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Miller" , Eric Dumazet , Jakub Kicinski , linux-rdma@vger.kernel.org, netdev@vger.kernel.org, Paolo Abeni , Saeed Mahameed Subject: Re: [PATCH rdma-next v1 2/3] RDMA/mlx5: Handling dct common resource destruction upon firmware failure Message-ID: References: <1a064e9d1b372a73860faf053b3ac12c3315e2cd.1678973858.git.leon@kernel.org> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1a064e9d1b372a73860faf053b3ac12c3315e2cd.1678973858.git.leon@kernel.org> X-ClientProxiedBy: BLAPR03CA0117.namprd03.prod.outlook.com (2603:10b6:208:32a::32) To LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV2PR12MB5869:EE_|DM4PR12MB5214:EE_ X-MS-Office365-Filtering-Correlation-Id: 2429758f-08d1-4df2-eab5-08db2977dada 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:(13230025)(4636009)(136003)(376002)(366004)(396003)(346002)(39860400002)(451199018)(186003)(2616005)(66476007)(6916009)(36756003)(26005)(4326008)(8676002)(66946007)(4744005)(478600001)(6486002)(83380400001)(6506007)(316002)(6512007)(41300700001)(2906002)(38100700002)(54906003)(86362001)(107886003)(8936002)(5660300002)(66556008);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Gu5bKxuyQKFkt4ZwqrAI7TxtOrWVScGpMPZvbUtPtnUOKoo5vmWktxu+qqgh?= =?us-ascii?Q?mfLiiDTwW5d9v1dSHSBsCLYdEvexg01VwtVsupa24l/KXsyYPkdZcQrLcO1Z?= =?us-ascii?Q?Zm7831h7yG9dN5H7zLS8LA03lL8tgE0+doQq7cQqVW9kEEEG93kqMZo7rbJm?= =?us-ascii?Q?WWoScqQSs3iEzCkD8/KBFrPLeveukITBzAIBTW/++NPY0Kth97rr6nWa1JaT?= =?us-ascii?Q?Od+AvlS7Bj52S/vfiq/MnR9eTW9FaIp+Pn6i12kTps5owNsYvDP2NaJLQ7ir?= =?us-ascii?Q?xkecPC44OLRsSL3dxYVBq/KWXmmw/qpqNqioZUfSXRV62eKpBxKjDqoRWtRV?= =?us-ascii?Q?MDroY4rxXiW3NIFNTCVYaJ3Kgb/A+DzOnoZ8fK80m69wfoeVQsAUld6lojbi?= =?us-ascii?Q?vMXhzGd8wix9Pw/yxgmOnzP6LHHadauVNvHKqp79Vdl3ViberTDKxqEfYvDN?= =?us-ascii?Q?hMQGfoaWNDAcH9KS+xz29+o/smhXSEqhYqwt1CLabLPovZIdb+E4vKIPTH0D?= =?us-ascii?Q?QgFmMZNLXMMsPVfVuXdfX8IDDXXzeFKDipuwt7DZySXXetjVPTGWv0fIbllH?= =?us-ascii?Q?p9w2IATyRJW6e55MVpQ6dNb7t9cegVwtmqe7SeqQtSkGIZSTjdgY3wn5XyXE?= =?us-ascii?Q?W8gd6/y8MaEwsTD3xIxTyLJk4pPc86hY2MdO/npEXuMRSgl+38mUxf4GuZn8?= =?us-ascii?Q?a6yfWZ3RaW96anJDYxxUcMfZOHGP3C4cr9f6yRLOZerdt/j5JD1Dhnp/94qF?= =?us-ascii?Q?oydE9clqaW0V4Y+NdTE7h95GDbgvan+m5Z+R8xKEnRKLtK00kN+gx6UP2p7Q?= =?us-ascii?Q?9ehiJ3w08oE2X9wtvzAEng8cKsTRl3znzaGe6Wf5B6rQRc+242ENEDHjAQ3x?= =?us-ascii?Q?oAQ45uGIHqIFY7baPQSMw1g/k13IvqccbQ2ulDtiZqx7luGayMw8Je6rilRk?= =?us-ascii?Q?cQAbyW9Rsbmal/pRCorlNw6NGVXLQheJeJSmtnR/ob0BSRkeC8tiiggiLa3Q?= =?us-ascii?Q?sARH9VLzfDGKDQSjVL5Ci38dtrPJvUEFFG4qTcGJrDrvvbKDW8ooXHg/wDVu?= =?us-ascii?Q?KwTxKG1ovibnxn8P6cLRLTkuNe+SjAEM6O988l1vkBN9XixEcv2G4pRVcOdM?= =?us-ascii?Q?RbX/qe6fG+AbIMWBMBKh9d6O9XCPWx30iAUIDbWZ7J9V2K4fzaAQaC9kcZw9?= =?us-ascii?Q?OQN/2i2v19ZgyP13yR5GPAGQrli9QSavZr1yjMxLKltkXdqKPBn14EKbgubr?= =?us-ascii?Q?va8U97tNupXv3FOXfPA5ZSRBdSaCZJKlW600pwn9WoNncb0n7prladdrm5PJ?= =?us-ascii?Q?UKFGVqqIWKwKIiCRFOsRGPJOjWng737uvbT7SECaF5iErble3DrvoMzdxCoi?= =?us-ascii?Q?Nup0KahTdniUZMpLkSEUhfNss3f8x7V0M1IyObs6NjjIU7jXP0PzOGdBSVy5?= =?us-ascii?Q?MowxwIoO+xfn/J7u/N4oDhuBbg5F32CtERn7Kb289wfFU3GbiLqx/tEXklgQ?= =?us-ascii?Q?YDA874J1Eif+WNZQJ7c6LaZ4jV8DWS0JVdlX4vvSK0qwr/rRHNHtPSntKLnS?= =?us-ascii?Q?meKdh5ZRu4ngmhiQTqJY/QLLm0W4qYefGtiPIrXW?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 2429758f-08d1-4df2-eab5-08db2977dada X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Mar 2023 19:18:15.4090 (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: yw53G7IVs8k3njbVFo11T0PdBRXFY4V7y/MRXU475pUT7ZuNFiQllFEZFjOrU258 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB5214 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Mar 16, 2023 at 03:39:27PM +0200, Leon Romanovsky wrote: > From: Patrisious Haddad > > Previously when destroying a DCT, if the firmware function for the > destruction failed, the common resource would have been destroyed > either way, since it was destroyed before the firmware object. > Which leads to kernel warning "refcount_t: underflow" which indicates > possible use-after-free. > Which is triggered when we try to destroy the common resource for the > second time and execute refcount_dec_and_test(&common->refcount). > > So, currently before destroying the common resource we check its > refcount and continue with the destruction only if it isn't zero. This seems super sketchy If the destruction fails why not set the refcount back to 1? Jason