INFO: task loop0:5256 blocked for more than 120 seconds.
      Not tainted 4.4.120-gd63fdf6 #28
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
loop0           D ffff8800aaf6ede0 26888  5256      2 0x00000000
 ffff8800aaf6ede0 ffffffff83fb2270 ffffffff81237410 0000000000000000
 0000000000000000 0000000000000000 ffff8801db21fdb8 ffff8801db21fde0
 ffff8801db21f4d8 ffffffff84217840 ffff8801cf108000 ffff8800aaf6f670
Call Trace:
 [<ffffffff8376582a>] schedule+0x7a/0x1b0 kernel/sched/core.c:3353
 [<ffffffff83770b40>] schedule_timeout+0x3a0/0x970 kernel/time/timer.c:1515
 [<ffffffff837637be>] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:4935
 [<ffffffff81ca6d55>] io_schedule include/linux/sched.h:447 [inline]
 [<ffffffff81ca6d55>] bt_get+0x305/0x760 block/blk-mq-tag.c:301
 [<ffffffff81ca7f9b>] __blk_mq_get_tag block/blk-mq-tag.c:325 [inline]
 [<ffffffff81ca7f9b>] blk_mq_get_tag+0x1eb/0x340 block/blk-mq-tag.c:353
 [<ffffffff81c983c4>] __blk_mq_alloc_request+0x24/0xa50 block/blk-mq.c:215
 [<ffffffff81c9e111>] blk_mq_map_request+0x8d1/0xde0 block/blk-mq.c:1190
 [<ffffffff81ca1f90>] blk_sq_make_request+0x1a0/0xfc0 block/blk-mq.c:1361
 [<ffffffff81c74681>] generic_make_request+0x311/0x990 block/blk-core.c:2081
 [<ffffffff81c74e7a>] submit_bio+0x17a/0x540 block/blk-core.c:2154
 [<ffffffff815e00f8>] dio_bio_submit fs/direct-io.c:409 [inline]
 [<ffffffff815e00f8>] do_blockdev_direct_IO+0x6ba8/0x8810 fs/direct-io.c:1283
 [<ffffffff815e1e0e>] __blockdev_direct_IO+0xae/0xe0 fs/direct-io.c:1342
 [<ffffffff815d0b42>] blkdev_direct_IO+0xb2/0xe0 fs/block_dev.c:167
 [<ffffffff81423c50>] generic_file_read_iter+0x360/0x1160 mm/filemap.c:1791
 [<ffffffff815d1ba5>] blkdev_read_iter+0x105/0x170 fs/block_dev.c:1679
 [<ffffffff8242433c>] lo_rw_aio drivers/block/loop.c:506 [inline]
 [<ffffffff8242433c>] lo_rw_simple drivers/block/loop.c:520 [inline]
 [<ffffffff8242433c>] do_req_filebacked drivers/block/loop.c:558 [inline]
 [<ffffffff8242433c>] loop_handle_cmd drivers/block/loop.c:1698 [inline]
 [<ffffffff8242433c>] loop_queue_work+0x1eac/0x31c0 drivers/block/loop.c:1710
 [<ffffffff81190b5b>] kthread_worker_fn+0x27b/0x600 kernel/kthread.c:602
 [<ffffffff81190788>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff83773d85>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:506
no locks held by loop0/5256.
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 485 Comm: khungtaskd Not tainted 4.4.120-gd63fdf6 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bb31c800 task.stack: ffff8800bacb8000
RIP: 0010:[<ffffffff810c3e67>]  [<ffffffff810c3e67>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810c3e67>]  [<ffffffff810c3e67>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810c3e67>]  [<ffffffff810c3e67>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810c3e67>]  [<ffffffff810c3e67>] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bacbfcb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bacbfce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426f420 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5e836a59b8 CR3: 00000001d34ba000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426f420 ffffffff847efb00 fffffbfff08fda14 dffffc0000000000
 ffff8801db31bca0 ffff8800bacbfd00 ffffffff810b999b ffffffff839f63c0
 0000000000000003 ffff8800bacbfd60 ffffffff81d0eff4 0000000000000000
Call Trace:
 [<ffffffff810b999b>] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81d0eff4>] nmi_trigger_all_cpu_backtrace+0x4a4/0x550 lib/nmi_backtrace.c:85
 [<ffffffff810b9a34>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff81368c9a>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff81368c9a>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81368c9a>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81368c9a>] watchdog+0x6fa/0xae0 kernel/hung_task.c:238
 [<ffffffff81190788>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff83773d85>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:506
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 6b 2f 17 00 4c 89 e7 57 9d 0f 1f 
NMI backtrace for cpu 1
CPU: 1 PID: 7635 Comm: syz-executor5 Not tainted 4.4.120-gd63fdf6 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800b67d6000 task.stack: ffff8800b6718000
RIP: 0010:[<ffffffff8241f996>]  [<ffffffff8241f996>] loop_set_fd drivers/block/loop.c:897 [inline]
RIP: 0010:[<ffffffff8241f996>]  [<ffffffff8241f996>] lo_ioctl+0x4e6/0x19c0 drivers/block/loop.c:1351
RSP: 0018:ffff8800b671fb98  EFLAGS: 00000246
RAX: 1ffff10017391d8d RBX: dffffc0000000000 RCX: ffffffff8241f983
RDX: 0000000000010000 RSI: ffffc900046f7000 RDI: ffff8800b9c8ec68
RBP: ffff8800b671fc18 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff10016ce3f2e R12: ffff8800b9c8e920
R13: ffff8800b8c7f600 R14: 0000000000000000 R15: ffff8800b9c8dc00
FS:  00007f2fa9771700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdb41b08000 CR3: 00000001d6080000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8800b671fbe0 1ffff10016ce3f78 0000000b00006000 ffff8800b8c7f750
 0000002900700000 ffff8800b9c8eb00 ffff8800b9c8e920 ffff8801d613d600
 ffff8800b9c8dcf0 000000000002001d ffff8800b8c7f758 ffff8800b9c8dc00
Call Trace:
 [<ffffffff81cac59b>] __blkdev_driver_ioctl block/ioctl.c:288 [inline]
 [<ffffffff81cac59b>] blkdev_ioctl+0x4ab/0x1990 block/ioctl.c:584
 [<ffffffff815d1cee>] block_ioctl+0xde/0x120 fs/block_dev.c:1625
 [<ffffffff81559daa>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff81559daa>] do_vfs_ioctl+0x7aa/0xee0 fs/ioctl.c:607
 [<ffffffff8155a56f>] SYSC_ioctl fs/ioctl.c:622 [inline]
 [<ffffffff8155a56f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:613
 [<ffffffff8377395f>] entry_SYSCALL_64_fastpath+0x1c/0x98
Code: 00 00 41 8b 44 24 4c c1 e8 14 83 f8 07 0f 85 0a 01 00 00 e8 cd 13 f4 fe 49 8d bc 24 48 03 00 00 48 89 f8 48 c1 e8 03 80 3c 18 00 <0f> 85 e4 13 00 00 4d 8b a4 24 48 03 00 00 4d 39 e7 0f 84 49 0e