======================================
| [   81.306045][   T71] ==================================================================
| [   81.306446][   T71] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   81.306831][   T71] Read of size 1 at addr ffff88800a1696ac by task kworker/u16:1/71
| [   81.307092][   T71]
[   81.307196][   T71] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   81.307200][   T71] Workqueue: netns cleanup_net
[   81.307212][   T71] Call Trace:
[   81.307216][   T71]  <TASK>
[   81.307220][   T71]  dump_stack_lvl (lib/dump_stack.c:123)
[   81.307228][   T71]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   81.307243][   T71]  ? kobject_put (lib/kobject.c:733)
[   81.307249][   T71]  print_report (mm/kasan/report.c:483)
[   81.307253][   T71]  ? kobject_put (lib/kobject.c:733)
[   81.307258][   T71]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   81.307263][   T71]  ? kobject_put (lib/kobject.c:733)
[   81.307268][   T71]  kasan_report (mm/kasan/report.c:597)
[   81.307273][   T71]  ? kobject_put (lib/kobject.c:733)
[   81.307279][   T71]  kobject_put (lib/kobject.c:733)
[   81.307284][   T71]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   81.307296][   T71]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   81.307304][   T71]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   81.307307][   T71]  ? generic_xdp_install (net/core/dev.c:11630)
[   81.307313][   T71]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   81.307318][   T71]  ? netns_get (net/core/net_namespace.c:223)
[   81.307321][   T71]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   81.307327][   T71]  cleanup_net (net/core/net_namespace.c:698)
[   81.307332][   T71]  ? net_passive_dec (net/core/net_namespace.c:660)
[   81.307336][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   81.307344][   T71]  process_one_work (kernel/workqueue.c:3268)
[   81.307356][   T71]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   81.307362][   T71]  ? assign_work (kernel/workqueue.c:1206)
[   81.307366][   T71]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   81.307372][   T71]  ? rescuer_thread (kernel/workqueue.c:3373)
[   81.307375][   T71]  kthread (kernel/kthread.c:463)
[   81.307382][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   81.307385][   T71]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   81.307389][   T71]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   81.307397][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   81.307400][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   81.307404][   T71]  ret_from_fork (arch/x86/kernel/process.c:164)
[   81.307406][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   81.307409][   T71]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   81.329367][   T71] refcount_t: underflow; use-after-free.
| [   81.329588][   T71] WARNING: CPU: 3 PID: 71 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   81.329978][   T71] Modules linked in: act_gact cls_flower sch_ingress macvlan 8021q vxlan ip6_udp_tunnel udp_tunnel bridge stp llc vrf veth
| [   81.331480][   T71] Tainted: [B]=BAD_PAGE
[   81.331649][   T71] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   81.331900][   T71] Workqueue: netns cleanup_net
[   81.332103][   T71] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   81.332364][   T71] 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 c5 a9 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 c5 a9 	mov    $0xffffffffa9c58d60,%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
[   81.333035][   T71] RSP: 0018:ffffc900004c7a08 EFLAGS: 00010282
[   81.333272][   T71] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   81.333569][   T71] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   81.333859][   T71] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff54be134
[   81.334124][   T71] R10: 0000000000000003 R11: ffffc900004c7580 R12: 0000000000000001
[   81.334415][   T71] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   81.334698][   T71] FS:  0000000000000000(0000) GS:ffff88808a972000(0000) knlGS:0000000000000000
[   81.335038][   T71] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   81.335276][   T71] CR2: 00007ffcfc0b3f90 CR3: 00000000023e4005 CR4: 0000000000772ef0
[   81.335569][   T71] PKRU: 55555554
[   81.335716][   T71] Call Trace:
[   81.335881][   T71]  <TASK>
[   81.335991][   T71]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   81.336177][   T71]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   81.336374][   T71]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   81.336568][   T71]  ? generic_xdp_install (net/core/dev.c:11630)
[   81.336765][   T71]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   81.336953][   T71]  ? netns_get (net/core/net_namespace.c:223)
[   81.337130][   T71]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   81.337327][   T71]  cleanup_net (net/core/net_namespace.c:698)
[   81.337521][   T71]  ? net_passive_dec (net/core/net_namespace.c:660)
[   81.337698][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   81.337906][   T71]  process_one_work (kernel/workqueue.c:3268)
[   81.338086][   T71]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   81.338281][   T71]  ? assign_work (kernel/workqueue.c:1206)
[   81.338499][   T71]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   81.338725][   T71]  ? rescuer_thread (kernel/workqueue.c:3373)
[   81.338956][   T71]  kthread (kernel/kthread.c:463)
[   81.339101][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   81.339345][   T71]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   81.339530][   T71]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   81.339743][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   81.339974][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   81.340152][   T71]  ret_from_fork (arch/x86/kernel/process.c:164)
[   81.340353][   T71]  ? 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