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Thu, 21 Nov 2024 20:57:18 +0000 Message-ID: <32cae443-95d2-408d-9864-b4fed172291b@intel.com> Date: Thu, 21 Nov 2024 12:57:17 -0800 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net] netpoll: Use rtnl_dereference() for npinfo pointer access To: Breno Leitao , "David S. Miller" , Eric Dumazet , Jakub Kicinski , "Paolo Abeni" , Simon Horman , Michal Kubiak CC: , , , Herbert Xu References: <20241121-netpoll_rcu_herbet_fix-v1-1-457c5fee9dfd@debian.org> Content-Language: en-US From: Jacob Keller In-Reply-To: <20241121-netpoll_rcu_herbet_fix-v1-1-457c5fee9dfd@debian.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MW4PR03CA0270.namprd03.prod.outlook.com (2603:10b6:303:b4::35) To CO1PR11MB5089.namprd11.prod.outlook.com (2603:10b6:303:9b::16) 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: CO1PR11MB5089:EE_|LV8PR11MB8700:EE_ X-MS-Office365-Filtering-Correlation-Id: b9832ce4-559a-4d2c-3db8-08dd0a6f1605 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|1800799024|366016|7416014|7053199007; X-Microsoft-Antispam-Message-Info: =?utf-8?B?cWVyc3A0cEp2MDJZUXI0VEN0MGpBN2VFbW5xam5LSVBJUzIwTERkdEdxUjE3?= =?utf-8?B?b2svMGFHdTI5MERIMDJyelVEejBVU3NDRm5kSUtaSXZ6T0xLelJIb0hML3BE?= =?utf-8?B?cS8vOTNGUWtFQzBEZzlyZVZGMGtOcFJvS3Z3bVNGQVF3dThCYWxuMWtPWHRp?= =?utf-8?B?OEJpM1oxNFRXZzZ4WXpsY0VJVkh4QkU1OUxER2xPcFdjV0tQQ0szdm9rVlE2?= =?utf-8?B?ckM0UFZqdjBmYXE2ZWFxaUNrNXNTYTJ0OXZLNFQ1cTAvb0t3RHk4VnFMYU56?= =?utf-8?B?Rm8wcW52ZzZxZXQyT1FwblhIYkQ1MEpzN2QzSmFWSTVFSE81eDV1NS9jRStJ?= =?utf-8?B?Y29OdXR0ZXl1ejhKdko1a2s1YkJya0QrY2ZHK1NnU2E1amtiY0xMZHJvQk14?= =?utf-8?B?ZHBVYUptZGhQd3c4SkFkbUF1TEtRK1RxS1JiSTVXd2lJTW1ObDByMmJPWU9M?= =?utf-8?B?YTNycCtKYkxBVTlzbHZydCtQNlM3T3FjZE5ibUxaZ1l5OWl1RDJDUFBYbEhq?= =?utf-8?B?RktPNmVEMEp4R0hpaUNnaGVEbENDMFh0RWZiV0tiek9QTzh4Z1UxalNzWDJW?= =?utf-8?B?b0hTWW5FenBXZkJCR3Q0TElBUk9VdHVma2FaaFlaT3VteG5CeDBLQldYMDcw?= =?utf-8?B?Q2ZnN0RVUjVFeTJ5L1dXTUVRWWliazZJMStzSW5HOGswZUgxUzJHUFdvOXB0?= =?utf-8?B?bTEweUdOM1ppT1pzMDNpWUtLeU9QUHVaR3AyQmlqV0xrcThWZGxkb3pQUzJE?= =?utf-8?B?czAybjBUajBpMVg0ZXVjaGJrNStsME0waTNpZmtPWWJrTjQ5ZHFZeHM5UWxK?= =?utf-8?B?dUtpSXRobXcvZklRbldkV2Q0anZOWWNETzVLQzFnZjJjSWdUSXE2cDFZbnhx?= =?utf-8?B?ZTlrSjJYQk9jL3M4ZThvQTc2bklnTS9kZ1crY2ZYcHdlVTRIUGhxNU14S212?= =?utf-8?B?R1BFa3NjRURTdXlIVk81VUpOaURmN1pDcDlPNTRUUzE2ZnVxMGZsenlCN0Zi?= =?utf-8?B?Rm5qQlcxKzhjamJDSW9YYnp4Mlh6UDBNeTNSYXBZTDFpVFM4WXJteldvQU1P?= =?utf-8?B?RkZNYzR5eWladXlveEtGdnNHVWdjclF4ZzdRYWNvSDJnS0RxeHVtUlRwTTE3?= =?utf-8?B?R1loeU5NZjhSRGk4REJkNXBSTHc3dURGOGMvSVNKOUtEQW91dkc1dG1adEQ0?= =?utf-8?B?K2FkdzBOY1lMeGdKNWFIODNlaGgzdGRJNDBCVm9KRVNiSFBRbUNMK0pGU25u?= =?utf-8?B?MmJTcVYwbmllQ1NMaS9aT2d0UXpmY1ZXTUpDUE9CaW03eEJOU3BFeW9pa1Rl?= =?utf-8?B?V2o3YURvckM5RlZZZXk3NVJBMCswZXdkNEFVdVZ1TGs2ZGxnWGROT2w2NDJC?= =?utf-8?B?bFVGRzVSWVp3cU5uanJWeEdWT0tGYUsyREk3WWtHbHgrZUpJSEh5NGxVVlgw?= =?utf-8?B?UHF6M2VMM1hEcmR0S3BOWlJNQ3Q1a2dwZlVhNWo5eDRFeXdFcE9Yd01BcXE0?= =?utf-8?B?Vm9qWDN1Z2YwNks3dGwrYUtudHB5bzRERUFia3NIWGkvejJPQk0rOGt3N1h1?= =?utf-8?B?OXd1WmpGcVVhNUVJSzdaMWRac2pDZmZvMEVHQ0hXS1hjZ2dsM0FPNEVaVUd4?= =?utf-8?B?R2NjdDlJdDZnY3RFeEdhb0tsQjRINUNUaE5JaFl2R014WUJkcW5ZeDFTRGdJ?= =?utf-8?B?ZmFCVWk3dGlmaUFJclFOMHBPNE1nL0ExR3dVMGpKUXByV1ZaR2NEdGhKcmxa?= =?utf-8?Q?4GlQtXdLY232oWNULHZnjd6lWyKs5P9jISLfzFs?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CO1PR11MB5089.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(1800799024)(366016)(7416014)(7053199007);DIR:OUT;SFP:1101; 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This > change is more appropriate, as suggested by Herbert Xu. > > The function is called with the RTNL mutex held, and the pointer is > being dereferenced later, so, dereference earlier and just reuse the > pointer for the if/else. > > The replacement ensures correct pointer access while maintaining > the existing locking and RCU semantics of the netpoll subsystem. > > Fixes: c75964e40e69 ("netpoll: Use rtnl_dereference() for npinfo pointer access") > Suggested-by: Herbert Xu > Signed-off-by: Breno Leitao > --- Reviewed-by: Jacob Keller