INFO: task syz-executor.3:2142 blocked for more than 140 seconds.
      Not tainted 4.9.170+ #45
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D24824  2142      1 0x00000004
 ffff8801d045af80 ffff8801d1f8ac00 ffff8801db621000 ffff8801cf75c740
 ffff8801db621018 ffff8801a67e7b28 ffffffff8280185e 0000000041b58ab3
 ffff8801a67e7aa0 00ffffff81bb61ac ffff8801db6218f0 1ffff10034cfcf54
Call Trace:
 [<000000004a0629fd>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
 [<0000000050985cde>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579
 [<00000000ade6b640>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<00000000ade6b640>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621
 [<000000005ce6b262>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664
 [<0000000077355549>] __blkdev_put+0x461/0x840 fs/block_dev.c:1606
 [<00000000658656b4>] blkdev_put+0x88/0x560 fs/block_dev.c:1671
 [<000000001b5a3422>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1678
 [<00000000b722aab9>] __fput+0x274/0x720 fs/file_table.c:208
 [<00000000755a718e>] ____fput+0x16/0x20 fs/file_table.c:244
 [<000000009393e16e>] task_work_run+0x108/0x180 kernel/task_work.c:116
 [<000000003fd39aee>] tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 [<000000003fd39aee>] exit_to_usermode_loop+0x13b/0x160 arch/x86/entry/common.c:162
 [<0000000059f2950e>] prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 [<0000000059f2950e>] syscall_return_slowpath arch/x86/entry/common.c:263 [inline]
 [<0000000059f2950e>] do_syscall_64+0x3f7/0x570 arch/x86/entry/common.c:290
 [<000000001db22f20>] 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: [<000000004b9c6388>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline]
 #0:  (rcu_read_lock){......}, at: [<000000004b9c6388>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263
 #1:  (tasklist_lock){.+.+..}, at: [<000000004075eb85>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339
1 lock held by rsyslogd/1915:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<000000002897c33a>] __fdget_pos+0xa8/0xd0 fs/file.c:782
2 locks held by getty/2043:
 #0:  (&tty->ldisc_sem){++++++}, at: [<000000002b040953>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<00000000cacee5ea>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.3/2142:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000415f6a75>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587
 #1:  (loop_index_mutex){+.+.+.}, at: [<000000005ce6b262>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664
2 locks held by syz-executor.4/2150:
 #0:  (loop_ctl_mutex/1){+.+.+.}, at: [<00000000c2133054>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<0000000012cbd09d>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
3 locks held by syz-executor.2/5646:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000415f6a75>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587
 #1:  (loop_index_mutex){+.+.+.}, at: [<000000005ce6b262>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664
 #2:  (loop_ctl_mutex#2){+.+.+.}, at: [<00000000e5727ac6>] __lo_release drivers/block/loop.c:1642 [inline]
 #2:  (loop_ctl_mutex#2){+.+.+.}, at: [<00000000e5727ac6>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665
1 lock held by blkid/5677:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<000000009ede210e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
2 locks held by blkid/5680:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<000000009ede210e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<00000000da5d8c0d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622
2 locks held by syz-executor.2/5724:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<000000009ede210e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<00000000da5d8c0d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.170+ #45
 ffff8801d98d7cc8 ffffffff81b4fb21 0000000000000000 0000000000000000
 0000000000000000 ffffffff81097401 dffffc0000000000 ffff8801d98d7d00
 ffffffff81b5adbc 0000000000000000 0000000000000000 0000000000000000
Call Trace:
 [<0000000093fbe77f>] __dump_stack lib/dump_stack.c:15 [inline]
 [<0000000093fbe77f>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<00000000622d3d3d>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99
 [<00000000aa7e0a40>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60
 [<00000000eb35c334>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<00000000694a90b4>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<00000000694a90b4>] check_hung_task kernel/hung_task.c:126 [inline]
 [<00000000694a90b4>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline]
 [<00000000694a90b4>] watchdog+0x670/0xaf0 kernel/hung_task.c:263
 [<00000000caee3376>] kthread+0x278/0x310 kernel/kthread.c:211
 [<00000000ef475d78>] 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 0xffffffff828108d2