======================================
| [   20.308007] ------------[ cut here ]------------
| [   20.308091] refcount_t: underflow; use-after-free.
| [   20.308155] WARNING: CPU: 0 PID: 835 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   20.308223] Modules linked in: bridge stp llc vrf veth
[   20.308431] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   20.308498] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   20.308558] Code: 8c e8 18 df ba ff 90 0f 0b 90 90 c3 80 3d f9 da eb 00 00 75 89 c6 05 f0 da eb 00 01 90 48 c7 c7 28 e0 f1 8c e8 f5 de ba ff 90 <0f> 0b 90 90 c3 80 3d d4 da eb 00 00 0f 85 62 ff ff ff c6 05 c7 da
All code
========
   0:	8c e8                	mov    %gs,%eax
   2:	18 df                	sbb    %bl,%bh
   4:	ba ff 90 0f 0b       	mov    $0xb0f90ff,%edx
   9:	90                   	nop
   a:	90                   	nop
   b:	c3                   	ret
   c:	80 3d f9 da eb 00 00 	cmpb   $0x0,0xebdaf9(%rip)        # 0xebdb0c
  13:	75 89                	jne    0xffffffffffffff9e
  15:	c6 05 f0 da eb 00 01 	movb   $0x1,0xebdaf0(%rip)        # 0xebdb0c
  1c:	90                   	nop
  1d:	48 c7 c7 28 e0 f1 8c 	mov    $0xffffffff8cf1e028,%rdi
  24:	e8 f5 de ba ff       	call   0xffffffffffbadf1e
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	c3                   	ret
  2f:	80 3d d4 da eb 00 00 	cmpb   $0x0,0xebdad4(%rip)        # 0xebdb0a
  36:	0f 85 62 ff ff ff    	jne    0xffffffffffffff9e
  3c:	c6                   	.byte 0xc6
  3d:	05                   	.byte 0x5
  3e:	c7                   	(bad)
  3f:	da                   	.byte 0xda

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	90                   	nop
   4:	c3                   	ret
   5:	80 3d d4 da eb 00 00 	cmpb   $0x0,0xebdad4(%rip)        # 0xebdae0
   c:	0f 85 62 ff ff ff    	jne    0xffffffffffffff74
  12:	c6                   	.byte 0xc6
  13:	05                   	.byte 0x5
  14:	c7                   	(bad)
  15:	da                   	.byte 0xda
[   20.308756] RSP: 0018:ffffbb2240c57730 EFLAGS: 00010282
[   20.308817] RAX: 0000000000000000 RBX: ffffbb2240c57740 RCX: 00000000ffffdfff
[   20.308892] RDX: 0000000000000000 RSI: 00000000ffffffea RDI: 0000000000000001
[   20.308998] RBP: ffffbb2240c57248 R08: ffffffff8d356a28 R09: 00000000ffffdfff
[   20.309086] R10: ffffffff8d276a40 R11: ffffffff8d326a40 R12: dead000000000122
[   20.309168] R13: 00000000fffbbadc R14: 0000000000000001 R15: ffff98a5c55d3000
[   20.309251] FS:  00007f18234c5800(0000) GS:ffff98a6711d9000(0000) knlGS:0000000000000000
[   20.309342] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   20.309405] CR2: 00000000004e68d0 CR3: 000000000788b001 CR4: 0000000000772ef0
[   20.309488] PKRU: 55555554
[   20.309521] Call Trace:
[   20.309551]  <TASK>
[   20.309582]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   20.309640]  rtnl_dellink (net/core/rtnetlink.c:3580)
[   20.309697]  ? virtio_fs_enqueue_req (fs/fuse/virtio_fs.c:1473)
[   20.309761]  ? netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11653)
[   20.309811]  ? rtnl_bridge_getlink (net/core/rtnetlink.c:3536)
[   20.309874]  rtnetlink_rcv_msg (net/core/rtnetlink.c:6959)
[   20.309927]  ? get_page_from_freelist (mm/page_alloc.c:1226 mm/page_alloc.c:1848 mm/page_alloc.c:1858 mm/page_alloc.c:3884)
[   20.309990]  ? rtnl_calcit.isra.0 (net/core/rtnetlink.c:6861)
[   20.310056]  netlink_rcv_skb (net/netlink/af_netlink.c:2550)
[   20.310108]  netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)
[   20.310157]  ? __alloc_skb (net/core/skbuff.c:690)
[   20.310207]  netlink_sendmsg (net/netlink/af_netlink.c:1894)
[   20.310256]  ____sys_sendmsg (net/socket.c:727 net/socket.c:742 net/socket.c:2630)
[   20.310311]  ? copy_msghdr_from_user (net/socket.c:2570)
[   20.310374]  ___sys_sendmsg (net/socket.c:2686)
[   20.310420]  ? do_wp_page (./include/linux/mmu_notifier.h:468 mm/memory.c:3786 mm/memory.c:4140)
[   20.310473]  ? ___pte_offset_map (./include/linux/pgtable.h:347 ./include/linux/pgtable.h:635 mm/pgtable-generic.c:288)
[   20.310526]  ? nfulnl_rcv_nl_event (net/netfilter/nfnetlink_log.c:836)
[   20.310592]  ? fsnotify_grab_connector (fs/notify/mark.c:709)
[   20.310655]  ? fsnotify_destroy_marks (fs/notify/mark.c:937)
[   20.310721]  __sys_sendmsg (net/socket.c:2716)
[   20.310771]  do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
[   20.310819]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   20.310884] RIP: 0033:0x7f18236931d7
[   20.310931] Code: 0e 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10
All code
========
   0:	0e                   	(bad)
   1:	00 f7                	add    %dh,%bh
   3:	d8 64 89 02          	fsubs  0x2(%rcx,%rcx,4)
   7:	48 c7 c0 ff ff ff ff 	mov    $0xffffffffffffffff,%rax
   e:	eb b9                	jmp    0xffffffffffffffc9
  10:	0f 1f 00             	nopl   (%rax)
  13:	f3 0f 1e fa          	endbr64
  17:	64 8b 04 25 18 00 00 	mov    %fs:0x18,%eax
  1e:	00 
  1f:	85 c0                	test   %eax,%eax
  21:	75 10                	jne    0x33
  23:	b8 2e 00 00 00       	mov    $0x2e,%eax
  28:	0f 05                	syscall
  2a:*	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax		<-- trapping instruction
  30:	77 51                	ja     0x83
  32:	c3                   	ret
  33:	48 83 ec 28          	sub    $0x28,%rsp
  37:	89 54 24 1c          	mov    %edx,0x1c(%rsp)
  3b:	48 89 74 24 10       	mov    %rsi,0x10(%rsp)

Code starting with the faulting instruction
===========================================
   0:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   6:	77 51                	ja     0x59
   8:	c3                   	ret
   9:	48 83 ec 28          	sub    $0x28,%rsp
   d:	89 54 24 1c          	mov    %edx,0x1c(%rsp)
  11:	48 89 74 24 10       	mov    %rsi,0x10(%rsp)
[   20.311136] RSP: 002b:00007ffc1bc76c28 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   20.311221] RAX: ffffffffffffffda RBX: 00007ffc1bc77350 RCX: 00007f18236931d7
[   20.311305] RDX: 0000000000000000 RSI: 00007ffc1bc76c90 RDI: 0000000000000005
[   20.311388] RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000078
[   20.311468] R10: 00007f182358ff60 R11: 0000000000000246 R12: 0000000000000002


Finger prints:
refcount_warn_saturate:netdev_run_todo:rtnl_dellink:rtnetlink_rcv_msg:netlink_rcv_skb