IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0
IPVS: stopping backup sync thread 10811 ...
INFO: task kworker/0:5:8946 blocked for more than 120 seconds.
      Not tainted 4.9.94-g8683408 #3
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/0:5     D28400  8946      2 0x00000000
Workqueue: events_power_efficient reg_check_chans_work
 ffff8801d3ece000 0000000000000000 ffff8801b76e3480 ffff8801d3c44800
 ffff8801db221b98 ffff8801a06afa18 ffffffff838c040d ffff8801d3ece8c8
 ffff8801d3c44800 ffff8801db221b80 00fffc0000000000 ffff8801db222468
Call Trace:
 [<ffffffff838c1a0f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff838c2393>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3590
 [<ffffffff838c6816>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff838c6816>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff82f8e6a7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
 [<ffffffff835baa74>] 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
 [<ffffffff838d14dc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373

Showing all locks held in the system:
2 locks held by khungtaskd/515:
 #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: [<ffffffff81423bb0>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
3 locks held by kworker/1:3/1807:
 #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: [<ffffffff82f8e6a7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
1 lock held by rsyslogd/3648:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d565c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3744:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838cf4b2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff82007082>] n_tty_read+0x202/0x16b0 drivers/tty/n_tty.c:2133
3 locks held by kworker/0:5/8946:
 #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: [<ffffffff82f8e6a7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
1 lock held by syz-executor7/10799:
 #0:  (ipvs->sync_mutex){+.+.+.}, at: [<ffffffff831bc2c5>] do_ip_vs_set_ctl+0x645/0xbd0 net/netfilter/ipvs/ip_vs_ctl.c:2402
2 locks held by syz-executor7/10810:
 #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff82f8e6a7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
 #1:  (ipvs->sync_mutex){+.+.+.}, at: [<ffffffff831bc58d>] do_ip_vs_set_ctl+0x90d/0xbd0 net/netfilter/ipvs/ip_vs_ctl.c:2397
1 lock held by ipvs-b:7:0/10811:
 #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff82f8e6a7>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70

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

NMI backtrace for cpu 0
CPU: 0 PID: 515 Comm: khungtaskd Not tainted 4.9.94-g8683408 #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8647d08 ffffffff81d9b509 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b7d60 ffff8801d8647d40
 ffffffff81da6837 0000000000000000 0000000000000000 0000000000000002
Call Trace:
 [<ffffffff81d9b509>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d9b509>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81da6837>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81da67ca>] 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
 [<ffffffff838d14dc>] 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
CPU: 1 PID: 3646 Comm: rs:main Q:Reg Not tainted 4.9.94-g8683408 #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801ba63b000 task.stack: ffff8801c4c68000
RIP: 0010:[<ffffffff8135c9d0>] 
c [<ffffffff8135c9d0>] __sanitizer_cov_trace_pc+0x0/0x50
RSP: 0018:ffff8801c4c6f3a8  EFLAGS: 00000246
RAX: ffff8801ba63b000 RBX: 0000000000000015 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff817ea9dc RDI: 0000000000000246
RBP: ffff8801c4c6f5f0 R08: ffff8801ba63b9b0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000014
R13: ffff8801999e803c R14: 0000000000000001 R15: dffffc0000000000
FS:  00007f0ee4ca2700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fde3c95e000 CR3: 00000001ce1f2000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff817ebeaf
c ffff8801c4c6f3f0
c ffffffff8122e3c2
c ffff8801ba63b8c0
c
 0000000000000246
c fffffbfff09459a8
c 1ffff1003898de95
c ffffffff81831da4
c
 fffffbfff09459b5
c ffff8801b6e8b060
c 0000000000000001
c ffff8801ce0e4400
c
Call Trace:
 [<ffffffff817f4645>] ext4_ext_truncate+0x185/0x280 fs/ext4/extents.c:4658
 [<ffffffff81749b75>] ext4_truncate+0xa15/0x12c0 fs/ext4/inode.c:4260
 [<ffffffff8174bd0b>] ext4_truncate_failed_write fs/ext4/truncate.h:15 [inline]
 [<ffffffff8174bd0b>] ext4_da_write_begin+0x4eb/0x1020 fs/ext4/inode.c:3015
 [<ffffffff81433b81>] generic_perform_write+0x301/0x510 mm/filemap.c:2741
 [<ffffffff8143b602>] __generic_file_write_iter+0x352/0x540 mm/filemap.c:2866
 [<ffffffff81721f63>] ext4_file_write_iter+0x463/0xd90 fs/ext4/file.c:165
 [<ffffffff8156c3a0>] new_sync_write fs/read_write.c:496 [inline]
 [<ffffffff8156c3a0>] __vfs_write+0x3e0/0x580 fs/read_write.c:509
 [<ffffffff81570197>] vfs_write+0x187/0x530 fs/read_write.c:557
 [<ffffffff81573fc9>] SYSC_write fs/read_write.c:604 [inline]
 [<ffffffff81573fc9>] SyS_write+0xd9/0x1c0 fs/read_write.c:596
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff838d1313>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
c1d 
c00 
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c89 
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cca 
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c48 
c89 
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c00 
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cff 
cff 
c66 
c2e 
c0f 
c1f 
c84 
c00 
c00 
c00 
c00 
c00 
c0f 
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c00 
c<55> 
c48 
c89 
ce5 
c65 
c48 
c8b 
c04 
c25 
c40 
c7d 
c01 
c00 
c65 
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c15 
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cb2 
ccb 
c7e 
c81 
c