INFO: task loop0:3758 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.
loop0           D ffff8801c629f298 27512  3758      2 0x00000000
 ffff8801c629f298 ffffffff81234260 ffff8800b9990238 ffffe8ffffd01800
 ffff8800b9990230 ffff8801c629f200 ffff8801db31f878 ffff8801db31f8a0
 ffff8801db31ef98 ffff8801da2dc740 ffff8800ba8edf00 ffff8801c6298000
Call Trace:
 [<ffffffff83765d3a>] schedule+0x9a/0x1c0 kernel/sched/core.c:3351
 [<ffffffff83770fd1>] schedule_timeout+0x3a1/0x970 kernel/time/timer.c:1508
 [<ffffffff83763cbe>] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:4932
 [<ffffffff815dcc04>] io_schedule include/linux/sched.h:447 [inline]
 [<ffffffff815dcc04>] dio_await_one fs/direct-io.c:449 [inline]
 [<ffffffff815dcc04>] dio_await_completion fs/direct-io.c:503 [inline]
 [<ffffffff815dcc04>] do_blockdev_direct_IO+0x4794/0x8830 fs/direct-io.c:1313
 [<ffffffff815e0d4e>] __blockdev_direct_IO+0xae/0xe0 fs/direct-io.c:1342
 [<ffffffff815cfa62>] blkdev_direct_IO+0xb2/0xe0 fs/block_dev.c:167
 [<ffffffff81420890>] generic_file_read_iter+0x360/0x1170 mm/filemap.c:1791
 [<ffffffff815d0ac5>] blkdev_read_iter+0x105/0x170 fs/block_dev.c:1679
 [<ffffffff8151b9d3>] vfs_iter_read+0x183/0x270 fs/read_write.c:344
 [<ffffffff82422e66>] lo_read_transfer drivers/block/loop.c:386 [inline]
 [<ffffffff82422e66>] do_req_filebacked drivers/block/loop.c:556 [inline]
 [<ffffffff82422e66>] loop_handle_cmd drivers/block/loop.c:1692 [inline]
 [<ffffffff82422e66>] loop_queue_work+0xac6/0x31c0 drivers/block/loop.c:1704
 [<ffffffff8118e298>] kthread_worker_fn+0x298/0x630 kernel/kthread.c:602
 [<ffffffff8118dea8>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff837740ef>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:468
no locks held by loop0/3758.
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.107-g610c835 #12
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffffffff84214840 task.stack: ffffffff84200000
RIP: 0010:[<ffffffff81234b86>]  [<ffffffff81234b86>] mark_irqflags kernel/locking/lockdep.c:2785 [inline]
RIP: 0010:[<ffffffff81234b86>]  [<ffffffff81234b86>] __lock_acquire+0x926/0x4b50 kernel/locking/lockdep.c:3169
RSP: 0018:ffffffff84207b40  EFLAGS: 00000046
RAX: 0000000000000002 RBX: ffffffff842150b0 RCX: 0000000000000000
RDX: 0000000000000007 RSI: 0000000000000000 RDI: ffffffff8421507c
RBP: ffffffff84207ce0 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 1ffffffff0840f7a R12: 000000000000002d
R13: ffffffff84214840 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1722193000 CR3: 00000000b120b000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff84214840 ffffffff842150b0 0000000000000023 ffffffff84214840
 ffffffff842b76e0 0000000000000000 ffffffff84207d20 ffffffff81234dbf
 00000000810afc4a 0000000000000046 ffffffff842150b0 ffffffff842150c8
Call Trace:
 [<ffffffff8123a61e>] lock_acquire+0x15e/0x460 kernel/locking/lockdep.c:3592
 [<ffffffff812bcfc6>] seqcount_lockdep_reader_access include/linux/seqlock.h:80 [inline]
 [<ffffffff812bcfc6>] read_seqcount_begin include/linux/seqlock.h:163 [inline]
 [<ffffffff812bcfc6>] ktime_get+0x76/0x1d0 kernel/time/timekeeping.c:756
 [<ffffffff812d4613>] tick_nohz_idle_exit+0x153/0x3d0 kernel/time/tick-sched.c:925
 [<ffffffff8121e727>] cpu_idle_loop kernel/sched/idle.c:267 [inline]
 [<ffffffff8121e727>] cpu_startup_entry+0x2e7/0x820 kernel/sched/idle.c:301
 [<ffffffff83760d89>] rest_init+0x189/0x190 init/main.c:409
 [<ffffffff8481a80c>] start_kernel+0x6b4/0x6e9 init/main.c:680
 [<ffffffff84819312>] x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:196
 [<ffffffff84819454>] x86_64_start_kernel+0x140/0x163 arch/x86/kernel/head64.c:185
Code: ba 00 00 00 00 00 fc ff df 48 89 fe 48 c1 ee 03 0f b6 34 16 48 89 fa 83 e2 07 83 c2 03 40 38 f2 7c 09 40 84 f6 0f 85 32 0c 00 00 <84> c0 41 8b 95 3c 08 00 00 0f 84 93 00 00 00 85 d2 0f 85 79 19 
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: ffff8800bb950000 task.stack: ffff8800bb368000
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:ffff8800bb36fcb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bb36fce0 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: 00007f108db9c9b8 CR3: 00000001d2d9a000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426abe0 ffffffff847e8600 00000000000194a0 0000000000000040
 dffffc0000000000 ffff8800bb36fd00 ffffffff810b8e1b ffffffff839f53e0
 0000000000000003 ffff8800bb36fd60 ffffffff81d0f4d7 0000000000000000
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