.outbound.protection.outlook.com (mail-westcentralusazon11010036.outbound.protection.outlook.com [40.93.198.36]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 47ptgaxtar-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 09 Jul 2025 13:17:29 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=S5msny2F/uYMckqN5iVphuk+b3RXc69eKi7s87tGbrF9Wz5l8LvDkNpBYSu+VVKRjh9p86hA47syiWji8NMqeypy4RnnpER+kxQ5Race4WPlNtBZWNgr9uVgO4Cmoi8xJDHgtCTyCYbaVLE9da7CZPAXX6ZwqjPx9j813nzq4opr8G686WXF/mLcsx+KxiAGbJs18q3iWvE1LPh2OAolcWKv9RcqU3Wf15p0x2aO+umglzDm3+JMJZnb6JPXnP6t51W0NrjFjOztzMAdNTs2a2uVZTznoEQ40w0dlDDyNuCZVRvEl3VOZmzJ+izIr2xWeBj5fCit+eMqTL1tUX+s0A== 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=wNKnvunkDqROstJL+8Y2ThvLCZqsrxwOV2DK9R25mAs=; b=cs+dOhhoFDSrsSM2X51/Op2WS3gBL7t1dhl4vNUPtuUNoLasHrjigI3wPkdWoI/2QlLSImrMNRoSy4DZTm9n8IymJhQcn7QoSPjASGwTXYbN+TQcV4binVt6vbVFFdSZw6RcIijrpxlkZqNtxwkHP3vW0T/yD6kwKeQzQrveXhjfNQt85w8athsHyv4gYPlNzDcM1bQ1kBo5VtiQpoTl6nByj9i4fTvSrAIFEN1+oLuM/gGwfwMYY+xuN3gvoRxLHoL2n2IlYYmEu0aBbGtcblE1d920dvl9Nwp1Lr2Rm4WhGRe92eEkpRap1ESKuS2KD78ulYi/RwuCESkiux7uuw== 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=wNKnvunkDqROstJL+8Y2ThvLCZqsrxwOV2DK9R25mAs=; b=kyvVAS7xtwfFSz+RNtQWqZtFrq3/gq1KB2jlRwVEkJ4WzTd1Hq2wg5jFpSNU+Zf9ulbkLZu9c9FZU6Uxj7F5nMQ887MWEtLiI5TRuRYNiQ+Gy1GwQp6xGlz4BRya5XZT509aXnZ7iC+GsTQcxddU/H+M/p2H2t6bagqbP/W7ihU= Received: from CH3PR10MB7329.namprd10.prod.outlook.com (2603:10b6:610:12c::16) by BLAPR10MB4914.namprd10.prod.outlook.com (2603:10b6:208:30d::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8901.21; Wed, 9 Jul 2025 13:17:24 +0000 Received: from CH3PR10MB7329.namprd10.prod.outlook.com ([fe80::c2a4:fdda:f0c2:6f71]) by CH3PR10MB7329.namprd10.prod.outlook.com ([fe80::c2a4:fdda:f0c2:6f71%4]) with mapi id 15.20.8901.028; Wed, 9 Jul 2025 13:17:24 +0000 From: Harry Yoo To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Andrey Ryabinin , Arnd Bergmann , Andrew Morton , Dennis Zhou , Tejun Heo , Christoph Lameter Cc: "H . Peter Anvin" , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , Juergen Gross , Kevin Brodsky , Muchun Song , Oscar Salvador , Joao Martins , Lorenzo Stoakes , Jane Chu , Alistair Popple , Mike Rapoport , Gwan-gyeong Mun , "Aneesh Kumar K . V" , x86@kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, Harry Yoo Subject: [RFC V1 PATCH mm-hotfixes 0/3] mm, arch: A more robust approach to sync top level kernel page tables Date: Wed, 9 Jul 2025 22:16:54 +0900 Message-ID: <20250709131657.5660-1-harry.yoo@oracle.com> X-Mailer: git-send-email 2.43.