INFO: task syz-executor.1:2114 blocked for more than 140 seconds.
      Not tainted 4.4.174+ #17
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D ffff8801c5e179c8 25168  2114      1 0x20020004
 ffff8801c5e179c8 ffff8800b73e2f80 fd772de5f172afc2 ffff8800b73e2f80
 0000000000000000 ffff8800b73e3800 ffff8801db71f180 ffff8801db71f1a8
 ffff8801db71e898 ffff8800a27217c0 ffff8800b73e2f80 ffffed0038bc2001
Call Trace:
 [<ffffffff82709b79>] schedule+0x99/0x1d0 kernel/sched/core.c:3355
 [<ffffffff8270a333>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3388
 [<ffffffff8270c492>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff8270c492>] mutex_lock_nested+0x3c2/0xb80 kernel/locking/mutex.c:621
 [<ffffffff81d46575>] lo_ioctl+0x85/0x1a70 drivers/block/loop.c:1416
 [<ffffffff81d4800d>] lo_compat_ioctl+0xad/0x140 drivers/block/loop.c:1618
 [<ffffffff81aa7200>] compat_blkdev_ioctl+0xca0/0x344f block/compat_ioctl.c:751
 [<ffffffff8159b2c3>] C_SYSC_ioctl fs/compat_ioctl.c:1592 [inline]
 [<ffffffff8159b2c3>] compat_SyS_ioctl+0x403/0x2210 fs/compat_ioctl.c:1544
 [<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 [<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397
 [<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a
1 lock held by syz-executor.1/2114:
 #0:  (loop_ctl_mutex/1){+.+.+.}, at: [<ffffffff81d46575>] lo_ioctl+0x85/0x1a70 drivers/block/loop.c:1416
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.174+ #17
task: ffffffff82e151c0 task.stack: ffffffff82e00000
RIP: 0010:[<ffffffff811f6f0a>]  [<ffffffff811f6f0a>] usage_match+0x2a/0x80 kernel/locking/lockdep.c:1329
RSP: 0018:ffff8801db6076f0  EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffffffff83e3fa40 RCX: 0000000000000005
RDX: 1ffffffff07c7f4a RSI: 0000000000000005 RDI: ffffffff83e3fa50
RBP: ffff8801db607700 R08: ffffffff83ad095c R09: ffffffff8284f700
R10: ffffffff82e15b00 R11: 0000000000000000 R12: ffffffff83de0ac0
R13: 0000000000000005 R14: dffffc0000000000 R15: ffffffff83e3fa40
FS:  0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f97dfdf8000 CR3: 00000000b930a000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff812a2843 ffffffff83a89290 ffff8801db607778 ffffffff811fa7c7
 ffffffff8123a761 ffff8801db6077d8 0000000000000046 fffffbfff08000d0
 ffff8801db607830 0000000000000000 0000000000000000 ffffffff811f6ee0
Call Trace:
 [<ffffffff811fa7c7>] __bfs kernel/locking/lockdep.c:1043 [inline]
 [<ffffffff811fa7c7>] __bfs+0x1f7/0x5e0 kernel/locking/lockdep.c:994
 [<ffffffff811fd3de>] __bfs_backwards kernel/locking/lockdep.c:1077 [inline]
 [<ffffffff811fd3de>] find_usage_backwards kernel/locking/lockdep.c:1375 [inline]
 [<ffffffff811fd3de>] check_usage+0x14e/0x5a0 kernel/locking/lockdep.c:1579
 [<ffffffff811fd8e1>] check_irq_usage kernel/locking/lockdep.c:1661 [inline]
 [<ffffffff811fd8e1>] check_irq_usage+0xb1/0xe0 kernel/locking/lockdep.c:1640
 [<ffffffff81201876>] check_prev_add_irq kernel/locking/lockdep_states.h:8 [inline]
 [<ffffffff81201876>] check_prev_add kernel/locking/lockdep.c:1857 [inline]
 [<ffffffff81201876>] check_prevs_add kernel/locking/lockdep.c:1958 [inline]
 [<ffffffff81201876>] validate_chain kernel/locking/lockdep.c:2144 [inline]
 [<ffffffff81201876>] __lock_acquire+0x22c6/0x4f50 kernel/locking/lockdep.c:3213
 [<ffffffff81205f6e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
 [<ffffffff82717c98>] __raw_spin_lock include/linux/spinlock_api_smp.h:144 [inline]
