INFO: task kworker/R-ipv6_:3182 blocked for more than 147 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/R-ipv6_ state:D stack:25624 pid:3182 tgid:3182 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0xc69/0x1ca0 kernel/locking/mutex.c:776 rtnl_net_lock include/linux/rtnetlink.h:130 [inline] addrconf_dad_work+0x120/0x14f0 net/ipv6/addrconf.c:4194 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] rescuer_thread+0x8c5/0xf10 kernel/workqueue.c:3528 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 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: ffffffff8e27ef08 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_detach_from_pool kernel/workqueue.c:2730 [inline] #0: ffffffff8e27ef08 (wq_pool_attach_mutex){+.+.}-{4:4}, at: rescuer_thread+0x69f/0xf10 kernel/workqueue.c:3560 6 locks held by kworker/0:0/9: 5 locks held by kworker/0:1/10: 3 locks held by kworker/u8:0/12: 3 locks held by kworker/u8:1/13: 1 lock held by kworker/R-mm_pe/14: 3 locks held by kworker/1:0/24: 1 lock held by khungtaskd/31: #0: ffffffff8e3c94a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e3c94a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e3c94a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:2/34: 4 locks held by kworker/1:1/43: 3 locks held by kworker/u8:3/50: 4 locks held by kworker/u8:4/60: 4 locks held by kworker/0:2/89: 4 locks held by kworker/1:2/938: #0: ffff88813ff55948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc90003bb7c90 (reg_work){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffffffff901426a8 (rtnl_mutex){+.+.}-{4:4}, at: reg_todo+0x1c/0x8d0 net/wireless/reg.c:3189 #3: ffff8880279c0788 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6363 [inline] #3: ffff8880279c0788 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: reg_process_self_managed_hints+0x9e/0x1b0 net/wireless/reg.c:3179 4 locks held by kworker/u8:5/1119: #0: ffff88803399a148 ((wq_completion)wg-kex-wg0#7){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc900040dfc90 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffff888033ddd308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0xec/0x610 drivers/net/wireguard/noise.c:529 #3: ffff88807e119708 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x100/0x610 drivers/net/wireguard/noise.c:530 3 locks held by kworker/u8:6/1152: 4 locks held by kworker/u8:7/1987: #0: ffff888030c37948 ((wq_completion)wg-kex-wg2){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc900051c7c90 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffff888034fc1308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0xec/0x610 drivers/net/wireguard/noise.c:529 #3: ffff88805e0eaad8 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x100/0x610 drivers/net/wireguard/noise.c:530 3 locks held by kworker/u8:8/2012: 5 locks held by kworker/R-mld/3181: 3 locks held by kworker/R-ipv6_/3182: #0: ffff88814d4bb148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc9000bdd7c30 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffffffff901426a8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff901426a8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x120/0x14f0 net/ipv6/addrconf.c:4194 2 locks held by kworker/R-bat_e/3407: 3 locks held by kworker/u8:9/3498: 3 locks held by kworker/u8:10/3648: 3 locks held by kworker/u8:11/3696: 3 locks held by kworker/u8:12/3773: 6 locks held by kworker/u8:14/4550: 1 lock held by klogd/5189: 1 lock held by udevd/5200: 1 lock held by dhcpcd/5495: 2 locks held by crond/5573: 2 locks held by getty/5589: #0: ffff888030e6d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x1510 drivers/tty/n_tty.c:2211 1 lock held by syz-executor/5817: 4 locks held by udevd/5820: 2 locks held by kworker/1:3/5826: 2 locks held by syz-executor/5835: 2 locks held by syz-executor/5837: 4 locks held by kworker/0:3/5842: #0: ffff88805f6d0948 ((wq_completion)wg-kex-wg1#8){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc9000424fc90 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __asm__ ("" : "=r"(__ptr) : "0"((__typeof__(*((worker))) *)(( unsigned long)((worker))))); (typeof((__typeof__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffff88805ec21308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_response+0xc5/0x5f0 drivers/net/wireguard/noise.c:678 #3: ffff88807e11b4c0 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_response+0xd8/0x5f0 drivers/net/wireguard/noise.c:679 5 locks held by kworker/u9:7/5849: #0: ffff88801c771948 ((wq_completion)hci0){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc900042bfc90 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffff8880634b4ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x175/0x470 net/bluetooth/hci_sync.c:331 #3: ffff8880634b40c0 (&hdev->lock){+.+.