INFO: task syz-executor.4:2116 blocked for more than 140 seconds.
      Not tainted 4.9.165+ #28
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D24872  2116      1 0x00000004
 ffff8801ceafc740 0000000000000000 ffff8801db621000 ffffffff83031180
 ffff8801db621018 ffff8801ab20fc48 ffffffff827fbd7e ffff8801ceafc740
 ffffffff8280b91a 0000000000000000 ffff8801db6218f0 1ffff10035641f78
Call Trace:
 [<ffffffff827fd652>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
 [<ffffffff827fdff3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579
 [<ffffffff827fff4d>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff827fff4d>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621
 [<ffffffff815cfcfb>] blkdev_put+0x2b/0x560 fs/block_dev.c:1629
 [<ffffffff815d02bb>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1678
 [<ffffffff81515d84>] __fput+0x274/0x720 fs/file_table.c:208
 [<ffffffff815162b6>] ____fput+0x16/0x20 fs/file_table.c:244
 [<ffffffff8113d1f8>] task_work_run+0x108/0x180 kernel/task_work.c:116
 [<ffffffff81003deb>] tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 [<ffffffff81003deb>] exit_to_usermode_loop+0x13b/0x160 arch/x86/entry/common.c:162
 [<ffffffff81005907>] prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 [<ffffffff81005907>] syscall_return_slowpath arch/x86/entry/common.c:263 [inline]
 [<ffffffff81005907>] do_syscall_64+0x3f7/0x570 arch/x86/entry/common.c:290
 [<ffffffff8280c213>] 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: [<ffffffff8131d3fc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131d3fc>] watchdog+0x13c/0xae0 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff8140072f>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/1898:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff81572b48>] __fdget_pos+0xa8/0xd0 fs/file.c:781
2 locks held by getty/2025:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff8280a2e3>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d3daee>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.4/2116:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815cfcfb>] blkdev_put+0x2b/0x560 fs/block_dev.c:1629
1 lock held by syz-executor.3/2133:
 #0:  (loop_ctl_mutex/1){+.+.+.}, at: [<ffffffff81deefe5>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405
1 lock held by syz-executor.2/2134:
 #0:  (loop_ctl_mutex/1){+.+.+.}, at: [<ffffffff81deefe5>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405
1 lock held by syz-executor.1/6811:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815cef2e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
3 locks held by blkid/6821:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815ce69b>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81df34fe>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664
 #2:  (loop_ctl_mutex#2){+.+.+.}, at: [<ffffffff81df3564>] __lo_release drivers/block/loop.c:1642 [inline]
 #2:  (loop_ctl_mutex#2){+.+.+.}, at: [<ffffffff81df3564>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665
2 locks held by syz-executor.5/6826:
 #0:  (loop_ctl_mutex/1){+.+.+.}, at: [<ffffffff81deefe5>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81b149ef>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
1 lock held by syz-executor.5/6831:
 #0:  (loop_ctl_mutex/1){+.+.+.}, at: [<ffffffff81deefe5>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405
1 lock held by syz-executor.5/6841:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815cef2e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
1 lock held by syz-executor.0/6833:
 #0:  (loop_ctl_mutex/1){+.+.+.}, at: [<ffffffff81deefe5>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405
2 locks held by blkid/6834:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815cef2e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81de8abd>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622
2 locks held by blkid/6835:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815cef2e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81de8abd>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622
2 locks held by blkid/6836:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815cef2e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81de8abd>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622
2 locks held by blkid/6839:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815cef2e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81de8abd>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.165+ #28
 ffff8801d98d7cc8 ffffffff81b4baf1 0000000000000001 0000000000000000
 0000000000000001 ffffffff81097401 dffffc0000000000 ffff8801d98d7d00
 ffffffff81b56d7c 0000000000000001 0000000000000000 0000000000000001
Call Trace:
 [<ffffffff81b4baf1>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b4baf1>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<ffffffff81b56d7c>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b56d04>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60
 [<ffffffff81097594>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131d921>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131d921>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131d921>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131d921>] watchdog+0x661/0xae0 kernel/hung_task.c:239
 [<ffffffff81142298>] kthread+0x278/0x310 kernel/kthread.c:211
 [<ffffffff8280c3dc>] 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
CPU: 0 PID: 1895 Comm: rs:main Q:Reg Not tainted 4.9.165+ #28
task: ffff8801d3c197c0 task.stack: ffff8801d3838000
RIP: 0010:[<ffffffff8131cd50>] 
c [<ffffffff8131cd50>] __sanitizer_cov_trace_pc+0x0/0x50 kernel/kcov.c:93
RSP: 0018:ffff8801d383fe00  EFLAGS: 00000283
RAX: ffff8801d3c197c0 RBX: ffff8801d3c2ca00 RCX: ffff8801d383fe88
RDX: 0000000000000000 RSI: ffffffff815106a5 RDI: ffff8801d3c1aae0
RBP: ffff8801d383fe40 R08: 0000000000000000 R09: ffff8801d3c1a090
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000400
R13: 00007ffffffff000 R14: ffff8801d383fe88 R15: ffff8801d3c2ca74
FS:  00007f7585911700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001afb000 CR3: 00000001d41fd000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff815106b4
c 0000000001aee740
c 0000000001aee340
c ffff8801d3c2ca03
c
 ffff8801d3c2ca00
c 1ffff1003a707fcd
c ffff8801d383fec8
c dffffc0000000000
c
 ffff8801d383fef0
c ffffffff8151452c
c ffff8801d3c2caf8
c 0000000000000400
c
Call Trace:
 [<ffffffff8151452c>] SYSC_write fs/read_write.c:606 [inline]
 [<ffffffff8151452c>] SyS_write+0xdc/0x1c0 fs/read_write.c:598
 [<ffffffff810056bd>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285
 [<ffffffff8280c213>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
cfe 
cff 
cff 
c48 
c89 
cdf 
ce8 
c90 
cb8 
c1d 
c00 
ce9 
c9a 
cfe 
cff 
cff 
c4c 
c89 
cef 
ce8 
c83 
cb8 
c1d 
c00 
ce9 
c1e 
cfe 
cff 
cff 
c66 
c2e 
c0f 
c1f 
c84 
c00 
c00 
c00 
c00 
c00 
c0f 
c1f 
c40 
c00 
c<55> 
c48 
c89 
ce5 
c48 
c8b 
c75 
c08 
c65 
c48 
c8b 
c04 
c25 
c00 
c7e 
c01 
c00 
c65 
c8b 
c15 
c28 
c