INFO: task kworker/u4:1:64 blocked for more than 140 seconds.
      Not tainted 4.9.131+ #50
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:1    D25352    64      2 0x80000000
Workqueue: writeback wb_workfn (flush-8:0)
 ffff8801d7fe5f00 0000000000000000 ffff8801d4c78580 ffffffff83029180
 ffff8801db621018 ffff8801d793f130 ffffffff827f3542 ffff8801d7fe5f00
 0000000000000000 0000000000000000 0000000000000000 ffff8801db6218f0
Call Trace:
 [<ffffffff827f4a6f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff817e53b5>] wait_transaction_locked+0x1a5/0x230 fs/jbd2/transaction.c:163
 [<ffffffff817e5888>] add_transaction_credits+0x408/0x980 fs/jbd2/transaction.c:191
 [<ffffffff817e6240>] start_this_handle+0x340/0xe40 fs/jbd2/transaction.c:361
 [<ffffffff817e80f6>] jbd2__journal_start+0x306/0x8b0 fs/jbd2/transaction.c:457
 [<ffffffff8178dbbc>] __ext4_journal_start_sb+0x10c/0x460 fs/ext4/ext4_jbd2.c:76
 [<ffffffff816d5895>] __ext4_journal_start fs/ext4/ext4_jbd2.h:318 [inline]
 [<ffffffff816d5895>] ext4_writepages+0xe75/0x2e00 fs/ext4/inode.c:2767
 [<ffffffff81433d0f>] do_writepages+0xef/0x1d0 mm/page-writeback.c:2331
 [<ffffffff8159eb89>] __writeback_single_inode+0xd9/0x1020 fs/fs-writeback.c:1320
 [<ffffffff8159ff7c>] writeback_sb_inodes+0x4ac/0xe70 fs/fs-writeback.c:1584
 [<ffffffff815a0a3b>] __writeback_inodes_wb+0xfb/0x1e0 fs/fs-writeback.c:1653
 [<ffffffff815a1032>] wb_writeback+0x512/0xbd0 fs/fs-writeback.c:1762
 [<ffffffff815a47ac>] wb_check_old_data_flush fs/fs-writeback.c:1877 [inline]
 [<ffffffff815a47ac>] wb_do_writeback fs/fs-writeback.c:1901 [inline]
 [<ffffffff815a47ac>] wb_workfn+0x8bc/0xe90 fs/fs-writeback.c:1930
 [<ffffffff81130e81>] process_one_work+0x831/0x1530 kernel/workqueue.c:2092
 [<ffffffff81131c56>] worker_thread+0xd6/0x1140 kernel/workqueue.c:2226
 [<ffffffff811429fd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff8280399c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131bbcc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131bbcc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813fe394>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
4 locks held by kworker/u4:1/64:
 #0:  ("writeback"){.+.+.+}, at: [<ffffffff81130d8c>] process_one_work+0x73c/0x1530 kernel/workqueue.c:2085
 #1:  ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff81130dc4>] process_one_work+0x774/0x1530 kernel/workqueue.c:2089
 #2:  (&type->s_umount_key#32){++++.+}, at: [<ffffffff81514b20>] trylock_super+0x20/0xf0 fs/super.c:393
 #3:  (&sbi->s_journal_flag_rwsem){.+.+.+}, at: [<ffffffff81433d0f>] do_writepages+0xef/0x1d0 mm/page-writeback.c:2331
3 locks held by rs:main Q:Reg/1894:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff8156cdac>] __fdget_pos+0xac/0xd0 fs/file.c:781
 #1:  (sb_writers#4){.+.+.+}, at: [<ffffffff8150af2b>] file_start_write include/linux/fs.h:2640 [inline]
 #1:  (sb_writers#4){.+.+.+}, at: [<ffffffff8150af2b>] vfs_write+0x3eb/0x520 fs/read_write.c:556
 #2:  (&sb->s_type->i_mutex_key#9){+.+.+.}, at: [<ffffffff816b2d92>] inode_lock include/linux/fs.h:766 [inline]
 #2:  (&sb->s_type->i_mutex_key#9){+.+.+.}, at: [<ffffffff816b2d92>] ext4_file_write_iter+0x122/0xd70 fs/ext4/file.c:100
2 locks held by getty/2024:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82801892>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d2b2b2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.131+ #50
 ffff8801d9907d08 ffffffff81b37029 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff81098450 ffff8801d9907d40
