======================================
| [   20.626666][  T258] ==================================================================
| [   20.626990][  T258] BUG: KASAN: use-after-free in kobject_put (lib/kobject.c:733)
| [   20.627216][  T258] Read of size 1 at addr ffff888005bf46ac by task packetdrill/258
| [   20.627506][  T258]
[   20.627602][  T258] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   20.627604][  T258] Call Trace:
[   20.627606][  T258]  <TASK>
[   20.627608][  T258]  dump_stack_lvl (lib/dump_stack.c:123)
[   20.627614][  T258]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   20.627624][  T258]  ? kobject_put (lib/kobject.c:733)
[   20.627628][  T258]  print_report (mm/kasan/report.c:483)
[   20.627632][  T258]  ? kobject_put (lib/kobject.c:733)
[   20.627635][  T258]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   20.627638][  T258]  ? kobject_put (lib/kobject.c:733)
[   20.627641][  T258]  kasan_report (mm/kasan/report.c:597)
[   20.627646][  T258]  ? kobject_put (lib/kobject.c:733)
[   20.627652][  T258]  kobject_put (lib/kobject.c:733)
[   20.627655][  T258]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   20.627662][  T258]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   20.627666][  T258]  ? netif_state_change (./include/net/netdev_lock.h:72 ./include/net/netdev_lock.h:80 net/core/dev.c:1577)
[   20.627669][  T258]  ? call_netdevice_notifiers_info (net/core/dev.c:1576)
[   20.627672][  T258]  ? generic_xdp_install (net/core/dev.c:11630)
[   20.627677][  T258]  ? tun_chr_close (drivers/net/tun.c:638 drivers/net/tun.c:3436) tun
[   20.627687][  T258] tun_chr_close (./include/net/sock.h:1990 drivers/net/tun.c:643 drivers/net/tun.c:3436) tun
[   20.627693][  T258]  __fput (fs/file_table.c:468)
[   20.627701][  T258]  fput_close_sync (fs/file_table.c:571)
[   20.627705][  T258]  ? alloc_file_clone (fs/file_table.c:571)
[   20.627710][  T258]  __x64_sys_close (fs/open.c:1592 fs/open.c:1574 fs/open.c:1574)
[   20.627714][  T258]  do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
[   20.627722][  T258]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   20.627726][  T258] RIP: 0033:0x4901eb
[   20.627730][  T258] Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 c3 78 04 00 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 21 79 04 00 8b 44
All code
========
   0:	03 00                	add    (%rax),%eax
   2:	00 00                	add    %al,(%rax)
   4:	0f 05                	syscall
   6:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   c:	77 41                	ja     0x4f
   e:	c3                   	ret
   f:	48 83 ec 18          	sub    $0x18,%rsp
  13:	89 7c 24 0c          	mov    %edi,0xc(%rsp)
  17:	e8 c3 78 04 00       	call   0x478df
  1c:	8b 7c 24 0c          	mov    0xc(%rsp),%edi
  20:	41 89 c0             	mov    %eax,%r8d
  23:	b8 03 00 00 00       	mov    $0x3,%eax
  28:	0f 05                	syscall
  2a:*	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax		<-- trapping instruction
  30:	77 35                	ja     0x67
  32:	44 89 c7             	mov    %r8d,%edi
  35:	89 44 24 0c          	mov    %eax,0xc(%rsp)
  39:	e8 21 79 04 00       	call   0x4795f
  3e:	8b                   	.byte 0x8b
  3f:	44                   	rex.R

Code starting with the faulting instruction
===========================================
   0:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   6:	77 35                	ja     0x3d
   8:	44 89 c7             	mov    %r8d,%edi
   b:	89 44 24 0c          	mov    %eax,0xc(%rsp)
   f:	e8 21 79 04 00       	call   0x47935
  14:	8b                   	.byte 0x8b
  15:	44                   	rex.R
[   20.627733][  T258] RSP: 002b:00007fff9eb9cc30 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
[   20.627737][  T258] RAX: ffffffffffffffda RBX: 00007fff9eb9d148 RCX: 00000000004901eb
[   20.627739][  T258] RDX: 0000000000000002 RSI: 0000000000000002 RDI: 0000000000000006
[   20.627740][  T258] RBP: 00007fff9eb9cc70 R08: 0000000000000000 R09: 0000000000000000
[   20.627742][  T258] R10: 0000000017feb050 R11: 0000000000000293 R12: 00007fff9eb9d108
[   20.627744][  T258] R13: 0000000000000001 R14: 000000000054e030 R15: 0000000000000001
| [   20.638768][  T258] refcount_t: underflow; use-after-free.
| [   20.639118][  T258] WARNING: CPU: 0 PID: 258 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   20.639416][  T258] Modules linked in: xt_tcpudp xt_conntrack nft_compat nf_tables x_tables nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 tun
| [   20.640205][  T258] Tainted: [B]=BAD_PAGE
[   20.640340][  T258] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   20.640552][  T258] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   20.640768][  T258] Code: 83 90 02 80 fb 01 0f 87 95 6b d6 fe 83 e3 01 0f 85 51 ff ff ff c6 05 b1 83 90 02 01 90 48 c7 c7 a0 de e5 8e e8 c2 8b 15 ff 90 <0f> 0b 90 90 e9 33 ff ff ff 48 89 df e8 f0 34 a1 ff e9 ba fe ff ff
All code
========
   0:	83 90 02 80 fb 01 0f 	adcl   $0xf,0x1fb8002(%rax)
   7:	87 95 6b d6 fe 83    	xchg   %edx,-0x7c012995(%rbp)
   d:	e3 01                	jrcxz  0x10
   f:	0f 85 51 ff ff ff    	jne    0xffffffffffffff66
  15:	c6 05 b1 83 90 02 01 	movb   $0x1,0x29083b1(%rip)        # 0x29083cd
  1c:	90                   	nop
  1d:	48 c7 c7 a0 de e5 8e 	mov    $0xffffffff8ee5dea0,%rdi
  24:	e8 c2 8b 15 ff       	call   0xffffffffff158beb
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	e9 33 ff ff ff       	jmp    0xffffffffffffff66
  33:	48 89 df             	mov    %rbx,%rdi
  36:	e8 f0 34 a1 ff       	call   0xffffffffffa1352b
  3b:	e9 ba fe ff ff       	jmp    0xfffffffffffffefa