 [<ffffffff82717c98>] _raw_spin_lock+0x38/0x50 kernel/locking/spinlock.c:151
 [<ffffffff81167b7e>] try_to_wake_up+0x20e/0x1110 kernel/sched/core.c:2047
 [<ffffffff81168bc5>] wake_up_process+0x15/0x20 kernel/sched/core.c:2142
 [<ffffffff81118f05>] destroy_worker+0x295/0x3f0 kernel/workqueue.c:1806
 [<ffffffff8111bbfd>] idle_worker_timeout+0x18d/0x2c0 kernel/workqueue.c:1828
 [<ffffffff812582dd>] call_timer_fn+0x18d/0x850 kernel/time/timer.c:1185
 [<ffffffff81258ebf>] __run_timers kernel/time/timer.c:1261 [inline]
 [<ffffffff81258ebf>] run_timer_softirq+0x51f/0xb70 kernel/time/timer.c:1444
 [<ffffffff8271bb16>] __do_softirq+0x226/0xa3f kernel/softirq.c:273
 [<ffffffff810e1a8a>] invoke_softirq kernel/softirq.c:350 [inline]
 [<ffffffff810e1a8a>] irq_exit+0x10a/0x150 kernel/softirq.c:391
 [<ffffffff8271b24e>] exiting_irq arch/x86/include/asm/apic.h:652 [inline]
 [<ffffffff8271b24e>] smp_apic_timer_interrupt+0x7e/0xb0 arch/x86/kernel/apic/apic.c:926
 [<ffffffff8271a59d>] apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:768
 <EOI> 
d [<ffffffff810a1dc2>] ? native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:52
 [<ffffffff81022d50>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:423
 [<ffffffff811eb4c8>] default_idle_call+0x48/0x70 kernel/sched/idle.c:93
 [<ffffffff811ebca1>] cpuidle_idle_call kernel/sched/idle.c:157 [inline]
 [<ffffffff811ebca1>] cpu_idle_loop kernel/sched/idle.c:253 [inline]
 [<ffffffff811ebca1>] cpu_startup_entry+0x6d1/0x810 kernel/sched/idle.c:301
 [<ffffffff827055f9>] rest_init+0x190/0x199 init/main.c:410
 [<ffffffff831d58a0>] start_kernel+0x64a/0x67e init/main.c:682
 [<ffffffff831d430a>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196
 [<ffffffff831d4443>] x86_64_start_kernel+0x137
NMI backtrace for cpu 1
CPU: 1 PID: 20 Comm: khungtaskd Not tainted 4.4.174+ #17
task: ffff8801da6c2f80 task.stack: ffff8800001e8000
RIP: 0010:[<ffffffff8109b617>]  [<ffffffff8109b617>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:62 [inline]
RIP: 0010:[<ffffffff8109b617>]  [<ffffffff8109b617>] flat_send_IPI_mask+0xf7/0x1b0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800001efc88  EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300
RBP: ffff8800001efcb8 R08: 0000000000000018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000007923e0 CR3: 00000001d5bb0000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000001 ffffffff82e5f2e0 ffffffff831a6ac0 fffffbfff0634c34
 000000000001b6c0 0000000000000008 ffff8800001efcd8 ffffffff81092bee
 0000000000000008 ffffffff82924260 ffff8800001efd30 ffffffff81ab8252
Call Trace:
 [<ffffffff81092bee>] nmi_raise_cpu_backtrace+0x5e/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81ab8252>] nmi_trigger_all_cpu_backtrace.cold+0xa1/0xae lib/nmi_backtrace.c:85
 [<ffffffff81092ca4>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff813b4762>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff813b4762>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff813b4762>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff813b4762>] watchdog.cold+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff811342c3>] kthread+0x273/0x310 kernel/kthread.c:211
 [<ffffffff82718fc5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
Code: 00 c3 5f ff 80 e6 10 75 e1 41 c1 e5 18 44 89 2c 25 10 c3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 c3 5f ff <41> f7 c4 00 02 00 00 75 1e 4c 89 e7 57 9d 0f 1f 44 00 00 e8 f1