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Howlett" , "Vlastimil Babka" , "Mike Rapoport" , "Suren Baghdasaryan" , "Michal Hocko" , "Kees Cook" , "Peter Zijlstra" , "Jann Horn" , "Pedro Falcato" , "Hugh Dickins" , "Pasha Tatashin" , "Pratyush Yadav" , "Matthew Wilcox (Oracle)" , "Jan Kara" , "Lance Yang" , "Rik van Riel" , "Harry Yoo" , "Alistair Popple" , "Nico Pache" , "Ryan Roberts" , "Dev Jain" , "Usama Arif" , "Kiryl Shutsemau" , "Matthew Brost" , "John Hubbard" , "Peter Xu" , "Will Deacon" , "Aneesh Kumar K.V" , "Nick Piggin" , "Oscar Salvador" , "Minchan Kim" , "Muchun Song" , "Xu Xin" , "Chengming Zhou" , "Chris Li" , "Kemeng Shi" , "Nhat Pham" , "Youngjun Park" , "Gregory Price" , "Joshua Hahn" , "Rakie Kim" , "Ying Huang" , "Jason Gunthorpe" From: "Zi Yan" Subject: Re: [PATCH 11/46] mm/huge_memory: properly handle refcounted PUD mappings on fork X-Mailer: aerc 0.22.0 References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-11-6f74bec9a5bb@kernel.org> In-Reply-To: <20261027-fixes_core-v1-11-6f74bec9a5bb@kernel.org> X-ClientProxiedBy: YQBPR01CA0147.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c01:7e::8) To IA0PR12MB8374.namprd12.prod.outlook.com (2603:10b6:208:40e::7) X-Archived-By: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: IA0PR12MB8374:EE_|IA4PR12MB243497:EE_ X-MS-Office365-Filtering-Correlation-Id: 364b219a-63e7-4001-5411-08df346ebed6 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|23010399003|1800799024|376014|7416014|366016|921020|261026121527099003|4143699003|56012099006|11063799006|261009223027099003|261021123027099003|261022105027099003|261021121427099003|18002099003|22082099003|10067099003|261026140227099003; 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Any remainin= g > huge PUDs are then copied without accounting for the new mappings. > Unmapping them in the child decrements accounting that was never added. > > Use vm_normal_page_pud() to identify refcounted mappings. Take a folio > reference and add the child's PUD rmap and RSS accounting before installi= ng > the copied entry. Pass src and dst VMAs consistently instead of src and > dst MM. Move the TODO. > > Fixes: aed877c2b4257 ("device/dax: properly refcount device dax pages whe= n mapping") > Cc: stable@vger.kernel.org > Signed-off-by: David Hildenbrand (Arm) > --- > include/linux/huge_mm.h | 5 ++--- > mm/huge_memory.c | 27 +++++++++++++++++++-------- > mm/memory.c | 4 +--- > 3 files changed, 22 insertions(+), 14 deletions(-) > Reviewed-by: Zi Yan --=20 Best Regards, Yan, Zi