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: SEWP216CA0055.KORP216.PROD.OUTLOOK.COM (2603:1096:101:2bd::6) To CH3PR10MB7329.namprd10.prod.outlook.com (2603:10b6:610:12c::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR10MB7329:EE_|BLAPR10MB4914:EE_ X-MS-Office365-Filtering-Correlation-Id: 5991f853-b6b5-45a3-e5ed-08ddbeeaf1a9 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|376014|7416014|921020; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?cGoF9gj+rRflM5bLK2qiNCGd1FmQPJ9M9gtI48ShZ59+7TcZVkVFbWJ9cw2j?= =?us-ascii?Q?UJ3qX+AWMaTnzP41A2p01Ivdntz+knir1gyxzCWE7ga/E0P6MBgUa8KlL0Rv?= =?us-ascii?Q?IOhLJittW/rx+w4e5yjsv/hyaT6FfTNMhl+7NZWBvxHKjisiH+SKAUbnVye5?= =?us-ascii?Q?Mz1xCacv6qDGuaiq8gzvsIQBtS2fJvKli2fEcPyqQzEByjx1o8sCFh7FPdH9?= =?us-ascii?Q?eGkLQfwfIuPDB/7T25BDFKsWhuyRw3yC5aeS7Xnleos10HRv6m6VZDSqoZnd?= =?us-ascii?Q?PutMuLYETJphcIYYGfbYhR98yKT/0/RT++8E9ilobKoSWbqanca7VGSpbh3C?= =?us-ascii?Q?9KWYjImwYQNtMSLD+B2o2fD76Bb2/c5eHq2a2FOr3z+62pHPVVegogCyif5u?= =?us-ascii?Q?Mhq5UpKW5M8J+26dk8v5rtsAoutmSeZNTKaSbZdQC5r+/wTbdbov083qwW7b?= =?us-ascii?Q?kB+/FUAAqO400eeYf9ESEpX2UXQ9LixfV2lZg64WmpLx+BYim0Ys/1+L9HuM?= =?us-ascii?Q?JP8k5sZ/dDhh+051fAOVUZ4J574SSyxU766afB1RaJVq8p7UFZDkFbJzxZdN?= =?us-ascii?Q?57pf67qmQBUXg0s+Sb3UafKKqekGpcacbWvwAE1i6bqviWvqvtp2p7oBEFg5?= =?us-ascii?Q?Lb6B7I+whi42TMbcnE9gyWRNgcG5I23RbE3B7F3/fCTHkNd8P6N/KzIRhBzB?= =?us-ascii?Q?7UkUSvMYJU9ivhnZy72NLcabkHIMP/7n4ijvwXZ6Th67PWpx4fImQgFU1saM?= =?us-ascii?Q?+U4YCoW7e+/ORodR1c2f0v8GmSMuTI0/xNxoIR2RI8owx0JGflEUt/8LmVPf?= =?us-ascii?Q?eAKCLxrXG3o0j4XJAoZovgKgWpzP/AS/7LR6Q3VedF/kumkubjd3iZYTJ6R3?= =?us-ascii?Q?zjFlImwoD7JkoKhmfXob+Q6RJL5253pSh/iaXd6Qm8KEUzOtZuO3K5rkKBVa?= =?us-ascii?Q?DSyli7UPpSggJOHYCySWQeTJInhJa1UQIW1SiN+Lnu73AS/+OZBhtj9F03+m?= =?us-ascii?Q?umKObt+sxjwv4dbG8+23Lff6YVk4CVaSRGDKloJihpLW7DjzKKeHZTCld6Q5?= =?us-ascii?Q?IaweL/s83MZmtu5uwfSJmBPogw7e2g9Dna8TXPYeHisg0wNxP94v7nhBfk7n?= =?us-ascii?Q?gcoNbgUBVhauZGPtnG/4NJLfvzBdGML4AgSAhkwn38+Amd+5aLdiiD3Oy18T?= =?us-ascii?Q?nLYoVyKScD2BHgLqXBlm6nCKAL28Y7iSTSjjClEoJA967HkSHVnHCsx/Nz76?= =?us-ascii?Q?YejapbNx91KpP5JHL0wSu19RkXx8sTzL8C/+BLZlt9RDoZFjoFfdBoZJhmli?= =?us-ascii?Q?PDYoi9BkUJQFfGWaMZr9OmDlPKrTetyzJ+ajDnmrZ0YYU0N/uruIeB8LaCAy?= =?us-ascii?Q?r29q5ghGh6g6fb4CPoIYH4ROyLGswDAmyzdxPsF37pLNnzpU++5NfLRxwTNv?= =?us-ascii?Q?3of2Ri6ORuQ3T+mZc6PBRV+vmQTOpnemiXxNmcAPp1zQzIbqw+FvuTAOzFpg?= =?us-ascii?Q?NI+g6Ki4AlC2hZw=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH3PR10MB7329.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(376014)(7416014)(921020);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?KaicH7y2xC+//GLVEZH8grOvsqCNSPHaksSLBaGaw7Iuff0x0I5w0slL5ydb?= =?us-ascii?Q?UmcT6sD6VmvmJOLcnHRxEb2oGSnyEfpFT2IRj2nlZtUD0FTd9pnS2be/6kvj?= =?us-ascii?Q?rKXUe9v9GuKTPmjJ/qCrDspedFTNrjdPzL6+S2WMvkRTYSZCV1TVdFbfs0Io?