From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from BYAPR05CU005.outbound.protection.outlook.com (mail-westusazon11010052.outbound.protection.outlook.com [52.101.85.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 12B6934D90D; Thu, 24 Sep 2026 19:28:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.85.52 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790278132; cv=fail; b=CoQt+WhuPVPLjyj83kOoWn/p4aopamW/GCxi2+hvdleG6kFiMbrpPGl1h3uXuzpV7xjvyZUytGWRzNq51Vx61CWC9zawe4vt/EhdJQIRaj3QbjLZyKsA1nU93u5fevmUrEagvuY5hG48gD3l36FTGNoTpIhHiO85AgajwC/M98s= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790278132; c=relaxed/simple; bh=ny8EbEvtbt9iqrScwz/pOR9WAVgerwBO6QW8MPc9WV8=; h=Content-Type:Date:Message-Id:Cc:To:From:Subject:References: In-Reply-To:MIME-Version; b=SrAeQUaY+VRxAikpUlhi3wrco+SrASGJt/QHC9kVimyWWj+q7knIUqQghwcmbAQjT1GS+nww2caTU4SN5VWAgLZZ9D+UkZXPI5kzztGd+zfp27HJtdptUGAQEbP/WfYzDMKz6JoRhfj65OVxzCmlwWwDbj26V+FQYlDERhIluX4= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=h+WaXW9a; arc=fail smtp.client-ip=52.101.85.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="h+WaXW9a" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=cjqlYp28LVRA1tlUe3pHgpcNtzuPmx8HtsSywXuC1NR+ZPFwniUWW/Qm6rQ/0M1T1eyUdRFAEd4TyZEpMXDUX7oVci/J5WN6Cw6jdc4Km+3FjnffxDISj1anGv3tyCEFbWi3iQ94ERo2TKcB00sXxNtAAppYz7pQl2AvHD6W0v1/3VY4YgaFKWzPXc/sUX6GdocahoDGUm4NVoIj2jDau0bhEWnGdHSXeqrsDD2efPXHZMYirzrezZz5WwoBs0FR4uwgkqaW0X7/o4ZxqvD0bdTihipeMxYRvC6blZuLRzqyL5LmaZ50M78kgpyUxYWBVhCaE+jOzUgVi+2LyYoAFg== 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=BanIIEJzpCiYkyUQdKsWNp/eZgx6p5TAqP8UPbXSTJI=; b=rCFzHE3rtPzAT2pO1Yzb9+YdowGNLOBxmdKJPzpJJD6IKidCRMPbK6PZ5z+9cR6oX80fc+pwQqpVp+/eq+ZB42PvjsF8PINhz7Du6dO0YUlCqhqlcnEkvTCS5xTpWWanNb0KwI52t2gy1ku88ZlP+2M2Jrl56poHrdtNj0QSfpYYi0L9rGr7lwvmJxHIlLMSJtZauH5fd9UtKE3Zfbyic7qOxEQy4hdX+D8pxQW+MvxMMuIZAXVzPKMz0V3olxlw5tQLOaDe8x7j5j8uvyAf3uXAEEOGfuasWqy20pO8VyzVZlkInH3nII0+fPo4my/16ebvh+svHH1agIxvTcPt9Q== 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=BanIIEJzpCiYkyUQdKsWNp/eZgx6p5TAqP8UPbXSTJI=; b=h+WaXW9a+e0rH30DQ/pbEOlAmWReoVVlftVQhSSoR6JAI1e31yewFWsS7UzhNHrs2EmzGy9pOm2lhENGwGL6RqDTm9f17Dmynq4tP/FUIBl9bVFO5Q+XoSJpo7K/7/gz91QJUyA+BsUl5C7rCN55SM91p92IindNt/y2Q4+wt1pTuNYE/tsg2Rn+oCpYKMt7EU64qYRMl2JbBYI5Z/V2mSWsn7YE/pItFbhaoStic+h56FdNtzyDKeKG+AQO7zIWw2AX01TLa6MGmGsWcjNJRdKUGLCTmIENy4/ZXwgyKRJwxws3F+BFlSczhH30reLmIDQEg+aEtEuZm4i8g1+xwQ== Authentication-Results: mx.microsoft.com 1; dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from IA0PR12MB8374.namprd12.prod.outlook.com (2603:10b6:208:40e::7) by SJ5PPF4D350AC80.namprd12.prod.outlook.com (2603:10b6:a0f:fc02::993) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.451.18; Thu, 24 Sep 2026 19:28:17 +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 