INFO: task kworker/u4:0:6 blocked for more than 120 seconds.
      Not tainted 4.4.107-g610c835 #12
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:0    D ffff8801da26f8b8 28344     6      2 0x00000000
Workqueue: events_unbound flush_to_ldisc
 ffff8801da26f8b8 dffffc0000000000 ffff8801da260870 ffff8801da26f898
 ffffffff8123364f ffff8801da260800 ffff8801db21f878 ffff8801db21f8a0
 ffff8801db21ef98 ffff8801d92e4740 ffff8801da260000 ffff8801da268000
Call Trace:
 [<ffffffff83765d3a>] schedule+0x9a/0x1c0 kernel/sched/core.c:3351
 [<ffffffff8376ffef>] rwsem_down_read_failed+0x1bf/0x300 kernel/locking/rwsem-xadd.c:250
 [<ffffffff81d34e44>] call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:90
 [<ffffffff81f56944>] n_tty_receive_buf_common+0x84/0x21c0 drivers/tty/n_tty.c:1705
 [<ffffffff81f58ab3>] n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1777
 [<ffffffff81f61acb>] receive_buf drivers/tty/tty_buffer.c:451 [inline]
 [<ffffffff81f61acb>] flush_to_ldisc+0x27b/0x4a0 drivers/tty/tty_buffer.c:516
 [<ffffffff8117d3f7>] process_one_work+0x7d7/0x16e0 kernel/workqueue.c:2064
 [<ffffffff8117e3df>] worker_thread+0xdf/0xfe0 kernel/workqueue.c:2196
 [<ffffffff8118dea8>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff837740ef>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:468
5 locks held by kworker/u4:0/6:
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8117d2dd>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8117d2dd>] set_work_data kernel/workqueue.c:625 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8117d2dd>] set_work_pool_and_clear_pending kernel/workqueue.c:652 [inline]
 #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8117d2dd>] process_one_work+0x6bd/0x16e0 kernel/workqueue.c:2057
 #1:  ((&buf->work)){+.+...}, at: [<ffffffff8117d317>] process_one_work+0x6f7/0x16e0 kernel/workqueue.c:2061
 #2:  (&tty->ldisc_sem){++++++}, at: [<ffffffff81f5ea5b>] tty_ldisc_ref+0x1b/0x80 drivers/tty/tty_ldisc.c:283
 #3:  (&port->buf.lock/1){+.+...}, at: [<ffffffff81f618d6>] flush_to_ldisc+0x86/0x4a0 drivers/tty/tty_buffer.c:488
 #4:  (&o_tty->termios_rwsem/1){++++.+}, at: [<ffffffff81f56944>] n_tty_receive_buf_common+0x84/0x21c0 drivers/tty/n_tty.c:1705
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 3166 Comm: rsyslogd Not tainted 4.4.107-g610c835 #12
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800b6744740 task.stack: ffff8800b6068000
RIP: 0010:[<ffffffff811a44ee>]  [<ffffffff811a44ee>] preempt_count_add+0x2e/0x170 kernel/sched/core.c:3065
RSP: 0018:ffff8800b606f770  EFLAGS: 00000206
RAX: 0000000000000003 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffff8800b606f858 RDI: ffffffff856f3600
RBP: ffff8800b606f780 R08: ffff8800b606f8b8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800b606f890
R13: ffffffffffff8000 R14: ffff8800b606f888 R15: ffff8801da001140
FS:  00007fbde2ae5700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd80244e9b8 CR3: 00000000b693f000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801da001140 ffff8800b606f890 ffff8800b606f798 ffffffff812f5a62
 ffff8801da001140 ffff8800b606f7b0 ffffffff8118926b 0000000000000000
 ffff8800b606f808 ffffffff81017a08 ffff8800b6068000 ffff8800b606f890
Call Trace:
 [<ffffffff812f5a62>] is_module_text_address+0x12/0x50 kernel/module.c:4076
 [<ffffffff8118926b>] __kernel_text_address+0x6b/0xa0 kernel/extable.c:103
 [<ffffffff81017a08>] print_context_stack+0x48/0xc0 arch/x86/kernel/dumpstack.c:107
 [<ffffffff81016be2>] dump_trace+0x142/0x350 arch/x86/kernel/dumpstack_64.c:243
 [<ffffffff81035c86>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fab93>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fae5d>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fae5d>] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:616
 [<ffffffff814fb432>] kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:554
 [<ffffffff814f6d8e>] slab_post_alloc_hook mm/slub.c:1349 [inline]
 [<ffffffff814f6d8e>] slab_alloc_node mm/slub.c:2615 [inline]
 [<ffffffff814f6d8e>] slab_alloc mm/slub.c:2623 [inline]
 [<ffffffff814f6d8e>] kmem_cache_alloc_trace+0xbe/0x2b0 mm/slub.c:2640
 [<ffffffff81265ccf>] kmalloc include/linux/slab.h:476 [inline]
 [<ffffffff81265ccf>] syslog_print kernel/printk/printk.c:1148 [inline]
 [<ffffffff81265ccf>] do_syslog+0x60f/0xae0 kernel/printk/printk.c:1331
 [<ffffffff8168e3d4>] kmsg_read+0x74/0xa0 fs/proc/kmsg.c:39
 [<ffffffff816651ff>] proc_reg_read+0xef/0x170 fs/proc/inode.c:202
 [<ffffffff8151aa73>] __vfs_read+0x103/0x440 fs/read_write.c:432
 [<ffffffff8151c913>] vfs_read+0x123/0x3a0 fs/read_write.c:454
 [<ffffffff8151f259>] SYSC_read fs/read_write.c:569 [inline]
 [<ffffffff8151f259>] SyS_read+0xd9/0x1b0 fs/read_write.c:562
 [<ffffffff83773d36>] entry_SYSCALL_64_fastpath+0x16/0x76
Code: 00 00 00 00 fc ff df 55 48 89 e5 41 54 53 89 fb 48 c7 c7 00 36 6f 85 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 <38> d0 7c 08 84 d2 0f 85 1b 01 00 00 8b 15 00 f1 54 04 65 01 1d 
NMI backtrace for cpu 1
CPU: 1 PID: 485 Comm: khungtaskd Not tainted 4.4.107-g610c835 #12
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bb2fdf00 task.stack: ffff8800bb250000
RIP: 0010:[<ffffffff810c32e7>]  [<ffffffff810c32e7>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810c32e7>]  [<ffffffff810c32e7>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810c32e7>]  [<ffffffff810c32e7>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810c32e7>]  [<ffffffff810c32e7>] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bb257cb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bb257ce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426abe0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0432195e68 CR3: 00000000b693f000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426abe0 ffffffff847e8600 00000000000194a0 0000000000000040
 dffffc0000000000 ffff8800bb257d00 ffffffff810b8e1b ffffffff839f53e0
 0000000000000003 ffff8800bb257d60 ffffffff81d0f4d7 ffffffff81417c73
Call Trace:
 [<ffffffff810b8e1b>] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81d0f4d7>] nmi_trigger_all_cpu_backtrace+0x4a7/0x550 lib/nmi_backtrace.c:85
 [<ffffffff810b8eb4>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff81365a7a>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff81365a7a>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81365a7a>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81365a7a>] watchdog+0x6fa/0xae0 kernel/hung_task.c:238
 [<ffffffff8118dea8>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff837740ef>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:468
Code: b3 5f ff f6 c4 10 75 e1 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 74 1a e8 3b 09 17 00 4c 89 e7 57 9d 0f 1f