BUG: workqueue lockup - pool[ 2006.343231] INFO: task kworker/1:3:14766 blocked for more than 140 seconds. Not tainted 4.9.172+ #50 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:3 D 28312 14766 2 0x80000000 Workqueue: events linkwatch_event ffff8801a4c48000 0000000000000000 ffff8801db721000 ffff880183680000 ffff8801db721018 ffff8801a7bb7a88 ffffffff8280081e ffff8801a4c48000 ffff8801a7bb7b60 0000000000000046 ffff8801db7218f0 1ffff10034f76f40Call Trace: [<0000000061218185>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<000000009acca018>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<00000000154e5b01>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<00000000154e5b01>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<00000000f993d7e4>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 [<000000006ff07a1e>] linkwatch_event+0xe/0x60 net/core/link_watch.c:236 [<00000000f4683350>] process_one_work+0x88b/0x1600 kernel/workqueue.c:2114 [<0000000067409541>] worker_thread+0x5df/0x11d0 kernel/workqueue.c:2251 [<0000000000e9e3b3>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000306a6fae>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Showing all locks held in the system: 3 locks held by kworker/0:1/23: #0: ("%s"("ipv6_addrconf")){.+.+..}, at: [<00000000602e08f8>] process_one_work+0x790/0x1600 kernel/workqueue.c:2107 ((addr_chk_work).work){+.+...}, at: [<0000000072da9803>] process_one_work+0x7ce/0x1600 kernel/workqueue.c:2111 (rtnl_mutex){+.+.+.}, at: [<00000000f993d7e4>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 #0: (rcu_read_lock){......}, at: [<00000000873a6d78>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] (rcu_read_lock){......}, at: [<00000000873a6d78>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 (tasklist_lock){.+.+..}, at: [<000000004bd3bb8f>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336 #0: (&f->f_pos_lock){+.+.+.}, at: [<00000000528d913b>] __fdget_pos+0xa8/0xd0 fs/file.c:782 #0: (&tty->ldisc_sem){++++++}, at: [<00000000f7fc85f0>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 (&ldata->atomic_read_lock){+.+...}, at: [<000000001be882ac>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 #0: ("events"){.+.+.+}, at: [<00000000602e08f8>] process_one_work+0x790/0x1600 kernel/workqueue.c:2107 ((linkwatch_work).work){+.+...}, at: [<0000000072da9803>] process_one_work+0x7ce/0x1600 kernel/workqueue.c:2111 (rtnl_mutex){+.+.+.}, at: [<00000000f993d7e4>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 #0: (rtnl_mutex){+.+.+.}, at: [<00000000f993d7e4>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 (rcu_preempt_state.exp_mutex){+.+...}, at: [<000000004d716e88>] exp_funnel_lock kernel/rcu/tree_exp.h:256 [inline] (rcu_preempt_state.exp_mutex){+.+...}, at: [<000000004d716e88>] _synchronize_rcu_expedited+0x339/0x850 kernel/rcu/tree_exp.h:569 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.172+ #50 ffff8801d98d7cc8 ffffffff81b4fc11 0000000000000001 0000000000000000 0000000000000001 ffffffff81097501 dffffc0000000000 ffff8801d98d7d00 ffffffff81b5aeac 0000000000000001 0000000000000000 0000000000000001Call Trace: [<00000000f1412f23>] __dump_stack lib/dump_stack.c:15 [inline] [<00000000f1412f23>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<00000000097c56c3>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<00000000f2804b05>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<00000000ff54d9d4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<00000000a2c2b9c3>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<00000000a2c2b9c3>] check_hung_task kernel/hung_task.c:126 [inline] [<00000000a2c2b9c3>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<00000000a2c2b9c3>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<0000000000e9e3b3>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000306a6fae>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.172+ #50 task: 00000000d20b47ec task.stack: 000000005f49598d RIP: 0010:[] c [<00000000ecc0e8c5>] io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:414 RSP: 0018:ffff8801db6077b0 EFLAGS: 00000002 RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: ffffffff81d6f6d1 RDI: ffffffff84b63b58 RBP: ffff8801db6077c0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: ffffffff841d23cd R12: ffffffff84b63b20 R13: 0000000000000020 R14: fffffbfff096c7ab R15: fffffbfff096c76d FS: 0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000001d60a5000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Stack: ffffffff84b63b20c 0000000000002705c ffff8801db607810c ffffffff81d71974c ffffffff841d2380c ffffffff84b63b68c ffffffff84b63d5ac ffffffff841d23b7c ffffffff84b63b20c 0000000000000072c dffffc0000000000c 0000000000000072c Call Trace: d [<000000001d89cd4d>] serial_in drivers/tty/serial/8250/8250.h:111 [inline] d [<000000001d89cd4d>] wait_for_xmitr+0x94/0x1e0 drivers/tty/serial/8250/8250_port.c:1997 [<00000000528d73ba>] serial8250_console_putchar+0x20/0x60 drivers/tty/serial/8250/8250_port.c:3103 [<000000004190531a>] uart_console_write+0x56/0xe0 drivers/tty/serial/serial_core.c:1886 [<0000000004881df7>] serial8250_console_write+0x2fb/0x860 drivers/tty/serial/8250/8250_port.c:3169 [<000000005f75aba7>] univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:594 [<000000006b399ad2>] call_console_drivers.isra.0.constprop.0+0x1ac/0x360 kernel/printk/printk.c:1594 [<00000000b50b98de>] console_unlock+0x47c/0xb20 kernel/printk/printk.c:2454 [<000000006a562750>] vprintk_emit+0x43f/0x6f0 kernel/printk/printk.c:1908 [<0000000096e137cd>] vprintk+0x28/0x30 kernel/printk/printk.c:1918 [<00000000cd51b44c>] vprintk_func kernel/printk/internal.h:36 [inline] [<00000000cd51b44c>] printk+0xc2/0xf5 kernel/printk/printk.c:1980 [<0000000018c3b6ce>] wq_watchdog_timer_fn.cold+0x11/0x66 kernel/workqueue.c:5432 [<0000000057b646f2>] call_timer_fn+0x167/0x6d0 kernel/time/timer.c:1319 [<00000000b1fc5b04>] expire_timers+0x25b/0x5c0 kernel/time/timer.c:1359 [<00000000bca8af35>] __run_timers kernel/time/timer.c:1674 [inline] [<00000000bca8af35>] run_timer_softirq+0x404/0x620 kernel/time/timer.c:1689 [<000000008c491022>] __do_softirq+0x22d/0x964 kernel/softirq.c:288 [<00000000da271845>] invoke_softirq kernel/softirq.c:368 [inline] [<00000000da271845>] irq_exit+0x119/0x160 kernel/softirq.c:409 [<00000000e6aa7d12>] exiting_irq arch/x86/include/asm/apic.h:669 [inline] [<00000000e6aa7d12>] smp_apic_timer_interrupt+0x7e/0xb0 arch/x86/kernel/apic/apic.c:962 [<00000000fc76d17b>] apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:648 d [<000000001b3ff229>] ? native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:56 [<00000000953aa6de>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:428 [<000000001b9a97cd>] default_idle_call+0x36/0x60 kernel/sched/idle.c:97 [<0000000056517ca3>] cpuidle_idle_call kernel/sched/idle.c:155 [inline] [<0000000056517ca3>] cpu_idle_loop kernel/sched/idle.c:248 [inline] [<0000000056517ca3>] cpu_startup_entry+0x283/0x3a0 kernel/sched/idle.c:303 [<000000008ce12ab3>] rest_init+0x18b/0x194 init/main.c:409 [<00000000ea961b0c>] start_kernel+0x61e/0x652 init/main.c:671 [<0000000077928769>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196 [<00000000199f3771>] x86_64_start_kernel+0x137/0x15a arch/x86/kernel/head64.c:177 Code: c24 cc9 c00 c00 c00 c49 c8d c7c c24 c38 c48 cb8 c00 c00 c00 c00 c00 cfc cff cdf c48 c89 cfa c48 cc1 cea c03 cd3 ce3 c80 c3c c02 c00 c75 c17 c41 c03 c5c c24 c38 c89 cda cec c<5b> c0f cb6 cc0 c41 c5c c5d cc3 ce8 c08 c97 c78 cff ceb cc2 ce8 c61 c97 c78 cff ceb c