15.21.0451.014; Thu, 24 Sep 2026 19:28:16 +0000 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Thu, 24 Sep 2026 15:28:10 -0400 Message-Id: Cc: , , , , , , , , , , , , , , , , , , , , , , , To: "Lorenzo Stoakes (ARM)" , "Andrew Morton" , "Liam R. Howlett" , "Vlastimil Babka" , "Jann Horn" , "Pedro Falcato" , "David Hildenbrand" , "Mike Rapoport" , "Suren Baghdasaryan" , "Michal Hocko" , "Jonathan Corbet" , "Greg Kroah-Hartman" , "Dennis Dalessandro" , "Jason Gunthorpe" , "Leon Romanovsky" , "Paul Moore" , "Stephen Smalley" , "Jaroslav Kysela" , "Takashi Iwai" , "Alexei Starovoitov" , "Daniel Borkmann" , "Andrii Nakryiko" , "Eduard Zingerman" , "Kumar Kartikeya Dwivedi" , "Baolin Wang" , "Nico Pache" , "Ryan Roberts" , "Dev Jain" , "Barry Song" , "Lance Yang" , "Usama Arif" , "Kiryl Shutsemau" , "Doug Gilbert" , "James E.J. Bottomley" , "Martin K. Petersen" , "Jaya Kumar" , "Simona Vetter" , "Helge Deller" , "Sebastian Reichel" , "John Hubbard" , "Peter Xu" , "Masami Hiramatsu" , "Oleg Nesterov" , "Peter Zijlstra" , "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "Dave Hansen" , , "Arnaldo Carvalho de Melo" , "Namhyung Kim" , "Mark Rutland" , "Rik van Riel" , "Harry Yoo" , "Juri Lelli" , "Vincent Guittot" , "Maarten Lankhorst" , "Maxime Ripard" , "Thomas Zimmermann" , "David Airlie" , "Will Deacon" , "Aneesh Kumar K.V" , "Nick Piggin" , "Arnd Bergmann" , "Muchun Song" , "Oscar Salvador" , "Matthew Wilcox (Oracle)" , "Jan Kara" , "Marc Zyngier" , "Oliver Upton" , "Catalin Marinas" , "Madhavan Srinivasan" , "Anup Patel" , "Paul Walmsley" , "Palmer Dabbelt" , "Albert Ou" , "Christian Borntraeger" , "Janosch Frank" , "Claudio Imbrenda" , "Alexander Gordeev" , "Gerald Schaefer" , "Heiko Carstens" , "Vasily Gorbik" , "David S. Miller" , "Andreas Larsson" , "Alexander Viro" , "Christian Brauner" , "Matthew Brost" , "Joshua Hahn" , "Rakie Kim" , "Byungchul Park" , "Gregory Price" , "Ying Huang" , "Alistair Popple" , "Chris Li" , "Kairui Song" , "Kemeng Shi" , "Nhat Pham" , "Baoquan He" , "Youngjun Park" , "Johannes Weiner" , "Qi Zheng" , "Shakeel Butt" , "Axel Rasmussen" , "Yuanchu Xie" , "Wei Xu" , "Chengming Zhou" , "Michal Hocko" , "Miklos Szeredi" , "Xu Xin" From: "Zi Yan" Subject: Re: [PATCH v3 05/40] mm/vma: ensure mmap_prepare doesn't set actions on a mergeable vma X-Mailer: aerc 0.22.0 References: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@kernel.org> <20260917-b4-mmap-prepare-vma-flag-sanify-v3-5-4583d8a23bca@kernel.org> In-Reply-To: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-5-4583d8a23bca@kernel.org> X-ClientProxiedBy: YQBPR0101CA0171.