}-{4:4}, at: hci_abort_conn_sync+0x13f/0xb20 net/bluetooth/hci_sync.c:5702 #4: ffffffff8e3d4bf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311 2 locks held by kworker/0:4/5887: 3 locks held by kworker/0:5/5894: 3 locks held by kworker/0:6/5901: #0: ffff88814dc25548 ((wq_completion)wg-kex-wg2#2){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc9000465fc90 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __asm__ ("" : "=r"(__ptr) : "0"((__typeof__(*((worker))) *)(( unsigned long)((worker))))); (typeof((__typeof__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffff88805e0eaad8 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_begin_session+0x30/0xe80 drivers/net/wireguard/noise.c:822 5 locks held by kworker/1:5/5919: 4 locks held by kworker/0:7/5922: 4 locks held by kworker/1:6/5933: 4 locks held by syz.3.8/5952: 4 locks held by kworker/1:7/5953: 4 locks held by kworker/u8:15/5954: #0: ffff88805ec81948 ((wq_completion)wg-kex-wg2#7){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232 #1: ffffc90004f1fc90 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233 #2: ffff88805ec25308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0xec/0x610 drivers/net/wireguard/noise.c:529 #3: ffff88807e11bea8 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x100/0x610 drivers/net/wireguard/noise.c:530 4 locks held by kworker/0:8/5955: 4 locks held by kworker/1:8/5956: 4 locks held by kworker/0:9/5958: 4 locks held by kworker/1:9/5959: 4 locks held by kworker/0:10/5960: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x133/0x180 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xe66/0x1180 kernel/hung_task.c:515 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 4550 Comm: kworker/u8:14 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events_unbound cfg80211_wiphy_work RIP: 0010:__rcu_read_lock+0x0/0xf0 kernel/rcu/tree_plugin.h:413 Code: 54 e5 88 90 48 89 34 24 e8 ed ae 84 00 48 8b 34 24 eb b9 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 b8 00 00 00 00 00 fc ff df 55 53 65 48 8b 1d d0 7b RSP: 0018:ffffc90000a07cf0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 1ffff92000140fa4 RCX: 0000000000000000 RDX: ffff888033d89e80 RSI: ffffffff8a4d111b RDI: 000000000000000a RBP: 000000000000000a R08: ffff88803751e3c0 R09: 0000000000000000 R10: 000000000000000a R11: ffff888033d8a9b0 R12: 0000000000000004 R13: ffff8880331d0000 R14: 0000000000000000 R15: ffffc90000a07f18 FS: 0000000000000000(0000) GS:ffff888124a01000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f17c63f0000 CR3: 000000007e1a4000 CR4: 00000000003526f0 Call Trace: rcu_read_lock include/linux/rcupdate.h:865 [inline] nf_hook+0xa0/0x7a0 include/linux/netfilter.h:242 NF_HOOK include/linux/netfilter.h:316 [inline] br_nf_post_routing+0x8bd/0x1190 net/bridge/br_netfilter_hooks.c:966 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xbe/0x200 net/netfilter/core.c:623 nf_hook+0x45e/0x780 include/linux/netfilter.h:273 NF_HOOK include/linux/netfilter.h:316 [inline] br_forward_finish+0xcd/0x130 net/bridge/br_forward.c:66 br_nf_hook_thresh+0x307/0x410 net/bridge/br_netfilter_hooks.c:1167 br_nf_forward_finish+0x66a/0xba0 net/bridge/br_netfilter_hooks.c:662 NF_HOOK include/linux/netfilter.h:318 [inline] NF_HOOK include/linux/netfilter.h:312 [inline] br_nf_forward_ip.part.0+0x609/0x810 net/bridge/br_netfilter_hooks.c:716 br_nf_forward_ip net/bridge/br_netfilter_hooks.c:676 [inline] br_nf_forward+0xf0f/0x1be0 net/bridge/br_netfilter_hooks.c:773 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xbe/0x200 net/netfilter/core.c:623 nf_hook+0x45e/0x780 include/linux/netfilter.h:273 NF_HOOK include/linux/netfilter.h:316 [inline] __br_forward+0x1be/0x5b0 net/bridge/br_forward.c:115 deliver_clone net/bridge/br_forward.c:131 [inline] maybe_deliver+0xf1/0x180 net/bridge/br_forward.c:191 br_flood+0x17c/0x650 net/bridge/br_forward.c:238 br_handle_frame_finish+0x1117/0x1f00 net/bridge/br_input.c:229 br_nf_hook_thresh+0x307/0x410 net/bridge/br_netfilter_hooks.c:1167 br_nf_pre_routing_finish_ipv6+0x76a/0xfc0 net/bridge/br_netfilter_ipv6.c:154 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x3cd/0x8c0 net/bridge/br_netfilter_ipv6.c:184 br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:508 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0xb28/0x14e0 net/bridge/br_input.c:442 __netif_receive_skb_core.constprop.0+0x6b3/0x35b0 net/core/dev.c:6024 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6135 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6250 process_backlog+0x4a2/0x1650 net/core/dev.c:6602 __napi_poll.constprop.0+0xb3/0x540 net/core/dev.c:7666 napi_poll net/core/dev.c:7729 [inline] net_rx_action+0x9f9/0xfa0 net/core/dev.c:7881 handle_softirqs+0x219/0x950 kernel/softirq.c:622 do_softirq kernel/softirq.c:523 [inline] do_softirq+0xb2/0xf0 kernel/softirq.c:510 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] cfg80211_put_bss+0x1b4/0x280 net/wireless/scan.c:3348 ieee80211_rx_bss_put net/mac80211/scan.c:37 [inline] ieee80211_rx_bss_put+0x43/0x60 net/mac80211/scan.c:32 ieee80211_rx_bss_info net/mac80211/ibss.c:1166 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1575 [inline] ieee80211_ibss_rx_queued_mgmt+0x1aa3/0x2fc0 net/mac80211/ibss.c:1602 ieee80211_iface_process_skb net/mac80211/iface.c:1736 [inline] ieee80211_iface_work+0xe28/0x1350 net/mac80211/iface.c:1790 cfg80211_wiphy_work+0x3fb/0x560 net/wireless/core.c:438 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 net_ratelimit: 15405 callbacks suppressed bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) net_ratelimit: 15616 callbacks suppressed bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:fa:f1:b0:1a:99:fd, vlan:0)