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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?4+ct+UhD/cN63eHaO778dLEH3NTxKXsXP18ALIzxJg0DTSMd0ffaK14Ndpag?= =?us-ascii?Q?/+43FpnuZXdaDXoUnaI4rG1blD4TbG7y7fjmdMqcZYE+xS0uSrA/i23mHMBd?= =?us-ascii?Q?fNTtjDCNX3bs1JtlJY5WGFtr1Wv+XR6eP/evonvLvGRfp1a9UMHel1/F1SUh?= =?us-ascii?Q?6uQM61GjKLkEQMEmqovXwA28frz98mhW8cNd8H6dgZRmshkMg23xpo+JyiuO?= =?us-ascii?Q?zvc+/nn8H0rNII1AqEueOPaquyZD37nthJl3C1rpY294SaUdfg85xwaM0Auy?= =?us-ascii?Q?eRplXtYHQZYVU2dcsiHujOXWCVeskftgIskZQX1b2wNsU/6g7NkncJ3CSsfZ?= =?us-ascii?Q?fNPdaQVeLkf0tWhfhNR1HvI3vu7g/ej4vl4HHYddcPrTlcPDA+lMrpA4XIyr?= =?us-ascii?Q?IpEMH6OiU6ckfPfl+u9amOuzZyzPXN+7hMsExs6uhRSKFHPxd6664ecQUF/R?= =?us-ascii?Q?tZVoBol3S0sTZ+rNhuWMPqCAsBsu9z1qR01ahNKYFouXS7CgkQuNE4Z49nyg?= =?us-ascii?Q?CV2XE+jQLe+C6tj9KBWKEojqvvtMt5j/Pvt7KxUzIA0osvJjbuBhnhBgXAz5?= =?us-ascii?Q?jguxClbvDP3awn8FnSOnGighiozxv1XB75KapfHo7pw3bRJYwtOj5RiRRzeU?= =?us-ascii?Q?SnB+8MGziyDw6wRRbrNa7/aEuD/pxATOGGY9Du5GfAp0y7yS2c4X/Gg+uZ7r?= =?us-ascii?Q?71F7veQIJhyG2J1HC225/z62vHot9Op3wjrYTrRVd2D2ag/xhuN3E7iDHbUT?= =?us-ascii?Q?59l0j/P9N3FJInSBbxnhcV8+DQZXv/Axwbe810+ircgha4aZCmnR+6WThKdW?= =?us-ascii?Q?Uyjbd8UH4tJvq2oRyRX0+gXwMm5VIVUN+p4zif5hCjQ+z6Z0mzA/hAhni+E7?= =?us-ascii?Q?SSg+Ttv5rA8KbvzpxuqcwSpAxXVGFmvn2Alb6Ig1xdL/lvKT3K0UvF56np5P?= =?us-ascii?Q?XvTqwmLN7fSS8ERGFwdO0/N8Djm+nH8AyOJBPLCDRDUoVEPXWbD6Qy3LiOLt?= =?us-ascii?Q?kQ+w4vwMinGHtDd2C+hY2R/cP1PolkDnToBfMW+uS+NLaisHErplYQN/ecLA?= =?us-ascii?Q?J2dTY9N+yJnPlcIa4BAi486o/0oUA365/rXnb31uT9mz5lWAAZY2clI/n6TN?= =?us-ascii?Q?HaKNrekVWjVBzWB5UjXyO6umnbrUfIZvNRemLl3P4Z5k3kVynBSIgwb7mI7U?= =?us-ascii?Q?uOQLxKYNt9FO+oUiiCjG4rrb4Kt3WjlZ6Mj2p8ghqRFlfQdhSFSOSZTDU+L/?= =?us-ascii?Q?tgjvkIgkEgBB1Hz5cvRAodNDsc9kKk0OqeuNj3mx/0tRKHmg+6wv5LxlWloz?= =?us-ascii?Q?tXv1OdJulOf7cIdRVPgglYX0pfSKG7KwHmVTLSN0Ba1VwvNNzEfuEat3axes?= =?us-ascii?Q?pSAYqmtMPaQ9Uu3ejfyxJ1vT8Qo0hMZPceQ+WfiqU/GrD+izHeqsrZzTqQx2?= =?us-ascii?Q?c9fln83b5ES9MaPEGGhLagzjvv1aBNrabQ38MizQeVnkRttSeh0NZxHCenk+?= =?us-ascii?Q?kiqwmRUiHYfWgu16xJWQXsWciGo234+xC0+SYveNK13nU37iVbvoSXHvbDGU?= =?us-ascii?Q?x1YoQoJdQ/h6XafmAUlvyRq1aQs+pIpfCHZB2jlC+K6uT8Kz/T3sL/AQeTrO?= =?us-ascii?Q?NoZtOKRmSCR3+FhTr1p0DAP9WV2CzbYijt+etzHn5bN5bvKif4QqtFQ7T+0a?= =?us-ascii?Q?No3EjKFw9n+6If5ESpLBdh7274icZbt6HQCBX0GTHWH7TmoXdZSl/iBIoGWt?= =?us-ascii?Q?XUdnUgFQxw=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 35fec646-6fa7-4786-d444-08df2ac91c40 X-MS-Exchange-CrossTenant-AuthSource: PH0PR12MB7957.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Oct 2026 14:32:16.2667 (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: AD2U0V0QU+l70JqzHPipLUHWE7N+dhMVNt8gZM1AWB7VmFPE741JfKelj3CuoVYj7ci4r2aDnh39fdqmAFgWMA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR12MB6885 On Thu, Oct 15, 2026 at 02:06:49PM +0900, Daehyeon Ko wrote: > ipv6_add_addr() checks idev state before allocating an ifaddr, but > publishes the object later. addrconf_ifdown() can mark and detach the > idev between the check and publication. > > This happens when a non-loopback device MTU falls below IPV6_MIN_MTU. A > forced interleaving published an address on a dead idev, and > ipv6_get_ifaddr() still returned it after teardown. Later device deletion > remained blocked with: > > unregister_netdevice: waiting for ac0 to become free. Usage count = 3 > > Protect the dead indication with idev->lock and keep that lock across > both hash and device-list publication. Recheck dead before publishing; > if teardown wins the lock, reject the unpublished object. > > Non-unregister teardown does not set dead. The preceding change covers an > add that misses the initial hash scan but reaches the per-device list > snapshot. Both changes are required when backporting this fix. > > Fixes: 8814c4b53381 ("[IPV6] ADDRCONF: Convert addrconf_lock to RCU.") > Cc: stable@vger.kernel.org > Link: https://lore.kernel.org/r/179161099408.434549.14449036924552933828@kernel.org > Link: https://lore.kernel.org/r/20261012145306.GB779501@shredder > Suggested-by: Ido Schimmel > Assisted-by: LLM > Signed-off-by: Daehyeon Ko <4ncienth@gmail.com> Reviewed-by: Ido Schimmel