INFO: task kworker/u8:4:60 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:4 state:D stack:22080 pid:60 tgid:60 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x14ea/0x5050 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0x164/0x360 kernel/sched/core.c:6964 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7021 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776 rtnl_net_lock include/linux/rtnetlink.h:130 [inline] addrconf_dad_work+0x11e/0x14c0 net/ipv6/addrconf.c:4194 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 INFO: task kworker/1:3:5888 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:3 state:D stack:19648 pid:5888 tgid:5888 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: events switchdev_deferred_process_work Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x14ea/0x5050 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0x164/0x360 kernel/sched/core.c:6964 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7021 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776 switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Showing all locks held in the system: 2 locks held by kthreadd/2: 1 lock held by kworker/R-kvfre/6: #0: ffffffff8e3f8c88 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2672 2 locks held by kworker/0:0/9: 4 locks held by kworker/0:1/10: #0: ffff88805843cd48 ((wq_completion)wg-kex-wg2#8){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88805843cd48 ((wq_completion)wg-kex-wg2#8){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc900000f7bc0 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc900000f7bc0 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffff888028b81308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x1a1/0x9a0 drivers/net/wireguard/noise.c:598 #3: ffff888056828338 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x58b/0x9a0 drivers/net/wireguard/noise.c:632 4 locks held by kworker/u8:1/13: 1 lock held by kworker/R-mm_pe/14: #0: ffffffff8e3f8c88 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_detach_from_pool kernel/workqueue.c:2730 [inline] #0: ffffffff8e3f8c88 (wq_pool_attach_mutex){+.+.}-{4:4}, at: rescuer_thread+0x593/0x1390 kernel/workqueue.c:3560 3 locks held by kworker/1:0/24: 1 lock held by khungtaskd/31: #0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 1 lock held by kworker/R-write/33: #0: ffffffff8e3f8c88 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2672 3 locks held by kworker/u8:3/49: 3 locks held by kworker/u8:4/60: #0: ffff88814cf2a148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88814cf2a148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc9000211fbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9000211fbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffffffff8f9ac148 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f9ac148 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x11e/0x14c0 net/ipv6/addrconf.c:4194 2 locks held by kworker/0:3/983: 2 locks held by kworker/u8:5/1106: 3 locks held by kworker/u8:6/1149: 4 locks held by kworker/u8:7/2931: 1 lock held by kworker/R-mld/3183: #0: ffffffff8e3f8c88 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_detach_from_pool kernel/workqueue.c:2730 [inline] #0: ffffffff8e3f8c88 (wq_pool_attach_mutex){+.+.}-{4:4}, at: rescuer_thread+0x593/0x1390 kernel/workqueue.c:3560 2 locks held by kworker/R-bat_e/3409: 3 locks held by kworker/u8:8/4286: 1 lock held by klogd/5184: 2 locks held by dhcpcd/5489: 1 lock held by dhcpcd/5490: 1 lock held by crond/5568: 2 locks held by getty/5584: #0: ffff88814e3e50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036c32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 1 lock held by syz-executor/5812: 1 lock held by syz-executor/5843: 5 locks held by syz-executor/5845: 1 lock held by kworker/R-wg-cr/5871: 1 lock held by kworker/R-wg-cr/5873: 3 locks held by kworker/1:3/5888: #0: ffff88813fe55948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88813fe55948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc90004c27bc0 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90004c27bc0 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffffffff8f9ac148 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104 5 locks held by kworker/0:4/5902: 4 locks held by kworker/0:5/5903: 3 locks held by kworker/1:5/5916: 3 locks held by kworker/1:6/5917: 3 locks