INFO: task syz-executor707:3828 blocked for more than 120 seconds.
      Not tainted 4.4.138-g226f96b #63
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor707 D ffff8800ba937a68 28688  3828   3825 0x00000000
 ffff8800ba937a68 0000000000000000 ffff8801d8a068e0 ffffed003b140d1b
 ffff8801d8a06000 ffff8801db31fdb8 ffff8801db31fde0 ffff8801db31f4d8
 ffff8801db31f4c0 ffff8801d9a41800 ffff8801d8a06000 0000000000000000
Call Trace:
 [<ffffffff838b46ea>] schedule+0x7a/0x1b0 kernel/sched/core.c:3359
 [<ffffffff838b4e83>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3392
 [<ffffffff838bafc7>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff838bafc7>] mutex_lock_nested+0x307/0x850 kernel/locking/mutex.c:621
 [<ffffffff8251bc0b>] lo_ioctl+0x8b/0x1ad0 drivers/block/loop.c:1355
 [<ffffffff81db7f68>] __blkdev_driver_ioctl block/ioctl.c:288 [inline]
 [<ffffffff81db7f68>] blkdev_ioctl+0x7b8/0x19c0 block/ioctl.c:584
 [<ffffffff815d3fce>] block_ioctl+0xde/0x120 fs/block_dev.c:1625
 [<ffffffff81559c8f>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff81559c8f>] file_ioctl fs/ioctl.c:470 [inline]
 [<ffffffff81559c8f>] do_vfs_ioctl+0x63f/0xf40 fs/ioctl.c:605
 [<ffffffff8155a61f>] SYSC_ioctl fs/ioctl.c:622 [inline]
 [<ffffffff8155a61f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:613
 [<ffffffff838c2725>] entry_SYSCALL_64_fastpath+0x22/0x9e
1 lock held by syz-executor707/3828:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff8251bc0b>] lo_ioctl+0x8b/0x1ad0 drivers/block/loop.c:1355
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 491 Comm: khungtaskd Not tainted 4.4.138-g226f96b #63
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bb363000 task.stack: ffff8801d8e30000
RIP: 0010:[<ffffffff810bfb26>]  [<ffffffff810bfb26>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810bfb26>]  [<ffffffff810bfb26>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810bfb26>]  [<ffffffff810bfb26>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810bfb26>]  [<ffffffff810bfb26>] flat_send_IPI_mask+0xf6/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8801d8e37cc8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8801d8e37cf0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: 0000000000000002 R15: ffffffff8446f6a0
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3d92087000 CR3: 00000001d849c000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8446f6a0 ffffffff84a18ee0 0000000000000007 fffffbfff0942c8c
 0000000000000040 ffff8801d8e37d10 ffffffff810b5ae1 ffffffff83c0b460
 0000000000000003 ffff8801d8e37d68 ffffffff81e19d83 ffffffff8140dd6f
Call Trace:
 [<ffffffff810b5ae1>] nmi_raise_cpu_backtrace+0x61/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81e19d83>] nmi_trigger_all_cpu_backtrace.cold.4+0x70/0xad lib/nmi_backtrace.c:85
 [<ffffffff810b5b84>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff8141a459>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff8141a459>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8141a459>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8141a459>] watchdog.cold.1+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff81190958>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff838c2b55>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510
Code: b3 5f ff f6 c4 10 75 e2 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 f2 09 da 80 cf 04 41 83 fe 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 75 1a 4c 89 e7 57 9d 0f 1f 44 00 00 e8 02 
NMI backtrace for cpu 1
CPU: 1 PID: 3827 Comm: syz-executor707 Not tainted 4.4.138-g226f96b #63
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800b002e000 task.stack: ffff8801d84c0000
RIP: 0010:[<ffffffff8122f685>]  [<ffffffff8122f685>] __lock_acquire+0x655/0x5270 kernel/locking/lockdep.c:3123
RSP: 0018:ffff8801d84c7940  EFLAGS: 00000006
RAX: 0000000000000003 RBX: ffffffff8538d900 RCX: 0000000000000000
RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffffffff844bdc28
RBP: ffff8801d84c7ad8 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff83a44740 R11: ffff8800b002e000 R12: 0000000000000000
R13: ffffffff844bdc20 R14: 0000000000000000 R15: 0000000000000002
FS:  0000000000ef1880(0063) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001a9b000 CR3: 00000001d3f3c000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000000 ffff8801d84c7988 ffffffff81229682 ffff8800b002b840
 ffff8800b002e920 ffffffff8538e9e0 ffff8800b002e8d0 ffff8800b002e8d8
 ffff8800b002e928 ffff8800b002e8e0 1ffff1003b098f34 0000000000054bd0
Call Trace:
 [<ffffffff81235a7e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
 [<ffffffff81c561fa>] rcu_lock_acquire include/linux/rcupdate.h:477 [inline]
 [<ffffffff81c561fa>] rcu_read_lock include/linux/rcupdate.h:861 [inline]
 [<ffffffff81c561fa>] avc_has_perm_noaudit security/selinux/avc.c:1110 [inline]
 [<ffffffff81c561fa>] avc_has_perm+0xea/0x4f0 security/selinux/avc.c:1148
 [<ffffffff81c623ca>] inode_has_perm.isra.31+0x10a/0x160 security/selinux/hooks.c:1614
 [<ffffffff81c63302>] file_has_perm+0x262/0x300 security/selinux/hooks.c:1692
 [<ffffffff81c685bb>] selinux_revalidate_file_permission security/selinux/hooks.c:3192 [inline]
 [<ffffffff81c685bb>] selinux_file_permission+0x2eb/0x450 security/selinux/hooks.c:3212
 [<ffffffff81c4d963>] security_file_permission+0x83/0x1e0 security/security.c:734
 [<ffffffff8151e2e0>] rw_verify_area+0xe0/0x300 fs/read_write.c:404
 [<ffffffff8151e95d>] vfs_write+0xfd/0x4e0 fs/read_write.c:534
 [<ffffffff81520ff9>] SYSC_write fs/read_write.c:585 [inline]
 [<ffffffff81520ff9>] SyS_write+0xd9/0x1c0 fs/read_write.c:577
 [<ffffffff838c2725>] entry_SYSCALL_64_fastpath+0x22/0x9e
Code: c2 00 e6 92 85 41 8b 8b d8 08 00 00 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 14 02 48 c7 c0 00 e6 92 85 83 e0 07 83 c0 03 <38> d0 7c 08 84 d2 0f 85 7a 34 00 00 8b 05 69 ef 6f 04 85 c0 40