INFO: rcu_sched self-detected stall on CPU
	0-....: (124999 ticks this GP) idle=d72/1/4611686018427387906 softirq=442550/442555 fqs=31231 
	 (t=125000 jiffies g=235542 c=235541 q=2184)
NMI backtrace for cpu 0
CPU: 0 PID: 28156 Comm: syz-executor1 Not tainted 4.17.0-rc7+ #71
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:156 [inline]
 rcu_dump_cpu_stacks+0x175/0x1c2 kernel/rcu/tree.c:1376
 print_cpu_stall kernel/rcu/tree.c:1525 [inline]
 check_cpu_stall.isra.61.cold.80+0x36c/0x59a kernel/rcu/tree.c:1593
 __rcu_pending kernel/rcu/tree.c:3356 [inline]
 rcu_pending kernel/rcu/tree.c:3401 [inline]
 rcu_check_callbacks+0x21b/0xad0 kernel/rcu/tree.c:2763
 update_process_times+0x2d/0x70 kernel/time/timer.c:1636
 tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:164
 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1274
 __run_hrtimer kernel/time/hrtimer.c:1398 [inline]
 __hrtimer_run_queues+0x3e3/0x10a0 kernel/time/hrtimer.c:1460
 hrtimer_interrupt+0x2f3/0x750 kernel/time/hrtimer.c:1518
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline]
 smp_apic_timer_interrupt+0x15d/0x710 arch/x86/kernel/apic/apic.c:1050
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863
 </IRQ>
RIP: 0010:is_loop_device drivers/block/loop.c:713 [inline]
RIP: 0010:loop_set_fd drivers/block/loop.c:901 [inline]
RIP: 0010:lo_ioctl+0x1b7d/0x2130 drivers/block/loop.c:1398
RSP: 0018:ffff8801880c7948 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff8801ce323b64 RBX: ffff8801d28d7200 RCX: 000000000037ffff
RDX: 0000000000040000 RSI: ffffffff84b30851 RDI: ffff8801ce323b64
RBP: ffff8801880c79c0 R08: ffff8801a946e740 R09: ffff8801880c7518
R10: 0000000000000003 R11: 0000000000000001 R12: 0000000000000000
R13: ffff8801ce323b18 R14: ffff8801b2c94760 R15: ffff8801b2c94680
 __blkdev_driver_ioctl block/ioctl.c:303 [inline]
 blkdev_ioctl+0x9b6/0x2020 block/ioctl.c:601
 block_ioctl+0xee/0x130 fs/block_dev.c:1877
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x1cf/0x16a0 fs/ioctl.c:684
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
 __do_sys_ioctl fs/ioctl.c:708 [inline]
 __se_sys_ioctl fs/ioctl.c:706 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455a09
RSP: 002b:00007f5689fccc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5689fcd6d4 RCX: 0000000000455a09
RDX: 0000000000000013 RSI: 0000000000004c00 RDI: 0000000000000015
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000002b2 R14: 00000000006f8150 R15: 0000000000000000