======================================
| [   22.884115][   T12] ==================================================================
| [   22.884442][   T12] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   22.884816][   T12] Read of size 1 at addr ffff8880088d169c by task kworker/u16:0/12
| [   22.885087][   T12]
[   22.885175][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   22.885178][   T12] Workqueue: netns cleanup_net
[   22.885187][   T12] Call Trace:
[   22.885189][   T12]  <TASK>
[   22.885191][   T12]  dump_stack_lvl (lib/dump_stack.c:123)
[   22.885197][   T12]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   22.885205][   T12]  ? kobject_put (lib/kobject.c:733)
[   22.885209][   T12]  print_report (mm/kasan/report.c:483)
[   22.885212][   T12]  ? kobject_put (lib/kobject.c:733)
[   22.885214][   T12]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   22.885217][   T12]  ? kobject_put (lib/kobject.c:733)
[   22.885219][   T12]  kasan_report (mm/kasan/report.c:597)
[   22.885222][   T12]  ? kobject_put (lib/kobject.c:733)
[   22.885228][   T12]  kobject_put (lib/kobject.c:733)
[   22.885230][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   22.885236][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   22.885239][   T12]  ? unregister_netdevice_many (net/core/dev.c:12241)
[   22.885242][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   22.885245][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   22.885255][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   22.885260][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   22.885263][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   22.885268][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   22.885272][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   22.885276][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   22.885285][   T12]  process_one_work (kernel/workqueue.c:3268)
[   22.885299][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   22.885310][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   22.885317][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   22.885328][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   22.885334][   T12]  kthread (kernel/kthread.c:463)
[   22.885340][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   22.885344][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   22.885351][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   22.885357][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   22.885361][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   22.885367][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   22.885372][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   22.885377][   T12]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   22.906938][   T12] refcount_t: underflow; use-after-free.
| [   22.907183][   T12] WARNING: CPU: 0 PID: 12 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   22.908575][   T12] Modules linked in:
| [   22.909050][   T12] Tainted: [B]=BAD_PAGE
[   22.909168][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   22.909482][   T12] Workqueue: netns cleanup_net
[   22.909695][   T12] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   22.909989][   T12] Code: a2 b5 02 80 fb 01 0f 87 db 6e d8 fe 83 e3 01 0f 85 51 ff ff ff c6 05 c2 a2 b5 02 01 90 48 c7 c7 60 a8 e5 af e8 72 c3 17 ff 90 <0f> 0b 90 90 e9 33 ff ff ff 48 89 df e8 20 69 a0 ff e9 ba fe ff ff
All code
========
   0:	a2 b5 02 80 fb 01 0f 	movabs %al,0xdb870f01fb8002b5
   7:	87 db 
   9:	6e                   	outsb  %ds:(%rsi),(%dx)
   a:	d8 fe                	fdivr  %st(6),%st
   c:	83 e3 01             	and    $0x1,%ebx
   f:	0f 85 51 ff ff ff    	jne    0xffffffffffffff66
  15:	c6 05 c2 a2 b5 02 01 	movb   $0x1,0x2b5a2c2(%rip)        # 0x2b5a2de
  1c:	90                   	nop
  1d:	48 c7 c7 60 a8 e5 af 	mov    $0xffffffffafe5a860,%rdi
  24:	e8 72 c3 17 ff       	call   0xffffffffff17c39b
  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 20 69 a0 ff       	call   0xffffffffffa0695b
  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 20 69 a0 ff       	call   0xffffffffffa06931
  11:	e9 ba fe ff ff       	jmp    0xfffffffffffffed0
[   22.910832][   T12] RSP: 0018:ffffc900000c7a08 EFLAGS: 00010282
[   22.911157][   T12] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   22.911572][   T12] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   22.911892][   T12] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff60fe134
[   22.912119][   T12] R10: 0000000000000003 R11: ffffc900000c7580 R12: 0000000000000001
[   22.912672][   T12] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   22.912944][   T12] FS:  0000000000000000(0000) GS:ffff88807e981000(0000) knlGS:0000000000000000
[   22.913440][   T12] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   22.913659][   T12] CR2: 00007f1169512760 CR3: 000000003cb35002 CR4: 0000000000772ef0
[   22.914033][   T12] PKRU: 55555554
[   22.914164][   T12] Call Trace:
[   22.914360][   T12]  <TASK>
[   22.914456][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   22.914664][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   22.914823][   T12]  ? unregister_netdevice_many (net/core/dev.c:12241)
[   22.915059][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   22.915335][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   22.915549][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   22.915700][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   22.915936][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   22.916138][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   22.916331][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   22.916542][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   22.916714][   T12]  process_one_work (kernel/workqueue.c:3268)
[   22.916864][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   22.917142][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   22.917351][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   22.917565][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   22.917826][   T12]  kthread (kernel/kthread.c:463)
[   22.917977][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   22.918141][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   22.918348][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   22.918646][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   22.918834][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   22.919021][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   22.919218][   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