INFO: task syz-executor4:9017 blocked for more than 140 seconds.
      Not tainted 4.9.133+ #54
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4   D26488  9017   2118 0x00000004
 ffff8801ca088000 ffff8801d1d0d280 ffff8801d1d0d280 ffff8801d5cedf00
 ffff8801db721018 ffff8801a4ff7b48 ffffffff827f3aa2 0000000000000000
 ffff8801ca0888b0 ffffed0039411115 00ff8801ca088000 ffff8801db7218f0
Call Trace:
 [<ffffffff827f4fcf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff827f5953>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff827f79cd>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff827f79cd>] mutex_lock_nested+0x38d/0x900 kernel/locking/mutex.c:621
 [<ffffffff81ddd4ba>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1941
 [<ffffffff81546e3c>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff81546e3c>] file_ioctl fs/ioctl.c:493 [inline]
 [<ffffffff81546e3c>] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677
 [<ffffffff81547ebf>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff81547ebf>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82803d13>] 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: [<ffffffff8131baec>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131baec>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813fe2b4>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/1894:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff8156cccc>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/2021:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82801df2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d2b472>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor4/9017:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81ddd4ba>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1941
2 locks held by syz-executor4/9026:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81ddd4ba>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1941
 #1:  (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<ffffffff81ddd5c6>] loop_control_ioctl+0x186/0x300 drivers/block/loop.c:1955
1 lock held by syz-executor4/9037:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81ddd4ba>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1941
1 lock held by syz-executor4/9041:
 #0:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81ddd4ba>] loop_control_ioctl+0x7a/0x300 drivers/block/loop.c:1941
2 locks held by syz-executor0/9032:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815c811b>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1579
 #1:  (loop_index_mutex){+.+.+.}, at: [<ffffffff81ddf97f>] lo_release+0x1f/0x1a0 drivers/block/loop.c:1631
2 locks held by syz-executor0/9036:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff81ddb68c>] lo_ioctl+0x8c/0x1910 drivers/block/loop.c:1372
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81affbee>] blkdev_reread_part+0x1e/0x40 block/ioctl.c:189
1 lock held by blkid/9035:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff81ddb68c>] lo_ioctl+0x8c/0x1910 drivers/block/loop.c:1372

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.133+ #54
 ffff8801d9907d08 ffffffff81b37069 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff81098330 ffff8801d9907d40
 ffffffff81b42179 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81b37069>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b37069>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81b42179>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b4210c>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff81098434>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131c07d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131c07d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131c07d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131c07d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff811428dd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff82803edc>] 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 0xffffffff82802936