======================================
| [  234.022992][   T73] ==================================================================
| [  234.023456][   T73] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [  234.023881][   T73] Read of size 1 at addr ffff888005e1169c by task kworker/u16:1/73
| [  234.024283][   T73]
[  234.024432][   T73] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  234.024437][   T73] Workqueue: netns cleanup_net
[  234.024451][   T73] Call Trace:
[  234.024454][   T73]  <TASK>
[  234.024460][   T73]  dump_stack_lvl (lib/dump_stack.c:123)
[  234.024470][   T73]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[  234.024480][   T73]  ? kobject_put (lib/kobject.c:733)
[  234.024486][   T73]  print_report (mm/kasan/report.c:483)
[  234.024490][   T73]  ? kobject_put (lib/kobject.c:733)
[  234.024493][   T73]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[  234.024498][   T73]  ? kobject_put (lib/kobject.c:733)
[  234.024501][   T73]  kasan_report (mm/kasan/report.c:597)
[  234.024507][   T73]  ? kobject_put (lib/kobject.c:733)
[  234.024515][   T73]  kobject_put (lib/kobject.c:733)
[  234.024520][   T73]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[  234.024528][   T73]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[  234.024533][   T73]  ? unregister_netdevice_many (net/core/dev.c:12241)
[  234.024538][   T73]  ? generic_xdp_install (net/core/dev.c:11630)
[  234.024542][   T73]  ? __lock_release (kernel/locking/lockdep.c:5536)
[  234.024566][   T73]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[  234.024574][   T73]  ? netns_get (net/core/net_namespace.c:223)
[  234.024579][   T73]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[  234.024588][   T73]  cleanup_net (net/core/net_namespace.c:698)
[  234.024594][   T73]  ? net_passive_dec (net/core/net_namespace.c:660)
[  234.024601][   T73]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  234.024611][   T73]  process_one_work (kernel/workqueue.c:3268)
[  234.024624][   T73]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[  234.024633][   T73]  ? assign_work (kernel/workqueue.c:1206)
[  234.024639][   T73]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[  234.024648][   T73]  ? rescuer_thread (kernel/workqueue.c:3373)
[  234.024654][   T73]  kthread (kernel/kthread.c:463)
[  234.024660][   T73]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  234.024664][   T73]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[  234.024673][   T73]  ? __lock_release (kernel/locking/lockdep.c:5536)
[  234.024679][   T73]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  234.024683][   T73]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  234.024689][   T73]  ret_from_fork (arch/x86/kernel/process.c:164)
[  234.024694][   T73]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  234.024699][   T73]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [  234.054474][   T73] refcount_t: underflow; use-after-free.
| [  234.054795][   T73] WARNING: CPU: 3 PID: 73 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [  234.055308][   T73] Modules linked in: cls_matchall
| [  234.056245][   T73] Tainted: [B]=BAD_PAGE
[  234.056497][   T73] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  234.056868][   T73] Workqueue: netns cleanup_net
[  234.057188][   T73] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[  234.057547][   T73] Code: a2 b5 02 80 fb 01 0f 87 db 6e d8 fe 83 e3 01 0f 85 51 ff ff ff c6 05 c2 a2 b5 02 01 90 48 c7 c7 60 a8 05 9d e8 72 c3 17 ff 90 <0f> 0b 90 90 e9 33 ff ff ff 48 89 df e8 20 69 a0 ff e9 ba fe ff ff
All code
========
   0:	a2 b5 02 80 fb 01 0f 	movabs %al,0xdb870f01fb8002b5
   7:	87 db 
   9:	6e                   	outsb  %ds:(%rsi),(%dx)
   a:	d8 fe                	fdivr  %st(6),%st
   c:	83 e3 01             	and    $0x1,%ebx
   f:	0f 85 51 ff ff ff    	jne    0xffffffffffffff66
  15:	c6 05 c2 a2 b5 02 01 	movb   $0x1,0x2b5a2c2(%rip)        # 0x2b5a2de
  1c:	90                   	nop
  1d:	48 c7 c7 60 a8 05 9d 	mov    $0xffffffff9d05a860,%rdi
  24:	e8 72 c3 17 ff       	call   0xffffffffff17c39b
  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 20 69 a0 ff       	call   0xffffffffffa0695b
  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 20 69 a0 ff       	call   0xffffffffffa06931
  11:	e9 ba fe ff ff       	jmp    0xfffffffffffffed0
[  234.058510][   T73] RSP: 0018:ffffc900004e7a08 EFLAGS: 00010282
[  234.058872][   T73] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[  234.059291][   T73] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[  234.059704][   T73] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff3b3e134
[  234.060116][   T73] R10: 0000000000000003 R11: ffffc900004e7580 R12: 0000000000000001
[  234.060539][   T73] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[  234.060965][   T73] FS:  0000000000000000(0000) GS:ffff888097501000(0000) knlGS:0000000000000000
[  234.061427][   T73] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  234.061784][   T73] CR2: 00007ffe0f05b558 CR3: 000000000c0be001 CR4: 0000000000772ef0
[  234.062203][   T73] PKRU: 55555554
[  234.062419][   T73] Call Trace:
[  234.062657][   T73]  <TASK>
[  234.062805][   T73]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[  234.063083][   T73]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[  234.063348][   T73]  ? unregister_netdevice_many (net/core/dev.c:12241)
[  234.063618][   T73]  ? generic_xdp_install (net/core/dev.c:11630)
[  234.063854][   T73]  ? __lock_release (kernel/locking/lockdep.c:5536)
[  234.064117][   T73]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[  234.064362][   T73]  ? netns_get (net/core/net_namespace.c:223)
[  234.064661][   T73]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[  234.064938][   T73]  cleanup_net (net/core/net_namespace.c:698)
[  234.065221][   T73]  ? net_passive_dec (net/core/net_namespace.c:660)
[  234.065495][   T73]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  234.065781][   T73]  process_one_work (kernel/workqueue.c:3268)
[  234.066063][   T73]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[  234.066336][   T73]  ? assign_work (kernel/workqueue.c:1206)
[  234.066613][   T73]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[  234.066903][   T73]  ? rescuer_thread (kernel/workqueue.c:3373)
[  234.067166][   T73]  kthread (kernel/kthread.c:463)
[  234.067371][   T73]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  234.067653][   T73]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[  234.067916][   T73]  ? __lock_release (kernel/locking/lockdep.c:5536)
[  234.068188][   T73]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  234.068449][   T73]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  234.068732][   T73]  ret_from_fork (arch/x86/kernel/process.c:164)
[  234.069024][   T73]  ? kthread_is_per_cpu (kernel/kthread.c:412)


Finger prints:
refcount_warn_saturate:netdev_run_todo:ops_undo_list:cleanup_net:process_one_work
print_report:kasan_report:kobject_put:netdev_run_todo:ops_undo_list