======================================
| [   60.283283][   T70] ==================================================================
| [   60.283600][   T70] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   60.283848][   T70] Read of size 1 at addr ffff8880096716ac by task kworker/u16:1/70
| [   60.284088][   T70]
[   60.284228][   T70] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   60.284231][   T70] Workqueue: netns cleanup_net
[   60.284239][   T70] Call Trace:
[   60.284243][   T70]  <TASK>
[   60.284246][   T70]  dump_stack_lvl (lib/dump_stack.c:123)
[   60.284254][   T70]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   60.284261][   T70]  ? kobject_put (lib/kobject.c:733)
[   60.284265][   T70]  print_report (mm/kasan/report.c:483)
[   60.284268][   T70]  ? kobject_put (lib/kobject.c:733)
[   60.284272][   T70]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   60.284275][   T70]  ? kobject_put (lib/kobject.c:733)
[   60.284278][   T70]  kasan_report (mm/kasan/report.c:597)
[   60.284281][   T70]  ? kobject_put (lib/kobject.c:733)
[   60.284287][   T70]  kobject_put (lib/kobject.c:733)
[   60.284290][   T70]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   60.284294][   T70]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   60.284299][   T70]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   60.284302][   T70]  ? generic_xdp_install (net/core/dev.c:11630)
[   60.284308][   T70]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   60.284316][   T70]  ? netns_get (net/core/net_namespace.c:223)
[   60.284320][   T70]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   60.284329][   T70]  cleanup_net (net/core/net_namespace.c:698)
[   60.284335][   T70]  ? net_passive_dec (net/core/net_namespace.c:660)
[   60.284341][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   60.284351][   T70]  process_one_work (kernel/workqueue.c:3268)
[   60.284363][   T70]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   60.284374][   T70]  ? assign_work (kernel/workqueue.c:1206)
[   60.284381][   T70]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   60.284392][   T70]  ? rescuer_thread (kernel/workqueue.c:3373)
[   60.284399][   T70]  kthread (kernel/kthread.c:463)
[   60.284406][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   60.284410][   T70]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   60.284416][   T70]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   60.284424][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   60.284429][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   60.284432][   T70]  ret_from_fork (arch/x86/kernel/process.c:164)
[   60.284435][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   60.284438][   T70]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   60.306163][   T70] refcount_t: underflow; use-after-free.
| [   60.306482][   T70] WARNING: CPU: 1 PID: 70 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   60.306928][   T70] Modules linked in: vxlan ip6_udp_tunnel udp_tunnel bridge stp llc 8021q sch_ingress vrf veth
| [   60.308066][   T70] Tainted: [B]=BAD_PAGE
[   60.308262][   T70] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   60.308579][   T70] Workqueue: netns cleanup_net
[   60.308848][   T70] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   60.309188][   T70] 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 45 9d 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 45 9d 	mov    $0xffffffff9d458d60,%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
[   60.310174][   T70] RSP: 0000:ffffc900004b7a08 EFLAGS: 00010282
[   60.310507][   T70] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   60.310883][   T70] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   60.311261][   T70] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff3bbe134
[   60.311834][   T70] R10: 0000000000000003 R11: ffffc900004b7580 R12: 0000000000000001
[   60.312232][   T70] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   60.312625][   T70] FS:  0000000000000000(0000) GS:ffff888097072000(0000) knlGS:0000000000000000
[   60.313247][   T70] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   60.313584][   T70] CR2: 00007f6939d2d440 CR3: 000000000bc6c005 CR4: 0000000000772ef0
[   60.314161][   T70] PKRU: 55555554
[   60.314354][   T70] Call Trace:
[   60.314551][   T70]  <TASK>
[   60.314691][   T70]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   60.314951][   T70]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   60.315395][   T70]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   60.315666][   T70]  ? generic_xdp_install (net/core/dev.c:11630)
[   60.315936][   T70]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   60.316248][   T70]  ? netns_get (net/core/net_namespace.c:223)
[   60.316676][   T70]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   60.316936][   T70]  cleanup_net (net/core/net_namespace.c:698)
[   60.317200][   T70]  ? net_passive_dec (net/core/net_namespace.c:660)
[   60.317465][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   60.317908][   T70]  process_one_work (kernel/workqueue.c:3268)
[   60.318181][   T70]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   60.318442][   T70]  ? assign_work (kernel/workqueue.c:1206)
[   60.318694][   T70]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   60.319139][   T70]  ? rescuer_thread (kernel/workqueue.c:3373)
[   60.319393][   T70]  kthread (kernel/kthread.c:463)
[   60.319602][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   60.319874][   T70]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   60.320305][   T70]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   60.320596][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   60.320873][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   60.321141][   T70]  ret_from_fork (arch/x86/kernel/process.c:164)
[   60.321583][   T70]  ? 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