INFO: rcu_sched self-detected stall on CPU
	0-...!: (124709 ticks this GP) idle=616/1/4611686018427387906 softirq=15563/15563 fqs=0 
	 (t=125000 jiffies g=7523 c=7522 q=13)
rcu_sched kthread starved for 125000 jiffies! g7523 c7522 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0
RCU grace-period kthread stack dump:
rcu_sched       R  running task    23896     9      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2859 [inline]
 __schedule+0x801/0x1e30 kernel/sched/core.c:3501
 schedule+0xef/0x430 kernel/sched/core.c:3545
 schedule_timeout+0x138/0x240 kernel/time/timer.c:1801
 rcu_gp_kthread+0x6b5/0x1940 kernel/rcu/tree.c:2231
 kthread+0x345/0x410 kernel/kthread.c:240
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412
NMI backtrace for cpu 0
CPU: 0 PID: 4498 Comm: syz-executor887 Not tainted 4.17.0-rc7+ #38
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:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:debug_lockdep_rcu_enabled.part.1+0x18/0x60 kernel/rcu/update.c:301
RSP: 0018:ffff8801d9a979c8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: ffff8801b2f78000 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffff8801b2f78838 RDI: ffffffff8909c8e0
RBP: ffff8801d9a979d0 R08: 0000000000000008 R09: 0000000000000004
R10: ffff8801b2f788d8 R11: ffff8801b2f78000 R12: ffff8801c98451a0
R13: dffffc0000000000 R14: ffff8801c9845220 R15: ffff8801d9a97b50
 debug_lockdep_rcu_enabled+0x77/0x90 kernel/rcu/update.c:300
 rcu_read_lock include/linux/rcupdate.h:633 [inline]
 d_walk+0x4a0/0xc80 fs/dcache.c:1303
 shrink_dcache_parent+0x179/0x230 fs/dcache.c:1486
 vfs_rmdir+0x202/0x470 fs/namei.c:3850
 do_rmdir+0x523/0x610 fs/namei.c:3911
 __do_sys_rmdir fs/namei.c:3929 [inline]
 __se_sys_rmdir fs/namei.c:3927 [inline]
 __x64_sys_rmdir+0x36/0x40 fs/namei.c:3927
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4413e7
RSP: 002b:00007fffb0ab7d28 EFLAGS: 00000207 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 00000000004413e7
RDX: 0000000000000000 RSI: 00000000006cd858 RDI: 00007fffb0ab8e10
RBP: 00007fffb0ab8e10 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000005 R11: 0000000000000207 R12: 0000000001ff98a0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000