rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=cde/1/0x4000000000000002 softirq=9253/9253 fqs=5 
	(t=10501 jiffies g=6785 q=58)
rcu: rcu_preempt kthread starved for 10492 jiffies! g6785 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29440    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3265 [inline]
 __schedule+0x76e/0x17a0 kernel/sched/core.c:3937
 schedule+0xd9/0x260 kernel/sched/core.c:4004
 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1893
 rcu_gp_fqs_loop kernel/rcu/tree.c:1639 [inline]
 rcu_gp_kthread+0x9b2/0x18d0 kernel/rcu/tree.c:1799
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.3.0-rc6-next-20190830 #75
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+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:2795 [inline]
 rcu_sched_clock_irq.cold+0x4fd/0xc12 kernel/rcu/tree.c:2244
 update_process_times+0x2d/0x70 kernel/time/timer.c:1724
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1299
 __run_hrtimer kernel/time/hrtimer.c:1504 [inline]
 __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1566
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1628
 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 include/linux/list.h:60 [inline]
RIP: 0010:list_add_tail include/linux/list.h:93 [inline]
RIP: 0010:list_move_tail include/linux/list.h:214 [inline]
RIP: 0010:hhf_dequeue+0x674/0xa20 net/sched/sch_hhf.c:439
Code: e8 03 42 80 3c 20 00 0f 85 5b 03 00 00 4d 8b bd 98 03 00 00 48 89 df 48 8b 55 c8 4c 89 fe e8 43 55 77 fd 31 ff 89 c6 88 45 b0 <e8> d7 e7 a6 fb 0f b6 75 b0 40 84 f6 0f 84 c6 f9 ff ff e8 85 e6 a6
RSP: 0018:ffff8880a99069a8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000001 RBX: ffff8880a34beaf8 RCX: ffffffff85cb6ed1
RDX: ffff8880a34beb90 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff8880a99069f8 R08: ffff8880a98f2440 R09: fffffbfff14ed341
R10: ffff8880a98f2da8 R11: ffff8880a98f2440 R12: dffffc0000000000
R13: ffff8880a34be800 R14: ffff8880a34beb98 R15: ffff8880a34beb90
 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+0x16f1/0x37c0 net/core/dev.c:3838
 dev_queue_xmit+0x18/0x20 net/core/dev.c:3902
 br_dev_queue_push_xmit+0x3f3/0x5e0 net/bridge/br_forward.c:52
 br_nf_dev_queue_xmit+0x34e/0x14b0 net/bridge/br_netfilter_hooks.c:796
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 br_nf_post_routing+0x1502/0x1d30 net/bridge/br_netfilter_hooks.c:844
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512
 nf_hook include/linux/netfilter.h:260 [inline]
 NF_HOOK include/linux/netfilter.h:303 [inline]
 br_forward_finish+0x215/0x400 net/bridge/br_forward.c:65
 br_nf_hook_thresh+0x2e9/0x370 net/bridge/br_netfilter_hooks.c:1015
 br_nf_forward_finish+0x66c/0xa90 net/bridge/br_netfilter_hooks.c:560
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 br_nf_forward_ip net/bridge/br_netfilter_hooks.c:630 [inline]
 br_nf_forward_ip+0xc74/0x21e0 net/bridge/br_netfilter_hooks.c:571
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512
 nf_hook include/linux/netfilter.h:260 [inline]
 NF_HOOK include/linux/netfilter.h:303 [inline]
 __br_forward+0x393/0xb00 net/bridge/br_forward.c:109
 deliver_clone+0x61/0xc0 net/bridge/br_forward.c:125
 br_flood+0x325/0x3d0 net/bridge/br_forward.c:232
 br_handle_frame_finish+0xb46/0x1670 net/bridge/br_input.c:162
 br_nf_hook_thresh+0x2e9/0x370 net/bridge/br_netfilter_hooks.c:1015
 br_nf_pre_routing_finish_ipv6+0x6fa/0xdb0 net/bridge/br_netfilter_ipv6.c:206
 NF_HOOK include/linux/netfilter.h:305 [inline]
 br_nf_pre_routing_ipv6+0x456/0x840 net/bridge/br_netfilter_ipv6.c:236
 br_nf_pre_routing+0x1743/0x2360 net/bridge/br_netfilter_hooks.c:501
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:223 [inline]
 br_handle_frame+0x806/0x1340 net/bridge/br_input.c:348
 __netif_receive_skb_core+0xfc1/0x3060 net/core/dev.c:4907
 __netif_receive_skb_one_core+0xa8/0x1a0 net/core/dev.c:5004
 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5120
 process_backlog+0x206/0x750 net/core/dev.c:5951
 napi_poll net/core/dev.c:6388 [inline]
 net_rx_action+0x50a/0x10d0 net/core/dev.c:6456
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 run_ksoftirqd kernel/softirq.c:603 [inline]
 run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595
 smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352