binder: 16151:16178 unknown command 0
binder: 16151:16178 ioctl c0306201 20008fd0 returned -22
binder: release 16151:16158 transaction 25 out, still active
binder: undelivered TRANSACTION_COMPLETE
binder: send failed reply for transaction 25, target dead
INFO: task loop0:13015 blocked for more than 120 seconds.
      Not tainted 4.17.0-rc2+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
loop0           D25232 13015      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2848 [inline]
 __schedule+0x801/0x1e30 kernel/sched/core.c:3490
 schedule+0xef/0x430 kernel/sched/core.c:3549
 schedule_timeout+0x1b5/0x240 kernel/time/timer.c:1777
 io_schedule_timeout+0x26/0x80 kernel/sched/core.c:5157
 do_wait_for_common kernel/sched/completion.c:83 [inline]
 __wait_for_common kernel/sched/completion.c:104 [inline]
 wait_for_common_io kernel/sched/completion.c:121 [inline]
 wait_for_completion_io+0x3e7/0x870 kernel/sched/completion.c:169
 submit_bio_wait+0x13c/0x1e0 block/bio.c:947
 blkdev_issue_flush+0x226/0x320 block/blk-flush.c:548
 blkdev_fsync+0x93/0xd0 fs/block_dev.c:632
 vfs_fsync_range+0x140/0x220 fs/sync.c:197
 vfs_fsync+0x29/0x30 fs/sync.c:211
 lo_req_flush drivers/block/loop.c:444 [inline]
 do_req_filebacked drivers/block/loop.c:594 [inline]
 loop_handle_cmd drivers/block/loop.c:1772 [inline]
 loop_queue_work+0x14e6/0x3a08 drivers/block/loop.c:1786
 kthread_worker_fn+0x357/0xa30 kernel/kthread.c:642
 loop_kthread_worker_fn+0x51/0x60 drivers/block/loop.c:863
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

Showing all locks held in the system:
2 locks held by khungtaskd/892:
 #0: 000000000308f499 (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
 #0: 000000000308f499 (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249
 #1: 000000006a2b0902 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470
1 lock held by rsyslogd/4310:
 #0: 0000000033981534 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1a9/0x1e0 fs/file.c:766
2 locks held by getty/4401:
 #0: 00000000ac639930 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000fef667b8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4402:
 #0: 000000000e4d96a2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000001c7c85dc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4403:
 #0: 00000000d4675fbb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000050dac30 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4404:
 #0: 000000007f1e595f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000000d8ac43f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4405:
 #0: 0000000062bed992 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000e6c3da3f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4406:
 #0: 00000000bfea8a7b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000b1d91657 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4407:
 #0: 000000007bdc0972 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000c075b486 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131

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

NMI backtrace for cpu 0
CPU: 0 PID: 892 Comm: khungtaskd Not tainted 4.17.0-rc2+ #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x151/0x192 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+0xc10/0xf60 kernel/hung_task.c:249
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54