INFO: task blkid:8474 blocked for more than 120 seconds.
      Not tainted 4.4.107-g610c835 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D ffff8801d2b57298 28120  8474   3394 0x00000006
 ffff8801d2b57298 ffffffff81234260 ffff8801d5a23818 0000000000000023
 ffff8801d5a22f80 ffffffff842b7600 ffff8801db21f878 ffff8801db21f8a0
 ffff8801db21ef98 ffff8800b665c740 ffff8801d5a22f80 ffff8801d2b50000
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
 [<ffffffff83766feb>] io_schedule include/linux/sched.h:447 [inline]
 [<ffffffff83766feb>] bit_wait_io+0x1b/0xc0 kernel/sched/wait.c:595
 [<ffffffff83766b2f>] __wait_on_bit_lock+0x8f/0x140 kernel/sched/wait.c:434
 [<ffffffff8141a9cd>] __lock_page+0x18d/0x1f0 mm/filemap.c:888
 [<ffffffff8144a807>] lock_page include/linux/pagemap.h:458 [inline]
 [<ffffffff8144a807>] truncate_inode_pages_range+0x8e7/0xe70 mm/truncate.c:362
 [<ffffffff8144adb4>] truncate_inode_pages+0x24/0x30 mm/truncate.c:390
 [<ffffffff815ceb9c>] kill_bdev+0xbc/0xf0 fs/block_dev.c:82
 [<ffffffff815d20f1>] __blkdev_put+0x191/0x7e0 fs/block_dev.c:1523
 [<ffffffff815d35b5>] blkdev_put+0x85/0x550 fs/block_dev.c:1600
 [<ffffffff815d3b0b>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1607
 [<ffffffff81521163>] __fput+0x233/0x6d0 fs/file_table.c:208
 [<ffffffff81521685>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff811890a4>] task_work_run+0x104/0x180 kernel/task_work.c:115
 [<ffffffff811304a1>] exit_task_work include/linux/task_work.h:21 [inline]
 [<ffffffff811304a1>] do_exit+0x871/0x2a20 kernel/exit.c:755
 [<ffffffff81136918>] do_group_exit+0x108/0x320 kernel/exit.c:885
 [<ffffffff81159de5>] get_signal+0x565/0x1660 kernel/signal.c:2315
 [<ffffffff8100e7fb>] do_signal+0x8b/0x1d40 arch/x86/kernel/signal.c:712
 [<ffffffff81003602>] exit_to_usermode_loop+0x122/0x170 arch/x86/entry/common.c:247
 [<ffffffff81006545>] prepare_exit_to_usermode arch/x86/entry/common.c:282 [inline]
 [<ffffffff81006545>] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:347
 [<ffffffff83773e9e>] int_ret_from_sys_call+0x25/0x9f
1 lock held by blkid/8474:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815d201c>] __blkdev_put+0xbc/0x7e0 fs/block_dev.c:1516
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 485 Comm: khungtaskd Not tainted 4.4.107-g610c835 #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bac48000 task.stack: ffff8800bb8f0000
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:ffff8800bb8f7cb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bb8f7ce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426abe0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c420009e80 CR3: 00000000b7dbf000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426abe0 ffffffff847e8600 00000000000194a0 0000000000000040
 dffffc0000000000 ffff8800bb8f7d00 ffffffff810b8e1b ffffffff839f53e0
 0000000000000003 ffff8800bb8f7d60 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 
NMI backtrace for cpu 1
CPU: 1 PID: 3159 Comm: rsyslogd Not tainted 4.4.107-g610c835 #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800b657af80 task.stack: ffff8800b6740000
RIP: 0010:[<ffffffff81017a6a>]  [<ffffffff81017a6a>] print_context_stack+0xaa/0xc0 arch/x86/kernel/dumpstack.c:111
RSP: 0018:ffff8800b6747440  EFLAGS: 00000202
RAX: ffff8800b6740000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff81d3fbe0 RDI: ffffffff856f3600
RBP: ffff8800b6747488 R08: ffff8800b6747538 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800b6747b00
R13: ffffffffffff8000 R14: ffff8800b6747ab0 R15: ffff8800b6747ac0
FS:  00007fe80af6e700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5034113000 CR3: 00000000b7dbf000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8800b6740000 ffff8800b6747b00 ffff8800b6747538 ffffffff83810a40
 0000000000000000 ffffffff83810a40 ffff8800b6747538 0000000000013ea0
 ffff8800b67474d8 ffff8800b6747510 ffffffff81016be2 ffff8800b67474d4
Call Trace:
 [<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
 [<ffffffff814fb4b2>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fb4b2>] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589
 [<ffffffff814f7f3c>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff814f7f3c>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff814f7f3c>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff814f7f3c>] kfree+0xfc/0x300 mm/slub.c:3749
 [<ffffffff82e0667d>] skb_free_head net/core/skbuff.c:571 [inline]
 [<ffffffff82e0667d>] skb_release_data+0x2ed/0x3b0 net/core/skbuff.c:602
 [<ffffffff82e0678a>] skb_release_all+0x4a/0x60 net/core/skbuff.c:661
 [<ffffffff82e06d93>] __kfree_skb net/core/skbuff.c:675 [inline]
 [<ffffffff82e06d93>] consume_skb+0xf3/0x3d0 net/core/skbuff.c:748
 [<ffffffff82e23e6a>] skb_free_datagram+0x1a/0xe0 net/core/datagram.c:280
 [<ffffffff832e8bb4>] unix_dgram_recvmsg+0x8b4/0xdb0 net/unix/af_unix.c:2196
 [<ffffffff82de8fcc>] sock_recvmsg_nosec net/socket.c:727 [inline]
 [<ffffffff82de8fcc>] sock_recvmsg+0x8c/0xc0 net/socket.c:735
 [<ffffffff82dee4dd>] ___sys_recvmsg+0x26d/0x560 net/socket.c:2116
 [<ffffffff82df06e3>] __sys_recvmsg+0xd3/0x190 net/socket.c:2162
 [<ffffffff82df07cd>] SYSC_recvmsg net/socket.c:2174 [inline]
 [<ffffffff82df07cd>] SyS_recvmsg+0x2d/0x50 net/socket.c:2169
 [<ffffffff83773d36>] entr