INFO: task syz-executor5:7154 blocked for more than 120 seconds.
      Not tainted 4.4.107-g610c835 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5   D ffff8801cef4f890 28832  7154   3567 0x20020004
 ffff8801cef4f890 ffff8801cef4f840 0000000000000246 0000000000000286
 0000000041b58ab3 ffffffff83fa7300 ffff8801db31f878 ffff8801db31f8a0
 ffff8801db31ef98 ffff8801ced30000 ffff8801ced9af80 ffff8801cef48000
Call Trace:
 [<ffffffff83765d3a>] schedule+0x9a/0x1c0 kernel/sched/core.c:3351
 [<ffffffff81c968a0>] blk_mq_freeze_queue_wait+0x120/0x240 block/blk-mq.c:95
 [<ffffffff81c9ee1d>] blk_freeze_queue block/blk-mq.c:112 [inline]
 [<ffffffff81c9ee1d>] blk_mq_freeze_queue+0x1d/0x20 block/blk-mq.c:121
 [<ffffffff8241bc52>] loop_set_status+0x1a2/0xfc0 drivers/block/loop.c:1112
 [<ffffffff8241cb0a>] loop_set_status_compat+0x9a/0x100 drivers/block/loop.c:1499
 [<ffffffff82420eb4>] lo_compat_ioctl+0x114/0x140 drivers/block/loop.c:1527
 [<ffffffff81cf85a4>] compat_blkdev_ioctl+0x3d4/0x3b10 block/compat_ioctl.c:751
 [<ffffffff8161d5ca>] C_SYSC_ioctl fs/compat_ioctl.c:1592 [inline]
 [<ffffffff8161d5ca>] compat_SyS_ioctl+0x28a/0x2540 fs/compat_ioctl.c:1544
 [<ffffffff81006d84>] do_syscall_32_irqs_on arch/x86/entry/common.c:390 [inline]
 [<ffffffff81006d84>] do_fast_syscall_32+0x314/0x890 arch/x86/entry/common.c:457
 [<ffffffff837754d7>] sysenter_flags_fixed+0xd/0x17
1 lock held by syz-executor5/7154:
 #0:  (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<ffffffff82420ea9>] lo_compat_ioctl+0x109/0x140 drivers/block/loop.c:1526
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 485 Comm: khungtaskd Not tainted 4.4.107-g610c835 #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bb8b0000 task.stack: ffff8800bace0000
RIP: 0010:[<ffffffff810c32e7>]  [<ffffffff810c32e7>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810c32e7>]  [<ffffffff810c32e7>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810c32e7>]  [<ffffffff810c32e7>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810c32e7>]  [<ffffffff810c32e7>] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bace7cb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bace7ce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426abe0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffce1cbcf8c CR3: 00000001d3976000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426abe0 ffffffff847e8600 00000000000194a0 0000000000000040
 dffffc0000000000 ffff8800bace7d00 ffffffff810b8e1b ffffffff839f53e0
 0000000000000003 ffff8800bace7d60 ffffffff81d0f4d7 ffffffff81417c73
Call Trace:
 [<ffffffff810b8e1b>] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81d0f4d7>] nmi_trigger_all_cpu_backtrace+0x4a7/0x550 lib/nmi_backtrace.c:85
 [<ffffffff810b8eb4>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff81365a7a>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff81365a7a>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81365a7a>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81365a7a>] watchdog+0x6fa/0xae0 kernel/hung_task.c:238
 [<ffffffff8118dea8>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff837740ef>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:468
Code: b3 5f ff f6 c4 10 75 e1 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 74 1a e8 3b 09 17 00 4c 89 e7 57 9d 0f 1f 
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.107-g610c835 #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801da2997c0 task.stack: ffff8801da2a8000
RIP: 0010:[<ffffffff8120f8bd>]  [<ffffffff8120f8bd>] queue_balance_callback kernel/sched/sched.h:848 [inline]
RIP: 0010:[<ffffffff8120f8bd>]  [<ffffffff8120f8bd>] queue_push_tasks kernel/sched/rt.c:360 [inline]
RIP: 0010:[<ffffffff8120f8bd>]  [<ffffffff8120f8bd>] pick_next_task_rt+0x3fd/0x710 kernel/sched/rt.c:1559
RSP: 0018:ffff8801da2afce8  EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff8801da299818 RCX: 0000000000000000
RDX: 1ffff1003b663ef4 RSI: ffff8801da2997c0 RDI: ffff8801db31f7a0
RBP: ffff8801da2afd18 R08: 0000000000000001 R09: ffffffff8510c2c0
R10: 0000000000000001 R11: 1ffff1003b455f6c R12: ffffffff838523a0
R13: 0000000000000000 R14: ffff8801db31ef80 R15: ffff8801da2997c0
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001a67000 CR3: 00000001d3976000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 000000000001ef80 ffff8801db31ef80 ffffffff838523a0 dffffc0000000000
 ffff8801db31ef80 ffff8801da2997c0 ffff8801da2afda0 ffffffff83764aa5
 0000000000000000 0000003810f68b7e ffff8801da2afd80 ffffffff812d2036
Call Trace:
 [<ffffffff83764aa5>] pick_next_task kernel/sched/core.c:3187 [inline]
 [<ffffffff83764aa5>] __schedule+0xc15/0x1c70 kernel/sched/core.c:3304
 [<ffffffff83765d3a>] schedule+0x9a/0x1c0 kernel/sched/core.c:3351
 [<ffffffff83766513>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3384
 [<ffffffff8121e742>] cpu_idle_loop kernel/sched/idle.c:279 [inline]
 [<ffffffff8121e742>] cpu_startup_entry+0x302/0x820 kernel/sched/idle.c:301
 [<ffffffff810ad2e4>] start_secondary+0x304/0x3e0 arch/x86/kernel/smpboot.c:251
Code: 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 66 02 00 00 49 8b 86 60 09 00 00 49 89 04 24 4d 89 a6 60 09 00 00 <48> 83 c4 08 4c 89 e8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48 8d 7b