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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Ido Schimmel , Jiri Pirko , Yifan Wu , Juefei Pu , Yuan Tan , Xin Liu , Haoze Xie Subject: Re: [PATCH net v2 1/1] net: l3mdev: Ignore non-L3 uppers in l3mdev_fib_table_rcu Message-ID: <20260407080259.GA760990@shredder> References: <429dd4a81d4ca5624ab9f6d7b53c5fe08552c734.1775443332.git.royenheart@gmail.com> <20260406154808.GA714138@shredder> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: TL2P290CA0015.ISRP290.PROD.OUTLOOK.COM (2603:1096:950:2::18) To SA3PR12MB7901.namprd12.prod.outlook.com (2603:10b6:806:306::12) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SA3PR12MB7901:EE_|IA1PR12MB6306:EE_ X-MS-Office365-Filtering-Correlation-Id: 67b18e11-4ebc-4b1f-eab3-08de947c1c8a X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|366016|18002099003|22082099003|56012099003; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?zT0DirLQZ7pEEciyjSIFdcdqf2vZwE879RSm8j8fS4EHf6XtWDSIdK46glXm?= =?us-ascii?Q?L241yN65fieA7RGDkRyJ1ogjjKErSD0HedLjJJHq6DVUrzeyJSdBTqDhas7w?= =?us-ascii?Q?SWUmXlJDSxlJzXYO24sQF4uEmcDwSlPtehCrJ6y7vf5I+uDIhkypbyiLG4h9?= =?us-ascii?Q?G8+efdSH5ssJp4GP6aWk90HM/Nm1fC9MFPRz0wyiRIgn13PFWCsm95VN5WZt?= =?us-ascii?Q?RafsCp26zK09C1YGBL0RePQyBuq7VthN3e59pI51sYe0rptWxYWlReEW+afJ?= =?us-ascii?Q?rmkT+5MM704cUqmVNSl9lifkWN0fwG0MWGSEb42ld/Cd/+NzhzHokYRpIlvH?= =?us-ascii?Q?l/mTn8JMU5BVDR+WaWc2DsFXpNfvpsTRNxAWwUUbAN5wyOxZ+Z3ZsPhiPLuG?= =?us-ascii?Q?uDbVJCLMYHUcikWTHZLHU7joWYGdM4XBz1IJSY4BFJn3sPIZxM2hGE5Joj0a?= =?us-ascii?Q?ha8e476O7JX06iMoJdJeLstb1jTMak1C7v/Q13nPnoMN1i+d+bO2I+CTbiUX?= =?us-ascii?Q?Pbuu8fjBgF92Dlp8Usqcvfb79s3suU096hZ2hzTYjCkK5seevX6a32Rn2Crj?= =?us-ascii?Q?ZLLltRCajoXB3JB0cTloI3/hzPzi3OUzq9v+tDRCq4WIx7GBmW2GyFsVJLoJ?= =?us-ascii?Q?BaXQUbX7s6Q/jcI+SfZ2VaBn2O9b2IOItTbujLPNOC5HhxjQMRN231UlSVxh?= =?us-ascii?Q?XOH15PwvVd73emtvAwIQL2bliSYKWsuuVurSIidIQMWVYfbdji1KCUaQ7pbC?= =?us-ascii?Q?B5XseoyYeWzb0XCu671NouOfy5Iojt6Ph1BC06re+kvMpbyi84N6bzUoCdoo?= =?us-ascii?Q?/LgeJFmaSb3gTGucKvUeN4Q6aIjLk+gwSEyDcnFhxz77tqW8WIzfzOPHHj27?= =?us-ascii?Q?Eq7vJgRfNVlUuWVjc2j2xxP+YxU5bNlZmsEHRWo+6e0CJrz1dYrLs7mkbA5W?= =?us-ascii?Q?JSbn94jsjw6E3iqmMAmwtgq713hKDt2BQIydttCgWXY2ajTrFMzMkOqPfu1E?= =?us-ascii?Q?ztlKEvEqQIpXcf3ivePmHcgljGwEl06T8kmeI21ZrYN9AlgLcHx+Kzwkr1+z?= =?us-ascii?Q?OteWve82eo4e1ZqWtalNnxGqYnGWDaz6vuWdEWdV001bgmtZVmWukL8UjxtX?= =?us-ascii?Q?EFX2JW4VPL/LBLdV19Po1GsAFlVSIefIkaZZej2AXVuDnxqMnOAtVdFozv+8?= =?us-ascii?Q?iKKT6tnxeAcnBgUUid9ug/86bplNRUF1ZOKfPTJrk/PekF/iY1ROghFXQ7Ty?= =?us-ascii?Q?iCHfAEBXupG5eGAV3A9sitOFIf9x9pINvHP5zcyCPx+k1OTT5p+1LQxjVmjq?= =?us-ascii?Q?Akv2T4WK+JoffUI5Bl5xhzpnJy7XZUScDwRoCSlu0siBwtBA2iZklYEgVwqi?= =?us-ascii?Q?rxcf9rFg10j1WnIMsOLZdKh+hHQMvNAxpa5cvQ5loztLRTng4U69bDhYZp1A?= =?us-ascii?Q?loLcxiTmWjHoyoALzGDhZGI8U5eCksgjuSLbVEvbh+gtxD0H8VMmrAtLI0e6?= =?us-ascii?Q?1k1tV2/njkEuS+8nUMpvsvGwAzRQu2dbrEmarBVs4CXlL2Uf2h9IFCLtNF+s?= =?us-ascii?Q?NC+kPU1qr5hpF1lheBViftlyqvWN17mKfvLJTnA0w4KR7tWI5328rTle6nSZ?= =?us-ascii?Q?/gEIzmM0HRg4o6o/Abz9wmyr95SdIzK2JWkpcpCPMYgw67zJKJ1WW0hMzo7y?= =?us-ascii?Q?RFFAy+tMEpi9FYmXYeMcTDQqM1jGVi1vYNSvj2j8bw+AfJA0jRaR5ne7auUv?= =?us-ascii?Q?mMSeJQOkIQ=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 67b18e11-4ebc-4b1f-eab3-08de947c1c8a X-MS-Exchange-CrossTenant-AuthSource: SA3PR12MB7901.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Apr 2026 08:03:11.1476 (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: JQ2j95AVMbVef6Pd+S69tHY5DxFZspjkrjEEnOngZYP2DzuGUcD8MeFIKYYmhVmGhLAnGocS1Pnvij1Ut622HA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB6306 On Mon, Apr 06, 2026 at 12:14:15PM -0600, David Ahern wrote: > On 4/6/26 9:48 AM, Ido Schimmel wrote: > > > > Don't we have the same problem in l3mdev_l3_rcv() and l3mdev_l3_out()? > > If so, please check if I missed more places and include them in v3. > > > > And I think that the part that I was missing earlier is that we don't > > have RCU synchronization in the unslaving path, so an RCU reader can > > either see the original master, NULL or a new master (e.g., bridge > > instead of the original VRF master). > > synchronize_rcu after the unlink (control path) seems like a better, > more robust option than adding more checks to the datapath. IMO it would be better to proceed with the original approach and look into adding RCU synchronization in net-next. The original approach is more surgical and the pattern of first checking netif_is_l3_master() already exists in other places.