IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0
IPVS: stopping backup sync thread 10132 ...
INFO: task kworker/0:2:4387 blocked for more than 120 seconds.
      Not tainted 4.9.95-gee0bcd6 #6
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/0:2     D27592  4387      2 0x00000000
Workqueue: events_power_efficient reg_check_chans_work
 ffff8801cf43b000 0000000000000000 ffff8801b7295500 ffffffff84429800
 ffff8801db221b98 ffff8801cf657a18 ffffffff839e140d ffff8801cf43b8c8
 ffffed0039e87718 ffff8801cf43b000 00fffc0000000000 ffff8801db222468
Call Trace:
 [<ffffffff839e2a0f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839e3393>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3590
 [<ffffffff839e7816>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff839e7816>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff830af6a7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
 [<ffffffff836dba74>] reg_check_chans_work+0x74/0xd90 net/wireless/reg.c:1652
 [<ffffffff8118ae01>] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092
 [<ffffffff8118bbf6>] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226
 [<ffffffff8119ad2d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f24dc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373

Showing all locks held in the system:
3 locks held by kworker/0:1/25:
 #0:  ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff8118ad0e>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff8118ad0e>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff8118ad0e>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff8118ad0e>] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085
 #1:  ((addr_chk_work).work){+.+...}, at: [<ffffffff8118ad48>] process_one_work+0x728/0x1500 kernel/workqueue.c:2089
 #2:  (rtnl_mutex){+.+.+.}, at: [<ffffffff830af6a7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
2 locks held by khungtaskd/518:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813646bc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813646bc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81423cb0>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3778:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f04b2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff8211cb02>] n_tty_read+0x202/0x16b0 drivers/tty/n_tty.c:2133
3 locks held by kworker/0:2/4387:
 #0:  ("events_power_efficient"){.+.+.+}, at: [<ffffffff8118ad0e>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("events_power_efficient"){.+.+.+}, at: [<ffffffff8118ad0e>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("events_power_efficient"){.+.+.+}, at: [<ffffffff8118ad0e>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("events_power_efficient"){.+.+.+}, at: [<ffffffff8118ad0e>] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085
 #1:  ((reg_check_chans).work){+.+...}, at: [<ffffffff8118ad48>] process_one_work+0x728/0x1500 kernel/workqueue.c:2089
 #2:  (rtnl_mutex){+.+.+.}, at: [<ffffffff830af6a7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
1 lock held by syz-executor3/10099:
 #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff830af6a7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
2 locks held by syz-executor7/10113:
 #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff830af6a7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
 #1:  (ipvs->sync_mutex){+.+.+.}, at: [<ffffffff832dd58d>] do_ip_vs_set_ctl+0x90d/0xbd0 net/netfilter/ipvs/ip_vs_ctl.c:2397
1 lock held by syz-executor7/10129:
 #0:  (ipvs->sync_mutex){+.+.+.}, at: [<ffffffff832dd2c5>] do_ip_vs_set_ctl+0x645/0xbd0 net/netfilter/ipvs/ip_vs_ctl.c:2402
1 lock held by ipvs-b:7:0/10132:
 #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff830af6a7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 518 Comm: khungtaskd Not tainted 4.9.95-gee0bcd6 #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8417d08 ffffffff81eb0f89 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b7d60 ffff8801d8417d40
 ffffffff81ebc2b7 0000000000000000 0000000000000000 0000000000000002
Call Trace:
 [<ffffffff81eb0f89>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb0f89>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebc2b7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebc24a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b7e64>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81364c54>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81364c54>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81364c54>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81364c54>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119ad2d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f24dc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff839f0f16