======================================
| [  406.738398][   T12] ==================================================================
| [  406.738839][   T12] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [  406.739277][   T12] Read of size 1 at addr ffff8880058696ac by task kworker/u16:0/12
| [  406.739670][   T12]
[  406.739825][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  406.739831][   T12] Workqueue: netns cleanup_net
[  406.739848][   T12] Call Trace:
[  406.739853][   T12]  <TASK>
[  406.739857][   T12]  dump_stack_lvl (lib/dump_stack.c:123)
[  406.739866][   T12]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[  406.739877][   T12]  ? kobject_put (lib/kobject.c:733)
[  406.739883][   T12]  print_report (mm/kasan/report.c:483)
[  406.739888][   T12]  ? kobject_put (lib/kobject.c:733)
[  406.739893][   T12]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[  406.739898][   T12]  ? kobject_put (lib/kobject.c:733)
[  406.739903][   T12]  kasan_report (mm/kasan/report.c:597)
[  406.739909][   T12]  ? kobject_put (lib/kobject.c:733)
[  406.739919][   T12]  kobject_put (lib/kobject.c:733)
[  406.739926][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[  406.739932][   T12]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[  406.739938][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[  406.739943][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[  406.739955][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[  406.739965][   T12]  ? netns_get (net/core/net_namespace.c:223)
[  406.739969][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[  406.739979][   T12]  cleanup_net (net/core/net_namespace.c:698)
[  406.739986][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[  406.739993][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  406.740003][   T12]  process_one_work (kernel/workqueue.c:3268)
[  406.740016][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[  406.740027][   T12]  ? assign_work (kernel/workqueue.c:1206)
[  406.740034][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[  406.740045][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[  406.740051][   T12]  kthread (kernel/kthread.c:463)
[  406.740058][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  406.740062][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[  406.740071][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[  406.740080][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  406.740085][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  406.740091][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[  406.740095][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  406.740100][   T12]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [  406.769770][   T12] refcount_t: underflow; use-after-free.
| [  406.770230][   T12] WARNING: CPU: 3 PID: 12 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [  406.770864][   T12] Modules linked in: act_gact cls_flower vxlan ip6_udp_tunnel udp_tunnel bridge stp llc sch_ingress vrf veth
| [  406.772169][   T12] Tainted: [B]=BAD_PAGE
[  406.772379][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  406.772867][   T12] Workqueue: netns cleanup_net
[  406.773069][   T12] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[  406.773314][   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 89 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 89 	mov    $0xffffffff89058d60,%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
[  406.774005][   T12] RSP: 0018:ffffc900000c7a08 EFLAGS: 00010282
[  406.774331][   T12] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[  406.774886][   T12] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[  406.775748][   T12] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff133e134
[  406.776164][   T12] R10: 0000000000000003 R11: ffffc900000c7580 R12: 0000000000000001
[  406.776575][   T12] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[  406.776968][   T12] FS:  0000000000000000(0000) GS:ffff8880ab572000(0000) knlGS:0000000000000000
[  406.777426][   T12] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  406.777769][   T12] CR2: 000055828fd3c928 CR3: 0000000023d35001 CR4: 0000000000772ef0
[  406.778157][   T12] PKRU: 55555554
[  406.778375][   T12] Call Trace:
[  406.778592][   T12]  <TASK>
[  406.778727][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[  406.779182][   T12]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[  406.779499][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[  406.779929][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[  406.780231][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[  406.780524][   T12]  ? netns_get (net/core/net_namespace.c:223)
[  406.780983][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[  406.781403][   T12]  cleanup_net (net/core/net_namespace.c:698)
[  406.781715][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[  406.781990][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  406.782249][   T12]  process_one_work (kernel/workqueue.c:3268)
[  406.782576][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[  406.782851][   T12]  ? assign_work (kernel/workqueue.c:1206)
[  406.783305][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[  406.783607][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[  406.783911][   T12]  kthread (kernel/kthread.c:463)
[  406.784111][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  406.784359][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[  406.784565][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[  406.784904][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  406.785161][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  406.785432][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[  406.785729][   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