IPVS: stopping master sync thread 7355 ...
INFO: task kworker/u4:1:22 blocked for more than 140 seconds.
      Not tainted 4.9.124-g09eb2ba #31
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:1    D27096    22      2 0x00000000
Workqueue: netns cleanup_net
 ffff8801d9aeb000 0000000000000000 ffff8801b6613480 ffff8801d9a6b000
 ffff8801db321c18 ffff8801d9bdf7a0 ffffffff839f0afd ffffffff85599a50
 ffff8801d9aeb000 000000000000363d 00ff8801d9aeb980 ffff8801db3224e8
Call Trace:
 [<ffffffff839f20ff>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff839fe511>] schedule_timeout+0x861/0xf70 kernel/time/timer.c:1768
 [<ffffffff839f52c3>] do_wait_for_common kernel/sched/completion.c:75 [inline]
 [<ffffffff839f52c3>] __wait_for_common kernel/sched/completion.c:93 [inline]
 [<ffffffff839f52c3>] wait_for_common kernel/sched/completion.c:101 [inline]
 [<ffffffff839f52c3>] wait_for_completion+0x203/0x2e0 kernel/sched/completion.c:122
 [<ffffffff811a00c6>] kthread_stop+0xa6/0x5d0 kernel/kthread.c:519
 [<ffffffff839dd80f>] stop_sync_thread.cold.10+0xcc/0x363 net/netfilter/ipvs/ip_vs_sync.c:1985
 [<ffffffff832ff61f>] ip_vs_sync_net_cleanup+0x2f/0x80 net/netfilter/ipvs/ip_vs_sync.c:2033
 [<ffffffff832cd45b>] __ip_vs_dev_cleanup+0x6b/0x80 net/netfilter/ipvs/ip_vs_core.c:2285
 [<ffffffff83060f20>] ops_exit_list.isra.6+0xb0/0x160 net/core/net_namespace.c:136
 [<ffffffff83063df1>] cleanup_net+0x321/0x630 net/core/net_namespace.c:473
 [<ffffffff8118f461>] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092
 [<ffffffff81190256>] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226
 [<ffffffff8119f3cd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff83a01b9c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373

Showing all locks held in the system:
1 lock held by kworker/dying/4:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
4 locks held by kworker/u4:1/22:
 #0:  ("%s""netns"){.+.+.+}, at: [<ffffffff8118f36e>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("%s""netns"){.+.+.+}, at: [<ffffffff8118f36e>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("%s""netns"){.+.+.+}, at: [<ffffffff8118f36e>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("%s""netns"){.+.+.+}, at: [<ffffffff8118f36e>] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085
 #1:  (net_cleanup_work){+.+.+.}, at: [<ffffffff8118f3a8>] process_one_work+0x728/0x1500 kernel/workqueue.c:2089
 #2:  (net_mutex){+.+.+.}, at: [<ffffffff83063c0f>] cleanup_net+0x13f/0x630 net/core/net_namespace.c:439
 #3:  (ipvs->sync_mutex){+.+.+.}, at: [<ffffffff832ff612>] ip_vs_sync_net_cleanup+0x22/0x80 net/netfilter/ipvs/ip_vs_sync.c:2032
2 locks held by khungtaskd/519:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813689dc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813689dc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81428248>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by rs:main Q:Reg/3680:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815dc7ec>] __fdget_pos+0xac/0xd0 fs/file.c:781
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff8157745e>] file_start_write include/linux/fs.h:2640 [inline]
 #1:  (sb_writers#3){.+.+.+}, at: [<ffffffff8157745e>] vfs_write+0x3ae/0x530 fs/read_write.c:556
2 locks held by getty/3780:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839ffba2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff82125402>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor0/3868:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor6/3876:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
2 locks held by kworker/u4:4/4126:
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085
 #1:  ((&sub_info->work)){+.+.+.}, at: [<ffffffff8118f3a8>] process_one_work+0x728/0x1500 kernel/workqueue.c:2089
2 locks held by kworker/u4:5/4214:
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085
 #1:  ((&sub_info->work)){+.+.+.}, at: [<ffffffff8118f3a8>] process_one_work+0x728/0x1500 kernel/workqueue.c:2089
2 locks held by kworker/u4:8/5809:
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085
 #1:  ((&sub_info->work)){+.+.+.}, at: [<ffffffff8118f3a8>] process_one_work+0x728/0x1500 kernel/workqueue.c:2089
1 lock held by ipvs-m:3:0/7355:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor3/7946:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
2 locks held by kworker/u4:9/9405:
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085
 #1:  ((&sub_info->work)){+.+.+.}, at: [<ffffffff8118f3a8>] process_one_work+0x728/0x1500 kernel/workqueue.c:2089
2 locks held by kworker/u4:10/9417:
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8118f36e>] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085
 #1:  ((&sub_info->work)){+.+.+.}, at: [<ffffffff8118f3a8>] process_one_work+0x728/0x1500 kernel/workqueue.c:2089
1 lock held by syz-executor1/13207:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor5/15599:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor3/16062:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
3 locks held by syz-executor3/16068:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8163530b>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1579
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff825d31af>] lo_release+0x1f/0x1a0 drivers/block/loop.c:1606
 #2:  (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<ffffffff825d3215>] __lo_release drivers/block/loop.c:1584 [inline]
 #2:  (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<ffffffff825d3215>] lo_release+0x85/0x1a0 drivers/block/loop.c:1607
1 lock held by syz-executor3/16089:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by loop3/16069:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor6/16120:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor6/16124:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor6/16133:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor6/16141:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor5/16122:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor5/16129:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor5/16137:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor5/16145:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor0/16134:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor0/16136:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor0/16139:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by modprobe/16138:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by blkid/16140:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81635b9c>] __blkdev_get+0x10c/0xd60 fs/block_dev.c:1268
1 lock held by syz-executor1/16142:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor1/16143:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor1/16146:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor1/16147:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor1/16149:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by syz-executor1/16150:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by modprobe/16144:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by modprobe/16148:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by modprobe/16151:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by modprobe/16152:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by getty/16153:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by getty/16154:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by getty/16155:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by getty/16156:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by getty/16157:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328
1 lock held by getty/16158:
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline]
 #0:  ((task_exit_notifier).rwsem){.+.+..}, at: [<ffffffff811a5138>] blocking_notifier_call_chain+0x68/0xa0 kernel/notifier.c:328

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.124-g09eb2ba #31
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8417d08 ffffffff81eb95e9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9fa0 ffff8801d8417d40
 ffffffff81ec4927 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb95e9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb95e9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ec4927>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ec48ba>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810ba0a4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81368f74>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81368f74>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81368f74>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81368f74>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119f3cd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff83a01b9c>] 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 0xffffffff83a00606