INFO: task kworker/0:1:22 blocked for more than 140 seconds. Not tainted 4.14.91+ #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:1 D28656 22 2 0x80000000 Workqueue: events linkwatch_event Call Trace: schedule+0x92/0x1c0 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+0x559/0x1430 kernel/locking/mutex.c:893 linkwatch_event+0xa/0x50 net/core/link_watch.c:236 process_one_work+0x7c6/0x14e0 kernel/workqueue.c:2114 worker_thread+0x5d7/0x1080 kernel/workqueue.c:2248 kthread+0x310/0x420 kernel/kthread.c:232 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402 Showing all locks held in the system: 3 locks held by kworker/0:1/22: #0: ("events"){+.+.}, at: [] process_one_work+0x6e5/0x14e0 kernel/workqueue.c:2085 #1: ((linkwatch_work).work){+.+.}, at: [] process_one_work+0x71b/0x14e0 kernel/workqueue.c:2089 #2: (rtnl_mutex){+.+.}, at: [] linkwatch_event+0xa/0x50 net/core/link_watch.c:236 1 lock held by khungtaskd/23: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541 3 locks held by kworker/1:1/68: #0: ("%s"("ipv6_addrconf")){+.+.}, at: [] process_one_work+0x6e5/0x14e0 kernel/workqueue.c:2085 #1: ((addr_chk_work).work){+.+.}, at: [] process_one_work+0x71b/0x14e0 kernel/workqueue.c:2089 #2: (rtnl_mutex){+.+.}, at: [] addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4430 2 locks held by getty/1746: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.91+ #1 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x10e lib/dump_stack.c:53 nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff8804e402