======================================
| [   82.091972][   T12] ==================================================================
| [   82.092254][   T12] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   82.092498][   T12] Read of size 1 at addr ffff8880080c969c by task kworker/u16:0/12
| [   82.092719][   T12]
[   82.092804][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   82.092808][   T12] Workqueue: netns cleanup_net
[   82.092817][   T12] Call Trace:
[   82.092819][   T12]  <TASK>
[   82.092822][   T12]  dump_stack_lvl (lib/dump_stack.c:123)
[   82.092828][   T12]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   82.092837][   T12]  ? kobject_put (lib/kobject.c:733)
[   82.092840][   T12]  print_report (mm/kasan/report.c:483)
[   82.092844][   T12]  ? kobject_put (lib/kobject.c:733)
[   82.092847][   T12]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   82.092851][   T12]  ? kobject_put (lib/kobject.c:733)
[   82.092854][   T12]  kasan_report (mm/kasan/report.c:597)
[   82.092857][   T12]  ? kobject_put (lib/kobject.c:733)
[   82.092863][   T12]  kobject_put (lib/kobject.c:733)
[   82.092866][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   82.092871][   T12]  ? irqentry_exit (kernel/entry/common.c:215)
[   82.092876][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   82.092879][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   82.092886][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   82.092891][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   82.092893][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   82.092899][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   82.092903][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   82.092908][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   82.092916][   T12]  process_one_work (kernel/workqueue.c:3268)
[   82.092927][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   82.092933][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   82.092937][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   82.092943][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   82.092947][   T12]  kthread (kernel/kthread.c:463)
[   82.092952][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   82.092955][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   82.092960][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   82.092966][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   82.092970][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   82.092974][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   82.092976][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   82.092980][   T12]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   82.110786][   T12] refcount_t: underflow; use-after-free.
| [   82.110971][   T12] WARNING: CPU: 0 PID: 12 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   82.111260][   T12] Modules linked in:
| [   82.111725][   T12] Tainted: [B]=BAD_PAGE
[   82.111842][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   82.112033][   T12] Workqueue: netns cleanup_net
[   82.112198][   T12] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   82.112392][   T12] 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 a1 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 a1 	mov    $0xffffffffa1a58d60,%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
[   82.112927][   T12] RSP: 0000:ffffc900000c7a08 EFLAGS: 00010282
[   82.113130][   T12] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   82.113356][   T12] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   82.113582][   T12] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff4482934
[   82.113807][   T12] R10: 0000000000000003 R11: ffffc900000c7580 R12: 0000000000000001
[   82.114034][   T12] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   82.114268][   T12] FS:  0000000000000000(0000) GS:ffff888092984000(0000) knlGS:0000000000000000
[   82.114534][   T12] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   82.114722][   T12] CR2: 00007f3615352178 CR3: 000000002f759001 CR4: 0000000000772ef0
[   82.114946][   T12] PKRU: 55555554
[   82.115059][   T12] Call Trace:
[   82.115181][   T12]  <TASK>
[   82.115269][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   82.115422][   T12]  ? irqentry_exit (kernel/entry/common.c:215)
[   82.115576][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   82.115726][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   82.115880][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   82.116032][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   82.116188][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   82.116347][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   82.116499][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   82.116651][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   82.116808][   T12]  process_one_work (kernel/workqueue.c:3268)
[   82.116964][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   82.117208][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   82.117360][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   82.117596][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   82.117750][   T12]  kthread (kernel/kthread.c:463)
[   82.117864][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   82.118014][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   82.118255][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   82.118412][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   82.118562][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   82.118797][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   82.119030][   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