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c01:f::14) To IA0PR12MB8374.namprd12.prod.outlook.com (2603:10b6:208:40e::7) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: IA0PR12MB8374:EE_|SJ5PPF4D350AC80:EE_ X-MS-Office365-Filtering-Correlation-Id: 81cafa58-af46-454b-9d3b-08df1a71fb9d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|7416014|23010399003|366016|6133799003|22082099003|18002099003|921020|56012099006|5023799004|11063799006|10067099003|4143699003; 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)(1800799024)(376014)(7416014)(23010399003)(366016)(6133799003)(22082099003)(18002099003)(921020)(56012099006)(5023799004)(11063799006)(10067099003)(4143699003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?TFJRa3hZU2JUMFpLQTd3N3EwaUFualBZakRQazRkMDNNN0ptazg1eENRZWtJ?= =?utf-8?B?T2M0dTAzUDM4a1pPbEVqaHJxU0ZYOTBjYk1mS0p4VXU1QytOMjNwcGwrMmd1?= =?utf-8?B?ZFR4R1lYSytvZFU2U2pKOE1sT2k0eHNONWhqTElQTDFyQXNRaGgyeGwyOXo0?= =?utf-8?B?cUhwWmdHdWVvOVUvUHc2TzUyZGJIejVmTHJPMm8wR2dXRDJpV0Y0SWlxSzB5?= =?utf-8?B?Vy9vVU1uU2hWOTk0MDdjSzBScW94RVVldnREY3lNcEN5RnViU2FQdUpVYTFH?= =?utf-8?B?L2xaVnhnaWt3SE5wMFFIQlRnb0lMOEp5cVVqYXJoSkNIcmNmTVhMSWM0TG8y?= =?utf-8?B?QkpGdFh6MWg2dG5hOVA0MSsxQzBSVGZXbHI4RTdCZDA2am9kKy9wVG53WUpu?= =?utf-8?B?dkU0Qk1WcUlzcUoraURKOHg1RHJnczl2SXhwK2Q3enRBTkY1b3Q5V3lac1VP?= =?utf-8?B?OFJmZktVbmc0NUt3ZEppSFY1cmM2Um9YajAyM2c0dzdSTzVybjN2Z0tadkRG?= =?utf-8?B?ZXppQndsSkRDbWpzMzhweFNQN2xXc1F4ZjBNUXJNZ1lCUjM1Z3BSdTE0TzVm?= =?utf-8?B?NGZQQTNjTWpxdkx1b0JxYlhYbHdjOHBrMGhCQndBNUlIbGNVY2plWTRCMWpW?= =?utf-8?B?VzI4R2RPdlNTQVpmWjR1U0R5NlZnVThpUTYrUitvSlBnRTBKREZjcHkvSGNr?= =?utf-8?B?UDhKV3BNWVFnWUp0SjJkZjhZaDhKSzRlUS84V3hSWHVDcHNnd3NsTXgwSUdu?= =?utf-8?B?N2FlNmVsbnZoQVN2cmplNmViQ3dJRWxGOGNaRnpYekYreUNzdnpVQmdrTWhV?= =?utf-8?B?bTdycHlZaDVjcGZ5eEpFaUJhNlUwVk8zVmRLclpQbXR4c1VBeWpXOFVBS2xy?= =?utf-8?B?cDZOcnJTT3VET3cxck9JdmRjNjUrUTdXU2gyN28rZDBnVnBpN3dhQ0R2MXlJ?= =?utf-8?B?UUhRcWhvVlFDamJhcE1JbW5CY3ZSVURDamgzSFJCL3NtU1QxSHBSa2Y1Q2Vn?= =?utf-8?B?b2FEWHF0bFFIdEMzSUdHMjZuMGREeTFncHpicXNicDV3aVJGQzA4aU9RVHho?= =?utf-8?B?dFVwVGFETnlmaWIvNFVuQUhHUU1UV3RYYjNiQ0NYSWFzUDFnbWZqdVlWR2Ro?= =?utf-8?B?bDZGakRqd0k1R0I5bDl0UDBxS3A3VHVHSkhrYzkvQkNMRVZyMGIwOUlIaUph?= =?utf-8?B?OExMVlV2bU1OM1ZaS2d2dGxDaVVQbzNRVysvK29nYXF6ZDZrczUwZzJObDFv?= =?utf-8?B?czZnMVE3QnN6NjZtdGx6T2hCZVg5UFhIOG5pWU50NWFTbHpTenhFdzJmKzhP?= =?utf-8?B?QjNYM082Rk9zRmxtd29IblBYODFVU3p1VytabzV3OWxrL04vUWV0RUlteTZl?= =?utf-8?B?d3VVcXNCN3NldHhyRzJjSGF1UktycTJaY1FUNDRXVkdiUzZGYmUwOXV5a0hF?= =?utf-8?B?REwzdHR1Y3lTbjdpK2pKdDVuc1RETnpKWmx2Tkc5a2tsbklUNFpiR3IzcmxT?= =?utf-8?B?emVKdXFMaWJpcTNLbU4wbmYrMVJiU21ab3JVZkdFL0FRb3doOFB3SjVESTdI?= =?utf-8?B?a2JuM3NEYnNDcWVvMUxiUDc0NFpzVmtrbnRYZ0s4UnN5eGRIczhrQmxqL2ll?= =?utf-8?B?enNWMGVSQzN6Y2R0bTlUR0lSaWpDYUxWWXZFNG9HRXhnejlVTGJPaElRYWs5?= =?utf-8?B?eUhnV1JpY2FNbVdXT2VzSVcyZ2Jpc3hJTDZwRmVlUURqSWFZK3ZHdFBlTzl3?= =?utf-8?B?aFFNK2xxenNOQlJ1VzJsTDlpZUkrNWJjNGlPZWdwWDlWVUNzUXYrbDllZjUr?