INFO: task kworker/1:1:68 blocked for more than 140 seconds. Not tainted 4.14.89+ #26 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:1 D26560 68 2 0x80000000 Workqueue: ipv6_addrconf addrconf_verify_work Call Trace: schedule+0x7f/0x1b0 kernel/sched/core.c:3490 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893 addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4430 process_one_work+0x86e/0x1670 kernel/workqueue.c:2114 worker_thread+0xdc/0x1000 kernel/workqueue.c:2248 kthread+0x348/0x420 kernel/kthread.c:232 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402 Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x74/0x20f kernel/locking/lockdep.c:4541 3 locks held by kworker/1:1/68: #0: ("%s"("ipv6_addrconf")){+.+.}, at: [] process_one_work+0x784/0x1670 kernel/workqueue.c:2085 #1: ((addr_chk_work).work){+.+.}, at: [] process_one_work+0x7bc/0x1670 kernel/workqueue.c:2089 #2: (rtnl_mutex){+.+.}, at: [] addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4430 2 locks held by getty/1758: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1ff/0x1700 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.89+ #26 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x11b lib/dump_stack.c:53 nmi_cpu_backtrace.cold.0+0x47/0x85 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x121/0x146 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline] watchdog+0x574/0xa70 kernel/hung_task.c:252 kthread+0x348/0x420 kernel/kthread.c:232 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffffa8a6a5c2