IPVS: stopping backup sync thread 24399 ...
IPVS: sync thread started: state = BACKUP, mcast_ifn = sit0, syncid = 0, id = 0
INFO: task kworker/0:1:25 blocked for more than 120 seconds.
      Not tainted 4.9.92-g7cd9561 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/0:1     D26920    25      2 0x00000000
Workqueue: ipv6_addrconf addrconf_verify_work
 ffff8801d9510000 0000000000000000 ffff8801b6bd0000 ffff8801ceff0000
 ffff8801db221b98 ffff8801d951fae8 ffffffff838c49cd ffff8801d95108c0
 ffff8801ceff0000 ffff8801db221b80 00fffc0000000000 ffff8801db222468
Call Trace:
 [<ffffffff838c5fcf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3556
 [<ffffffff838c6953>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3589
 [<ffffffff838cadd6>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff838cadd6>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff82f92567>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
 [<ffffffff8345e5ae>] addrconf_verify_work+0xe/0x20 net/ipv6/addrconf.c:4363
 [<ffffffff8118ac51>] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092
 [<ffffffff8118ba46>] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226
 [<ffffffff8119ab0d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838d5a9c>] 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: [<ffffffff8118ab5e>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff8118ab5e>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff8118ab5e>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff8118ab5e>] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085
 #1:  ((addr_chk_work).work){+.+...}, at: [<ffffffff8118ab98>] process_one_work+0x728/0x1500 kernel/workqueue.c:2089
 #2:  (rtnl_mutex){+.+.+.}, at: [<ffffffff82f92567>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
2 locks held by khungtaskd/515:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813643ec>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813643ec>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81423dc0>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3652:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d582c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3748:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838d3a72>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff82008052>] n_tty_read+0x202/0x16b0 drivers/tty/n_tty.c:2133
1 lock held by syz-executor3/24397:
 #0:  (ipvs->sync_mutex){+.+.+.}, at: [<ffffffff831c02f5>] do_ip_vs_set_ctl+0x645/0xbd0 net/netfilter/ipvs/ip_vs_ctl.c:2402
2 locks held by syz-executor3/24402:
 #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff82f92567>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
 #1:  (ipvs->sync_mutex){+.+.+.}, at: [<ffffffff831c05bd>] do_ip_vs_set_ctl+0x90d/0xbd0 net/netfilter/ipvs/ip_vs_ctl.c:2397
1 lock held by ipvs-b:3:0/24399:
 #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff82f92567>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70

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

NMI backtrace for cpu 1
CPU: 1 PID: 515 Comm: khungtaskd Not tainted 4.9.92-g7cd9561 #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d93efd08 ffffffff81d9c489 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b7d90 ffff8801d93efd40
 ffffffff81da77c7 0000000000000001 0000000000000000 0000000000000002
Call Trace:
 [<ffffffff81d9c489>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d9c489>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81da77c7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81da775a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b7e94>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81364984>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81364984>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81364984>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81364984>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119ab0d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838d5a9c>] 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 skipped: idling at pc 0xffffffff838d44d6