======================================
| [   68.424605][   T12] ==================================================================
| [   68.424951][   T12] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   68.425273][   T12] Read of size 1 at addr ffff888011f116ac by task kworker/u16:0/12
| [   68.425567][   T12]
[   68.425686][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   68.425689][   T12] Workqueue: netns cleanup_net
[   68.425699][   T12] Call Trace:
[   68.425702][   T12]  <TASK>
[   68.425705][   T12]  dump_stack_lvl (lib/dump_stack.c:123)
[   68.425713][   T12]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   68.425721][   T12]  ? kobject_put (lib/kobject.c:733)
[   68.425727][   T12]  print_report (mm/kasan/report.c:483)
[   68.425732][   T12]  ? kobject_put (lib/kobject.c:733)
[   68.425737][   T12]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   68.425742][   T12]  ? kobject_put (lib/kobject.c:733)
[   68.425746][   T12]  kasan_report (mm/kasan/report.c:597)
[   68.425750][   T12]  ? kobject_put (lib/kobject.c:733)
[   68.425755][   T12]  kobject_put (lib/kobject.c:733)
[   68.425759][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   68.425764][   T12]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   68.425769][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   68.425773][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   68.425779][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   68.425784][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   68.425787][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   68.425793][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   68.425797][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   68.425801][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   68.425809][   T12]  process_one_work (kernel/workqueue.c:3268)
[   68.425818][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   68.425824][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   68.425829][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   68.425834][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   68.425838][   T12]  kthread (kernel/kthread.c:463)
[   68.425843][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   68.425845][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   68.425850][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   68.425857][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   68.425860][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   68.425863][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   68.425866][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   68.425868][   T12]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   68.446788][   T12] refcount_t: underflow; use-after-free.
| [   68.446999][   T12] WARNING: CPU: 0 PID: 12 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   68.447344][   T12] Modules linked in: vxlan ip6_udp_tunnel udp_tunnel bridge stp llc 8021q sch_ingress vrf veth
| [   68.448185][   T12] Tainted: [B]=BAD_PAGE
[   68.448346][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   68.448619][   T12] Workqueue: netns cleanup_net
[   68.448841][   T12] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   68.449069][   T12] Code: 7d 93 02 80 fb 01 0f 87 bb 99 d9 fe 83 e3 01 0f 85 51 ff ff ff c6 05 a8 7d 93 02 01 90 48 c7 c7 60 8d 85 9b e8 32 bf 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:	7d 93                	jge    0xffffffffffffff95
   2:	02 80 fb 01 0f 87    	add    -0x78f0fe05(%rax),%al
   8:	bb 99 d9 fe 83       	mov    $0x83fed999,%ebx
   d:	e3 01                	jrcxz  0x10
   f:	0f 85 51 ff ff ff    	jne    0xffffffffffffff66
  15:	c6 05 a8 7d 93 02 01 	movb   $0x1,0x2937da8(%rip)        # 0x2937dc4
  1c:	90                   	nop
  1d:	48 c7 c7 60 8d 85 9b 	mov    $0xffffffff9b858d60,%rdi
  24:	e8 32 bf 18 ff       	call   0xffffffffff18bf5b
  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
[   68.449769][   T12] RSP: 0000:ffffc900000c7a08 EFLAGS: 00010282
[   68.449998][   T12] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   68.450258][   T12] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   68.450579][   T12] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff383e134
[   68.450868][   T12] R10: 0000000000000003 R11: ffffc900000c7580 R12: 0000000000000001
[   68.451136][   T12] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   68.451429][   T12] FS:  0000000000000000(0000) GS:ffff888098bf2000(0000) knlGS:0000000000000000
[   68.451770][   T12] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   68.451999][   T12] CR2: 00007f536fd8aff0 CR3: 0000000015ca9006 CR4: 0000000000772ef0
[   68.452292][   T12] PKRU: 55555554
[   68.452433][   T12] Call Trace:
[   68.452575][   T12]  <TASK>
[   68.452669][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   68.452864][   T12]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[   68.453054][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   68.453237][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   68.453495][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   68.453772][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   68.454026][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   68.454312][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   68.454587][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   68.454827][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   68.455119][   T12]  process_one_work (kernel/workqueue.c:3268)
[   68.455408][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   68.455694][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   68.455972][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   68.456251][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   68.456536][   T12]  kthread (kernel/kthread.c:463)
[   68.456730][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   68.457004][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   68.457296][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   68.457573][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   68.457849][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   68.458122][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   68.458404][   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