INFO: task loop0:22228 blocked for more than 120 seconds.
      Not tainted 4.9.98-gf5a861c #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
loop0           D27080 22228      2 0x00000000
 ffff88019adf6000 ffff8801d7121500 ffff8801d7121500 ffff88019b526000
 ffff8801db321b98 ffff8801a235edf0 ffffffff839e375d 0000000041b58ab3
 ffffffff843c0f58 ffffffff81234380 00ffffff839f3d5a ffff8801db322468
Call Trace:
 [<ffffffff839e4d5f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839f1171>] schedule_timeout+0x861/0xf70 kernel/time/timer.c:1768
 [<ffffffff839e2f3a>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:5180
 [<ffffffff81e4f0ac>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff81e4f0ac>] bt_get.isra.8+0x27c/0x780 block/blk-mq-tag.c:141
 [<ffffffff81e4ffbc>] __blk_mq_get_tag block/blk-mq-tag.c:163 [inline]
 [<ffffffff81e4ffbc>] blk_mq_get_tag+0xac/0x220 block/blk-mq-tag.c:192
 [<ffffffff81e3f6ea>] __blk_mq_alloc_request+0x2a/0xaa0 block/blk-mq.c:196
 [<ffffffff81e41aeb>] blk_mq_map_request.isra.38+0x3ab/0x900 block/blk-mq.c:1207
 [<ffffffff81e49f36>] blk_sq_make_request+0x1d6/0x1220 block/blk-mq.c:1374
 [<ffffffff81e1ce6e>] generic_make_request+0x20e/0x9b0 block/blk-core.c:2055
 [<ffffffff81e1d6c0>] submit_bio+0xb0/0x460 block/blk-core.c:2126
 [<ffffffff816410aa>] dio_bio_submit fs/direct-io.c:420 [inline]
 [<ffffffff816410aa>] do_blockdev_direct_IO+0x35da/0x5a80 fs/direct-io.c:1301
 [<ffffffff816435f5>] __blockdev_direct_IO+0xa5/0xd0 fs/direct-io.c:1360
 [<ffffffff8162d1a0>] blkdev_direct_IO+0xa0/0xd0 fs/block_dev.c:183
 [<ffffffff8143c760>] generic_file_read_iter+0x660/0x1a90 mm/filemap.c:1951
 [<ffffffff8162fda5>] blkdev_read_iter+0x105/0x170 fs/block_dev.c:1738
 [<ffffffff825cae93>] lo_rw_aio+0x6b3/0x8a0 drivers/block/loop.c:506
 [<ffffffff825cb457>] do_req_filebacked drivers/block/loop.c:543 [inline]
 [<ffffffff825cb457>] loop_handle_cmd drivers/block/loop.c:1698 [inline]
 [<ffffffff825cb457>] loop_queue_work+0x3d7/0x2320 drivers/block/loop.c:1710
 [<ffffffff8119b139>] kthread_worker_fn+0x249/0x6b0 kernel/kthread.c:627
 [<ffffffff8119ad5d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f481c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373

Showing all locks held in the system:
2 locks held by khungtaskd/519:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813646ec>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813646ec>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81423ce0>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3770:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f2802>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff8211ccf2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
1 lock held by syz-executor0/3858:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff825c77fb>] lo_ioctl+0x8b/0x1aa0 drivers/block/loop.c:1344
1 lock held by syz-executor7/29201:
 #0:  (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<ffffffff825c9320>] lo_compat_ioctl+0x110/0x140 drivers/block/loop.c:1522
1 lock held by syz-executor7/29234:
 #0:  (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<ffffffff825c9320>] lo_compat_ioctl+0x110/0x140 drivers/block/loop.c:1522

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

NMI backtrace for cpu 1
CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.98-gf5a861c #19
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d861fd08 ffffffff81eb0fc9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b7da0 ffff8801d861fd40
 ffffffff81ebc2c7 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb0fc9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb0fc9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebc2c7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebc25a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b7ea4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81364c84>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81364c84>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81364c84>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81364c84>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119ad5d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f481c>] 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 0xffffffff839f3266