INFO: task kworker/u4:2:31 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:2 state:D stack:23976 pid:31 tgid:31 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 rtnl_net_lock include/linux/rtnetlink.h:130 [inline] addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4194 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 2 locks held by kworker/0:0/9: 2 locks held by kworker/u4:0/12: 3 locks held by kworker/u4:1/13: 1 lock held by khungtaskd/26: #0: ffffffff8e33a0e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e33a0e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e33a0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u4:2/31: #0: ffff88803f040948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88803f040948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90000527bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90000527bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4194 4 locks held by kworker/u5:0/45: #0: ffff8880366c1948 ((wq_completion)hci15#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff8880366c1948 ((wq_completion)hci15#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90000607bc0 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90000607bc0 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff888050de80b8 (&hdev->lock){+.+.}-{4:4}, at: hci_remote_features_evt+0x9b/0x8e0 net/bluetooth/hci_event.c:3684 #3: ffffffff8f8a1028 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_connect_cfm include/net/bluetooth/hci_core.h:2079 [inline] #3: ffffffff8f8a1028 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_remote_features_evt+0x516/0x8e0 net/bluetooth/hci_event.c:3718 4 locks held by kworker/u4:4/53: 1 lock held by hwrng/755: 3 locks held by kworker/u4:5/965: 3 locks held by kworker/u4:6/1038: 2 locks held by kworker/u4:7/1041: #0: ffff88801a879148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88801a879148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000259fbc0 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000259fbc0 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 2 locks held by kworker/u4:8/1043: #0: ffff88801a879148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88801a879148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc900025cfbc0 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc900025cfbc0 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 4 locks held by kworker/u4:10/3062: #0: ffff888011b94948 ((wq_completion)wg-kex-wg1){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff888011b94948 ((wq_completion)wg-kex-wg1){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000d9cfbc0 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000d9cfbc0 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff88805607d308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x10a/0x7e0 drivers/net/wireguard/noise.c:529 #3: ffff888054211708 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x11b/0x7e0 drivers/net/wireguard/noise.c:530 2 locks held by getty/5142: #0: ffff88803bb150a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000018e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 3 locks held by kworker/u5:2/5418: #0: ffff888050066148 ((wq_completion)hci1){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff888050066148 ((wq_completion)hci1){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000d517bc0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000d517bc0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff88801efa4dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1d4/0x3a0 net/bluetooth/hci_sync.c:331 5 locks held by kworker/0:4/5444: 2 locks held by syz-executor/5507: 1 lock held by syz-executor/5512: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3433 1 lock held by syz-executor/5522: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3433 1 lock held by syz-executor/5524: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3433 1 lock held by syz-executor/5527: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3433 4 locks held by kworker/0:5/5671: 3 locks held by kworker/0:6/5683: #0: ffff88801a8d4148 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88801a8d4148 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000cf2fbc0 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000cf2fbc0 ((reg_check_chans).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: reg_check_chans_work+0x95/0xf30 net/wireless/reg.c:2483 2 locks held by kworker/0:7/5708: 2 locks held by kworker/0:8/5709: 4 locks held by kworker/u4:11/5767: 3 locks held by kworker/u4:12/5768: #0: ffff88801a879148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88801a879148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000cd7fbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000cd7fbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 3 locks held by kworker/u4:13/5770: 4 locks held by kworker/u4:14/5772: 4 locks held by kworker/u4:15/5773: 3 locks held by kworker/u4:16/5774: 4 locks held by kworker/u4:17/5776: 3 locks held by kworker/0:10/5777: 2 locks held by kworker/0:11/5778: 1 lock held by syz.0.33/5780: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3433 2 locks held by kworker/0:12/5782: 5 locks held by kworker/0:13/5783: 3 locks held by kworker/0:14/5784: 1 lock held by syz-executor/5790: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/5793: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 4 locks held by kworker/0:17/5803: 1 lock held by syz-executor/5805: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 3 locks held by kworker/u4:18/5810: 2 locks held by kworker/0:19/5813: 1 lock held by syz-executor/5818: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/5821: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/5824: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/5838: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/5846: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/5861: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/5862: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/5866: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 5 locks held by kworker/u5:4/5867: #0: ffff8880348d7148 ((wq_completion)hci3){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff8880348d7148 ((wq_completion)hci3){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000d527bc0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000d527bc0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff888033764dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1d4/0x3a0 net/bluetooth/hci_sync.c:331 #3: ffff8880337640b8 (&hdev->lock){+.+.}-{4:4}, at: hci_abort_conn_sync+0x242/0xe30 net/bluetooth/hci_sync.c:5670 #4: ffffffff8e33fb78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #4: ffffffff8e33fb78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:957 3 locks held by kworker/u4:19/5878: 3 locks held by kworker/u4:20/5879: 1 lock held by syz-executor/5881: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/5891: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/5896: #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f73c0c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 3 locks held by modprobe/5917: 1 lock held by modprobe/5918: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 26 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf93/0xfe0 kernel/hung_task.c:491 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245