Buffer I/O error on dev loop0, logical block 3, async page read
INFO: task syz-executor3:29210 blocked for more than 120 seconds.
      Not tainted 4.16.0-rc6+ #360
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor3   D23232 29210   4165 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2862 [inline]
 __schedule+0x8fb/0x1ec0 kernel/sched/core.c:3440
 schedule+0xf5/0x430 kernel/sched/core.c:3499
 io_schedule+0x1c/0x70 kernel/sched/core.c:5115
 wait_on_page_bit_common+0x4b3/0x770 mm/filemap.c:1099
 wait_on_page_bit mm/filemap.c:1132 [inline]
 wait_on_page_writeback include/linux/pagemap.h:546 [inline]
 __filemap_fdatawait_range+0x282/0x430 mm/filemap.c:533
 filemap_fdatawait_keep_errors+0x2a/0xb0 mm/filemap.c:600
 fdatawait_one_bdev+0x50/0x70 fs/sync.c:95
 iterate_bdevs+0x109/0x260 fs/block_dev.c:2162
 sys_sync+0x120/0x1c0 fs/sync.c:117
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x453e69
RSP: 002b:00007fd9c929bc68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fd9c929c6d4 RCX: 0000000000453e69
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000061a R14: 00000000006f9310 R15: 0000000000000000

Showing all locks held in the system:
1 lock held by rcu_sched/8:
 #0:  (&rq->lock){-.-.}, at: [<00000000263617db>] rq_lock kernel/sched/sched.h:1760 [inline]
 #0:  (&rq->lock){-.-.}, at: [<00000000263617db>] __schedule+0x24e/0x1ec0 kernel/sched/core.c:3378
2 locks held by khungtaskd/801:
 #0:  (rcu_read_lock){....}, at: [<0000000031480d82>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
 #0:  (rcu_read_lock){....}, at: [<0000000031480d82>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249
 #1:  (tasklist_lock){.+.+}, at: [<000000005ad7abb5>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470
1 lock held by rsyslogd/3962:
 #0:  (&f->f_pos_lock){+.+.}, at: [<00000000491d89db>] __fdget_pos+0x12b/0x190 fs/file.c:765
2 locks held by getty/4084:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000450d49bb>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000426d7ff3>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4085:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000450d49bb>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000426d7ff3>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4086:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000450d49bb>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000426d7ff3>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4087:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000450d49bb>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000426d7ff3>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4088:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000450d49bb>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000426d7ff3>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4089:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000450d49bb>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000426d7ff3>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
2 locks held by getty/4090:
 #0:  (&tty->ldisc_sem){++++}, at: [<00000000450d49bb>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000426d7ff3>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131
3 locks held by kworker/u4:5/6631:
 #0:  ((wq_completion)"writeback"){+.+.}, at: [<000000001fcca556>] work_static include/linux/workqueue.h:198 [inline]
 #0:  ((wq_completion)"writeback"){+.+.}, at: [<000000001fcca556>] set_work_data kernel/workqueue.c:619 [inline]
 #0:  ((wq_completion)"writeback"){+.+.}, at: [<000000001fcca556>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
 #0:  ((wq_completion)"writeback"){+.+.}, at: [<000000001fcca556>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084
 #1:  ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: [<00000000cf04cffb>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088
 #2:  (&type->s_umount_key#27){++++}, at: [<00000000ac1258fe>] trylock_super+0x20/0x100 fs/super.c:395
1 lock held by blkid/28639:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000fe33589a>] blkdev_put+0x2a/0x4f0 fs/block_dev.c:1808
1 lock held by syz-executor3/29210:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<000000004c247111>] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2160
1 lock held by syz-executor3/29225:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<000000004c247111>] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2160

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

NMI backtrace for cpu 1
CPU: 1 PID: 801 Comm: khungtaskd Not tainted 4.16.0-rc6+ #360
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x24d lib/dump_stack.c:53
 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x123/0x180 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
 check_hung_task kernel/hung_task.c:132 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
 watchdog+0x90c/0xd60 kernel/hung_task.c:249
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54