======================================
| [   39.891274][   T71] ==================================================================
| [   39.891584][   T71] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   39.891853][   T71] Read of size 1 at addr ffff888009dc16ac by task kworker/u16:1/71
| [   39.892106][   T71]
[   39.892200][   T71] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   39.892203][   T71] Workqueue: netns cleanup_net
[   39.892208][   T71] Call Trace:
[   39.892210][   T71]  <TASK>
[   39.892213][   T71]  dump_stack_lvl (lib/dump_stack.c:123)
[   39.892219][   T71]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   39.892225][   T71]  ? kobject_put (lib/kobject.c:733)
[   39.892230][   T71]  print_report (mm/kasan/report.c:483)
[   39.892233][   T71]  ? kobject_put (lib/kobject.c:733)
[   39.892236][   T71]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   39.892240][   T71]  ? kobject_put (lib/kobject.c:733)
[   39.892243][   T71]  kasan_report (mm/kasan/report.c:597)
[   39.892247][   T71]  ? kobject_put (lib/kobject.c:733)
[   39.892253][   T71]  kobject_put (lib/kobject.c:733)
[   39.892257][   T71]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   39.892262][   T71]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   39.892266][   T71]  ? generic_xdp_install (net/core/dev.c:11630)
[   39.892272][   T71]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   39.892279][   T71]  ? netns_get (net/core/net_namespace.c:223)
[   39.892283][   T71]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   39.892288][   T71]  cleanup_net (net/core/net_namespace.c:698)
[   39.892291][   T71]  ? net_passive_dec (net/core/net_namespace.c:660)
[   39.892295][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   39.892301][   T71]  process_one_work (kernel/workqueue.c:3268)
[   39.892309][   T71]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   39.892315][   T71]  ? assign_work (kernel/workqueue.c:1206)
[   39.892319][   T71]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   39.892324][   T71]  ? rescuer_thread (kernel/workqueue.c:3373)
[   39.892328][   T71]  kthread (kernel/kthread.c:463)
[   39.892332][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   39.892334][   T71]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   39.892340][   T71]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   39.892347][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   39.892352][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   39.892357][   T71]  ret_from_fork (arch/x86/kernel/process.c:164)
[   39.892362][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   39.892366][   T71]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   39.911755][   T71] refcount_t: underflow; use-after-free.
| [   39.911946][   T71] WARNING: CPU: 0 PID: 71 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   39.912265][   T71] 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
| [   39.913158][   T71] Tainted: [B]=BAD_PAGE
[   39.913292][   T71] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   39.913517][   T71] Workqueue: netns cleanup_net
[   39.913705][   T71] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   39.913925][   T71] 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 65 b0 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 65 b0 	mov    $0xffffffffb065dea0,%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
[   39.914568][   T71] RSP: 0018:ffffc900004c7a08 EFLAGS: 00010282
[   39.914786][   T71] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   39.915138][   T71] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   39.915404][   T71] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff61fe220
[   39.915756][   T71] R10: 0000000000000003 R11: ffffc900004c7580 R12: 0000000000000001
[   39.916012][   T71] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   39.916280][   T71] FS:  0000000000000000(0000) GS:ffff888083dec000(0000) knlGS:0000000000000000
[   39.916677][   T71] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   39.916889][   T71] CR2: 000055e6c1a30588 CR3: 0000000005134003 CR4: 0000000000772ef0
[   39.917245][   T71] PKRU: 55555554
[   39.917464][   T71] Call Trace:
[   39.917602][   T71]  <TASK>
[   39.917696][   T71]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   39.917955][   T71]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   39.918141][   T71]  ? generic_xdp_install (net/core/dev.c:11630)
[   39.918315][   T71]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   39.918498][   T71]  ? netns_get (net/core/net_namespace.c:223)
[   39.918679][   T71]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   39.918853][   T71]  cleanup_net (net/core/net_namespace.c:698)
[   39.919020][   T71]  ? net_passive_dec (net/core/net_namespace.c:660)
[   39.919202][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   39.919380][   T71]  process_one_work (kernel/workqueue.c:3268)
[   39.919557][   T71]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   39.919730][   T71]  ? assign_work (kernel/workqueue.c:1206)
[   39.919897][   T71]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   39.920165][   T71]  ? rescuer_thread (kernel/workqueue.c:3373)
[   39.920331][   T71]  kthread (kernel/kthread.c:463)
[   39.920559][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   39.920812][   T71]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   39.920978][   T71]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   39.921152][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   39.921315][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   39.921586][   T71]  ret_from_fork (arch/x86/kernel/process.c:164)
[   39.921758][   T71]  ? 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