======================================
| [   54.916496][   T12] ==================================================================
| [   54.916953][   T12] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   54.917375][   T12] Read of size 1 at addr ffff888005c396ac by task kworker/u16:0/12
| [   54.917779][   T12]
[   54.917932][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   54.917937][   T12] Workqueue: netns cleanup_net
[   54.917948][   T12] Call Trace:
[   54.917951][   T12]  <TASK>
[   54.917955][   T12]  dump_stack_lvl (lib/dump_stack.c:123)
[   54.917964][   T12]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   54.917973][   T12]  ? kobject_put (lib/kobject.c:733)
[   54.917979][   T12]  print_report (mm/kasan/report.c:483)
[   54.917984][   T12]  ? kobject_put (lib/kobject.c:733)
[   54.917988][   T12]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   54.917993][   T12]  ? kobject_put (lib/kobject.c:733)
[   54.917998][   T12]  kasan_report (mm/kasan/report.c:597)
[   54.918005][   T12]  ? kobject_put (lib/kobject.c:733)
[   54.918014][   T12]  kobject_put (lib/kobject.c:733)
[   54.918021][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   54.918027][   T12]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   54.918035][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   54.918041][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   54.918052][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   54.918062][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   54.918067][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   54.918077][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   54.918083][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   54.918091][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   54.918102][   T12]  process_one_work (kernel/workqueue.c:3268)
[   54.918116][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   54.918127][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   54.918134][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   54.918145][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   54.918151][   T12]  kthread (kernel/kthread.c:463)
[   54.918159][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   54.918163][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   54.918169][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   54.918179][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   54.918184][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   54.918191][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   54.918196][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   54.918201][   T12]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   54.943348][   T12] refcount_t: underflow; use-after-free.
| [   54.943565][   T12] WARNING: CPU: 3 PID: 12 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   54.943920][   T12] Modules linked in: vxlan ip6_udp_tunnel udp_tunnel bridge stp llc sch_ingress vrf veth
| [   54.944874][   T12] Tainted: [B]=BAD_PAGE
[   54.945047][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   54.945357][   T12] Workqueue: netns cleanup_net
[   54.945556][   T12] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   54.945790][   T12] 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 8c 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 8c 	mov    $0xffffffff8c058d60,%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
[   54.946635][   T12] RSP: 0000:ffffc900000c7a08 EFLAGS: 00010282
[   54.946874][   T12] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   54.947152][   T12] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   54.947419][   T12] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff193e134
[   54.947877][   T12] R10: 0000000000000003 R11: ffffc900000c7580 R12: 0000000000000001
[   54.948158][   T12] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   54.948433][   T12] FS:  0000000000000000(0000) GS:ffff8880a8572000(0000) knlGS:0000000000000000
[   54.948767][   T12] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   54.949013][   T12] CR2: 00007fad4e5eb75b CR3: 0000000013735002 CR4: 0000000000772ef0
[   54.949290][   T12] PKRU: 55555554
[   54.949424][   T12] Call Trace:
[   54.949578][   T12]  <TASK>
[   54.949670][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   54.949867][   T12]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   54.950147][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   54.950330][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   54.950514][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   54.950833][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   54.951125][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   54.951305][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   54.951482][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   54.951681][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   54.951877][   T12]  process_one_work (kernel/workqueue.c:3268)
[   54.952076][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   54.952254][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   54.952448][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   54.952628][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   54.952809][   T12]  kthread (kernel/kthread.c:463)
[   54.952949][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   54.953144][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   54.953334][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   54.953519][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   54.953724][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   54.953905][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   54.954179][   T12]  ? 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