======================================
| [ 2097.740638][   T67] ==================================================================
| [ 2097.741253][   T67] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [ 2097.741751][   T67] Read of size 1 at addr ffff888008e8c6c4 by task kworker/u16:1/67
| [ 2097.742175][   T67]
[ 2097.742348][   T67] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 2097.742355][   T67] Workqueue: netns cleanup_net
[ 2097.742379][   T67] Call Trace:
[ 2097.742385][   T67]  <TASK>
[ 2097.742389][   T67]  dump_stack_lvl (lib/dump_stack.c:123)
[ 2097.742402][   T67]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[ 2097.742423][   T67]  ? kobject_put (lib/kobject.c:733)
[ 2097.742429][   T67]  print_report (mm/kasan/report.c:483)
[ 2097.742435][   T67]  ? kobject_put (lib/kobject.c:733)
[ 2097.742439][   T67]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[ 2097.742446][   T67]  ? kobject_put (lib/kobject.c:733)
[ 2097.742451][   T67]  kasan_report (mm/kasan/report.c:597)
[ 2097.742458][   T67]  ? kobject_put (lib/kobject.c:733)
[ 2097.742468][   T67]  kobject_put (lib/kobject.c:733)
[ 2097.742474][   T67]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[ 2097.742482][   T67]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[ 2097.742488][   T67]  ? generic_xdp_install (net/core/dev.c:11630)
[ 2097.742496][   T67]  ? net_generic (./include/linux/rcupdate.h:341 ./include/linux/rcupdate.h:897 ./include/net/netns/generic.h:48)
[ 2097.742514][   T67]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[ 2097.742524][   T67]  ? rtnl_net_dumpid_one (net/core/net_namespace.c:223)
[ 2097.742530][   T67]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[ 2097.742540][   T67]  cleanup_net (net/core/net_namespace.c:698)
[ 2097.742547][   T67]  ? net_passive_dec (net/core/net_namespace.c:660)
[ 2097.742556][   T67]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[ 2097.742579][   T67]  process_one_work (kernel/workqueue.c:3268)
[ 2097.742602][   T67]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[ 2097.742611][   T67]  ? assign_work (kernel/workqueue.c:1206)
[ 2097.742619][   T67]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[ 2097.742630][   T67]  ? rescuer_thread (kernel/workqueue.c:3373)
[ 2097.742637][   T67]  kthread (kernel/kthread.c:463)
[ 2097.742645][   T67]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[ 2097.742651][   T67]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[ 2097.742663][   T67]  ? __lock_release (kernel/locking/lockdep.c:5536)
[ 2097.742673][   T67]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[ 2097.742679][   T67]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[ 2097.742686][   T67]  ret_from_fork (arch/x86/kernel/process.c:164)
[ 2097.742691][   T67]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[ 2097.742696][   T67]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [ 2097.774746][   T67] refcount_t: underflow; use-after-free.
| [ 2097.775009][   T67] WARNING: CPU: 3 PID: 67 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [ 2097.775369][   T67] Modules linked in: xt_HL nft_compat nf_tables amt
| [ 2097.776102][   T67] Tainted: [B]=BAD_PAGE
[ 2097.776247][   T67] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 2097.776494][   T67] Workqueue: netns cleanup_net
[ 2097.776710][   T67] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[ 2097.776934][   T67] Code: cc 38 03 80 fb 01 0f 87 29 33 d7 fe 83 e3 01 0f 85 51 ff ff ff c6 05 17 cc 38 03 01 90 48 c7 c7 40 ba a5 8d e8 62 d6 16 ff 90 <0f> 0b 90 90 e9 33 ff ff ff 48 89 df e8 c0 9d a0 ff e9 ba fe ff ff
All code
========
   0:	cc                   	int3
   1:	38 03                	cmp    %al,(%rbx)
   3:	80 fb 01             	cmp    $0x1,%bl
   6:	0f 87 29 33 d7 fe    	ja     0xfffffffffed73335
   c:	83 e3 01             	and    $0x1,%ebx
   f:	0f 85 51 ff ff ff    	jne    0xffffffffffffff66
  15:	c6 05 17 cc 38 03 01 	movb   $0x1,0x338cc17(%rip)        # 0x338cc33
  1c:	90                   	nop
  1d:	48 c7 c7 40 ba a5 8d 	mov    $0xffffffff8da5ba40,%rdi
  24:	e8 62 d6 16 ff       	call   0xffffffffff16d68b
  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 c0 9d a0 ff       	call   0xffffffffffa09dfb
  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 c0 9d a0 ff       	call   0xffffffffffa09dd1
  11:	e9 ba fe ff ff       	jmp    0xfffffffffffffed0
[ 2097.777578][   T67] RSP: 0018:ffffc90000487a08 EFLAGS: 00010282
[ 2097.777809][   T67] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[ 2097.778059][   T67] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[ 2097.778345][   T67] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff1d40934
[ 2097.778634][   T67] R10: 0000000000000003 R11: ffffc90000487580 R12: 0000000000000001
[ 2097.778895][   T67] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[ 2097.779153][   T67] FS:  0000000000000000(0000) GS:ffff8880dd288000(0000) knlGS:0000000000000000
[ 2097.779468][   T67] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2097.779675][   T67] CR2: 00007f3504073000 CR3: 0000000011549001 CR4: 0000000000772ef0
[ 2097.779949][   T67] PKRU: 55555554
[ 2097.780088][   T67] Call Trace:
[ 2097.780219][   T67]  <TASK>
[ 2097.780310][   T67]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[ 2097.780528][   T67]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[ 2097.780703][   T67]  ? generic_xdp_install (net/core/dev.c:11630)
[ 2097.780873][   T67]  ? net_generic (./include/linux/rcupdate.h:341 ./include/linux/rcupdate.h:897 ./include/net/netns/generic.h:48)
[ 2097.781103][   T67]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[ 2097.781268][   T67]  ? rtnl_net_dumpid_one (net/core/net_namespace.c:223)
[ 2097.781637][   T67]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[ 2097.781795][   T67]  cleanup_net (net/core/net_namespace.c:698)
[ 2097.781969][   T67]  ? net_passive_dec (net/core/net_namespace.c:660)
[ 2097.782224][   T67]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[ 2097.782515][   T67]  process_one_work (kernel/workqueue.c:3268)
[ 2097.782695][   T67]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[ 2097.782856][   T67]  ? assign_work (kernel/workqueue.c:1206)
[ 2097.783019][   T67]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[ 2097.783214][   T67]  ? rescuer_thread (kernel/workqueue.c:3373)
[ 2097.783388][   T67]  kthread (kernel/kthread.c:463)
[ 2097.783537][   T67]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[ 2097.783700][   T67]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[ 2097.783900][   T67]  ? __lock_release (kernel/locking/lockdep.c:5536)
[ 2097.784067][   T67]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[ 2097.784266][   T67]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[ 2097.784472][   T67]  ret_from_fork (arch/x86/kernel/process.c:164)
[ 2097.784748][   T67]  ? 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