INFO: task syz-executor.0:13072 blocked for more than 140 seconds.
      Not tainted 4.9.194+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D27032 13072  12259 0x00000004
 0000000000000087 ffff8801ac35af80 0000000000000000 ffff8801db621000
 ffff8801da6817c0 ffff8801db621018 ffff8801cbc177c8 ffffffff8281af8e
 ffff8801cbc17738 ffffffff81bcd65c 00ffffff81bcd65c ffff8801db6218f0
Call Trace:
 [<00000000a5950422>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
 [<00000000959cf3bd>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579
 [<00000000679a1a22>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<00000000679a1a22>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621
 [<0000000093fa5d85>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
 [<00000000b6fc2b4b>] loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:637
 [<000000008cbc6767>] loop_set_status+0xc02/0x1260 drivers/block/loop.c:1196
 [<00000000248377a5>] loop_set_status64+0xd7/0x130 drivers/block/loop.c:1305
 [<0000000035e17c6e>] lo_ioctl+0x4c7/0x1b10 drivers/block/loop.c:1430
 [<00000000231cb043>] __blkdev_driver_ioctl block/ioctl.c:294 [inline]
 [<00000000231cb043>] blkdev_ioctl+0xe14/0x19e0 block/ioctl.c:590
 [<00000000a4b8c8c5>] block_ioctl+0xde/0x120 fs/block_dev.c:1696
 [<00000000c8324ff2>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<00000000c8324ff2>] file_ioctl fs/ioctl.c:493 [inline]
 [<00000000c8324ff2>] do_vfs_ioctl+0xb87/0x11d0 fs/ioctl.c:677
 [<00000000e7061f1b>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<00000000e7061f1b>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<0000000032c84fd3>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
 [<0000000065eeafe4>] 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: [<0000000082a352ce>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline]
 #0:  (rcu_read_lock){......}, at: [<0000000082a352ce>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263
 #1:  (tasklist_lock){.+.+..}, at: [<0000000054e368ab>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336
2 locks held by getty/2030:
 #0:  (&tty->ldisc_sem){++++++}, at: [<00000000675ffde4>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<00000000469c81a0>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.0/13072:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<00000000031a33df>] lo_ioctl+0x8e/0x1b10 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<0000000093fa5d85>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
2 locks held by syz-executor.1/13073:
 #0:  (loop_index_mutex){+.+.+.}, at: [<00000000047ecc44>] loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973
 #1:  (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<0000000063b5f141>] loop_control_ioctl+0x17f/0x320 drivers/block/loop.c:1987
2 locks held by blkid/13078:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<0000000065ca432e>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
 #1:  (loop_index_mutex){+.+.+.}, at: [<00000000cd400cf7>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621
1 lock held by syz-executor.5/13093:
 #0:  (loop_index_mutex){+.+.+.}, at: [<00000000047ecc44>] loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.194+ #0
 ffff8801d98efcc8 ffffffff81b67001 0000000000000000 0000000000000000
 0000000000000000 ffffffff81099d01 dffffc0000000000 ffff8801d98efd00
 ffffffff81b7229c 0000000000000000 0000000000000000 0000000000000000
Call Trace:
 [<0000000041f53d3f>] __dump_stack lib/dump_stack.c:15 [inline]
 [<0000000041f53d3f>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<00000000a7c1dc18>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99
 [<000000004f4370fb>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60
 [<00000000d1229e7e>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<00000000e47f8ceb>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<00000000e47f8ceb>] check_hung_task kernel/hung_task.c:126 [inline]
 [<00000000e47f8ceb>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline]
 [<00000000e47f8ceb>] watchdog+0x670/0xaf0 kernel/hung_task.c:263
 [<000000000dc943f9>] kthread+0x278/0x310 kernel/kthread.c:211
 [<0000000099222f67>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff8282a0e1