INFO: task blkid:6013 blocked for more than 120 seconds.
      Not tainted 4.4.114-gfe09418 #3
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D ffff8801d7a97878 26968  6013   2558 0x00000006
 ffff8801d7a97878 ffff8800ba5cdf00 0000000000000000 0000000000000007
 ffff8800ba5cdf00 dffffc0000000000 ffff8801db21fdb8 ffff8801db21fde0
 ffff8801db21f4d8 ffffffff84217840 ffff8800ba5cdf00 0000000000000000
Call Trace:
 [<ffffffff837652da>] schedule+0x7a/0x1b0 kernel/sched/core.c:3352
 [<ffffffff83765ad3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3385
 [<ffffffff8376a096>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff8376a096>] mutex_lock_nested+0x306/0x850 kernel/locking/mutex.c:621
 [<ffffffff815d375a>] blkdev_put+0x2a/0x550 fs/block_dev.c:1558
 [<ffffffff815d3d0b>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1607
 [<ffffffff81522a03>] __fput+0x233/0x6d0 fs/file_table.c:208
 [<ffffffff81522f25>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8118b9a4>] task_work_run+0x104/0x180 kernel/task_work.c:115
 [<ffffffff81132f7a>] exit_task_work include/linux/task_work.h:21 [inline]
 [<ffffffff81132f7a>] do_exit+0x82a/0x2a10 kernel/exit.c:755
 [<ffffffff81139418>] do_group_exit+0x108/0x320 kernel/exit.c:885
 [<ffffffff8115c872>] get_signal+0x4f2/0x1550 kernel/signal.c:2317
 [<ffffffff8100e7fb>] do_signal+0x8b/0x1d40 arch/x86/kernel/signal.c:712
 [<ffffffff810035fa>] exit_to_usermode_loop+0x11a/0x160 arch/x86/entry/common.c:247
 [<ffffffff81006535>] prepare_exit_to_usermode arch/x86/entry/common.c:282 [inline]
 [<ffffffff81006535>] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:347
 [<ffffffff837735a9>] int_ret_from_sys_call+0x25/0xa3
1 lock held by blkid/6013:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815d375a>] blkdev_put+0x2a/0x550 fs/block_dev.c:1558
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 486 Comm: khungtaskd Not tainted 4.4.114-gfe09418 #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bac1df00 task.stack: ffff8800bb2e0000
RIP: 0010:[<ffffffff810c3d57>]  [<ffffffff810c3d57>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810c3d57>]  [<ffffffff810c3d57>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810c3d57>]  [<ffffffff810c3d57>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810c3d57>]  [<ffffffff810c3d57>] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bb2e7cb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bb2e7ce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426f3a0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001cae000 CR3: 00000000ab7ac000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426f3a0 ffffffff847ef6c0 fffffbfff08fd98c dffffc0000000000
 ffff8801db31bca0 ffff8800bb2e7d00 ffffffff810b988b ffffffff839f6180
 0000000000000003 ffff8800bb2e7d60 ffffffff81d0ddd4 ffffffff8141a703
Call Trace:
 [<ffffffff810b988b>] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81d0ddd4>] nmi_trigger_all_cpu_backtrace+0x4a4/0x550 lib/nmi_backtrace.c:85
 [<ffffffff810b9924>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff813681da>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff813681da>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff813681da>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff813681da>] watchdog+0x6fa/0xae0 kernel/hung_task.c:238
 [<ffffffff811907a8>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff83773845>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:506
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 8b 25 17 00 4c 89 e7 57 9d 0f 1f 
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.114-gfe09418 #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d9b497c0 task.stack: ffff8801d9b58000
RIP: 0010:[<ffffffff8123d5be>]  [<ffffffff8123d5be>] __lock_release kernel/locking/lockdep.c:3437 [inline]
RIP: 0010:[<ffffffff8123d5be>]  [<ffffffff8123d5be>] lock_release+0x5de/0xc10 kernel/locking/lockdep.c:3611
RSP: 0018:ffff8801d9b5fcf0  EFLAGS: 00000046
RAX: ffff8801d9b497c0 RBX: 0000000000000000 RCX: ffffffff81195693
RDX: 1ffff1003b369405 RSI: ffffffff842bdba0 RDI: ffff8801d9b4a028
RBP: ffff8801d9b5fda0 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff1003b36bf82 R12: ffffffff842bdba0
R13: 0000000000000000 R14: ffff8801d9b4a038 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7ca13d09b8 CR3: 00000000ab7ac000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d9b497c0 0000000000000000 0000000000000000 0000000000000002
 0000000000000000 ffff8801d9b5fda0 0000000000000246 0000000000000000
 ffff8801d9b5fd70 ffff8801d9b4a030 00000000d9b5fda0 0000000000000246
Call Trace:
 [<ffffffff811956ab>] rcu_lock_release include/linux/rcupdate.h:482 [inline]
 [<ffffffff811956ab>] rcu_read_unlock include/linux/rcupdate.h:917 [inline]
 [<ffffffff811956ab>] __atomic_notifier_call_chain kernel/notifier.c:184 [inline]
 [<ffffffff811956ab>] atomic_notifier_call_chain+0xbb/0x140 kernel/notifier.c:193
 [<ffffffff8112df7e>] idle_notifier_call_chain+0x1e/0x30 kernel/cpu.c:865
 [<ffffffff810293ff>] __exit_idle arch/x86/kernel/process.c:248 [inline]
 [<ffffffff810293ff>] arch_cpu_idle_exit+0x1f/0x30 arch/x86/kernel/process.c:269
 [<ffffffff81220ce5>] cpu_idle_loop kernel/sched/idle.c:255 [inline]
 [<ffffffff81220ce5>] cpu_startup_entry+0x265/0x8f0 kernel/sched/idle.c:301
 [<ffffffff810adb54>] start_secondary+0x304/0x3e0 arch/x86/kernel/smpboot.c:242
Code: 8b 4d b8 4c 89 5c 24 08 4c 89 14 24 89 44 24 18 e8 78 93 ff ff 85 c0 0f 84 84 00 00 00 41 83 c7 01 44 39 7d d0 0f 87 15 fe ff ff <48> c7 c2 80 06 70 85 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03