= =?us-ascii?Q?8GFykXovI4FQait1V0nYfGQ4z6Lym/iASpDBlHY7LoNXQ/XQ/HgK5l5hiuPs?= =?us-ascii?Q?7qBYtkscNH+GelwxMZNTycOcUbnO58uhrXOwoSk6C5dpAa4b1szDMoQLNMui?= =?us-ascii?Q?QLO5997ixNytC/zzvUHb52PanKw5QpOYM6Lbfu+I2+v7tSR0Gh789EPaI3Ov?= =?us-ascii?Q?Yp7wtgIMTgSOJSbe5qrL2oHl35Zle5Ja4Pqed2avi0TymTsRf5BxrZBQShmS?= =?us-ascii?Q?Ax9TS6k+hRt06VK7kGFIljWEI5TE7I7KNhzJa7YChmsJFa0G9itGX6Cmvl04?= =?us-ascii?Q?42w4RR0DKAP6tr2c/DTrDgyiqEGzLHeI7P5SOwcLXinHYeRj47l96C/kgwJa?= =?us-ascii?Q?hcCYd40M9UR47wnn7GzTf4kWpZ9nmcpotTRajxhaTMD/o5dzInI4dlKPwT3T?= =?us-ascii?Q?J7nGEQt7tDCsHZRksj/PjX37H/7xtUEg8fUkgTbDvFsvMLUzosGl9U/yR8T3?= =?us-ascii?Q?uXG05DFu2G3Ib2OFPmA9rXPbBJmJ0qnMSaJcUqgmlxpOJ6c0y0H1t+JSd/sZ?= =?us-ascii?Q?6uz2cIP6PamtuoE4oTMXlWEjlPx7ux8PyH4wWsBX4hAGZreEMsy33haTg6Ey?= =?us-ascii?Q?zUBa/v+UsUEVvUepBp74SHQU7DFgLevqJ+2q9Hn0+zV1vyU3TIuoLb44rHrF?= =?us-ascii?Q?V4UBEy47zDLWE+T6/JEcxnYElayEsr1KIcNbvoI1xKPAaU8oGudeJZNtPbd+?= =?us-ascii?Q?zTeACFr7c867R79mpKVJxkOpPP6AKYFHvU9ZadbzumaEsKPQYvvBy3T4N0MH?= =?us-ascii?Q?xGN+2K1HijhNpGpUxRAziuBPAgxtbZiQOU11lH7nJ3pYkXiYnelLlKwZgXCB?= =?us-ascii?Q?x8bqXjDfIAyIz06QiMWP224DVvVVmA4jvCw/+7pz197u70UyklX45E3/ReOz?= =?us-ascii?Q?9gU3CjrJSzhRHfrZPrU3co35V3V7lyyCw68E0xSoIySBBxOUcq0zlyOL+Ni2?= =?us-ascii?Q?+MI3ty7/CNSHGPWCxNrUb0J6qfnys1ssOLKSVOYBvBgpxvmQohtF8KdSrE3X?= =?us-ascii?Q?wntrJls/o2hER8viQp2volSCRUyCKNYddzLcFfDYtfGqowzJWcZwGLKCNcTS?= =?us-ascii?Q?tBhCFNji5pw3RvMZtQfUZHPYJBzfBqFmU2lBQyH0tk5NfTwmD+R5OYLE30Nv?= =?us-ascii?Q?/c4EB06Wok+uBhC12JHd+b6Yie7SlaUaq6po4F4Pvctd2Rv8OI+gW3/BT6IX?= =?us-ascii?Q?FT/7BPn45Qkqqh7sui04oIzP95b9mTUJXQ6M+7IRiq/aFAHtPGWq+cospf0A?= =?us-ascii?Q?WIsVSilW8vGDeMcXLA+mFhFXalZG5yBw6VkeDIheviKpXZCLVtvLRWLesbF2?= =?us-ascii?Q?NbWx5hMWtemJYQukrg09O0AwR5iZCaqI2/Jjihe3F0tWKl8s5mFWXeqiQV9J?= =?us-ascii?Q?yugR/Vxu5GzeubDmTDxzR600O6u36vT4lLU3Peu+?= 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: 5991f853-b6b5-45a3-e5ed-08ddbeeaf1a9 X-MS-Exchange-CrossTenant-AuthSource: CH3PR10MB7329.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Jul 2025 13:17:24.4603 (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: UuzuIZxmwKB/Zzx7Iq6c+3nlGY9thu8GC50Vxsty/L9QQCDf8XX1YYepkAprJjwP7APuGgJx4DoUNpRLGdrGxw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BLAPR10MB4914 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.7,FMLib:17.12.80.40 definitions=2025-07-09_02,2025-07-08_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 adultscore=0 suspectscore=0 mlxlogscore=999 phishscore=0 malwarescore=0 mlxscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2505160000 definitions=main-2507090119 X-Authority-Analysis: v=2.4 cv=e4EGSbp/ c=1 sm=1 tr=0 ts=686e6bea cx=c_pps