======================================
| [   58.986825][   T68] ==================================================================
| [   58.987280][   T68] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   58.987682][   T68] Read of size 1 at addr ffff88800bf1c6ac by task kworker/u16:1/68
| [   58.988074][   T68]
[   58.988229][   T68] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   58.988233][   T68] Workqueue: netns cleanup_net
[   58.988242][   T68] Call Trace:
[   58.988245][   T68]  <TASK>
[   58.988250][   T68]  dump_stack_lvl (lib/dump_stack.c:123)
[   58.988258][   T68]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   58.988265][   T68]  ? kobject_put (lib/kobject.c:733)
[   58.988271][   T68]  print_report (mm/kasan/report.c:483)
[   58.988275][   T68]  ? kobject_put (lib/kobject.c:733)
[   58.988279][   T68]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   58.988284][   T68]  ? kobject_put (lib/kobject.c:733)
[   58.988288][   T68]  kasan_report (mm/kasan/report.c:597)
[   58.988293][   T68]  ? kobject_put (lib/kobject.c:733)
[   58.988303][   T68]  kobject_put (lib/kobject.c:733)
[   58.988308][   T68]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   58.988313][   T68]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   58.988320][   T68]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   58.988326][   T68]  ? generic_xdp_install (net/core/dev.c:11630)
[   58.988335][   T68]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   58.988344][   T68]  ? netns_get (net/core/net_namespace.c:223)
[   58.988348][   T68]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   58.988358][   T68]  cleanup_net (net/core/net_namespace.c:698)
[   58.988364][   T68]  ? net_passive_dec (net/core/net_namespace.c:660)
[   58.988370][   T68]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   58.988381][   T68]  process_one_work (kernel/workqueue.c:3268)
[   58.988394][   T68]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   58.988403][   T68]  ? assign_work (kernel/workqueue.c:1206)
[   58.988411][   T68]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   58.988421][   T68]  ? rescuer_thread (kernel/workqueue.c:3373)
[   58.988427][   T68]  kthread (kernel/kthread.c:463)
[   58.988434][   T68]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   58.988438][   T68]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   58.988443][   T68]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   58.988452][   T68]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   58.988456][   T68]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   58.988462][   T68]  ret_from_fork (arch/x86/kernel/process.c:164)
[   58.988466][   T68]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   58.988471][   T68]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   59.020779][   T68] refcount_t: underflow; use-after-free.
| [   59.021065][   T68] WARNING: CPU: 0 PID: 68 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   59.021464][   T68] Modules linked in: vxlan ip6_udp_tunnel udp_tunnel bridge stp llc 8021q sch_ingress vrf veth
| [   59.022437][   T68] Tainted: [B]=BAD_PAGE
[   59.022608][   T68] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   59.022840][   T68] Workqueue: netns cleanup_net
[   59.023065][   T68] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   59.023376][   T68] 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 e5 8c 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 e5 8c 	mov    $0xffffffff8ce58d60,%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
[   59.025134][   T68] RSP: 0000:ffffc90000497a08 EFLAGS: 00010282
[   59.025411][   T68] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   59.025727][   T68] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   59.026018][   T68] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff1afe134
[   59.026364][   T68] R10: 0000000000000003 R11: ffffc90000497580 R12: 0000000000000001
[   59.026624][   T68] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   59.026901][   T68] FS:  0000000000000000(0000) GS:ffff8880a75f2000(0000) knlGS:0000000000000000
[   59.027296][   T68] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   59.027537][   T68] CR2: 00007f9a87b0b888 CR3: 000000000b979005 CR4: 0000000000772ef0
[   59.027894][   T68] PKRU: 55555554
[   59.028026][   T68] Call Trace:
[   59.028182][   T68]  <TASK>
[   59.028286][   T68]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   59.028533][   T68]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   59.028736][   T68]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   59.028930][   T68]  ? generic_xdp_install (net/core/dev.c:11630)
[   59.029140][   T68]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   59.029379][   T68]  ? netns_get (net/core/net_namespace.c:223)
[   59.029570][   T68]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   59.029758][   T68]  cleanup_net (net/core/net_namespace.c:698)
[   59.030014][   T68]  ? net_passive_dec (net/core/net_namespace.c:660)
[   59.030249][   T68]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   59.030467][   T68]  process_one_work (kernel/workqueue.c:3268)
[   59.030706][   T68]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   59.030938][   T68]  ? assign_work (kernel/workqueue.c:1206)
[   59.031137][   T68]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   59.031317][   T68]  ? rescuer_thread (kernel/workqueue.c:3373)
[   59.031494][   T68]  kthread (kernel/kthread.c:463)
[   59.031631][   T68]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   59.031803][   T68]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   59.031976][   T68]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   59.032163][   T68]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   59.032340][   T68]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   59.032512][   T68]  ret_from_fork (arch/x86/kernel/process.c:164)
[   59.032686][   T68]  ? 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