Buffer I/O error on dev loop0, logical block 1, lost async page write
INFO: task syz-executor3:5928 blocked for more than 120 seconds.
      Not tainted 4.9.89-ge34e318 #64
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor3   D29472  5928   3879 0x00000004
 ffff8801c7ad0000 0000000000000000 ffff8801bb7fdf80 ffff8801d9b73000
 ffff8801db321b98 ffff8801ae33fa10 ffffffff838a4c0b 0000000041b58ab3
 ffffffff84193da8 00ffffff81239af0 ffff8801db322468 ffff8801db322490
Call Trace:
 [<ffffffff838a61af>] schedule+0x7f/0x1b0 kernel/sched/core.c:3551
 [<ffffffff838b216c>] schedule_timeout+0x56c/0x10b0 kernel/time/timer.c:1768
 [<ffffffff838a43be>] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:5173
 [<ffffffff838a7629>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff838a7629>] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582
 [<ffffffff838a6d07>] __wait_on_bit+0x57/0x120 kernel/sched/wait.c:383
 [<ffffffff81430204>] wait_on_page_bit+0xf4/0x140 mm/filemap.c:802
 [<ffffffff81430411>] wait_on_page_writeback include/linux/pagemap.h:526 [inline]
 [<ffffffff81430411>] __filemap_fdatawait_range+0x1c1/0x2b0 mm/filemap.c:453
 [<ffffffff81430525>] filemap_fdatawait_range+0x25/0x50 mm/filemap.c:483
 [<ffffffff81614bdb>] SYSC_sync_file_range fs/sync.c:346 [inline]
 [<ffffffff81614bdb>] SyS_sync_file_range+0x1bb/0x220 fs/sync.c:283
 [<ffffffff81006504>] do_syscall_64+0x1a4/0x490 arch/x86/entry/common.c:282
 [<ffffffff838b5ad3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
3 locks held by kworker/u4:0/6:
 #0:  ("writeback"){.+.+.+}, at: [<ffffffff81189f42>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("writeback"){.+.+.+}, at: [<ffffffff81189f42>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("writeback"){.+.+.+}, at: [<ffffffff81189f42>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("writeback"){.+.+.+}, at: [<ffffffff81189f42>] process_one_work+0x6f2/0x1610 kernel/workqueue.c:2085
 #1:  ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff81189f7c>] process_one_work+0x72c/0x1610 kernel/workqueue.c:2089
 #2:  (&type->s_umount_key#22){.+.+..}, at: [<ffffffff81577b80>] trylock_super+0x20/0x100 fs/super.c:393
2 locks held by khungtaskd/516:
 #0:  (rcu_read_lock){......}, at: [<ffffffff81370ca5>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff81370ca5>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81235c50>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336
2 locks held by getty/3778:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838b3ce2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff82008bc4>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133

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

NMI backtrace for cpu 0
CPU: 0 PID: 516 Comm: khungtaskd Not tainted 4.9.89-ge34e318 #64
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d85dfd00 ffffffff81d93609 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810bb690 ffff8801d85dfd38
 ffffffff81d9e72d 0000000000000000 0000000000000000 ffff8801bb461c18
Call Trace:
 [<ffffffff81d93609>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d93609>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81d9e72d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81d9e867>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810bb784>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81371270>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81371270>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81371270>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81371270>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff8119af4d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838b5c9c>] 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 skipped: idling at pc 0xffffffff838b4756