rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=64a/1/0x4000000000000004 softirq=13291/13292 fqs=4719 
rcu: 	 (t=10500 jiffies g=8997 q=2014)
NMI backtrace for cpu 0
CPU: 0 PID: 7721 Comm: syz-fuzzer Not tainted 4.19.72 #0
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+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b0/0x1f8 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+0x189/0x1d5 kernel/rcu/tree.c:1340
 print_cpu_stall kernel/rcu/tree.c:1478 [inline]
 check_cpu_stall kernel/rcu/tree.c:1550 [inline]
 __rcu_pending kernel/rcu/tree.c:3293 [inline]
 rcu_pending kernel/rcu/tree.c:3336 [inline]
 rcu_check_callbacks.cold+0x5e3/0xd90 kernel/rcu/tree.c:2682
 update_process_times+0x32/0x80 kernel/time/timer.c:1636
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:164
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1274
 __run_hrtimer kernel/time/hrtimer.c:1398 [inline]
 __hrtimer_run_queues+0x33b/0xdc0 kernel/time/hrtimer.c:1460
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1518
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline]
 smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1092
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
RIP: 0010:write_comp_data+0x68/0x70 kernel/kcov.c:146
Code: 00 00 4e 8d 14 dd 28 00 00 00 4d 39 d0 72 1b 49 83 c1 01 4a 89 7c 10 e0 4a 89 74 10 e8 4a 89 54 10 f0 4a 89 4c d8 20 4c 89 08 <c3> 0f 1f 80 00 00 00 00 55 40 0f b6 d6 40 0f b6 f7 31 ff 48 89 e5
RSP: 0000:ffff8880ae807530 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000501 RBX: ffff88808c9c22f8 RCX: ffffffff858e7de6
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffff8880ae807538 R08: ffff888097e44640 R09: 0000000000000005
R10: ffff888097e44f88 R11: 00000000199629a7 R12: dffffc0000000000
R13: ffff88808c9c2040 R14: 0000000000000001 R15: 0000000000000000
 __list_del_entry include/linux/list.h:117 [inline]
 list_move_tail include/linux/list.h:182 [inline]
 hhf_dequeue+0x5b6/0xa00 net/sched/sch_hhf.c:438
 dequeue_skb net/sched/sch_generic.c:277 [inline]
 qdisc_restart net/sched/sch_generic.c:380 [inline]
 __qdisc_run+0x1e7/0x1960 net/sched/sch_generic.c:398
 __dev_xmit_skb net/core/dev.c:3501 [inline]
 __dev_queue_xmit+0x165c/0x2fe0 net/core/dev.c:3811
 dev_queue_xmit+0x18/0x20 net/core/dev.c:3876
 neigh_direct_output+0x16/0x20 net/core/neighbour.c:1409
 neigh_output include/net/neighbour.h:501 [inline]
 ip6_finish_output2+0xb7f/0x2550 net/ipv6/ip6_output.c:120
 ip6_finish_output+0x574/0xbe0 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip6_output+0x235/0x7c0 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:447 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ndisc_send_skb+0xf3b/0x1460 net/ipv6/ndisc.c:491
 ndisc_send_rs+0x134/0x6d0 net/ipv6/ndisc.c:685
 addrconf_rs_timer+0x30f/0x680 net/ipv6/addrconf.c:3821
 call_timer_fn+0x18d/0x720 kernel/time/timer.c:1326
 expire_timers kernel/time/timer.c:1363 [inline]
 __run_timers kernel/time/timer.c:1682 [inline]
 __run_timers kernel/time/timer.c:1650 [inline]
 run_timer_softirq+0x652/0x1700 kernel/time/timer.c:1695
 __do_softirq+0x25c/0x921 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x180/0x1d0 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x13b/0x550 arch/x86/kernel/apic/apic.c:1094
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
 </IRQ>
RIP: 0033:0x426cd4
Code: 00 00 e8 af 8d ff ff 8b 05 e1 8d 3d 01 83 f8 02 75 18 48 8b 44 24 60 48 89 04 24 e8 66 91 ff ff 48 8b 6c 24 70 48 83 c4 78 c3 <0f> b6 05 1b 8d 3d 01 84 c0 75 dd eb e9 31 c0 eb 26 48 89 44 24 50
RSP: 002b:000000c420149f38 EFLAGS: 00000297 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000001 RBX: 0000000000000002 RCX: 000000c420084480
