======================================
| [   57.834041][   T12] ==================================================================
| [   57.834408][   T12] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   57.834674][   T12] Read of size 1 at addr ffff88800895c6ac by task kworker/u16:0/12
| [   57.834955][   T12]
[   57.835103][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   57.835106][   T12] Workqueue: netns cleanup_net
[   57.835113][   T12] Call Trace:
[   57.835115][   T12]  <TASK>
[   57.835118][   T12]  dump_stack_lvl (lib/dump_stack.c:123)
[   57.835124][   T12]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   57.835130][   T12]  ? kobject_put (lib/kobject.c:733)
[   57.835135][   T12]  print_report (mm/kasan/report.c:483)
[   57.835137][   T12]  ? kobject_put (lib/kobject.c:733)
[   57.835140][   T12]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   57.835144][   T12]  ? kobject_put (lib/kobject.c:733)
[   57.835147][   T12]  kasan_report (mm/kasan/report.c:597)
[   57.835150][   T12]  ? kobject_put (lib/kobject.c:733)
[   57.835158][   T12]  kobject_put (lib/kobject.c:733)
[   57.835163][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   57.835168][   T12]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   57.835174][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   57.835180][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   57.835192][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   57.835201][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   57.835205][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   57.835216][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   57.835223][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   57.835230][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   57.835240][   T12]  process_one_work (kernel/workqueue.c:3268)
[   57.835254][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   57.835265][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   57.835272][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   57.835283][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   57.835289][   T12]  kthread (kernel/kthread.c:463)
[   57.835296][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   57.835300][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   57.835305][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   57.835314][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   57.835320][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   57.835326][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   57.835330][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   57.835335][   T12]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   57.859310][   T12] refcount_t: underflow; use-after-free.
| [   57.860363][   T12] WARNING: CPU: 1 PID: 12 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   57.860799][   T12] Modules linked in: macvlan 8021q vxlan ip6_udp_tunnel udp_tunnel bridge stp llc vrf veth
| [   57.861621][   T12] Tainted: [B]=BAD_PAGE
[   57.861751][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   57.861960][   T12] Workqueue: netns cleanup_net
[   57.862134][   T12] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   57.862350][   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 25 97 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 25 97 	mov    $0xffffffff97258d60,%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
[   57.863060][   T12] RSP: 0018:ffffc900000c7a08 EFLAGS: 00010282
[   57.863286][   T12] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   57.863660][   T12] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   57.863924][   T12] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff2f7e134
[   57.864176][   T12] R10: 0000000000000003 R11: ffffc900000c7580 R12: 0000000000000001
[   57.864427][   T12] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   57.864879][   T12] FS:  0000000000000000(0000) GS:ffff88809d272000(0000) knlGS:0000000000000000
[   57.865166][   T12] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   57.865382][   T12] CR2: 000055acafec6dec CR3: 0000000004f70002 CR4: 0000000000772ef0
[   57.865746][   T12] PKRU: 55555554
[   57.865876][   T12] Call Trace:
[   57.865998][   T12]  <TASK>
[   57.866166][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   57.866333][   T12]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   57.866616][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   57.866779][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   57.866957][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   57.867122][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   57.867375][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   57.867651][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   57.867818][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   57.867982][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   57.868146][   T12]  process_one_work (kernel/workqueue.c:3268)
[   57.868403][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   57.868689][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   57.868857][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   57.869027][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   57.869198][   T12]  kthread (kernel/kthread.c:463)
[   57.869406][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   57.869690][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   57.869859][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   57.870024][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   57.870196][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   57.870360][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   57.870751][   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