 ffffffff81b42139 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81b37029>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b37029>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81b42139>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b420cc>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff81098554>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131c15d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131c15d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131c15d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131c15d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff811429fd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff8280399c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2153 Comm: syz-executor348 Not tainted 4.9.131+ #50
task: ffff8801cb192f80 task.stack: ffff8801cad20000
RIP: 0010:[<ffffffff81202a26>] 
c [<ffffffff81202a26>] arch_local_save_flags arch/x86/include/asm/paravirt.h:763 [inline]
RIP: 0010:[<ffffffff81202a26>] 
c [<ffffffff81202a26>] arch_local_irq_save arch/x86/include/asm/paravirt.h:785 [inline]
RIP: 0010:[<ffffffff81202a26>] 
c [<ffffffff81202a26>] lock_is_held+0x56/0x140 kernel/locking/lockdep.c:3790
RSP: 0018:ffff8801cad274a8  EFLAGS: 00000246
RAX: 0000000000000246 RBX: ffff8801cb192f80 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81b9be7b RDI: ffff8801cb19382c
RBP: ffff8801cad274c0 R08: ffff8801cb193918 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801c5094c78
R13: ffffffff830cc2e0 R14: ffff8801c5094c78 R15: 0000000000000000
FS:  0000000001197880(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004550a0 CR3: 00000001cb136000 CR4: 00000000001606b0
Stack:
 0000000000000003
c ffff8801c5094c78
c dffffc0000000000
c ffff8801cad274d8
c
 ffffffff81243993
c 0000000000000000
c ffff8801cad27528
c ffffffff815bc6db
c
 00001000cad27528
c 0000000000008608
c ffff8801d9180b80
c 0000000000008608
c
Call Trace:
 [<ffffffff81243993>] rcu_read_lock_sched_held+0x103/0x120 kernel/rcu/update.c:112
 [<ffffffff815bc6db>] trace_block_touch_buffer include/trace/events/block.h:44 [inline]
 [<ffffffff815bc6db>] touch_buffer fs/buffer.c:64 [inline]
 [<ffffffff815bc6db>] __find_get_block+0x3eb/0x4d0 fs/buffer.c:1364
 [<ffffffff815bd8d8>] __getblk_gfp+0x38/0x700 fs/buffer.c:1382
 [<ffffffff817705ad>] sb_getblk_gfp include/linux/buffer_head.h:325 [inline]
 [<ffffffff817705ad>] __read_extent_tree_block+0xad/0x770 fs/ext4/extents.c:521
 [<ffffffff81773df1>] ext4_find_extent+0x351/0x940 fs/ext4/extents.c:920
 [<ffffffff817b9d56>] get_ext_path fs/ext4/move_extent.c:39 [inline]
 [<ffffffff817b9d56>] mext_check_coverage.constprop.2+0x256/0x400 fs/ext4/move_extent.c:106
 [<ffffffff817bb76b>] move_extent_per_page fs/ext4/move_extent.c:333 [inline]
 [<ffffffff817bb76b>] ext4_move_extents+0x17bb/0x2a50 fs/ext4/move_extent.c:681
 [<ffffffff816ed7fc>] ext4_ioctl+0x27fc/0x3620 fs/ext4/ioctl.c:594
 [<ffffffff81546f1c>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff81546f1c>] file_ioctl fs/ioctl.c:493 [inline]
 [<ffffffff81546f1c>] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677
 [<ffffffff81547f9f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff81547f9f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff828037d3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
cea 
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c00 
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c<0f> 
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c48 
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cfa 
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c44 
c00 
c00 
c65 
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c24 
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c00 
c