======================================
| [ 1549.276322][    C3] page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0)
| [ 1549.276990][    C3] ------------[ cut here ]------------
| [ 1549.277176][    C3] kernel BUG at include/linux/mm.h:1140!
| [ 1549.277389][    C3] Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
[ 1549.277842][    C3] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 1549.278173][ C3] RIP: 0010:__free_pages (./include/linux/mm.h:1140 ./include/linux/mm.h:1138 mm/page_alloc.c:4819) 
[ 1549.278334][ C3] Code: 0f 94 c3 e9 ba fe ff ff 48 c7 c6 a0 18 98 8e 4c 89 e7 e8 df bf f4 ff 90 0f 0b 48 c7 c6 40 29 98 8e 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 98 8e 	mov    $0xffffffff8e9818a0,%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 98 8e 	mov    $0xffffffff8e982940,%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
[ 1549.278857][    C3] RSP: 0018:ffffc9000026fcb0 EFLAGS: 00010246
[ 1549.279044][    C3] RAX: 000000000000003e RBX: 0000000000000000 RCX: 1ffffffff1ebb43c
[ 1549.279270][    C3] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
[ 1549.279484][    C3] RBP: ffffea0000285474 R08: 0000000000000000 R09: fffffbfff1ebb43c
[ 1549.279702][    C3] R10: 0000000000000003 R11: 205d334320202020 R12: ffffea0000285440
[ 1549.279914][    C3] R13: ffffc9000026fd78 R14: 0000000000000000 R15: 0000000000000007
[ 1549.280133][    C3] FS:  0000000000000000(0000) GS:ffff888036180000(0000) knlGS:0000000000000000
[ 1549.280382][    C3] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1549.280563][    C3] CR2: 0000564917c0ea48 CR3: 00000000045b0003 CR4: 0000000000772ef0
[ 1549.280783][    C3] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1549.280993][    C3] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1549.281202][    C3] PKRU: 55555554
[ 1549.281310][    C3] Call Trace:
[ 1549.281417][    C3]  <TASK>
[ 1549.281497][ C3] ? die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434 arch/x86/kernel/dumpstack.c:447) 
[ 1549.281614][ C3] ? do_trap (arch/x86/kernel/traps.c:156 arch/x86/kernel/traps.c:197) 
[ 1549.281723][ C3] ? __free_pages (./include/linux/mm.h:1140 ./include/linux/mm.h:1138 mm/page_alloc.c:4819) 
[ 1549.281869][ C3] ? do_error_trap (./arch/x86/include/asm/traps.h:58 arch/x86/kernel/traps.c:218) 
[ 1549.282015][ C3] ? __free_pages (./include/linux/mm.h:1140 ./include/linux/mm.h:1138 mm/page_alloc.c:4819) 
[ 1549.282157][ C3] ? __free_pages (./include/linux/mm.h:1140 ./include/linux/mm.h:1138 mm/page_alloc.c:4819) 
[ 1549.282298][ C3] ? handle_invalid_op (arch/x86/kernel/traps.c:256) 
[ 1549.282439][ C3] ? __free_pages (./include/linux/mm.h:1140 ./include/linux/mm.h:1138 mm/page_alloc.c:4819) 
[ 1549.282584][ C3] ? exc_invalid_op (arch/x86/kernel/traps.c:315) 
[ 1549.282726][ C3] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621) 
[ 1549.282876][ C3] ? __free_pages (./include/linux/mm.h:1140 ./include/linux/mm.h:1138 mm/page_alloc.c:4819) 
[ 1549.283018][ C3] ? rcu_do_batch (kernel/rcu/tree.c:2567) 
[ 1549.283169][ C3] neigh_hash_free_rcu (net/core/neighbour.c:554) 
[ 1549.283316][ C3] rcu_do_batch (kernel/rcu/tree.c:2567) 
[ 1549.283459][ C3] ? __pfx___lock_release (kernel/locking/lockdep.c:5477) 
[ 1549.283602][ C3] ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2491) 
[ 1549.283747][ C3] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4339 kernel/locking/lockdep.c:4406) 
[ 1549.283924][ C3] rcu_core (kernel/rcu/tree.c:2825) 
[ 1549.284037][ C3] handle_softirqs (kernel/softirq.c:554) 
[ 1549.284179][ C3] ? __pfx_run_ksoftirqd (kernel/softirq.c:920) 
[ 1549.284320][ C3] run_ksoftirqd (kernel/softirq.c:411 kernel/softirq.c:928 kernel/softirq.c:919) 
[ 1549.284465][ C3] smpboot_thread_fn (kernel/smpboot.c:164 (discriminator 3)) 
[ 1549.284610][ C3] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 1549.284750][ C3] ? __pfx_smpboot_thread_fn (kernel/smpboot.c:107) 
[ 1549.284893][ C3] kthread (kernel/kthread.c:389) 
[ 1549.285006][ C3] ? __pfx_kthread (kernel/kthread.c:342) 
[ 1549.285149][ C3] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 1549.285296][ C3] ? __pfx_kthread (kernel/kthread.c:342) 


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