= =?utf-8?B?K2hCSlpHMTk1bU9IT0R4MVV6OEZYL3dmL2ZhbUFxUmR2RFVEa2IrNVVmcFgx?= =?utf-8?B?WGQ1WjFmY2l1SzUwdHdCNGFOS1ZjUXNVVDgxZGZtWG42WHJhTXR0a3JtYmFr?= =?utf-8?B?eFFPd2RXdnZhei9TNkRQMi8wR2FLS1U4SGZVeTFpdmYrK2ZYVWEyYkZlWlBw?= =?utf-8?B?eUFUUEZmdXRWa241Vm0vTkhnMG9WMEg1bENyc1Nha1N5bDJRQWRzOGx1a3RG?= =?utf-8?B?bjNEZ0hUOEFzdC9LZTdrWkpUcEF3b3lqdGRhUzZnZXZuZVVHaERKc09OSXQ1?= =?utf-8?B?SjdJRzM5dG1RRlh5N0RDSGs5QkYwczF5UWs0VXhPQzNUVXhrQWQvaEMvT3lq?= =?utf-8?B?T0trck9hVkxlWndDN2FSQU1pZGFYOXBVMGVJdzBWSFo1cEhwOEJvaVNNVFVk?= =?utf-8?B?N0xjK2JKUS9tN1ZtaVJhMnR3ckFYUE43MmVZVjVTUnpXMUZLMy9veFNVWk1J?= =?utf-8?Q?mnhPx5KyssRyBx3roV?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 81cafa58-af46-454b-9d3b-08df1a71fb9d X-MS-Exchange-CrossTenant-AuthSource: IA0PR12MB8374.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Sep 2026 19:28:16.6733 (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: ZiW9MVdMq6VFSl8GT1lYphVqy9SethyWUgkCOI3oIPh50dtSXfkTKjmN2rT8UU8a X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ5PPF4D350AC80 On Thu Sep 17, 2026 at 12:22 PM EDT, Lorenzo Stoakes (ARM) wrote: > When a user requests an mmap_action be performed in mmap_prepare, this > involves populating the VMA range with data. > > However, if the VMA is mergeable, it might then mistakenly be merged with > another VMA without having populated the range. > > Every mmap action currently available sets VMA flags such that the VMA > cannot be merged. > > However, to ensure that no future mmap action falls foul of this, assert > that this is the case upon mmap_prepare validation. > > Signed-off-by: Lorenzo Stoakes (ARM) > --- > mm/vma.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/mm/vma.c b/mm/vma.c > index d6ed10cefc8f..62f2ce1ad5a1 100644 > --- a/mm/vma.c > +++ b/mm/vma.c > @@ -2809,6 +2809,15 @@ static int mmap_validate(unsigned long prev_start,= unsigned long prev_end, > int mmap_prepare_validate(const struct vm_area_desc *prev_desc, > const struct vm_area_desc *desc) > { > + /* > + * It is not valid to execute mmap actions for VMAs which can be merged= , Is it better to say "for VMAs ... after mmap_action_prepare()"? When I first read this, I wonder why the check is done after mmap_action_prepare(), which does some work based on action.type. Then, I realize mmap_action_prepare() changes desc->vma_flags and affect its mergeablitiy. > + * as any such merge would leave portions of the mapping incorrectly > + * unmapped. > + */ > + if (vma_flags_can_merge(&desc->vma_flags) && > + WARN_ON_ONCE(desc->action.type !=3D MMAP_NOTHING)) > + return -EINVAL; > + > return mmap_validate(prev_desc->start, prev_desc->end, > desc->start, desc->end, > &prev_desc->vma_flags, &desc->vma_flags); Otherwise, LGTM. Reviewed-by: Zi Yan --=20 Best Regards, Yan, Zi