======================================
| [    2.080359] ------------[ cut here ]------------
| [    2.080446] refcount_t: underflow; use-after-free.
| [    2.080506] WARNING: CPU: 3 PID: 235 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [    2.080582] Modules linked in: netdevsim
[    2.080676] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[    2.080717] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[    2.080757] Code: a9 e8 88 98 ba ff 90 0f 0b 90 90 c3 80 3d 69 b4 eb 00 00 75 89 c6 05 60 b4 eb 00 01 90 48 c7 c7 98 6e 14 a9 e8 65 98 ba ff 90 <0f> 0b 90 90 c3 80 3d 44 b4 eb 00 00 0f 85 62 ff ff ff c6 05 37 b4
All code
========
   0:	a9 e8 88 98 ba       	test   $0xba9888e8,%eax
   5:	ff 90 0f 0b 90 90    	call   *-0x6f6ff4f1(%rax)
   b:	c3                   	ret
   c:	80 3d 69 b4 eb 00 00 	cmpb   $0x0,0xebb469(%rip)        # 0xebb47c
  13:	75 89                	jne    0xffffffffffffff9e
  15:	c6 05 60 b4 eb 00 01 	movb   $0x1,0xebb460(%rip)        # 0xebb47c
  1c:	90                   	nop
  1d:	48 c7 c7 98 6e 14 a9 	mov    $0xffffffffa9146e98,%rdi
  24:	e8 65 98 ba ff       	call   0xffffffffffba988e
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	c3                   	ret
  2f:	80 3d 44 b4 eb 00 00 	cmpb   $0x0,0xebb444(%rip)        # 0xebb47a
  36:	0f 85 62 ff ff ff    	jne    0xffffffffffffff9e
  3c:	c6                   	.byte 0xc6
  3d:	05                   	.byte 0x5
  3e:	37                   	(bad)
  3f:	b4                   	.byte 0xb4

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	90                   	nop
   4:	c3                   	ret
   5:	80 3d 44 b4 eb 00 00 	cmpb   $0x0,0xebb444(%rip)        # 0xebb450
   c:	0f 85 62 ff ff ff    	jne    0xffffffffffffff74
  12:	c6                   	.byte 0xc6
  13:	05                   	.byte 0x5
  14:	37                   	(bad)
  15:	b4                   	.byte 0xb4
[    2.080874] RSP: 0018:ffffb6f5002b3730 EFLAGS: 00010282
[    2.080917] RAX: 0000000000000000 RBX: ffffb6f5002b3740 RCX: 00000000ffffdfff
[    2.080971] RDX: 0000000000000000 RSI: 00000000ffffffea RDI: 0000000000000001
[    2.081048] RBP: ffffb6f5002b3258 R08: ffffffffa9556a28 R09: 00000000ffffdfff
[    2.081108] R10: ffffffffa9476a40 R11: ffffffffa9526a40 R12: dead000000000122
[    2.081174] R13: 00000000fffb73b8 R14: 0000000000000001 R15: ffff921542dbe000
[    2.081235] FS:  00007f4cf1eff800(0000) GS:ffff9215d5137000(0000) knlGS:0000000000000000
[    2.081295] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    2.081359] CR2: 00007f42619415f0 CR3: 0000000004de2002 CR4: 0000000000772ef0
[    2.081414] PKRU: 55555554
[    2.081434] Call Trace:
[    2.081459]  <TASK>
[    2.081481]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[    2.081521]  rtnl_dellink (net/core/rtnetlink.c:3580)
[    2.081560]  ? virtio_fs_enqueue_req (fs/fuse/virtio_fs.c:1473)
[    2.081608]  ? netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11653)
[    2.081639]  ? rtnl_bridge_getlink (net/core/rtnetlink.c:3536)
[    2.081677]  rtnetlink_rcv_msg (net/core/rtnetlink.c:6959)
[    2.081711]  ? get_page_from_freelist (mm/page_alloc.c:1226 mm/page_alloc.c:1848 mm/page_alloc.c:1858 mm/page_alloc.c:3884)
[    2.081757]  ? rtnl_calcit.isra.0 (net/core/rtnetlink.c:6861)
[    2.081796]  netlink_rcv_skb (net/netlink/af_netlink.c:2550)
[    2.081838]  netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)
[    2.081869]  ? __alloc_skb (net/core/skbuff.c:690)
[    2.081905]  netlink_sendmsg (net/netlink/af_netlink.c:1894)
[    2.081936]  ____sys_sendmsg (net/socket.c:727 net/socket.c:742 net/socket.c:2630)
