INFO: task syz-executor3:8639 blocked for more than 120 seconds.
      Not tainted 4.4.124-g851fb4d #60
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor3   D ffff8801d7b1fa80 28832  8639   3870 0x00000004
 ffff8801d7b1fa80 0000000000000246 0000000000000296 0000000041b58ab3
 ffffffff83fabb00 ffff8801db31fdb8 ffff8801db31fde0 ffff8801db31f4d8
 ffff8801db31f4c0 ffff8801d72f4800 ffff8800b9954800 0000000000000000
Call Trace:
 [<ffffffff8376b59a>] schedule+0x7a/0x1b0 kernel/sched/core.c:3359
 [<ffffffff81c989e0>] blk_mq_freeze_queue_wait+0x120/0x240 block/blk-mq.c:95
 [<ffffffff81ca0f5d>] blk_freeze_queue block/blk-mq.c:112 [inline]
 [<ffffffff81ca0f5d>] blk_mq_freeze_queue+0x1d/0x20 block/blk-mq.c:121
 [<ffffffff82422e8f>] loop_switch drivers/block/loop.c:610 [inline]
 [<ffffffff82422e8f>] loop_change_fd drivers/block/loop.c:693 [inline]
 [<ffffffff82422e8f>] lo_ioctl+0xfef/0x19c0 drivers/block/loop.c:1354
 [<ffffffff81caeb5b>] __blkdev_driver_ioctl block/ioctl.c:288 [inline]
 [<ffffffff81caeb5b>] blkdev_ioctl+0x4ab/0x1990 block/ioctl.c:584
 [<ffffffff815d256e>] block_ioctl+0xde/0x120 fs/block_dev.c:1625
 [<ffffffff8155a58a>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff8155a58a>] do_vfs_ioctl+0x7aa/0xee0 fs/ioctl.c:607
 [<ffffffff8155ad4f>] SYSC_ioctl fs/ioctl.c:622 [inline]
 [<ffffffff8155ad4f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:613
 [<ffffffff837796e5>] entry_SYSCALL_64_fastpath+0x22/0x9e
1 lock held by syz-executor3/8639:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff82421f2f>] lo_ioctl+0x8f/0x19c0 drivers/block/loop.c:1348
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 486 Comm: khungtaskd Not tainted 4.4.124-g851fb4d #60
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d8f4c800 task.stack: ffff8800bb380000
RIP: 0010:[<ffffffff810c3fa7>]  [<ffffffff810c3fa7>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810c3fa7>]  [<ffffffff810c3fa7>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810c3fa7>]  [<ffffffff810c3fa7>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810c3fa7>]  [<ffffffff810c3fa7>] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bb387cb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bb387ce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426f5a0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000025acba0 CR3: 00000000aba7a000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426f5a0 ffffffff847f09c0 fffffbfff08fdbec dffffc0000000000
 ffff8801db31bca0 ffff8800bb387d00 ffffffff810b9adb ffffffff839f6e40
 0000000000000003 ffff8800bb387d60 ffffffff81d115a4 ffffffff8141b803
Call Trace:
 [<ffffffff810b9adb>] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81d115a4>] nmi_trigger_all_cpu_backtrace+0x4a4/0x550 lib/nmi_backtrace.c:85
 [<ffffffff810b9b74>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff8136944a>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff8136944a>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8136944a>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8136944a>] watchdog+0x6fa/0xae0 kernel/hung_task.c:238
 [<ffffffff811909c8>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff83779b15>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510
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 8b 31 17 00 4c 89 e7 57 9d 0f 1f 
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.124-g851fb4d #60
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d9b49800 task.stack: ffff8801d9b58000
RIP: 0010:[<ffffffff812c0511>]  [<ffffffff812c0511>] seqcount_lockdep_reader_access include/linux/seqlock.h:80 [inline]
RIP: 0010:[<ffffffff812c0511>]  [<ffffffff812c0511>] read_seqcount_begin include/linux/seqlock.h:163 [inline]
RIP: 0010:[<ffffffff812c0511>]  [<ffffffff812c0511>] ktime_get+0x61/0x1d0 kernel/time/timekeeping.c:754
RSP: 0018:ffff8801d9b5fd70  EFLAGS: 00000046
RAX: ffffffff812d7f23 RBX: 0000000000000093 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8801d9b4a0a8
RBP: ffff8801d9b5fdc0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 1ffff1003b36bf82 R12: ffffffff85705640
R13: ffff8801db319cd0 R14: ffffffff847ece38 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f58642d7000 CR3: 00000000aba7a000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d9b5fdb0 ffffffff81d663fb 0000000000000002 0000000000019c40
 0000000000000046 ffff8801db319c40 ffff8801db319cb4 ffff8801db319cd0
 ffffffff847ece38 ffff8801d9b60000 ffff8801d9b5fdf8 ffffffff812d7f23
Call Trace:
 [<ffffffff812d7f23>] tick_nohz_idle_exit+0x153/0x3d0 kernel/time/tick-sched.c:940
 [<ffffffff81221b75>] cpu_idle_loop kernel/sched/idle.c:267 [inline]
 [<ffffffff81221b75>] cpu_startup_entry+0x2a5/0x8f0 kernel/sched/idle.c:301
 [<ffffffff810adcf4>] start_secondary+0x304/0x3e0 arch/x86/kernel/smpboot.c:242
Code: 16 10 0a 00 9c 58 0f 1f 44 00 00 48 89 c3 fa 66 0f 1f 44 00 00 e8 10 ed f6 ff 48 8b 45 08 45 31 c9 31 d2 31 f6 41 b8 01 00 00 00 <b9> 02 00 00 00 48 c7 c7 48 56 70 85 48 89 04 24 e8 aa d4 f7 ff