RDX: 000000c420000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: 000000c420149fa8 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000009a9442 R11: 0000000000000004 R12: 0000000000000000
R13: 0000000000000000 R14: 000000c42002b2b0 R15: 0000000000000100
rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
rcu: 	0-....: (10676 ticks this GP) idle=64a/1/0x4000000000000002 softirq=13051/13292 fqs=4712 
rcu: 	(detected by 1, t=10534 jiffies, g=-963, q=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7721 Comm: syz-fuzzer Not tainted 4.19.72 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:list_add_tail include/linux/list.h:93 [inline]
RIP: 0010:list_move_tail include/linux/list.h:183 [inline]
RIP: 0010:hhf_dequeue+0x636/0xa00 net/sched/sch_hhf.c:438
Code: 48 c1 ea 03 42 80 3c 22 00 0f 85 7c 03 00 00 4d 89 3e e8 3d d8 dc fb 4d 8d b5 58 03 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 <0f> 85 4e 03 00 00 4d 8b bd 58 03 00 00 48 89 df 48 8b 55 c8 4c 89
RSP: 0000:ffff8880ae807548 EFLAGS: 00000246
RAX: 1ffff11011938473 RBX: ffff88808c9c22f8 RCX: ffffffff858e7de6
RDX: 0000000000000100 RSI: ffffffff858e7e53 RDI: ffff88808c9c2398
RBP: ffff8880ae807598 R08: ffff888097e44640 R09: 0000000000000005
R10: ffff888097e44f88 R11: 00000000199629a7 R12: dffffc0000000000
R13: ffff88808c9c2040 R14: ffff88808c9c2398 R15: ffff88808c9c2390
FS:  000000c42013a090(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c440c35000 CR3: 00000000832bb000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000480 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 dequeue_skb net/sched/sch_generic.c:277 [inline]
 qdisc_restart net/sched/sch_generic.c:380 [inline]
 __qdisc_run+0x1e7/0x1960 net/sched/sch_generic.c:398
 __dev_xmit_skb net/core/dev.c:3501 [inline]
 __dev_queue_xmit+0x165c/0x2fe0 net/core/dev.c:3811
 dev_queue_xmit+0x18/0x20 net/core/dev.c:3876
 neigh_direct_output+0x16/0x20 net/core/neighbour.c:1409
 neigh_output include/net/neighbour.h:501 [inline]
 ip6_finish_output2+0xb7f/0x2550 net/ipv6/ip6_output.c:120
 ip6_finish_output+0x574/0xbe0 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip6_output+0x235/0x7c0 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:447 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ndisc_send_skb+0xf3b/0x1460 net/ipv6/ndisc.c:491
 ndisc_send_rs+0x134/0x6d0 net/ipv6/ndisc.c:685
 addrconf_rs_timer+0x30f/0x680 net/ipv6/addrconf.c:3821
 call_timer_fn+0x18d/0x720 kernel/time/timer.c:1326
 expire_timers kernel/time/timer.c:1363 [inline]
 __run_timers kernel/time/timer.c:1682 [inline]
 __run_timers kernel/time/timer.c:1650 [inline]
 run_timer_softirq+0x652/0x1700 kernel/time/timer.c:1695
 __do_softirq+0x25c/0x921 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x180/0x1d0 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x13b/0x550 arch/x86/kernel/apic/apic.c:1094
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
 </IRQ>
RIP: 0033:0x426cd4
Code: 00 00 e8 af 8d ff ff 8b 05 e1 8d 3d 01 83 f8 02 75 18 48 8b 44 24 60 48 89 04 24 e8 66 91 ff ff 48 8b 6c 24 70 48 83 c4 78 c3 <0f> b6 05 1b 8d 3d 01 84 c0 75 dd eb e9 31 c0 eb 26 48 89 44 24 50
RSP: 002b:000000c420149f38 EFLAGS: 00000297 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000001 RBX: 0000000000000002 RCX: 000000c420084480
RDX: 000000c420000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: 000000c420149fa8 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000009a9442 R11: 0000000000000004 R12: 0000000000000000
R13: 0000000000000000 R14: 000000c42002b2b0 R15: 0000000000000100