[    2.081977]  ? copy_msghdr_from_user (net/socket.c:2570)
[    2.082014]  ___sys_sendmsg (net/socket.c:2686)
[    2.082045]  ? do_wp_page (./include/linux/mmu_notifier.h:468 mm/memory.c:3786 mm/memory.c:4140)
[    2.082075]  ? ___pte_offset_map (./include/linux/pgtable.h:347 ./include/linux/pgtable.h:635 mm/pgtable-generic.c:288)
[    2.082107]  ? __handle_mm_fault (mm/memory.c:6193 mm/memory.c:6318)
[    2.082151]  ? fsnotify_grab_connector (fs/notify/mark.c:709)
[    2.082201]  ? fsnotify_destroy_marks (fs/notify/mark.c:937)
[    2.082240]  __sys_sendmsg (net/socket.c:2716)
[    2.082271]  do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
[    2.082315]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[    2.082357] RIP: 0033:0x7f4cf20cd1d7
[    2.082401] 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)
[    2.082543] RSP: 002b:00007fffbcb86338 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[    2.082615] RAX: ffffffffffffffda RBX: 00007fffbcb86a60 RCX: 00007f4cf20cd1d7
[    2.082662] RDX: 0000000000000000 RSI: 00007fffbcb863a0 RDI: 0000000000000005
[    2.082721] RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000078
[    2.082785] R10: 00007f4cf1fc9f60 R11: 0000000000000246 R12: 0000000000000001
[    2.082834] R13: 00000000690de85a R14: 0000000000499600 R15: 0000000000000000
| [    2.415359] ------------[ cut here ]------------
| [    2.415512] kernel BUG at net/core/net-sysfs.c:2246!
| [    2.415584] Oops: invalid opcode: 0000 [#1] SMP
| [    2.415767] Tainted: [W]=WARN
[    2.415807] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[    2.415877] RIP: 0010:netdev_release (net/core/net-sysfs.c:2246 net/core/net-sysfs.c:2242)
[    2.415940] Code: fa 0f 1f 44 00 00 80 7f e0 04 75 1d 55 48 8d af d0 fa ff ff 48 8b bf 00 fc ff ff e8 cd ff a3 ff 48 89 ef 5d e9 84 06 a4 ff 90 <0f> 0b 90 f3 0f 1e fa 0f 1f 44 00 00 55 48 89 f5 48 8d 97 e8 fb ff
All code
========
   0:	fa                   	cli
   1:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
   6:	80 7f e0 04          	cmpb   $0x4,-0x20(%rdi)
   a:	75 1d                	jne    0x29
   c:	55                   	push   %rbp
   d:	48 8d af d0 fa ff ff 	lea    -0x530(%rdi),%rbp
  14:	48 8b bf 00 fc ff ff 	mov    -0x400(%rdi),%rdi
  1b:	e8 cd ff a3 ff       	call   0xffffffffffa3ffed
  20:	48 89 ef             	mov    %rbp,%rdi
  23:	5d                   	pop    %rbp
  24:	e9 84 06 a4 ff       	jmp    0xffffffffffa406ad
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	f3 0f 1e fa          	endbr64
  31:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  36:	55                   	push   %rbp
  37:	48 89 f5             	mov    %rsi,%rbp
  3a:	48                   	rex.W
  3b:	8d                   	.byte 0x8d
  3c:	97                   	xchg   %eax,%edi
  3d:	e8                   	.byte 0xe8
  3e:	fb                   	sti
  3f:	ff                   	.byte 0xff

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	f3 0f 1e fa          	endbr64
   7:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
   c:	55                   	push   %rbp
   d:	48 89 f5             	mov    %rsi,%rbp
  10:	48                   	rex.W
  11:	8d                   	.byte 0x8d
  12:	97                   	xchg   %eax,%edi
  13:	e8                   	.byte 0xe8
  14:	fb                   	sti
  15:	ff                   	.byte 0xff
[    2.416111] RSP: 0018:ffffb6f50056fbf0 EFLAGS: 00010297
[    2.416161] RAX: ffffffffa8b5a5d0 RBX: 00000000ffffffff RCX: 0000000000000002
