======================================
| [   56.839330][   T12] ==================================================================
| [   56.839619][   T12] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   56.839914][   T12] Read of size 1 at addr ffff88800ea696ac by task kworker/u16:0/12
| [   56.840178][   T12]
[   56.840284][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   56.840287][   T12] Workqueue: netns cleanup_net
[   56.840297][   T12] Call Trace:
[   56.840299][   T12]  <TASK>
[   56.840302][   T12]  dump_stack_lvl (lib/dump_stack.c:123)
[   56.840308][   T12]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   56.840315][   T12]  ? kobject_put (lib/kobject.c:733)
[   56.840319][   T12]  print_report (mm/kasan/report.c:483)
[   56.840323][   T12]  ? kobject_put (lib/kobject.c:733)
[   56.840326][   T12]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   56.840329][   T12]  ? kobject_put (lib/kobject.c:733)
[   56.840332][   T12]  kasan_report (mm/kasan/report.c:597)
[   56.840336][   T12]  ? kobject_put (lib/kobject.c:733)
[   56.840341][   T12]  kobject_put (lib/kobject.c:733)
[   56.840345][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   56.840349][   T12]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   56.840367][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   56.840371][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   56.840377][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   56.840382][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   56.840385][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   56.840391][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   56.840395][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   56.840399][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   56.840408][   T12]  process_one_work (kernel/workqueue.c:3268)
[   56.840417][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   56.840422][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   56.840426][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   56.840432][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   56.840436][   T12]  kthread (kernel/kthread.c:463)
[   56.840440][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   56.840442][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   56.840447][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   56.840454][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   56.840457][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   56.840461][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   56.840463][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   56.840466][   T12]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   56.860553][   T12] refcount_t: underflow; use-after-free.
| [   56.860806][   T12] WARNING: CPU: 0 PID: 12 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   56.861261][   T12] Modules linked in: macvlan 8021q vxlan ip6_udp_tunnel udp_tunnel bridge stp llc vrf veth
| [   56.862038][   T12] Tainted: [B]=BAD_PAGE
[   56.862169][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   56.862366][   T12] Workqueue: netns cleanup_net
[   56.862540][   T12] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   56.862744][   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 65 ae 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 65 ae 	mov    $0xffffffffae658d60,%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
[   56.863440][   T12] RSP: 0018:ffffc900000c7a08 EFLAGS: 00010282
[   56.863666][   T12] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   56.863994][   T12] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   56.864251][   T12] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff5dfe134
[   56.864575][   T12] R10: 0000000000000003 R11: ffffc900000c7580 R12: 0000000000000001
[   56.864804][   T12] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   56.865036][   T12] FS:  0000000000000000(0000) GS:ffff888085df2000(0000) knlGS:0000000000000000
[   56.865330][   T12] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   56.865532][   T12] CR2: 00007fbc6d3988cb CR3: 000000000a041003 CR4: 0000000000772ef0
[   56.865761][   T12] PKRU: 55555554
[   56.865970][   T12] Call Trace:
[   56.866085][   T12]  <TASK>
[   56.866179][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   56.866353][   T12]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   56.866557][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   56.866708][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   56.866882][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   56.867045][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   56.867212][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   56.867369][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   56.867531][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   56.867685][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   56.867844][   T12]  process_one_work (kernel/workqueue.c:3268)
[   56.868082][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   56.868259][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   56.868410][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   56.868573][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   56.868724][   T12]  kthread (kernel/kthread.c:463)
[   56.868846][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   56.869085][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   56.869260][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   56.869422][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   56.869667][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   56.869818][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   56.869972][   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