Buffer I/O error on dev loop0, logical block 0, async page read
INFO: task syz-executor1:21866 blocked for more than 120 seconds.
      Not tainted 4.9.89-gf361eb3 #2
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor1   D27776 21866   3874 0x20020004
 ffff8801cbcec800 0000000000000000 ffff8801cdb07480 ffff8801d9b73000
 ffff8801db321b98 ffff8801d7a77140 ffffffff838a6c0b 0000000041b58ab3
 ffffffff84194320 00ffffff8123c550 ffff8801db322468 ffff8801db322490
Call Trace:
 [<ffffffff838a81af>] schedule+0x7f/0x1b0 kernel/sched/core.c:3551
 [<ffffffff838b416c>] schedule_timeout+0x56c/0x10b0 kernel/time/timer.c:1768
 [<ffffffff838a63be>] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:5173
 [<ffffffff838a9629>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff838a9629>] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582
 [<ffffffff838a8e92>] __wait_on_bit_lock+0xc2/0x1c0 kernel/sched/wait.c:421
 [<ffffffff8143346f>] __lock_page+0xff/0x160 mm/filemap.c:934
 [<ffffffff8146b708>] lock_page include/linux/pagemap.h:454 [inline]
 [<ffffffff8146b708>] invalidate_inode_pages2_range+0x668/0xad0 mm/truncate.c:614
 [<ffffffff8143c118>] generic_file_direct_write+0x418/0x500 mm/filemap.c:2629
 [<ffffffff8143c41f>] __generic_file_write_iter+0x21f/0x570 mm/filemap.c:2823
 [<ffffffff8162dcac>] blkdev_write_iter+0x1bc/0x380 fs/block_dev.c:1718
 [<ffffffff8156e830>] vfs_iter_write+0x2e0/0x450 fs/read_write.c:390
 [<ffffffff81613a95>] iter_file_splice_write+0x5b5/0xb60 fs/splice.c:768
 [<ffffffff8160e8d5>] do_splice_from fs/splice.c:870 [inline]
 [<ffffffff8160e8d5>] direct_splice_actor+0x125/0x180 fs/splice.c:1037
 [<ffffffff8160fe9c>] splice_direct_to_actor+0x2cc/0x800 fs/splice.c:992
 [<ffffffff81610577>] do_splice_direct+0x1a7/0x270 fs/splice.c:1080
 [<ffffffff8157354b>] do_sendfile+0x54b/0xd30 fs/read_write.c:1393
 [<ffffffff81575601>] C_SYSC_sendfile fs/read_write.c:1469 [inline]
 [<ffffffff81575601>] compat_SyS_sendfile+0xd1/0x160 fs/read_write.c:1458
 [<ffffffff81006f95>] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline]
 [<ffffffff81006f95>] do_fast_syscall_32+0x2f5/0x870 arch/x86/entry/common.c:387
 [<ffffffff838b9210>] 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/515:
 #0:  (rcu_read_lock){......}, at: [<ffffffff81373705>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff81373705>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff812386b0>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3650:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d449f>] __fdget_pos+0x9f/0xc0 fs/file.c:781
2 locks held by getty/3778:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838b5ce2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff8200b5a4>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
1 lock held by blkid/20246:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8162e61c>] __blkdev_put+0xbc/0x7e0 fs/block_dev.c:1579

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

NMI backtrace for cpu 0
CPU: 0 PID: 515 Comm: khungtaskd Not tainted 4.9.89-gf361eb3 #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d87d7d00 ffffffff81d96069 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810bb690 ffff8801d87d7d38
 ffffffff81da118d 0000000000000000 0000000000000000 ffff8801ce7acc18
Call Trace:
 [<ffffffff81d96069>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d96069>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81da118d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81da12c7>] 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
 [<ffffffff81373cd0>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81373cd0>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81373cd0>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81373cd0>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff8119af4d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838b7c9c>] 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 0xffffffff838b6756