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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 94D92C982ED for ; Mon, 21 Sep 2026 15:31:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A2FEB6B00C9; Mon, 21 Sep 2026 11:31:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A08076B00CC; Mon, 21 Sep 2026 11:31:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8F8216B00CD; Mon, 21 Sep 2026 11:31:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 5A6456B00C9 for ; Mon, 21 Sep 2026 11:31:06 -0400 (EDT) Received: from smtpin19.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id D3958A508E for ; Mon, 21 Sep 2026 15:31:05 +0000 (UTC) X-FDA: 85238157690.19.FFBDACC Received: from BL2PR02CU003.outbound.protection.outlook.com (mail-eastusazon11011003.outbound.protection.outlook.com [52.101.52.3]) by imf03.hostedemail.com (Postfix) with ESMTP id EAFC52000F for ; Mon, 21 Sep 2026 15:31:02 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=pR0kZgoc; spf=pass (imf03.hostedemail.com: domain of ziy@nvidia.com designates 52.101.52.3 as permitted sender) smtp.mailfrom=ziy@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1790004663; 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=ZflvH9+x2U1qkKUD5MJHwa3+VJYyoWdC9wzpixpduCs=; b=FpBGZ+jvy+caMgj0q9UWf+3H9n7iG6vPk8QdoPLVDItNXOtbL0ZzONtOHV9M0ODl4eE25d DAelBPKY4CdVubdJ2AILheCr+NdJi8u35lUArCKffeRU8eCkU1j1V/B4rvAFLtWORVFtfb q7JR1In2SKCpLwqLKcbOSFlkYILh6Mk= ARC-Seal: i=2; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=pass; t=1790004663; b=wv1nRsF6UTeWQN/bYfHtvZKMWi7+4wBzgM5RnbxdDcFEsTceDPCPlbsVUtmlMQaRi6QiEP BCNrIiRr0y8pOlYo7yhUlLgeJ0NaQYfVH4q3FEuyCouiapX/kKlODDHlTDEKy6aRsLX5hv a4qZJjxn74O1rKzhEzQZhB9B0G2INMg= ARC-Authentication-Results: i=2; imf03.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=pR0kZgoc; spf=pass (imf03.hostedemail.com: domain of ziy@nvidia.com designates 52.101.52.3 as permitted sender) smtp.mailfrom=ziy@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=N7tcC7EnBF02fFU4AqakhW4YyAeqNacMTQD99gAP+IGeRFC4AXPTcBUDMY8fbe07ZLimi1V/UTW3VX5Gvk3NWBrIVP0uAVNOR5fUJkvsO5oDfGpyG8rnwsVMfSmopGb5m5MoNaiwitXhmt1LQrz5jE1dCVnMfx3YCCVMHOCfreUDwKsnMVMmT52pmpLdxpSNXs999JIqG1zrc8kSl7NBITqPlJSai5zA6jlpNiNTY4kJuVb4vTUzQzoqmcomXyuKyBIp7uz9JNBlMNh13RuTBFNsfNXoaBywOh7G87C4ChSxjzM6Kko7Rnsm5TLGefl9Y01FfCdFk1joZmklOBSZlQ== 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=ZflvH9+x2U1qkKUD5MJHwa3+VJYyoWdC9wzpixpduCs=; b=b8l0Ji0p4D8LfzckWZwUaZomXKGua4TSONIYtcr3bJWx2uGfwLeTdBhjFSevUSxowoMDHrEbbDtwU43gSSGH6E0hqLehDH0UdA4dpsi9EcjqeXILfgzoLg7egV11JAfdF0zIXuk0MeFsPUVCrAyf2zRT3TsV4HweqHg2Aj6D2bK/l7390dmoj3XN/p+GA0YOJONyD6c7DnP2VMqn+m76Tyh6lC8fspYldR3RZotr3736wMYDjXP2N6NxKSbG+A6WqDRaDy6EfTMQKekVVKuMGyOGtuutjNlj+UEKDsWXSqPgH7LjujSJoEX6KaAYERmq7EJZ2wUKDVvVsAnPgLFMIA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=ZflvH9+x2U1qkKUD5MJHwa3+VJYyoWdC9wzpixpduCs=; b=pR0kZgocWHMaavnixzn0+SBX+EOlkFudxUFCifc+EGskqcpXYU2iVIQ3dTcDTgszYflIuEMSS6ZcJPvdtU/RcLc/kULr5n+XmnIipU5/uw4Dl7BrfKTsZXSSA97uJn0/fv+n/JeUP9OgfN4ZqVV8PRxOUDLhNvrTOp3RpzZ0bvrE09uuNBZG1Pr6xm4Yb0xhgWcrx6HewhmlJXoCl7Up0SJGsVpbSgO3f0lnw1QGR99ulFnANHFOvY7U4xGUK2NZQz7E8JgOozNkGrV7prJuepXMRo6kfPdRP36zJJpk8/qTxH+pngEMbxiBodNpjQm8zmRKHfEuyPTCUPqY0YDtvw== Received: from IA0PR12MB8374.namprd12.prod.outlook.com (2603:10b6:208:40e::7) by PH9PR12MB995114.namprd12.prod.outlook.com (2603:10b6:510:426::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.428.16; Mon, 21 Sep 2026 15:30:57 +0000 Received: from IA0PR12MB8374.namprd12.prod.outlook.com ([fe80::d85f:4c87:ae84:3f16]) by IA0PR12MB8374.namprd12.prod.outlook.com ([fe80::d85f:4c87:ae84:3f16%6]) with mapi id 15.21.0428.015; Mon, 21 Sep 2026 15:30:57 +0000 From: Zi Yan To: Lance Yang Cc: akpm@linux-foundation.org, david@kernel.org, baolin.wang@linux.alibaba.com, liam@infradead.org, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, usama.arif@linux.dev, kas@kernel.org, ljs@kernel.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/1] mm: disallow raw PFN mappings of huge/shared zeropage Date: Mon, 21 Sep 2026 11:30:56 -0400 X-Mailer: MailMate (3.0r7032) Message-ID: In-Reply-To: <20260921054225.28537-1-lance.yang@linux.dev> References: <20260921054225.28537-1-lance.yang@linux.dev> Content-Type: text/plain X-MS-Reactions: disallow X-ClientProxiedBy: BLAPR03CA0075.namprd03.prod.outlook.com (2603:10b6:208:329::20) To IA0PR12MB8374.namprd12.prod.outlook.com (2603:10b6:208:40e::7) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: IA0PR12MB8374:EE_|PH9PR12MB995114:EE_ X-MS-Office365-Filtering-Correlation-Id: e9d5e255-9407-4a61-eba1-08df17f5556c X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|23010399003|1800799024|366016|7416014|376014|10067099003|11063799006|18002099003|22082099003|56012099006|13003099007; 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:IA0PR12MB8374.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(23010399003)(1800799024)(366016)(7416014)(376014)(10067099003)(11063799006)(18002099003)(22082099003)(56012099006)(13003099007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?lFFNshj2xv5Xyv+kbduf44sLOEBpxQY8GkTER+3xHIQCbbrIxwjQl/xnwOsV?= =?us-ascii?Q?/20F6IRr+nC47KTjldrU+9VRatWNWqW4q17GTiStc4K0Wm5ewc/myAfJ/uYK?= =?us-ascii?Q?UQI90op1kEY3mYFEan9MOixhzMAd1pD0Mx0DH0lyhlwbEYGfsalqzBFInmdg?= =?us-ascii?Q?915Akx+7sVz847g6ssuUnNDwpyS26dYKoIscEMQskU1196vY+yEAdyVqvw9c?= =?us-ascii?Q?V/k/yQnTPh+NbBQ8ULr6XBfMpqCBh1J2VNy+lgG4Y7AzgIVnKWh5Ok0H406t?= =?us-ascii?Q?Eg7vkHGt60sVWesbew4cMLCb/4Ax5EVCQcmggpNBYtyQOBxd+Wc0o07NxtMa?= =?us-ascii?Q?7awRRqEk+Qv3KNYF6C0CHzIU5PpXiWcp7GyVeZAD7tM4t2rx/RKALeBAOBcT?= =?us-ascii?Q?nbwcHXwYbBCDP9Al6XbPQ8JPCw8KpUswCcp0vEKyk1iMpk3WSpdhU5JW7bTZ?= =?us-ascii?Q?e8Ofhiv563xceXMjY8jfk8YgQxy4Kws3ptjiJdhp49eQK3AwjtJq4nORTTIt?= =?us-ascii?Q?ot/qFeIKKVhqloZhPurgf9xOK30hKsvARH35C7K8yaex60j3NcP1Tk6wwt9j?= =?us-ascii?Q?9TYvhc9tLlKpCTjcsyrP8UpKbPl+HmDtu6FlID+JjS9x0kg1hpwhCqEe+z0S?= =?us-ascii?Q?RK/auLZAIYlub5NtCUGbs64rBLAs9lAM10GijsDDpBKTW6+gy3wv/srEBv8v?= =?us-ascii?Q?fPxQyCGUjs+p4id0MoMcrV3BJ54rfoCodQdn8f/wsmm69F/YiICtkGCiE8za?= =?us-ascii?Q?oteg2/3050GGQ1uZTsQ5yPOgJ7N5eeJ0wjkmpXL0ZtUSuLKqdHki636+Xwbk?= =?us-ascii?Q?LIFO0d91iOkHF+r7EyCvhD04rcGvTyoWNp7FX0fE2A3NfVBH0PVWJ8RD92Z4?= =?us-ascii?Q?/JUfxhizrp0j1K2C/+G1NyLcR1FvrJgpL4TEkYG2OCuK5kst/9x6yKTeEk+D?= =?us-ascii?Q?yLqVazkp4TrSH4pkaKJGTHKektHhOJMImhkqnvrbhGmmYh8hwsy/vMV6YaXl?