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Tsirkin" , Nicolin Chen , Niklas Schnelle , Shameerali Kolothum Thodi , Yi Liu , Keqian Zhu Subject: Re: [PATCH v3 8/15] iommufd: Algorithms for PFN storage Message-ID: References: <0-v3-402a7d6459de+24b-iommufd_jgg@nvidia.com> <8-v3-402a7d6459de+24b-iommufd_jgg@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: MN2PR15CA0044.namprd15.prod.outlook.com (2603:10b6:208:237::13) To LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV2PR12MB5869:EE_|CY5PR12MB6598:EE_ X-MS-Office365-Filtering-Correlation-Id: 8321a62c-a3d8-40bd-f216-08dabe815089 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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:LV2PR12MB5869.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(4636009)(39860400002)(136003)(376002)(346002)(396003)(366004)(451199015)(54906003)(110136005)(316002)(6486002)(478600001)(5660300002)(8936002)(4744005)(7406005)(2616005)(7416002)(8676002)(36756003)(41300700001)(26005)(6512007)(186003)(4326008)(2906002)(6506007)(66556008)(66476007)(66946007)(38100700002)(86362001)(921005);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?lRHBZ0UAc+ueLS15gRUdPNPurwz45MSAR2C3KlPlVR8LLx1gc70u4ZYB/JkK?= =?us-ascii?Q?tTqVwbjlajVu3uNPuHLG9iNfqo38x5PKqBB7fVqLeEvKYdxSijsDaZ+H8xFO?= =?us-ascii?Q?Dk2QCEwRYbY49inSulOY95YEpLEkdIKrPhksBcXFau7ULrjZF3f0L4XldGQp?= =?us-ascii?Q?Y9DgvIlY7rc4joPBmj30pk1PFB/8NEmXICNztekNaFyC1VnWKJz4N0rEw8He?= =?us-ascii?Q?jcKESajXrFj7iJENXVhwPI0Tu7OuR1Y/2gi1cXWwiPpHXJ7KNAAc4MBB+1hF?= =?us-ascii?Q?Bnw29Ip2WETwIskXbUgfYEVuA+21r8feL9Q63+4Aay0BJpmoIMz5VzIzDyyr?= =?us-ascii?Q?P+UBETCJQtGQot01xUojB4bSJdG0hBNvM/yqYe1P3fAKiVjfJKZhB94hoClJ?= =?us-ascii?Q?lwWs9arCyK3cf+r+j2nyI7vWCB6NkIF82PpQHonWwIQSjMpApayqEZopTJfi?= =?us-ascii?Q?qCKm7jfLQvWysUSiS/cB7cbBbyyebbLJiFtgrX7sAxSb+cMfL4dybPKZpUNA?= =?us-ascii?Q?Mb2uijoquM+/lrpsb6nu3UkfQGn+7vwAdCUZGZxQftmRpZ81WSB/BW6Cfdy4?= =?us-ascii?Q?V3MHHJ0Umlq1GHTLwhDuyt08S7KPcHzuushrL4tst5bLSu2PnKCMxEH2k5FD?= =?us-ascii?Q?daFs/DyIaSj1aEITBfb94BN8xa86hADitfd949N5KgGKUy88N0O0b/HrMzuU?= =?us-ascii?Q?QIXhzyPskCAuCl3uhcif7Q+Aj2lqCP9eixXJJGcWCSb0VOKJZIFdEYkFBjqA?= =?us-ascii?Q?3uecjK4GwiEDlKBWmKYw96ZNyDXNTAFYPIt+rXoXbCFDCjQy17BQvBVNO/qk?= =?us-ascii?Q?lhcq8Hor8smEHrKDTVQfHuRVTRqqLINn1Z+G4QvNlaHkRZ+3oM8bLL6VGXCN?= =?us-ascii?Q?2ZUPU0b96EQReD0xbQCCT4V0qjXSq/KOK5YeqhLZ5glJE4LCRpa9s56EBzex?= =?us-ascii?Q?gSPR9iz9InCjF2AH1ji6orTELF1OrevyCCmNBBEXvKZWDEYRCx/lhvAx2riT?= =?us-ascii?Q?Vrq5E4Ha/RTKk1F9ewQrvRVkgdjMScdYYiWD+kNw94MOA6TLQ8pgvBrxzWa2?= =?us-ascii?Q?GrzEfTM6xJK1jv+NOtjUfTtKtnYuwNBrbGmr+SCUqyGSiUPLVVs6m+H+AVX0?= =?us-ascii?Q?XqIYSxPkhglLq+6zrIt/S/6xG8SluUYIkdQmR31Zahd/S7GnLs6OdhsMi7gP?= =?us-ascii?Q?CHsiHVdD4EjUf/4K18D4YqtO6G+qG8wwyyG5Bk6ETbih2RoNGuN0/Thj+phw?= =?us-ascii?Q?7qFyFaVlQA/s6ii9MfJZbm5bYOdmvSKtVNF/e0NxgrGrIZN8ML0kinGfZUFi?= =?us-ascii?Q?8Ks+I9MQlq49pi1cTIN+HmAFAE0t+SA1lT8POslyjcsr3D20cEq26+6m+W1W?= =?us-ascii?Q?pOTbNCT/xV1Uy2e4/ikJQAFx+DpF1PEWxXzfN4AXFRp+1dg2/IdX1gShFEDc?= =?us-ascii?Q?NSoNHqTc00fVXcXWS0cmlwSERawbQTsU1QOp2axwFCgka4lqtHe4ydFpcHqO?= =?us-ascii?Q?YcY/GOcl8ChzQbNfI0k6KqqHN9wXLfhj9v+cBki9n2JxcqHwiqeMTaN/1qLg?= =?us-ascii?Q?LcJsv3SKXdIxi0dIXs8=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8321a62c-a3d8-40bd-f216-08dabe815089 X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Nov 2022 16:26:23.9966 (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: Q1glTGEXH7f8IvZpWPhKisjTIPfIU+D1LjTgas5QSGiFWgEkEYEmUJzhSmDkMgwo X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY5PR12MB6598 Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Thu, Nov 03, 2022 at 05:08:08PM -0300, Jason Gunthorpe wrote: > +static void pfn_reader_release_pins(struct pfn_reader *pfns) > { > struct iopt_pages *pages = pfns->pages; > > @@ -1005,12 +1013,20 @@ static void pfn_reader_destroy(struct pfn_reader *pfns) > unpin_user_pages(pfns->user.upages + (pfns->batch_end_index - > pfns->user.upages_start), > npages); > + iopt_pages_sub_npinned(pages, npages); > + pfns->user.upages_end = pfns->batch_end_index; > } Syzkaller says the hidden if above is no good on error paths where the pfn_reader has already advanced - it makes npages go negative: - if (pfns->user.upages) { + if (pfns->user.upages_end > pfns->batch_end_index) { Jason