======================================
| [   45.749138][   T70] ==================================================================
| [   45.749447][   T70] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   45.749762][   T70] Read of size 1 at addr ffff8880055716ac by task kworker/u16:1/70
| [   45.750074][   T70]
[   45.750188][   T70] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   45.750192][   T70] Workqueue: netns cleanup_net
[   45.750199][   T70] Call Trace:
[   45.750201][   T70]  <TASK>
[   45.750204][   T70]  dump_stack_lvl (lib/dump_stack.c:123)
[   45.750211][   T70]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   45.750219][   T70]  ? kobject_put (lib/kobject.c:733)
[   45.750224][   T70]  print_report (mm/kasan/report.c:483)
[   45.750227][   T70]  ? kobject_put (lib/kobject.c:733)
[   45.750231][   T70]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   45.750235][   T70]  ? kobject_put (lib/kobject.c:733)
[   45.750238][   T70]  kasan_report (mm/kasan/report.c:597)
[   45.750242][   T70]  ? kobject_put (lib/kobject.c:733)
[   45.750248][   T70]  kobject_put (lib/kobject.c:733)
[   45.750252][   T70]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   45.750258][   T70]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   45.750262][   T70]  ? generic_xdp_install (net/core/dev.c:11630)
[   45.750269][   T70]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   45.750278][   T70]  ? netns_get (net/core/net_namespace.c:223)
[   45.750281][   T70]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   45.750286][   T70]  cleanup_net (net/core/net_namespace.c:698)
[   45.750289][   T70]  ? net_passive_dec (net/core/net_namespace.c:660)
[   45.750293][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   45.750303][   T70]  process_one_work (kernel/workqueue.c:3268)
[   45.750318][   T70]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   45.750329][   T70]  ? assign_work (kernel/workqueue.c:1206)
[   45.750336][   T70]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   45.750345][   T70]  ? rescuer_thread (kernel/workqueue.c:3373)
[   45.750350][   T70]  kthread (kernel/kthread.c:463)
[   45.750358][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   45.750362][   T70]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   45.750369][   T70]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   45.750378][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   45.750382][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   45.750387][   T70]  ret_from_fork (arch/x86/kernel/process.c:164)
[   45.750392][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   45.750397][   T70]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   45.773931][   T70] refcount_t: underflow; use-after-free.
| [   45.774110][   T70] WARNING: CPU: 0 PID: 70 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   45.774439][   T70] Modules linked in: nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib ip6t_rpfilter ipt_rpfilter xt_tcpudp nft_compat nf_tables x_tables dummy veth
| [   45.775396][   T70] Tainted: [B]=BAD_PAGE
[   45.775568][   T70] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   45.775814][   T70] Workqueue: netns cleanup_net
[   45.776043][   T70] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   45.776343][   T70] Code: 83 90 02 80 fb 01 0f 87 95 6b d6 fe 83 e3 01 0f 85 51 ff ff ff c6 05 b1 83 90 02 01 90 48 c7 c7 a0 de c5 b3 e8 c2 8b 15 ff 90 <0f> 0b 90 90 e9 33 ff ff ff 48 89 df e8 f0 34 a1 ff e9 ba fe ff ff
All code
========
   0:	83 90 02 80 fb 01 0f 	adcl   $0xf,0x1fb8002(%rax)
   7:	87 95 6b d6 fe 83    	xchg   %edx,-0x7c012995(%rbp)
   d:	e3 01                	jrcxz  0x10
   f:	0f 85 51 ff ff ff    	jne    0xffffffffffffff66
  15:	c6 05 b1 83 90 02 01 	movb   $0x1,0x29083b1(%rip)        # 0x29083cd
  1c:	90                   	nop
  1d:	48 c7 c7 a0 de c5 b3 	mov    $0xffffffffb3c5dea0,%rdi
  24:	e8 c2 8b 15 ff       	call   0xffffffffff158beb
  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 f0 34 a1 ff       	call   0xffffffffffa1352b
  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 f0 34 a1 ff       	call   0xffffffffffa13501
  11:	e9 ba fe ff ff       	jmp    0xfffffffffffffed0
[   45.777032][   T70] RSP: 0018:ffffc900004b7a08 EFLAGS: 00010282
[   45.777466][   T70] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   45.777769][   T70] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   45.778134][   T70] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff68be220
[   45.778476][   T70] R10: 0000000000000003 R11: ffffc900004b7580 R12: 0000000000000001
[   45.778777][   T70] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   45.779030][   T70] FS:  0000000000000000(0000) GS:ffff8880807ec000(0000) knlGS:0000000000000000
[   45.779412][   T70] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   45.779614][   T70] CR2: 00007ffecb370b50 CR3: 000000001e335004 CR4: 0000000000772ef0
[   45.779905][   T70] PKRU: 55555554
[   45.780039][   T70] Call Trace:
[   45.780163][   T70]  <TASK>
[   45.780362][   T70]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   45.780575][   T70]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   45.780783][   T70]  ? generic_xdp_install (net/core/dev.c:11630)
[   45.780990][   T70]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   45.781194][   T70]  ? netns_get (net/core/net_namespace.c:223)
[   45.781477][   T70]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   45.781678][   T70]  cleanup_net (net/core/net_namespace.c:698)
[   45.781835][   T70]  ? net_passive_dec (net/core/net_namespace.c:660)
[   45.782068][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   45.782332][   T70]  process_one_work (kernel/workqueue.c:3268)
[   45.782518][   T70]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   45.782688][   T70]  ? assign_work (kernel/workqueue.c:1206)
[   45.782878][   T70]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   45.783130][   T70]  ? rescuer_thread (kernel/workqueue.c:3373)
[   45.783398][   T70]  kthread (kernel/kthread.c:463)
[   45.783524][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   45.783680][   T70]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   45.783874][   T70]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   45.784052][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   45.784221][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   45.784449][   T70]  ret_from_fork (arch/x86/kernel/process.c:164)
[   45.784619][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)


Finger prints:
print_report:kasan_report:kobject_put:netdev_run_todo:ops_undo_list
refcount_warn_saturate:netdev_run_todo:ops_undo_list:cleanup_net:process_one_work