INFO: task syz-executor.4:2113 blocked for more than 140 seconds.
      Not tainted 4.9.185+ #8
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D25016  2113      1 0x00000004
 0000000000000087 ffff8801c833c740 ffff8801d1326300 ffff8801db621000
 ffff8801d22fc740 ffff8801db621018 ffff8801a62d76a8 ffffffff8280c5ae
 0000000000000246 ffffffff831f3408 00ff8801c833cfe8 ffff8801db6218f0
Call Trace:
 [<000000000b0a3120>] schedule+0x92/0x1c0 /kernel/sched/core.c:3546
 [<00000000779089d0>] schedule_preempt_disabled+0x13/0x20 /kernel/sched/core.c:3579
 [<000000000b9d964f>] __mutex_lock_common /kernel/locking/mutex.c:582 [inline]
 [<000000000b9d964f>] mutex_lock_nested+0x38d/0x920 /kernel/locking/mutex.c:621
 [<00000000d062ed1f>] __blkdev_get+0x10e/0xeb0 /fs/block_dev.c:1273
 [<000000006c0e4ff1>] blkdev_get+0x2e8/0x920 /fs/block_dev.c:1424
 [<00000000b26d9959>] blkdev_open+0x1aa/0x250 /fs/block_dev.c:1579
 [<00000000a4b095ca>] do_dentry_open+0x422/0xd20 /fs/open.c:772
 [<00000000bfee746c>] vfs_open+0x105/0x230 /fs/open.c:885
 [<000000000f9c6d5f>] do_last /fs/namei.c:3457 [inline]
 [<000000000f9c6d5f>] path_openat+0xbf5/0x2f60 /fs/namei.c:3581
 [<000000004680a9dd>] do_filp_open+0x1a1/0x280 /fs/namei.c:3615
 [<00000000969dadc4>] do_sys_open+0x2f0/0x610 /fs/open.c:1078
 [<0000000066a984fd>] SYSC_open /fs/open.c:1096 [inline]
 [<0000000066a984fd>] SyS_open+0x2d/0x40 /fs/open.c:1091
 [<000000006280b378>] do_syscall_64+0x1ad/0x5c0 /arch/x86/entry/common.c:288
 [<000000003a383c19>] 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: [<000000009771c23c>] check_hung_uninterruptible_tasks /kernel/hung_task.c:169 [inline]
 #0:  (rcu_read_lock){......}, at: [<000000009771c23c>] watchdog+0x14b/0xaf0 /kernel/hung_task.c:263
 #1:  (tasklist_lock){.+.+..}, at: [<000000001f10a445>] debug_show_all_locks+0x7f/0x21f /kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/1897:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<000000000694b0b6>] __fdget_pos+0xa8/0xd0 /fs/file.c:782
2 locks held by getty/2025:
 #0:  (&tty->ldisc_sem){++++++}, at: [<00000000884391c2>] ldsem_down_read+0x33/0x40 /drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<00000000b9c775eb>] n_tty_read+0x1fe/0x1820 /drivers/tty/n_tty.c:2156
1 lock held by syz-executor.4/2113:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000d062ed1f>] __blkdev_get+0x10e/0xeb0 /fs/block_dev.c:1273
2 locks held by syz-executor.0/11614:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<00000000156bd7c2>] lo_ioctl+0x8e/0x1b10 /drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000d2571c37>] blkdev_reread_part+0x1f/0x40 /block/ioctl.c:189
1 lock held by syz-executor.0/11632:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000d062ed1f>] __blkdev_get+0x10e/0xeb0 /fs/block_dev.c:1273
2 locks held by syz-executor.5/11612:
 #0:  (loop_index_mutex){+.+.+.}, at: [<0000000098a89429>] loop_control_ioctl+0x7a/0x320 /drivers/block/loop.c:1973
 #1:  (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<000000006974ac7d>] loop_control_ioctl+0x17f/0x320 /drivers/block/loop.c:1987
2 locks held by blkid/11626:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000d062ed1f>] __blkdev_get+0x10e/0xeb0 /fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<00000000c38ff8e7>] lo_open+0x1d/0xb0 /drivers/block/loop.c:1621
2 locks held by blkid/11628:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<00000000d062ed1f>] __blkdev_get+0x10e/0xeb0 /fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<00000000c38ff8e7>] lo_open+0x1d/0xb0 /drivers/block/loop.c:1621

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.185+ #8
 ffff8801d98d7cc8 ffffffff81b5a081 0000000000000001 0000000000000000
 0000000000000001 ffffffff81099a01 dffffc0000000000 ffff8801d98d7d00
 ffffffff81b6531c 0000000000000001 0000000000000000 0000000000000001
Call Trace:
 [<000000006fe76c77>] __dump_stack /lib/dump_stack.c:15 [inline]
 [<000000006fe76c77>] dump_stack+0xc1/0x120 /lib/dump_stack.c:51
 [<000000006b283381>] nmi_cpu_backtrace.cold+0x47/0x87 /lib/nmi_backtrace.c:99
 [<00000000e042f1c2>] nmi_trigger_cpumask_backtrace+0x124/0x155 /lib/nmi_backtrace.c:60
 [<000000007d2b8f6a>] arch_trigger_cpumask_backtrace+0x14/0x20 /arch/x86/kernel/apic/hw_nmi.c:37
 [<00000000ce61d4b4>] trigger_all_cpu_backtrace /./include/linux/nmi.h:58 [inline]
 [<00000000ce61d4b4>] check_hung_task /kernel/hung_task.c:126 [inline]
 [<00000000ce61d4b4>] check_hung_uninterruptible_tasks /kernel/hung_task.c:183 [inline]
 [<00000000ce61d4b4>] watchdog+0x670/0xaf0 /kernel/hung_task.c:263
 [<00000000960790dd>] kthread+0x278/0x310 /kernel/kthread.c:211
 [<000000007fae58d9>] ret_from_fork+0x5c/0x70 /arch/x86/entry/entry_64.S:375
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff8281b701