IPv6: NLM_F_REPLACE set, but no existing node found!
INFO: task blkid:19794 blocked for more than 120 seconds.
      Not tainted 4.9.40-ged32335 #11
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28112 19794   1837 0x00000006
 ffff8801ca7baf00 ffff8801c8e3cfc0 ffff8801d932e4c0 ffff8801c6b4af00
 ffff8801db321498 ffff8801a74d7270 ffffffff8388f2bb 0000000041b58ab3
 ffffffff8418bae8 00ffffff812373d0 ffff8801db321db0 ffff8801db321dd8
Call Trace:
 [<ffffffff83890872>] schedule+0x92/0x1b0 kernel/sched/core.c:3624
 [<ffffffff8389cb12>] schedule_timeout+0x6a2/0xec0 kernel/time/timer.c:1738
 [<ffffffff8388ea6e>] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:5242
 [<ffffffff83891ce9>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff83891ce9>] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582
 [<ffffffff83891552>] __wait_on_bit_lock+0xc2/0x1c0 kernel/sched/wait.c:421
 [<ffffffff8142cf0f>] __lock_page+0xff/0x160 mm/filemap.c:934
 [<ffffffff814668aa>] lock_page include/linux/pagemap.h:454 [inline]
 [<ffffffff814668aa>] truncate_inode_pages_range+0xc1a/0x12c0 mm/truncate.c:373
 [<ffffffff81466f74>] truncate_inode_pages+0x24/0x30 mm/truncate.c:401
 [<ffffffff8162347c>] kill_bdev+0xbc/0xf0 fs/block_dev.c:96
 [<ffffffff81626c81>] __blkdev_put+0x191/0x7e0 fs/block_dev.c:1584
 [<ffffffff816280a5>] blkdev_put+0x85/0x550 fs/block_dev.c:1661
 [<ffffffff816285fb>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1668
 [<ffffffff8156ee2c>] __fput+0x28c/0x6e0 fs/file_table.c:208
 [<ffffffff8156f305>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff81195e25>] task_work_run+0x115/0x190 kernel/task_work.c:116
 [<ffffffff8113cf76>] exit_task_work include/linux/task_work.h:21 [inline]
 [<ffffffff8113cf76>] do_exit+0x826/0x2a40 kernel/exit.c:833
 [<ffffffff81143658>] do_group_exit+0x108/0x320 kernel/exit.c:937
 [<ffffffff8116628c>] get_signal+0x55c/0x1600 kernel/signal.c:2315
 [<ffffffff81052b97>] do_signal+0x87/0x1960 arch/x86/kernel/signal.c:807
 [<ffffffff81003a35>] exit_to_usermode_loop+0xe5/0x130 arch/x86/entry/common.c:156
 [<ffffffff81006350>] prepare_exit_to_usermode arch/x86/entry/common.c:190 [inline]
 [<ffffffff81006350>] syscall_return_slowpath+0x1a0/0x1e0 arch/x86/entry/common.c:259
 [<ffffffff838a0766>] entry_SYSCALL_64_fastpath+0xc4/0xc6

Showing all locks held in the system:
2 locks held by khungtaskd/513:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136d275>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136d275>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81233524>] debug_show_all_locks+0x74/0x290 kernel/locking/lockdep.c:4329
2 locks held by getty/3214:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff8389e8c2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff81fff0f4>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
1 lock held by blkid/19794:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81626bac>] __blkdev_put+0xbc/0x7e0 fs/block_dev.c:1577
1 lock held by syz-executor1/20490:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8162a468>] iterate_bdevs+0xc8/0x260 fs/block_dev.c:1974

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 513 Comm: khungtaskd Not tainted 4.9.40-ged32335 #11
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8917d00 ffffffff81d8d829 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810bd010 ffff8801d8917d38
 ffffffff81d9893d 0000000000000001 0000000000000000 ffff8801ca7bb298
Call Trace:
 [<ffffffff81d8d829>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d8d829>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81d9893d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81d98a77>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810bd104>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8136d840>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8136d840>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8136d840>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8136d840>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff8119ad8d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838a096a>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.40-ged32335 #11
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffffffff84426880 task.stack: ffffffff84400000
RIP: 0010:[<ffffffff838a26d0>] 
c [<ffffffff838a26d0>] reschedule_interrupt+0x0/0xa0 arch/x86/entry/entry_64.S:731
RSP: 0018:ffffffff84407d88  EFLAGS: 00000046
RAX: 0000000000000007 RBX: ffffffff84a1c208 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff844270ac
RBP: ffffffff84407db8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff84a2b078 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001c09000 CR3: 00000001d030e000 CR4: 00000000001406f0
Stack:
 ffffffff8389f336
c 0000000000000010
c 0000000000000246
c ffffffff84407db8
c
 0000000000000018
c ffffffff81236dad
c ffffffff84407df0
c ffffffff8389e965
c
 ffffffff84426880
c ffffffff84426880
c 0000000000000000
c ffffffff84a2b078
c
Call Trace:
 [<ffffffff8389e965>] arch_safe_halt arch/x86/include/asm/paravirt.h:103 [inline]
 [<ffffffff8389e965>] default_idle+0x55/0x360 arch/x86/kernel/process.c:295
 [<ffffffff8106c35a>] arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:286
 [<ffffffff8389f786>] default_idle_call+0x36/0x60 kernel/sched/idle.c:97
 [<ffffffff812263bc>] cpuidle_idle_call kernel/sched/idle.c:155 [inline]
 [<ffffffff812263bc>] cpu_idle_loop kernel/sched/idle.c:248 [inline]
 [<ffffffff812263bc>] cpu_startup_entry+0x30c/0x3d0 kernel/sched/idle.c:303
 [<ffffffff8388be94>] rest_init+0x184/0x190 init/main.c:408
 [<ffffffff84a638a7>] start_kernel+0x679/0x6ae init/main.c:662
 [<ffffffff84a6229d>] x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:196
 [<ffffffff84a623df>] x86_64_start_kernel+0x140/0x163 arch/x86/kernel/head64.c:177
Code: 
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c