======================================
| [   22.273023][    C1] 1 lock held by swapper/1/0:
| [ 22.273269][ C1] #0: ffffc900001e0d60 ((&n->timer)){+.-.}-{0:0}, at: call_timer_fn (./include/linux/lockdep.h:31 kernel/time/timer.c:1779) 
| [   22.273568][    C1]
| [   22.273568][    C1] stack backtrace:
[   22.273807][    C1] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   22.273809][    C1] Call Trace:
[   22.273810][    C1]  <IRQ>
[ 22.273814][ C1] dump_stack_lvl (lib/dump_stack.c:123) 
[ 22.273823][ C1] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6848) 
[ 22.273836][ C1] icmp6_send (./include/net/net_namespace.h:404 ./include/linux/netdevice.h:2669 net/ipv6/icmp.c:476) 
[ 22.273865][ C1] ? __pfx_icmp6_send (net/ipv6/icmp.c:452) 
[ 22.273877][ C1] ? __pfx_validate_chain (kernel/locking/lockdep.c:3862) 
[ 22.273884][ C1] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:230) 
[ 22.273889][ C1] ? mark_lock (kernel/locking/lockdep.c:4729 (discriminator 3)) 
[ 22.273906][ C1] ? __lock_acquire (kernel/locking/lockdep.c:5228) 
[ 22.273916][ C1] ? find_held_lock (kernel/locking/lockdep.c:5341) 
[ 22.273923][ C1] ? __lock_release (kernel/locking/lockdep.c:5527) 
[ 22.273925][ C1] ? neigh_invalidate (net/core/neighbour.c:1008) 
[ 22.273930][ C1] ? __pfx___lock_release (kernel/locking/lockdep.c:5503) 
[ 22.273934][ C1] ? lock_acquire.part.0 (kernel/locking/lockdep.c:469 kernel/locking/lockdep.c:5853) 
[ 22.273945][ C1] ip6_link_failure (./include/linux/skbuff.h:1152 net/ipv6/route.c:2801) 
[ 22.273953][ C1] ndisc_error_report (./include/net/dst.h:429 net/ipv6/ndisc.c:731) 
[ 22.273960][ C1] neigh_invalidate (net/core/neighbour.c:1008) 
[ 22.273969][ C1] neigh_timer_handler (net/core/neighbour.c:1109 (discriminator 2)) 
[ 22.273979][ C1] ? __pfx_neigh_timer_handler (net/core/neighbour.c:1032) 
[ 22.273982][ C1] call_timer_fn (kernel/time/timer.c:1789) 
[ 22.273985][ C1] ? call_timer_fn (./include/linux/lockdep.h:31 kernel/time/timer.c:1779) 
[ 22.273988][ C1] ? call_timer_fn (./include/linux/lockdep.h:31 kernel/time/timer.c:1779) 
[ 22.273992][ C1] ? __pfx_call_timer_fn (kernel/time/timer.c:1766) 
[ 22.273995][ C1] ? mark_lock (kernel/locking/lockdep.c:4729 (discriminator 3)) 
[ 22.274012][ C1] __run_timers (kernel/time/timer.c:1841 kernel/time/timer.c:2414) 
[ 22.274015][ C1] ? __pfx_neigh_timer_handler (net/core/neighbour.c:1032) 
[ 22.274025][ C1] ? __pfx___run_timers (kernel/time/timer.c:2385) 
[ 22.274028][ C1] ? clockevents_program_event (kernel/time/clockevents.c:326) 
[ 22.274037][ C1] ? do_raw_spin_lock (./arch/x86/include/asm/atomic.h:107 ./include/linux/atomic/atomic-arch-fallback.h:2170 ./include/linux/atomic/atomic-instrumented.h:1302 ./include/asm-generic/qspinlock.h:111 kernel/locking/spinlock_debug.c:116) 
[ 22.274043][ C1] ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114) 
[ 22.274048][ C1] ? lock_acquire (kernel/locking/lockdep.c:5824) 
[ 22.274051][ C1] ? run_timer_softirq (kernel/time/timer.c:2426 kernel/time/timer.c:2418 kernel/time/timer.c:2435 kernel/time/timer.c:2445) 
[ 22.274060][ C1] run_timer_softirq (kernel/time/timer.c:2427 kernel/time/timer.c:2418 kernel/time/timer.c:2435 kernel/time/timer.c:2445) 
[ 22.274065][ C1] handle_softirqs (kernel/softirq.c:561) 
[ 22.274078][ C1] __irq_exit_rcu (kernel/softirq.c:596 kernel/softirq.c:435 kernel/softirq.c:662) 
[ 22.274081][ C1] irq_exit_rcu (kernel/softirq.c:680) 
[ 22.274084][ C1] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[   22.274088][    C1]  </IRQ>
[   22.274089][    C1]  <TASK>
[ 22.274091][ C1] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 22.274096][ C1] RIP: 0010:default_idle (./arch/x86/include/asm/irqflags.h:37 ./arch/x86/include/asm/irqflags.h:92 arch/x86/kernel/process.c:744) 
[ 22.274099][ C1] Code: 4c 01 c7 4c 29 c2 e9 72 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 23 cc 14 00 fb f4 <fa> c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
All code
========
   0:	4c 01 c7             	add    %r8,%rdi
   3:	4c 29 c2             	sub    %r8,%rdx
   6:	e9 72 ff ff ff       	jmp    0xffffffffffffff7d
   b:	90                   	nop
   c:	90                   	nop
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	f3 0f 1e fa          	endbr64
  1f:	66 90                	xchg   %ax,%ax
  21:	0f 00 2d 23 cc 14 00 	verw   0x14cc23(%rip)        # 0x14cc4b
  28:	fb                   	sti
  29:	f4                   	hlt
  2a:*	fa                   	cli		<-- trapping instruction
  2b:	c3                   	ret
  2c:	cc                   	int3
  2d:	cc                   	int3
  2e:	cc                   	int3
  2f:	cc                   	int3
  30:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
  37:	00 00 00 00 
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop

Code starting with the faulting instruction
===========================================
   0:	fa                   	cli
   1:	c3                   	ret
   2:	cc                   	int3
   3:	cc                   	int3
   4:	cc                   	int3
   5:	cc                   	int3
   6:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
   d:	00 00 00 00 
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
[   22.274102][    C1] RSP: 0018:ffffc90000157df8 EFLAGS: 00000246
[   22.274106][    C1] RAX: 000000000010e5b7 RBX: 1ffff9200002afc1 RCX: ffffffffb1d14b15
[   22.274108][    C1] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffaf569634
[   22.274109][    C1] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c1703a
[   22.274111][    C1] R10: ffff8880360b81d3 R11: ffff888001b2c5c0 R12: 0000000000000000
[   22.274113][    C1] R13: ffff888001b2c5c0 R14: dffffc0000000000 R15: 0000000000000000
[ 22.274122][ C1] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:147) 
[ 22.274126][ C1] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 22.274135][ C1] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 22.274138][ C1] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 22.274142][ C1] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 22.274149][ C1] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) 
[ 22.274158][ C1] do_idle (kernel/sched/idle.c:325) 
[ 22.274164][ C1] cpu_startup_entry (kernel/sched/idle.c:422 (discriminator 1)) 
[ 22.274172][ C1] start_secondary (arch/x86/kernel/smpboot.c:203 arch/x86/kernel/smpboot.c:283) 
[ 22.274176][ C1] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:233) 


Finger prints:
lockdep_rcu_suspicious:icmp6_send:ip6_link_failure:ndisc_error_report:neigh_invalidate