rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=8c6/1/0x4000000000000002 softirq=21715/21716 fqs=5250 
	(t=10502 jiffies g=30013 q=2207)
NMI backtrace for cpu 0
CPU: 0 PID: 9109 Comm: kworker/0:5 Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events rt6_probe_deferred
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:164 [inline]
 rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
 rcu_pending kernel/rcu/tree.c:2736 [inline]
 rcu_sched_clock_irq.cold+0x4dd/0xc13 kernel/rcu/tree.c:2183
 update_process_times+0x32/0x80 kernel/time/timer.c:1639
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1296
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1106 [inline]
 smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1131
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 </IRQ>
RIP: 0010:__list_add_valid+0x2d/0xa0 lib/list_debug.c:23
Code: 00 00 00 00 fc ff df 55 48 89 e5 41 55 49 89 fd 48 8d 7a 08 41 54 49 89 d4 48 89 fa 48 83 ec 08 48 c1 ea 03 80 3c 02 00 75 52 <49> 8b 54 24 08 48 39 f2 0f 85 5a 01 00 00 48 b8 00 00 00 00 00 fc
RSP: 0018:ffff88806857f410 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: ffff88809bd914f8 RCX: ffffffff85c7e0d1
RDX: 1ffff110137b22b3 RSI: ffff88809bd91590 RDI: ffff88809bd91598
RBP: ffff88806857f428 R08: ffff8880a481a540 R09: fffffbfff14e9555
R10: ffff8880a481aec0 R11: ffff8880a481a540 R12: ffff88809bd91590
R13: ffff88809bd914f8 R14: ffff88809bd91598 R15: ffff88809bd91590
 __list_add include/linux/list.h:60 [inline]
 list_add_tail include/linux/list.h:93 [inline]
 list_move_tail include/linux/list.h:214 [inline]
 hhf_dequeue+0x66d/0xa20 net/sched/sch_hhf.c:439
 dequeue_skb net/sched/sch_generic.c:258 [inline]
 qdisc_restart net/sched/sch_generic.c:361 [inline]
 __qdisc_run+0x1e7/0x19d0 net/sched/sch_generic.c:379
 __dev_xmit_skb net/core/dev.c:3533 [inline]
 __dev_queue_xmit+0x16f1/0x3650 net/core/dev.c:3838
 dev_queue_xmit+0x18/0x20 net/core/dev.c:3902
 neigh_resolve_output net/core/neighbour.c:1490 [inline]
 neigh_resolve_output+0x5a5/0x970 net/core/neighbour.c:1470
 neigh_output include/net/neighbour.h:511 [inline]
 ip6_finish_output2+0x1034/0x2520 net/ipv6/ip6_output.c:116
 __ip6_finish_output+0x444/0xa50 net/ipv6/ip6_output.c:142
 ip6_finish_output+0x38/0x1f0 net/ipv6/ip6_output.c:152
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip6_output+0x235/0x7c0 net/ipv6/ip6_output.c:175
 dst_output include/net/dst.h:436 [inline]
 NF_HOOK include/linux/netfilter.h:305 [inline]
 ndisc_send_skb+0xf29/0x1450 net/ipv6/ndisc.c:505
 ndisc_send_ns+0x3a9/0x850 net/ipv6/ndisc.c:647
 rt6_probe_deferred+0xe3/0x1a0 net/ipv6/route.c:615
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352