INFO: task syz-executor4:14902 blocked for more than 140 seconds.
      Not tainted 4.9.127+ #43
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4   D29120 14902   2101 0x20020004
 ffff8801d6b7c740 ffff8801ae55b180 ffff8801caa0c200 ffff8801d3d58000
 ffff8801db721018 ffff8801d6eff948 ffffffff8277dc12 0000000000000001
 ffff8801d6b7cff0 ffffed003ad6f9fd 00ff8801d6b7c740 ffff8801db7218f0
Call Trace:
 [<ffffffff8277f13f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff8277fac3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff82781746>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff82781746>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff81abaabe>] blkdev_reread_part+0x1e/0x40 block/ioctl.c:189
 [<ffffffff81d84b3c>] loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:637
 [<ffffffff81d855ce>] loop_set_status+0xa7e/0xfe0 drivers/block/loop.c:1180
 [<ffffffff81d85fcf>] loop_set_status64+0xbf/0x110 drivers/block/loop.c:1289
 [<ffffffff81d89855>] lo_ioctl+0x345/0x1670 drivers/block/loop.c:1379
 [<ffffffff81d8ac32>] lo_compat_ioctl+0xb2/0x140 drivers/block/loop.c:1549
 [<ffffffff81aea564>] compat_blkdev_ioctl+0x3a4/0x38c0 block/compat_ioctl.c:751
 [<ffffffff815f320d>] C_SYSC_ioctl fs/compat_ioctl.c:1602 [inline]
 [<ffffffff815f320d>] compat_SyS_ioctl+0x12d/0x1fd0 fs/compat_ioctl.c:1549
 [<ffffffff81005fd1>] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline]
 [<ffffffff81005fd1>] do_fast_syscall_32+0x2f1/0x860 arch/x86/entry/common.c:387
 [<ffffffff8278e260>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff81309d9c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff81309d9c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813e6edc>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/1911:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff8154c72c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/2038:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff8278ade2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff81cddbf2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
2 locks held by syz-executor4/14902:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff81d8959c>] lo_ioctl+0x8c/0x1670 drivers/block/loop.c:1353
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81abaabe>] blkdev_reread_part+0x1e/0x40 block/ioctl.c:189
1 lock held by syz-executor4/14942:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff81d8959c>] lo_ioctl+0x8c/0x1670 drivers/block/loop.c:1353
1 lock held by syz-executor4/14943:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff81d8959c>] lo_ioctl+0x8c/0x1670 drivers/block/loop.c:1353
1 lock held by syz-executor4/14945:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff81d8959c>] lo_ioctl+0x8c/0x1670 drivers/block/loop.c:1353
1 lock held by syz-executor4/14948:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff81d8959c>] lo_ioctl+0x8c/0x1670 drivers/block/loop.c:1353
2 locks held by syz-executor0/14910:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81d8b12a>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1915
 #1:  (&lo->lo_ctl_mutex#2){+.+...}, at: [<ffffffff81d8b236>] loop_control_ioctl+0x186/0x300 drivers/block/loop.c:1929
1 lock held by syz-executor0/14925:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81d8b12a>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1915
1 lock held by syz-executor0/14939:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81d8b12a>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1915
1 lock held by syz-executor0/14946:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81d8b12a>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1915
2 locks held by blkid/14917:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815a489c>] __blkdev_get+0x10c/0xd60 fs/block_dev.c:1268
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81d834fb>] lo_open+0x1b/0xa0 drivers/block/loop.c:1564

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.127+ #43
 ffff8801d9907d08 ffffffff81af11e9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810967d0 ffff8801d9907d40
 ffffffff81afbf49 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81af11e9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81af11e9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81afbf49>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81afbedc>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff810968d4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8130a32d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8130a32d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8130a32d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8130a32d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff8113dd2d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff8278cedc>] 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 0xffffffff8278b926