======================================
| [  468.172998][   T69] ==================================================================
| [  468.173288][   T69] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [  468.173562][   T69] Read of size 1 at addr ffff8880100946ac by task kworker/u16:1/69
| [  468.173800][   T69]
[  468.173892][   T69] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  468.173899][   T69] Workqueue: netns cleanup_net
[  468.173910][   T69] Call Trace:
[  468.173915][   T69]  <TASK>
[  468.173918][   T69]  dump_stack_lvl (lib/dump_stack.c:123)
[  468.173925][   T69]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[  468.173936][   T69]  ? kobject_put (lib/kobject.c:733)
[  468.173940][   T69]  print_report (mm/kasan/report.c:483)
[  468.173943][   T69]  ? kobject_put (lib/kobject.c:733)
[  468.173946][   T69]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[  468.173950][   T69]  ? kobject_put (lib/kobject.c:733)
[  468.173953][   T69]  kasan_report (mm/kasan/report.c:597)
[  468.173956][   T69]  ? kobject_put (lib/kobject.c:733)
[  468.173962][   T69]  kobject_put (lib/kobject.c:733)
[  468.173966][   T69]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[  468.173972][   T69]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[  468.173977][   T69]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[  468.173980][   T69]  ? generic_xdp_install (net/core/dev.c:11630)
[  468.173987][   T69]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[  468.173991][   T69]  ? netns_get (net/core/net_namespace.c:223)
[  468.173994][   T69]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[  468.173999][   T69]  cleanup_net (net/core/net_namespace.c:698)
[  468.174003][   T69]  ? net_passive_dec (net/core/net_namespace.c:660)
[  468.174007][   T69]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  468.174019][   T69]  process_one_work (kernel/workqueue.c:3268)
[  468.174028][   T69]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[  468.174035][   T69]  ? assign_work (kernel/workqueue.c:1206)
[  468.174040][   T69]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[  468.174045][   T69]  ? rescuer_thread (kernel/workqueue.c:3373)
[  468.174049][   T69]  kthread (kernel/kthread.c:463)
[  468.174053][   T69]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  468.174056][   T69]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[  468.174062][   T69]  ? __lock_release (kernel/locking/lockdep.c:5536)
[  468.174070][   T69]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  468.174073][   T69]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  468.174076][   T69]  ret_from_fork (arch/x86/kernel/process.c:164)
[  468.174078][   T69]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  468.174081][   T69]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [  468.192466][   T69] refcount_t: underflow; use-after-free.
| [  468.192661][   T69] WARNING: CPU: 1 PID: 69 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [  468.192933][   T69] Modules linked in: act_gact cls_flower vxlan ip6_udp_tunnel udp_tunnel bridge stp llc sch_ingress vrf veth
| [  468.193687][   T69] Tainted: [B]=BAD_PAGE
[  468.193804][   T69] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  468.194002][   T69] Workqueue: netns cleanup_net
[  468.194173][   T69] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[  468.194395][   T69] Code: 7d 93 02 80 fb 01 0f 87 bb 99 d9 fe 83 e3 01 0f 85 51 ff ff ff c6 05 a8 7d 93 02 01 90 48 c7 c7 60 8d 05 87 e8 32 bf 18 ff 90 <0f> 0b 90 90 e9 33 ff ff ff 48 89 df e8 b0 63 a1 ff e9 ba fe ff ff
All code
========
   0:	7d 93                	jge    0xffffffffffffff95
   2:	02 80 fb 01 0f 87    	add    -0x78f0fe05(%rax),%al
   8:	bb 99 d9 fe 83       	mov    $0x83fed999,%ebx
   d:	e3 01                	jrcxz  0x10
   f:	0f 85 51 ff ff ff    	jne    0xffffffffffffff66
  15:	c6 05 a8 7d 93 02 01 	movb   $0x1,0x2937da8(%rip)        # 0x2937dc4
  1c:	90                   	nop
  1d:	48 c7 c7 60 8d 05 87 	mov    $0xffffffff87058d60,%rdi
  24:	e8 32 bf 18 ff       	call   0xffffffffff18bf5b
  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 b0 63 a1 ff       	call   0xffffffffffa163eb
  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 b0 63 a1 ff       	call   0xffffffffffa163c1
  11:	e9 ba fe ff ff       	jmp    0xfffffffffffffed0
[  468.195049][   T69] RSP: 0018:ffffc900004a7a08 EFLAGS: 00010282
[  468.195252][   T69] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[  468.195502][   T69] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[  468.195798][   T69] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff0f3e134
[  468.196122][   T69] R10: 0000000000000003 R11: ffffc900004a7580 R12: 0000000000000001
[  468.196359][   T69] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[  468.196603][   T69] FS:  0000000000000000(0000) GS:ffff8880ad472000(0000) knlGS:0000000000000000
[  468.196965][   T69] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  468.197160][   T69] CR2: 00000000004061e9 CR3: 000000000f64c001 CR4: 0000000000772ef0
[  468.197411][   T69] PKRU: 55555554
[  468.197641][   T69] Call Trace:
[  468.197760][   T69]  <TASK>
[  468.197845][   T69]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[  468.198009][   T69]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[  468.198211][   T69]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[  468.198467][   T69]  ? generic_xdp_install (net/core/dev.c:11630)
[  468.198644][   T69]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[  468.198806][   T69]  ? netns_get (net/core/net_namespace.c:223)
[  468.198959][   T69]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[  468.201488][   T69]  cleanup_net (net/core/net_namespace.c:698)
[  468.201713][   T69]  ? net_passive_dec (net/core/net_namespace.c:660)
[  468.201869][   T69]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  468.202043][   T69]  process_one_work (kernel/workqueue.c:3268)
[  468.202284][   T69]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[  468.202470][   T69]  ? assign_work (kernel/workqueue.c:1206)
[  468.202648][   T69]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[  468.202817][   T69]  ? rescuer_thread (kernel/workqueue.c:3373)
[  468.203055][   T69]  kthread (kernel/kthread.c:463)
[  468.203170][   T69]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  468.203330][   T69]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[  468.203500][   T69]  ? __lock_release (kernel/locking/lockdep.c:5536)
[  468.203779][   T69]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  468.203933][   T69]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  468.204085][   T69]  ret_from_fork (arch/x86/kernel/process.c:164)
[  468.204239][   T69]  ? 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