======================================
| [ 1646.238996][    C1] page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0)
| [ 1646.239229][    C1] ------------[ cut here ]------------
| [ 1646.239412][    C1] kernel BUG at include/linux/mm.h:1140!
| [ 1646.239574][    C1] Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
[ 1646.239989][    C1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 1646.240277][ C1] RIP: 0010:__free_pages (./include/linux/mm.h:1140 ./include/linux/mm.h:1138 mm/page_alloc.c:4819) 
[ 1646.240418][ C1] Code: 0f 94 c3 e9 ba fe ff ff 48 c7 c6 a0 18 78 b0 4c 89 e7 e8 df bf f4 ff 90 0f 0b 48 c7 c6 40 29 78 b0 4c 89 e7 e8 cd bf f4 ff 90 <0f> 0b 48 89 ef e8 72 03 09 00 e9 c5 fe ff ff e8 98 03 09 00 e9 35
All code
========
   0:	0f 94 c3             	sete   %bl
   3:	e9 ba fe ff ff       	jmp    0xfffffffffffffec2
   8:	48 c7 c6 a0 18 78 b0 	mov    $0xffffffffb07818a0,%rsi
   f:	4c 89 e7             	mov    %r12,%rdi
  12:	e8 df bf f4 ff       	call   0xfffffffffff4bff6
  17:	90                   	nop
  18:	0f 0b                	ud2
  1a:	48 c7 c6 40 29 78 b0 	mov    $0xffffffffb0782940,%rsi
  21:	4c 89 e7             	mov    %r12,%rdi
  24:	e8 cd bf f4 ff       	call   0xfffffffffff4bff6
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	48 89 ef             	mov    %rbp,%rdi
  2f:	e8 72 03 09 00       	call   0x903a6
  34:	e9 c5 fe ff ff       	jmp    0xfffffffffffffefe
  39:	e8 98 03 09 00       	call   0x903d6
  3e:	e9                   	.byte 0xe9
  3f:	35                   	.byte 0x35

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	48 89 ef             	mov    %rbp,%rdi
   5:	e8 72 03 09 00       	call   0x9037c
   a:	e9 c5 fe ff ff       	jmp    0xfffffffffffffed4
   f:	e8 98 03 09 00       	call   0x903ac
  14:	e9                   	.byte 0xe9
  15:	35                   	.byte 0x35
[ 1646.240869][    C1] RSP: 0018:ffffc900001bfcb0 EFLAGS: 00010246
[ 1646.241040][    C1] RAX: 000000000000003e RBX: 0000000000000000 RCX: 1ffffffff627b43c
[ 1646.241234][    C1] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
[ 1646.241418][    C1] RBP: ffffea000015ff34 R08: 0000000000000000 R09: fffffbfff627b43c
[ 1646.241605][    C1] R10: 0000000000000003 R11: 205d314320202020 R12: ffffea000015ff00
[ 1646.241792][    C1] R13: ffffc900001bfd78 R14: 0000000000000000 R15: 0000000000000000
[ 1646.241989][    C1] FS:  0000000000000000(0000) GS:ffff88802f680000(0000) knlGS:0000000000000000
[ 1646.242213][    C1] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1646.242368][    C1] CR2: 00007f30a3f18270 CR3: 000000000a326004 CR4: 0000000000772ef0
[ 1646.242558][    C1] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1646.242743][    C1] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1646.242937][    C1] PKRU: 55555554
[ 1646.243043][    C1] Call Trace:
[ 1646.243137][    C1]  <TASK>
[ 1646.243203][ C1] ? die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434 arch/x86/kernel/dumpstack.c:447) 
[ 1646.243335][ C1] ? do_trap (arch/x86/kernel/traps.c:156 arch/x86/kernel/traps.c:197) 
[ 1646.243433][ C1] ? __free_pages (./include/linux/mm.h:1140 ./include/linux/mm.h:1138 mm/page_alloc.c:4819) 
[ 1646.243563][ C1] ? do_error_trap (./arch/x86/include/asm/traps.h:58 arch/x86/kernel/traps.c:218) 
[ 1646.243688][ C1] ? __free_pages (./include/linux/mm.h:1140 ./include/linux/mm.h:1138 mm/page_alloc.c:4819) 
[ 1646.243811][ C1] ? __free_pages (./include/linux/mm.h:1140 ./include/linux/mm.h:1138 mm/page_alloc.c:4819) 
[ 1646.243943][ C1] ? handle_invalid_op (arch/x86/kernel/traps.c:256) 
[ 1646.244086][ C1] ? __free_pages (./include/linux/mm.h:1140 ./include/linux/mm.h:1138 mm/page_alloc.c:4819) 
[ 1646.244216][ C1] ? exc_invalid_op (arch/x86/kernel/traps.c:315) 
[ 1646.244386][ C1] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621) 
[ 1646.244568][ C1] ? __free_pages (./include/linux/mm.h:1140 ./include/linux/mm.h:1138 mm/page_alloc.c:4819) 
[ 1646.244756][ C1] ? rcu_do_batch (kernel/rcu/tree.c:2567) 
[ 1646.244952][ C1] neigh_hash_free_rcu (net/core/neighbour.c:555) 
[ 1646.245155][ C1] rcu_do_batch (kernel/rcu/tree.c:2567) 
[ 1646.245340][ C1] ? __pfx___lock_release (kernel/locking/lockdep.c:5477) 
[ 1646.245535][ C1] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2491) 
[ 1646.245735][ C1] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4339 kernel/locking/lockdep.c:4406) 
[ 1646.245980][ C1] rcu_core (kernel/rcu/tree.c:2825) 
[ 1646.246137][ C1] handle_softirqs (kernel/softirq.c:554) 
[ 1646.246344][ C1] ? __pfx_run_ksoftirqd (kernel/softirq.c:920) 
[ 1646.246542][ C1] run_ksoftirqd (kernel/softirq.c:411 kernel/softirq.c:928 kernel/softirq.c:919) 
[ 1646.246741][ C1] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 1646.246945][ C1] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 1646.247141][ C1] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 1646.247341][ C1] kthread (kernel/kthread.c:389) 
[ 1646.247496][ C1] ? __pfx_kthread (kernel/kthread.c:342) 
[ 1646.247699][ C1] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 1646.247899][ C1] ? __pfx_kthread (kernel/kthread.c:342) 


Finger prints:
__free_pages:neigh_hash_free_rcu:rcu_do_batch:rcu_core:handle_softirqs