INFO: task syz-executor.3:2113 blocked for more than 140 seconds.
      Not tainted 4.9.169+ #43
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D24840  2113      1 0x00000004
 ffff8801d02a5f00 ffff8801d3048000 ffff8801db721000 ffff8801d3b897c0
 ffff8801db721018 ffff8801ab297a28 ffffffff8280152e ffffffff82e2ba28
 ffffffff81208040 00ff8801ab297a48 ffff8801db7218f0 1ffff10035652f34
Call Trace:
 [<00000000fcbcc019>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
 [<00000000e4851ceb>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579
 [<00000000957ab515>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<00000000957ab515>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621
 [<000000000cd9bdda>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405
 [<000000004a9f4bb9>] __blkdev_driver_ioctl block/ioctl.c:294 [inline]
 [<000000004a9f4bb9>] blkdev_ioctl+0xe14/0x19e0 block/ioctl.c:590
 [<000000006a98cf06>] block_ioctl+0xde/0x120 fs/block_dev.c:1696
 [<00000000b465bbe3>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<00000000b465bbe3>] file_ioctl fs/ioctl.c:493 [inline]
 [<00000000b465bbe3>] do_vfs_ioctl+0xb87/0x11d0 fs/ioctl.c:677
 [<00000000073d0719>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<00000000073d0719>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<000000005da9d28f>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285
 [<00000000988059e7>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<00000000c7e02324>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<00000000c7e02324>] watchdog+0x13c/0xae0 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<0000000016cc509e>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339
2 locks held by getty/2022:
 #0:  (&tty->ldisc_sem){++++++}, at: [<000000005dd4b568>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<0000000092fa22b3>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.3/2113:
 #0:  (loop_ctl_mutex/1){+.+.+.}, at: [<000000000cd9bdda>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405
1 lock held by syz-executor.4/2119:
 #0:  (loop_ctl_mutex/1){+.+.+.}, at: [<000000000cd9bdda>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405
1 lock held by syz-executor.1/2128:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<0000000037364f0b>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
3 locks held by syz-executor.2/2130:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000cbd5847c>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587
 #1:  (loop_index_mutex){+.+.+.}, at: [<00000000b906c0b0>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664
 #2:  (loop_ctl_mutex#2){+.+.+.}, at: [<000000003991f4c9>] __lo_release drivers/block/loop.c:1642 [inline]
 #2:  (loop_ctl_mutex#2){+.+.+.}, at: [<000000003991f4c9>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665
2 locks held by syz-executor.5/15549:
 #0:  (loop_ctl_mutex/1){+.+.+.}, at: [<000000000cd9bdda>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<000000003957d6ad>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
2 locks held by blkid/15558:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<0000000037364f0b>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<00000000796840b4>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622
2 locks held by blkid/15560:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<0000000037364f0b>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<00000000796840b4>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622
1 lock held by blkid/15562:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<0000000037364f0b>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.169+ #43
 ffff8801d98d7cc8 ffffffff81b4f7f1 0000000000000000 0000000000000000
 0000000000000000 ffffffff81097401 dffffc0000000000 ffff8801d98d7d00
 ffffffff81b5aa8c 0000000000000000 0000000000000000 0000000000000000
Call Trace:
 [<000000000f1f8e2d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<000000000f1f8e2d>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<00000000708e7561>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99
 [<00000000091ab042>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60
 [<00000000abc9aa0d>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<00000000ace0012c>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<00000000ace0012c>] check_hung_task kernel/hung_task.c:125 [inline]
 [<00000000ace0012c>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<00000000ace0012c>] watchdog+0x661/0xae0 kernel/hung_task.c:239
 [<00000000505c0dbb>] kthread+0x278/0x310 kernel/kthread.c:211
 [<0000000068b4a6b0>] 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 0xffffffff828105a2