held by kworker/0:7/5935: 3 locks held by kworker/1:7/5944: 1 lock held by kworker/R-bond3/13455: #0: ffffffff8e3f8c88 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_attach_to_pool+0x2e/0x3a0 kernel/workqueue.c:2672 4 locks held by kworker/u8:0/16060: 2 locks held by syz.1.5789/18145: 3 locks held by syz.2.5796/18158: 4 locks held by kworker/u8:2/18163: #0: ffff88802939c148 ((wq_completion)wg-kex-wg1){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88802939c148 ((wq_completion)wg-kex-wg1){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc9000214fbc0 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9000214fbc0 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffff88807a675308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x12f/0x830 drivers/net/wireguard/noise.c:529 #3: ffff888057058d20 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x140/0x830 drivers/net/wireguard/noise.c:530 2 locks held by syz-executor/18164: 4 locks held by kworker/u8:9/18165: 4 locks held by kworker/u8:10/18166: #0: ffff8880216da948 ((wq_completion)wg-kex-wg2#7){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff8880216da948 ((wq_completion)wg-kex-wg2#7){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc9001d0f7bc0 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9001d0f7bc0 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffff888028b81308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x12f/0x830 drivers/net/wireguard/noise.c:529 #3: ffff888056828338 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x140/0x830 drivers/net/wireguard/noise.c:530 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xf90/0xfe0 kernel/hung_task.c:515 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5902 Comm: kworker/0:4 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: events_power_efficient neigh_periodic_work RIP: 0010:find_match+0x6a/0xb40 net/ipv6/route.c:-1 Code: ee 03 43 0f b6 04 2e 84 c0 0f 85 d2 09 00 00 44 0f b6 2b 44 89 ee 83 e6 01 31 ff e8 00 0b 82 f7 41 83 e5 01 0f 85 82 00 00 00 <89> 6c 24 04 4c 8b 6c 24 18 4c 89 ed 48 c1 ed 03 48 b8 00 00 00 00 RSP: 0018:ffffc90000006858 EFLAGS: 00000246 RAX: ffffffff8a426f50 RBX: ffff8880561bf4df RCX: 0000000000000100 RDX: ffff88802e6f1e80 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 000000000000000d R08: ffffc90000006b60 R09: ffffc90000006b70 R10: ffffc900000069c0 R11: fffff52000000d3a R12: 0000000000000003 R13: 0000000000000000 R14: 1ffff1100ac37e9b R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8881256f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff0e65abb40 CR3: 00000000594ce000 CR4: 00000000003526f0 Call Trace: __find_rr_leaf+0x248/0x760 net/ipv6/route.c:868 find_rr_leaf net/ipv6/route.c:889 [inline] rt6_select net/ipv6/route.c:933 [inline] fib6_table_lookup+0x3b4/0xa80 net/ipv6/route.c:2244 ip6_pol_route+0x228/0x13d0 net/ipv6/route.c:2280 pol_lookup_func include/net/ip6_fib.h:617 [inline] fib6_rule_lookup+0x556/0x730 net/ipv6/fib6_rules.c:120 ip6_route_input_lookup net/ipv6/route.c:2349 [inline] ip6_route_input+0x730/0xad0 net/ipv6/route.c:2652 ip6_rcv_finish+0x141/0x2e0 net/ipv6/ip6_input.c:77 ip_sabotage_in+0x1e1/0x270 net/bridge/br_netfilter_hooks.c:990 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316 __netif_receive_skb_one_core net/core/dev.c:6152 [inline] __netif_receive_skb net/core/dev.c:6265 [inline] netif_receive_skb_internal net/core/dev.c:6351 [inline] netif_receive_skb+0x278/0xbb0 net/core/dev.c:6410 NF_HOOK+0xa4/0x3a0 include/linux/netfilter.h:319 br_handle_frame_finish+0x14b2/0x1b40 net/bridge/br_input.c:-1 br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0xa3a/0xd70 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x374/0x6f0 net/bridge/br_netfilter_ipv6.c:184 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x1277/0x1510 net/bridge/br_input.c:442 __netif_receive_skb_core+0x98f/0x30a0 net/core/dev.c:6039 __netif_receive_skb_one_core net/core/dev.c:6150 [inline] __netif_receive_skb net/core/dev.c:6265 [inline] process_backlog+0x76d/0x1950 net/core/dev.c:6617 __napi_poll+0xae/0x340 net/core/dev.c:7681 napi_poll net/core/dev.c:7744 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7896 handle_softirqs+0x22a/0x7c0 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] neigh_periodic_work+0xc28/0xe50 net/core/neighbour.c:1039 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246