Buffer I/O error on dev loop1, logical block 1440, async page read
INFO: task syz-executor5:27466 blocked for more than 120 seconds.
      Not tainted 4.9.94-g8683408 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5   D26872 27466   3869 0x20020004
 ffff8801a64c8000 ffff8801b77af480 ffff8801b77af480 ffff8801cb21e000
 ffff8801db321b98 ffff8801cb6d6fa0 ffffffff839e140d 1ffff100396dade8
 ffffffff85341f38 0000000041b58ab3 00ffffff841c03b8 ffff8801db322468
Call Trace:
 [<ffffffff839e2a0f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839eee21>] schedule_timeout+0x861/0xf70 kernel/time/timer.c:1768
 [<ffffffff839e0bea>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:5180
 [<ffffffff839e3e59>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff839e3e59>] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582
 [<ffffffff839e36fe>] __wait_on_bit_lock+0xce/0x1c0 kernel/sched/wait.c:421
 [<ffffffff8143240f>] __lock_page+0xff/0x160 mm/filemap.c:934
 [<ffffffff81456a78>] lock_page include/linux/pagemap.h:454 [inline]
 [<ffffffff81456a78>] write_cache_pages+0x638/0xef0 mm/page-writeback.c:2214
 [<ffffffff8145740a>] generic_writepages+0xda/0x150 mm/page-writeback.c:2333
 [<ffffffff8162d3ad>] blkdev_writepages+0x1d/0x30 fs/block_dev.c:1764
 [<ffffffff8145ca1f>] do_writepages+0xef/0x1d0 mm/page-writeback.c:2347
 [<ffffffff8143aa83>] __filemap_fdatawrite_range+0x1b3/0x250 mm/filemap.c:390
 [<ffffffff8143ad49>] filemap_write_and_wait_range+0x59/0xb0 mm/filemap.c:580
 [<ffffffff8162c6d6>] blkdev_fsync+0x66/0xb0 fs/block_dev.c:369
 [<ffffffff81617cfc>] vfs_fsync_range+0x10c/0x260 fs/sync.c:195
 [<ffffffff81630de9>] generic_write_sync include/linux/fs.h:2607 [inline]
 [<ffffffff81630de9>] blkdev_write_iter+0x2a9/0x370 fs/block_dev.c:1720
 [<ffffffff8156dea0>] vfs_iter_write+0x2e0/0x460 fs/read_write.c:390
 [<ffffffff81614d2b>] iter_file_splice_write+0x5fb/0xb30 fs/splice.c:768
 [<ffffffff8160fd98>] do_splice_from fs/splice.c:870 [inline]
 [<ffffffff8160fd98>] direct_splice_actor+0x128/0x190 fs/splice.c:1037
 [<ffffffff816110e1>] splice_direct_to_actor+0x2c1/0x7e0 fs/splice.c:992
 [<ffffffff816117a3>] do_splice_direct+0x1a3/0x270 fs/splice.c:1080
 [<ffffffff81572d70>] do_sendfile+0x4f0/0xc60 fs/read_write.c:1393
 [<ffffffff81574f51>] C_SYSC_sendfile fs/read_write.c:1469 [inline]
 [<ffffffff81574f51>] compat_SyS_sendfile+0xd1/0x160 fs/read_write.c:1458
 [<ffffffff81006da7>] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline]
 [<ffffffff81006da7>] do_fast_syscall_32+0x2f7/0x870 arch/x86/entry/common.c:387
 [<ffffffff839f3a10>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

Showing all locks held in the system:
2 locks held by khungtaskd/518:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813646bc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813646bc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81423bb0>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3681:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d565c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3778:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f04b2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff8211c622>] n_tty_read+0x202/0x16b0 drivers/tty/n_tty.c:2133
3 locks held by kworker/u4:0/4502:
 #0:  ("writeback"){++++.+}, at: [<ffffffff8118ad0e>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("writeback"){++++.+}, at: [<ffffffff8118ad0e>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("writeback"){++++.+}, at: [<ffffffff8118ad0e>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("writeback"){++++.+}, at: [<ffffffff8118ad0e>] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085
 #1:  ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff8118ad48>] process_one_work+0x728/0x1500 kernel/workqueue.c:2089
 #2:  (&type->s_umount_key#29){++++..}, at: [<ffffffff81579e90>] trylock_super+0x20/0xf0 fs/super.c:393

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

NMI backtrace for cpu 1
CPU: 1 PID: 518 Comm: khungtaskd Not tainted 4.9.94-g8683408 #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d876fd08 ffffffff81eb0aa9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b7d60 ffff8801d876fd40
 ffffffff81ebbdd7 0000000000000001 0000000000000000 0000000000000002
Call Trace:
 [<ffffffff81eb0aa9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb0aa9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebbdd7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebbd6a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b7e64>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81364c54>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81364c54>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81364c54>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81364c54>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119ad2d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f24dc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff839f0f16