a=OOZaFjgC48PWsiFpTAqLcw==:117 a=OOZaFjgC48PWsiFpTAqLcw==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=wKuvFiaSGQ0qltdbU6+NXLB8nM8=:19 a=Ol13hO9ccFRV9qXi2t6ftBPywas=:19 a=xqWC_Br6kY4A:10 a=Wb1JkmetP80A:10 a=GoEa3M9JfhUA:10 a=VwQbUJbxAAAA:8 a=QyXUC8HyAAAA:8 a=XaHTuPSUgyWGxnsc4b8A:9 X-Proofpoint-GUID: Tvv6auSB7fXBD1BKlplbeAli7wXgsQgP X-Proofpoint-ORIG-GUID: Tvv6auSB7fXBD1BKlplbeAli7wXgsQgP X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNzA5MDExOSBTYWx0ZWRfX1qGFpmeKRLtj QDTFXlWUu1KA9cqZTHW1gSM+EbEnHFxaR1mTUVWnudYSfnyeHBZUiyHYPwfBeqeSIMYD4n5Dv+R RZAH/jsMkXeQzB5hgmt38ZecwNVryD5jsrNAZP6YePnySklKEl1xwBDNsa4skHfvtH69L5pk+FT 3Le0HGmWcQxQ8JpATSOkIORGMgqCQkPgpKXqorbqtpJfieJ4VqtsorR7tvcbG72Y+fKZgdMvzjY dJsvLah5vWAnVfwwK3tv3YzOmzW9kwDAMhMkUgFTO0gOK3zgSUlyxcZVYTJ2jr8zKp4U6SjOV9w z8dKlFjSM8TE9PFD+3IwWF1C9OSDIxzAdmzynb9jm7XVRw1dwOxsVCRYt4A9+8AsZzUfi6d3m0U XfJBuu5L7+GhhsM0e1+wcDECVXfJddENMx/X+7GmAZRPkrDsgGahjyYAkc5PN6MPz5g4mALy X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: A73B01A000D X-Stat-Signature: xwfzdjb1pruuftrxz1m4w4yuucaz9rd5 X-Rspam-User: X-HE-Tag: 1752067077-967532 X-HE-Meta: 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 tuMxqklY 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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: Hi all, During our internal testing, we started observing intermittent boot failures when the machine uses 4-level paging and has a large amount of persistent memory: BUG: unable to handle page fault for address: ffffe70000000034 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI RIP: 0010:__init_single_page+0x9/0x6d Call Trace: __init_zone_device_page+0x17/0x5d memmap_init_zone_device+0x154/0x1bb pagemap_range+0x2e0/0x40f memremap_pages+0x10b/0x2f0 devm_memremap_pages+0x1e/0x60 dev_dax_probe+0xce/0x2ec [device_dax] dax_bus_probe+0x6d/0xc9 [... snip ...] It turns out that the kernel panics while initializing vmemmap (struct page array) when the vmemmap region spans two PGD entries, because the new PGD entry is only installed in init_mm.pgd, but not in the page tables of other tasks. And looking at __populate_section_memmap(): if (vmemmap_can_optimize(altmap, pgmap)) // does not sync top level page tables r = vmemmap_populate_compound_pages(pfn, start, end, nid, pgmap); else // sync top level page tables in x86 r = vmemmap_populate(start, end, nid, altmap); In the normal path, vmemmap_populate() in arch/x86/mm/init_64.c synchronizes the top level page table (See commit 9b861528a801 ("x86-64, mem: Update all PGDs for direct mapping and vmemmap mapping changes")) so that all tasks in the system can see the new vmemmap area. However, when vmemmap_can_optimize() returns