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	90                   	nop
   4:	e9 33 ff ff ff       	jmp    0xffffffffffffff3c
   9:	48 89 df             	mov    %rbx,%rdi
   c:	e8 f0 34 a1 ff       	call   0xffffffffffa13501
  11:	e9 ba fe ff ff       	jmp    0xfffffffffffffed0
[   20.641379][  T258] RSP: 0018:ffffc90000b77ce8 EFLAGS: 00010282
[   20.641596][  T258] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   20.641849][  T258] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   20.642109][  T258] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff1efe220
[   20.642364][  T258] R10: 0000000000000003 R11: ffffc90000b77880 R12: 0000000000000001
[   20.642623][  T258] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   20.642885][  T258] FS:  0000000017fe33c0(0000) GS:ffff8880a55ec000(0000) knlGS:0000000000000000
[   20.643180][  T258] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   20.643395][  T258] CR2: 00007ff346643000 CR3: 0000000009411005 CR4: 0000000000772ef0
[   20.643652][  T258] PKRU: 55555554
[   20.643780][  T258] Call Trace:
[   20.643916][  T258]  <TASK>
[   20.644005][  T258]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   20.644177][  T258]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   20.644359][  T258]  ? netif_state_change (./include/net/netdev_lock.h:72 ./include/net/netdev_lock.h:80 net/core/dev.c:1577)
[   20.644527][  T258]  ? call_netdevice_notifiers_info (net/core/dev.c:1576)
[   20.644736][  T258]  ? generic_xdp_install (net/core/dev.c:11630)
[   20.644919][  T258]  ? tun_chr_close (drivers/net/tun.c:638 drivers/net/tun.c:3436) tun
[   20.645095][  T258] tun_chr_close (./include/net/sock.h:1990 drivers/net/tun.c:643 drivers/net/tun.c:3436) tun
[   20.645266][  T258]  __fput (fs/file_table.c:468)
[   20.645398][  T258]  fput_close_sync (fs/file_table.c:571)
[   20.645571][  T258]  ? alloc_file_clone (fs/file_table.c:571)
[   20.645744][  T258]  __x64_sys_close (fs/open.c:1592 fs/open.c:1574 fs/open.c:1574)
[   20.645924][  T258]  do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
[   20.646099][  T258]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   20.646310][  T258] RIP: 0033:0x4901eb
[   20.646448][  T258] Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 c3 78 04 00 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 21 79 04 00 8b 44
All code
========
   0:	03 00                	add    (%rax),%eax
   2:	00 00                	add    %al,(%rax)
   4:	0f 05                	syscall
   6:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   c:	77 41                	ja     0x4f
   e:	c3                   	ret
   f:	48 83 ec 18          	sub    $0x18,%rsp
  13:	89 7c 24 0c          	mov    %edi,0xc(%rsp)
  17:	e8 c3 78 04 00       	call   0x478df
  1c:	8b 7c 24 0c          	mov    0xc(%rsp),%edi
  20:	41 89 c0             	mov    %eax,%r8d
  23:	b8 03 00 00 00       	mov    $0x3,%eax
  28:	0f 05                	syscall
  2a:*	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax		<-- trapping instruction
  30:	77 35                	ja     0x67
  32:	44 89 c7             	mov    %r8d,%edi
  35:	89 44 24 0c          	mov    %eax,0xc(%rsp)
  39:	e8 21 79 04 00       	call   0x4795f
  3e:	8b                   	.byte 0x8b
  3f:	44                   	rex.R

Code starting with the faulting instruction
===========================================
   0:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   6:	77 35                	ja     0x3d
   8:	44 89 c7             	mov    %r8d,%edi
   b:	89 44 24 0c          	mov    %eax,0xc(%rsp)
   f:	e8 21 79 04 00       	call   0x47935
  14:	8b                   	.byte 0x8b
  15:	44                   	rex.R
[   20.647062][  T258] RSP: 002b:00007fff9eb9cc30 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
[   20.647317][  T258] RAX: ffffffffffffffda RBX: 00007fff9eb9d148 RCX: 00000000004901eb
[   20.647574][  T258] RDX: 0000000000000002 RSI: 0000000000000002 RDI: 0000000000000006
[   20.647832][  T258] RBP: 00007fff9eb9cc70 R08: 0000000000000000 R09: 0000000000000000
[   20.648095][  T258] R10: 0000000017feb050 R11: 0000000000000293 R12: 00007fff9eb9d108


Finger prints:
refcount_warn_saturate:netdev_run_todo:tun_chr_close:__fput:fput_close_sync
print_report:kasan_report:kobject_put:netdev_run_todo:tun_chr_close