INFO: task loop4:2092 blocked for more than 120 seconds.
      Not tainted 4.4.132-gc3c51ea #45
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
loop4           D ffff8800bb9eed40 26880  2092      2 0x00000000
 ffff8800bb9eed40 ffff8800aeb7e8d8 ffff8800aeb7e900 ffff8800aeb7e8e0
 1ffff1001773dd00 ffff8801db31fdb8 ffff8801db31fde0 ffff8801db31f4d8
 ffff8801db31f4c0 ffff8801c83ae000 ffff8800aeb7e000 ffff8800bb9ef610
Call Trace:
 [<ffffffff838b220a>] schedule+0x7a/0x1b0 kernel/sched/core.c:3359
 [<ffffffff838bd621>] schedule_timeout+0x481/0x8b0 kernel/time/timer.c:1515
 [<ffffffff838b00ca>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:4941
 [<ffffffff81db15cf>] io_schedule include/linux/sched.h:447 [inline]
 [<ffffffff81db15cf>] bt_get+0x2af/0x760 block/blk-mq-tag.c:301
 [<ffffffff81db28c5>] __blk_mq_get_tag block/blk-mq-tag.c:325 [inline]
 [<ffffffff81db28c5>] blk_mq_get_tag+0x1f5/0x360 block/blk-mq-tag.c:353
 [<ffffffff81da2587>] __blk_mq_alloc_request+0x27/0xa40 block/blk-mq.c:215
 [<ffffffff81da8732>] blk_mq_map_request.isra.42+0x732/0xe00 block/blk-mq.c:1190
 [<ffffffff81dac7ad>] blk_sq_make_request+0x1ad/0xe60 block/blk-mq.c:1361
 [<ffffffff81d7e7c1>] generic_make_request+0x211/0x9b0 block/blk-core.c:2081
 [<ffffffff81d7f03f>] submit_bio+0xdf/0x3b0 block/blk-core.c:2154
 [<ffffffff815e10fb>] dio_bio_submit fs/direct-io.c:409 [inline]
 [<ffffffff815e10fb>] do_blockdev_direct_IO+0x5aab/0x82f0 fs/direct-io.c:1283
 [<ffffffff815e39ee>] __blockdev_direct_IO+0xae/0xe0 fs/direct-io.c:1342
 [<ffffffff815d07d2>] blkdev_direct_IO+0xb2/0xe0 fs/block_dev.c:167
 [<ffffffff81422a3c>] generic_file_read_iter+0x35c/0x1150 mm/filemap.c:1790
 [<ffffffff815d34d5>] blkdev_read_iter+0x105/0x170 fs/block_dev.c:1679
 [<ffffffff8251d261>] lo_rw_aio+0x481/0x870 drivers/block/loop.c:506
 [<ffffffff8251f4b7>] lo_rw_simple drivers/block/loop.c:520 [inline]
 [<ffffffff8251f4b7>] do_req_filebacked drivers/block/loop.c:558 [inline]
 [<ffffffff8251f4b7>] loop_handle_cmd drivers/block/loop.c:1705 [inline]
 [<ffffffff8251f4b7>] loop_queue_work+0x12b7/0x1620 drivers/block/loop.c:1717
 [<ffffffff81190a83>] kthread_worker_fn+0x1c3/0x610 kernel/kthread.c:602
 [<ffffffff81190768>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff838c0655>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510
no locks held by loop4/2092.
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.132-gc3c51ea #45
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffffffff84417840 task.stack: ffffffff84400000
RIP: 0010:[<ffffffff810cc306>]  [<ffffffff810cc306>] native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:49
RSP: 0018:ffffffff84407dc8  EFLAGS: 00000246
RAX: 0000000000000007 RBX: ffffffff84a05b28 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff8441811c
RBP: ffffffff84407dc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: fffffbfff074890c R15: ffffffff84a05b28
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c420143e80 CR3: 00000001cfc54000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff84407e00 ffffffff81025da5 ffffffff84408000 0000000000000000
 0000000000000000 fffffbfff074890c ffffffff84a05b28 ffffffff84407e10
 ffffffff810272f0 ffffffff84407e28 ffffffff8121b9e7 dffffc0000000000
Call Trace:
 [<ffffffff81025da5>] arch_safe_halt arch/x86/include/asm/paravirt.h:117 [inline]
 [<ffffffff81025da5>] default_idle+0x55/0x3c0 arch/x86/kernel/process.c:290
 [<ffffffff810272f0>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:281
 [<ffffffff8121b9e7>] default_idle_call+0x57/0x70 kernel/sched/idle.c:93
 [<ffffffff8121c18f>] cpuidle_idle_call kernel/sched/idle.c:157 [inline]
 [<ffffffff8121c18f>] cpu_idle_loop kernel/sched/idle.c:253 [inline]
 [<ffffffff8121c18f>] cpu_startup_entry+0x6af/0x780 kernel/sched/idle.c:301
 [<ffffffff838ad371>] rest_init+0x188/0x18e init/main.c:410
 [<ffffffff84a4b8a1>] start_kernel+0x6b3/0x6e7 init/main.c:682
 [<ffffffff84a4a30f>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196
 [<ffffffff84a4a450>] x86_64_start_kernel+0x13f/0x162 arch/x86/kernel/head64.c:185
Code: 00 00 00 00 00 55 48 89 e5 fa 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb f4 <5d> c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 f4 5d c3 66 0f 1f 84 
NMI backtrace for cpu 1
CPU: 1 PID: 491 Comm: khungtaskd Not tainted 4.4.132-gc3c51ea #45
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bac61800 task.stack: ffff8801d9270000
RIP: 0010:[<ffffffff810bfe16>]  [<ffffffff810bfe16>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810bfe16>]  [<ffffffff810bfe16>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810bfe16>]  [<ffffffff810bfe16>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810bfe16>]  [<ffffffff810bfe16>] flat_send_IPI_mask+0xf6/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8801d9277cc8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8801d9277cf0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: 0000000000000002 R15: ffffffff8446f7a0
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc9b8f92140 CR3: 00000001cfc54000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8446f7a0 ffffffff84a18a60 0000000000000007 fffffbfff0942bfc
 0000000000000040 ffff8801d9277d10 ffffffff810b5dd1 ffffffff83c0b1a0
 0000000000000003 ffff8801d9277d68 ffffffff81e19003 ffff8800aeb7e000
Call Trace:
 [<ffffffff810b5dd1>] nmi_raise_cpu_backtrace+0x61/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81e19003>] nmi_trigger_all_cpu_backtrace.cold.4+0x70/0xad lib/nmi_backtrace.c:85
 [<ffffffff810b5e74>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff8141a0b9>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff8141a0b9>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8141a0b9>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8141a0b9>] watchdog.cold.1+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff81190768>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff838c0655>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510
Code: b3 5f ff f6 c4 10 75 e2 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 f2 09 da 80 cf 04 41 83 fe 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 75 1a 4c 89 e7 57 9d 0f 1f 44 00 00 e8 f2