INFO: task loop0:4014 blocked for more than 120 seconds.
      Not tainted 4.9.64-gfbb7468 #94
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
loop0           D26848  4014      2 0x00000000
 ffff8801ca911800 ffff8801aac33480 ffff8801c85ef480 ffff8801aa451800
 ffff8801db221418 ffff8801ce846d30 ffffffff83897fdb ffffffff812395a0
 0000000000000000 00ff8801ce846e98 ffff8801db221d40 ffff8801db221d68
Call Trace:
 [<ffffffff8389957f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3540
 [<ffffffff838a57b3>] schedule_timeout+0x643/0x1220 kernel/time/timer.c:1770
 [<ffffffff8389778e>] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:5162
 [<ffffffff81d2dec2>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff81d2dec2>] bt_get.isra.8+0x2d2/0x780 block/blk-mq-tag.c:141
 [<ffffffff81d2ecbc>] __blk_mq_get_tag block/blk-mq-tag.c:163 [inline]
 [<ffffffff81d2ecbc>] blk_mq_get_tag+0xac/0x230 block/blk-mq-tag.c:192
 [<ffffffff81d1e8e7>] __blk_mq_alloc_request+0x27/0xab0 block/blk-mq.c:196
 [<ffffffff81d21021>] blk_mq_map_request+0x3f1/0x920 block/blk-mq.c:1207
 [<ffffffff81d28e2f>] blk_sq_make_request+0x1cf/0x12d0 block/blk-mq.c:1374
 [<ffffffff81cfbc0e>] generic_make_request+0x30e/0x990 block/blk-core.c:2053
 [<ffffffff81cfc386>] submit_bio+0xf6/0x4e0 block/blk-core.c:2124
 [<ffffffff816364b1>] dio_bio_submit fs/direct-io.c:420 [inline]
 [<ffffffff816364b1>] do_blockdev_direct_IO+0x61b1/0x7ab0 fs/direct-io.c:1301
 [<ffffffff81637e55>] __blockdev_direct_IO+0xa5/0xd0 fs/direct-io.c:1360
 [<ffffffff81626fa0>] blkdev_direct_IO+0xa0/0xd0 fs/block_dev.c:183
 [<ffffffff81439fe3>] generic_file_read_iter+0x793/0x1ac0 mm/filemap.c:1952
 [<ffffffff81627f95>] blkdev_read_iter+0x105/0x170 fs/block_dev.c:1738
 [<ffffffff824b1b13>] lo_rw_aio+0x4b3/0x890 drivers/block/loop.c:506
 [<ffffffff824b34f4>] do_req_filebacked drivers/block/loop.c:543 [inline]
 [<ffffffff824b34f4>] loop_handle_cmd drivers/block/loop.c:1685 [inline]
 [<ffffffff824b34f4>] loop_queue_work+0x1604/0x22b0 drivers/block/loop.c:1697
 [<ffffffff81198a76>] kthread_worker_fn+0x306/0x6a0 kernel/kthread.c:627
 [<ffffffff811985dd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838a9a2a>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433

Showing all locks held in the system:
2 locks held by khungtaskd/514:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136fed5>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136fed5>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81235700>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3119:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815cf99f>] __fdget_pos+0x9f/0xc0 fs/file.c:781
2 locks held by getty/3207:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a79a2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff82001b14>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133

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

NMI backtrace for cpu 1
CPU: 1 PID: 514 Comm: khungtaskd Not tainted 4.9.64-gfbb7468 #94
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d93b7d00 ffffffff81d90429 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810ba170 ffff8801d93b7d38
 ffffffff81d9b54d 0000000000000001 0000000000000000 ffff8801ca911c18
Call Trace:
 [<ffffffff81d90429>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d90429>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81d9b54d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81d9b687>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810ba264>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff813704a0>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff813704a0>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff813704a0>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff813704a0>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff811985dd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838a9a2a>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff838a8416