======================================
| xx__-> [   23.899320][   T70] ==================================================================
| [   23.899606][   T70] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   23.899852][   T70] Read of size 1 at addr ffff888008fa469c by task kworker/u16:1/70
| [   23.900080][   T70]
[   23.900168][   T70] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   23.900171][   T70] Workqueue: netns cleanup_net
[   23.900179][   T70] Call Trace:
[   23.900181][   T70]  <TASK>
[   23.900184][   T70]  dump_stack_lvl (lib/dump_stack.c:123)
[   23.900190][   T70]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   23.900197][   T70]  ? kobject_put (lib/kobject.c:733)
[   23.900201][   T70]  print_report (mm/kasan/report.c:483)
[   23.900204][   T70]  ? kobject_put (lib/kobject.c:733)
[   23.900207][   T70]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   23.900211][   T70]  ? kobject_put (lib/kobject.c:733)
[   23.900214][   T70]  kasan_report (mm/kasan/report.c:597)
[   23.900222][   T70]  ? kobject_put (lib/kobject.c:733)
[   23.900228][   T70]  kobject_put (lib/kobject.c:733)
[   23.900231][   T70]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   23.900237][   T70]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   23.900240][   T70]  ? generic_xdp_install (net/core/dev.c:11630)
[   23.900246][   T70]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   23.900251][   T70]  ? netns_get (net/core/net_namespace.c:223)
[   23.900254][   T70]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   23.900259][   T70]  cleanup_net (net/core/net_namespace.c:698)
[   23.900263][   T70]  ? net_passive_dec (net/core/net_namespace.c:660)
[   23.900267][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   23.900276][   T70]  process_one_work (kernel/workqueue.c:3268)
[   23.900286][   T70]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   23.900291][   T70]  ? assign_work (kernel/workqueue.c:1206)
[   23.900296][   T70]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   23.900302][   T70]  ? rescuer_thread (kernel/workqueue.c:3373)
[   23.900306][   T70]  kthread (kernel/kthread.c:463)
[   23.900311][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   23.900314][   T70]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   23.900319][   T70]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   23.900325][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   23.900329][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   23.900333][   T70]  ret_from_fork (arch/x86/kernel/process.c:164)
[   23.900335][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   23.900339][   T70]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   23.918435][   T70] refcount_t: underflow; use-after-free.
| [   23.918626][   T70] WARNING: CPU: 3 PID: 70 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   23.918924][   T70] Modules linked in:
| [   23.919433][   T70] Tainted: [B]=BAD_PAGE
[   23.919577][   T70] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   23.919815][   T70] Workqueue: netns cleanup_net
[   23.920007][   T70] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   23.920253][   T70] Code: 32 b8 02 80 fb 01 0f 87 cb 8b d9 fe 83 e3 01 0f 85 51 ff ff ff c6 05 e5 32 b8 02 01 90 48 c7 c7 60 8d a5 b5 e8 42 c1 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:	32 b8 02 80 fb 01    	xor    0x1fb8002(%rax),%bh
   6:	0f 87 cb 8b d9 fe    	ja     0xfffffffffed98bd7
   c:	83 e3 01             	and    $0x1,%ebx
   f:	0f 85 51 ff ff ff    	jne    0xffffffffffffff66
  15:	c6 05 e5 32 b8 02 01 	movb   $0x1,0x2b832e5(%rip)        # 0x2b83301
  1c:	90                   	nop
  1d:	48 c7 c7 60 8d a5 b5 	mov    $0xffffffffb5a58d60,%rdi
  24:	e8 42 c1 18 ff       	call   0xffffffffff18c16b
  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
[   23.920898][   T70] RSP: 0018:ffffc900004b7a08 EFLAGS: 00010282
[   23.921110][   T70] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   23.921364][   T70] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   23.921609][   T70] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff6c82934
[   23.921867][   T70] R10: 0000000000000003 R11: ffffc900004b7580 R12: 0000000000000001
[   23.922129][   T70] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   23.922395][   T70] FS:  0000000000000000(0000) GS:ffff888078d04000(0000) knlGS:0000000000000000
[   23.922706][   T70] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   23.922930][   T70] CR2: 00007ffe983cf868 CR3: 0000000008a52002 CR4: 0000000000772ef0
[   23.923202][   T70] PKRU: 55555554
[   23.923348][   T70] Call Trace:
[   23.923485][   T70]  <TASK>
[   23.923581][   T70]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   23.923857][   T70]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   23.924039][   T70]  ? generic_xdp_install (net/core/dev.c:11630)
[   23.924215][   T70]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   23.924405][   T70]  ? netns_get (net/core/net_namespace.c:223)
[   23.924666][   T70]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   23.924862][   T70]  cleanup_net (net/core/net_namespace.c:698)
[   23.925046][   T70]  ? net_passive_dec (net/core/net_namespace.c:660)
[   23.925232][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   23.925422][   T70]  process_one_work (kernel/workqueue.c:3268)
[   23.925611][   T70]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   23.925803][   T70]  ? assign_work (kernel/workqueue.c:1206)
[   23.925985][   T70]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   23.926260][   T70]  ? rescuer_thread (kernel/workqueue.c:3373)
[   23.926450][   T70]  kthread (kernel/kthread.c:463)
[   23.926591][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   23.926778][   T70]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   23.927052][   T70]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   23.927243][   T70]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   23.927424][   T70]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   23.927609][   T70]  ret_from_fork (arch/x86/kernel/process.c:164)
[   23.927967][   T70]  ? 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