true, the optimized path skips synchronization of top-level page tables. This is because vmemmap_populate_compound_pages() is implemented in core MM code, which does not handle synchronization of the top-level page tables. Instead, the core MM has historically relied on each architecture to perform this synchronization manually. We're not the first party to encounter a crash caused by not-sync'd top level page tables: earlier this year, Gwan-gyeong Mun attempted to address the issue [1] [2] after hitting a kernel panic when x86 code accessed the vmemmap area before the corresponding top-level entries were synced. At that time, the issue was believed to be triggered only when struct page was enlarged for debugging purposes, and the patch did not get further updates. It turns out that current approach of relying on each arch to handle the page table sync manually is fragile because 1) it's easy to forget to sync the top level page table, and 2) it's also easy to overlook that the kernel should not access vmemmap / direct mapping area before the sync. To address this, Dave Hansen suggested [3] [4] introducing {pgd,p4d}_populate_kernel() for updating kernel portion of the page tables and allow each architecture to explicitly perform synchronization when installing top-level entries. With this approach, we no longer need to worry about missing the sync step, reducing the risk of future regressions. This patch series implements Dave Hansen's suggestion and hence added Suggested-by: Dave Hansen. This is an RFC primarily because this involves non-trivial change and I would like to fix it in a way that aligns with community consensus. Cc stable because lack of this series opens the door to intermittent boot failures. [1] https://lore.kernel.org/linux-mm/20250220064105.808339-1-gwan-gyeong.mun@intel.com [2] https://lore.kernel.org/linux-mm/20250311114420.240341-1-gwan-gyeong.mun@intel.com [3] https://lore.kernel.org/linux-mm/d1da214c-53d3-45ac-a8b6-51821c5416e4@intel.com [4] https://lore.kernel.org/linux-mm/4d800744-7b88-41aa-9979-b245e8bf794b@intel.com Harry Yoo (3): mm: introduce and use {pgd,p4d}_populate_kernel() x86/mm: define p*d_populate_kernel() and top level page table sync x86/mm: convert {pgd,p4d}_populate{,_init} to _kernel variant arch/x86/include/asm/pgalloc.h | 41 +++++++++ arch/x86/mm/init_64.c | 147 ++++++++++++++++----------------- arch/x86/mm/kasan_init_64.c | 8 +- include/asm-generic/pgalloc.h | 4 + include/linux/pgalloc.h | 0 mm/kasan/init.c | 10 +-- mm/percpu.c | 4 +- mm/sparse-vmemmap.c | 4 +- 8 files changed, 130 insertions(+), 88 deletions(-) create mode 100644 include/linux/pgalloc.h -- 2.43.0