[    2.416243] RDX: 0000000000000006 RSI: ffffffffa8953ba4 RDI: ffff9215413c4530
[    2.416323] RBP: ffff9215413c4530 R08: 0000000000000010 R09: 0000000000000190
[    2.416401] R10: 0000000000000400 R11: 0000000000000190 R12: ffff921541ae4800
[    2.416477] R13: ffffffffa8eb1d20 R14: ffff921542e58580 R15: ffff9215413c4000
[    2.416558] FS:  00007fe712ce4000(0000) GS:ffff9215d4fb7000(0000) knlGS:0000000000000000
[    2.416643] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    2.416716] CR2: 00007f42619415f0 CR3: 0000000004dc9003 CR4: 0000000000772ef0
[    2.416803] PKRU: 55555554
[    2.416832] Call Trace:
[    2.416860]  <TASK>
[    2.416883]  device_release (drivers/base/core.c:2569)
[    2.416930]  kobject_put (lib/kobject.c:693 lib/kobject.c:720 ./include/linux/kref.h:65 lib/kobject.c:737)
[    2.416984]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[    2.417036] nsim_destroy (drivers/net/netdevsim/netdevsim.h:396 drivers/net/netdevsim/netdev.c:1186) netdevsim
[    2.417094] __nsim_dev_port_del (drivers/net/netdevsim/dev.c:441 drivers/net/netdevsim/dev.c:1474) netdevsim
[    2.417149] nsim_dev_reload_destroy (drivers/net/netdevsim/dev.c:1483 drivers/net/netdevsim/dev.c:1707) netdevsim
[    2.417208] nsim_drv_remove (drivers/net/netdevsim/dev.c:1724) netdevsim
[    2.417273]  device_release_driver_internal (drivers/base/dd.c:1276 drivers/base/dd.c:1297)
[    2.417328]  bus_remove_device (./include/linux/kobject.h:193 (discriminator 3) drivers/base/base.h:73 (discriminator 3) drivers/base/bus.c:586 (discriminator 3))
[    2.417375]  device_del (drivers/base/core.c:3879)
[    2.417414]  device_unregister (drivers/base/core.c:3796 drivers/base/core.c:3920)
[    2.417452] del_device_store (drivers/net/netdevsim/bus.c:248) netdevsim
[    2.417510]  kernfs_fop_write_iter (fs/kernfs/file.c:88 fs/kernfs/file.c:356)
[    2.417569]  vfs_write (fs/read_write.c:594 fs/read_write.c:686)
[    2.417617]  ksys_write (fs/read_write.c:738)
[    2.417658]  do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
[    2.417697]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[    2.417748] RIP: 0033:0x7fe712de4257
[    2.417788] Code: 0f 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
All code
========
   0:	0f 00                	(bad)
   2:	f7 d8                	neg    %eax
   4:	64 89 02             	mov    %eax,%fs:(%rdx)
   7:	48 c7 c0 ff ff ff ff 	mov    $0xffffffffffffffff,%rax
   e:	eb b7                	jmp    0xffffffffffffffc7
  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 01 00 00 00       	mov    $0x1,%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:	48 89 54 24 18       	mov    %rdx,0x18(%rsp)
  3c:	48                   	rex.W
  3d:	89                   	.byte 0x89
  3e:	74 24                	je     0x64

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:	48 89 54 24 18       	mov    %rdx,0x18(%rsp)
  12:	48                   	rex.W
  13:	89                   	.byte 0x89
  14:	74 24                	je     0x3a
[    2.417976] RSP: 002b:00007ffc9dbaccc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[    2.418050] RAX: ffffffffffffffda RBX: 00007fe712ee0780 RCX: 00007fe712de4257
[    2.418128] RDX: 0000000000000004 RSI: 00005610a64a0a90 RDI: 0000000000000001
[    2.418204] RBP: 0000000000000004 R08: 0000000000000000 R09: 00007fe712e96d20
[    2.418285] R10: 00007fe712e96c20 R11: 0000000000000246 R12: 0000000000000004


Finger prints:
netdev_release:device_release:kobject_put:netdev_run_todo:nsim_destroy
refcount_warn_saturate:netdev_run_todo:rtnl_dellink:rtnetlink_rcv_msg:netlink_rcv_skb