= =?us-ascii?Q?kJNidPGJVC8WS0STRUZfj849nAk2JQemnOv14MwIEIu3mdeDtOq8WJABMr77?= =?us-ascii?Q?BjYkOasWAjf8c3ZbI+TQl6zpFYBMifHclMYYr8jhlyl8+jrqCj5j8PIfziZu?= =?us-ascii?Q?HB0Vobg2r7TzZaNDDO5f07I8G5/A5/X3BsRLMaDLq0+3pIDMttBWZgXoZHXH?= =?us-ascii?Q?jrmakEERE9FX7O6YgEmkiBUickjMKdqhIh3lWGSsiCDYm8S8L8YscFfNilsG?= =?us-ascii?Q?qbZJ4ubn5qgc09jnCaFkaER1dcItF9Snfre2etR4+Eg2awkVWK2M+rittnsn?= =?us-ascii?Q?3CPtP5OT+dONIDaGbKm9LuFvHLhLpALMFEl0o9pBT99HTrkQRpE2DAf6p+U1?= =?us-ascii?Q?bBPKudoLnKOzz3HBZQDsw1IJ1pu8yTCSJ7ukAkAiK33KngBR/kunq+t+ZYcc?= =?us-ascii?Q?k5w0kyV6B9gPDs78L8CaBSURVbe6PlQtopDYP7xnf/1ieUEufxAOas/faGd6?= =?us-ascii?Q?iYYlT608sSHuImCf8tPKSiZdXefe60Bv5JXuD5fCKQ7GUXF5JTWewZlWk/YS?= =?us-ascii?Q?W9vg5QGU6UJM7t+Vr072OX5lUCv9rvLbSulDag/WLcSWG37wKX/Xm4m5pBvj?= =?us-ascii?Q?oFFPH1+ggk0d/q2dTYKuR7lSbcqmCG/lZdAqHrX1uDBwGubRA3/R3eG3DIsq?= =?us-ascii?Q?oLkmQ3JMiHxsiK766ESE9XuDBFQKv/yLeWqmwQ3f3HvqpBs/6LGj0Z5PrZKN?= =?us-ascii?Q?BvmTUbD+qA=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: e9d5e255-9407-4a61-eba1-08df17f5556c X-MS-Exchange-CrossTenant-AuthSource: IA0PR12MB8374.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Sep 2026 15:30:57.8620 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: mNbJNNLYzeR6PYksvfdTUD0YYGqIMznXMoAMXu47ObHHmKIxhXrWYx0plPO/aqXi X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH9PR12MB995114 X-Stat-Signature: 53pxxzq5twog1obq1qngurp4uq3codbu X-Rspam-User: X-Rspamd-Queue-Id: EAFC52000F X-Rspamd-Server: rspam03 X-HE-Tag: 1790004662-670528 X-HE-Meta: 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 FMWGVqRp 3A6K2AH9eYS0HKw/d72X73ymH0vjgkOdeIvXu+YgZjI6CDQshUU26BU8YLdZUwtstWjMM/1BGWw4zEiDBK5JLz7Xz1WHBjHjGXrzRAHgLoBzf/zFRfQXDnmnSzhT2WtemUYui7qr/Ai18BBuvZp2ctQrpoYDAH1eV/K6foprQafW333Tpqd1KSA3SbFStGEbo5ejsmMt8un+V74Lu4slAdsJpZiI0fd3sF5LquVUva2OBQW1MjzxwBUEMiZsN3FoPdLOa00A8dAZZbEi4Ruz/1Qunp2Qf6cnwbBoqZzApV1hXZm6asM7gPVopKlBWGnP/G7G6bOv8jTnVuqCJeN9+/uqt2JD9yEZdpT2WFBnQP0MX+ZnrLLlrop7RAnxwz/j50zLbRQxyrMyqcmi7IelLVV5irNDIQEZo2ofb Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 21 Sep 2026, at 1:42, Lance Yang wrote: > From: Lance Yang > > Handling the huge/shared zeropage correctly in vmf_insert_pfn_pmd() and > vmf_insert_pfn_prot() is more involved. We would need to check whether the > VMA allows it and keep the mapping read-only, similar to the checks in > vm_mixed_ok(). > > No in-tree user needs that support, so reject these mappings with > VM_FAULT_SIGBUS rather than complicate the code for now. > > Link: https://lore.kernel.org/all/20260917121010.60966-1-lance.yang@linux.dev/ > Suggested-by: Kiryl Shutsemau (Meta) > Suggested-by: David Hildenbrand (Arm) > Reviewed-by: Kiryl Shutsemau (Meta) > Signed-off-by: Lance Yang > --- > v1 -> v2: > - Reject the shared zeropage in vmf_insert_pfn_prot() (per Kiryl) - thanks! > - Explain the VMA validation and read-only requirements (per David) - thanks! > - Pick up Kiryl's Reviewed-by tag. > - https://lore.kernel.org/all/20260917121010.60966-1-lance.yang@linux.dev/ > > mm/huge_memory.c | 3 +++ > mm/memory.c | 3 +++ > 2 files changed, 6 insertions(+) > Makes sense to me. Acked-by: Zi Yan Best Regards, Yan, Zi