======================================
| [   28.157980][   T71] ==================================================================
| [   28.158384][   T71] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   28.158751][   T71] Read of size 1 at addr ffff888007e996ac by task kworker/u16:1/71
| [   28.159135][   T71]
[   28.159270][   T71] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   28.159274][   T71] Workqueue: netns cleanup_net
[   28.159285][   T71] Call Trace:
[   28.159289][   T71]  <TASK>
[   28.159293][   T71]  dump_stack_lvl (lib/dump_stack.c:123)
[   28.159309][   T71]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   28.159320][   T71]  ? kobject_put (lib/kobject.c:733)
[   28.159328][   T71]  print_report (mm/kasan/report.c:483)
[   28.159333][   T71]  ? kobject_put (lib/kobject.c:733)
[   28.159338][   T71]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   28.159345][   T71]  ? kobject_put (lib/kobject.c:733)
[   28.159350][   T71]  kasan_report (mm/kasan/report.c:597)
[   28.159357][   T71]  ? kobject_put (lib/kobject.c:733)
[   28.159366][   T71]  kobject_put (lib/kobject.c:733)
[   28.159372][   T71]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   28.159380][   T71]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   28.159387][   T71]  ? generic_xdp_install (net/core/dev.c:11630)
[   28.159397][   T71]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   28.159409][   T71]  ? netns_get (net/core/net_namespace.c:223)
[   28.159415][   T71]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   28.159422][   T71]  cleanup_net (net/core/net_namespace.c:698)
[   28.159427][   T71]  ? net_passive_dec (net/core/net_namespace.c:660)
[   28.159433][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   28.159442][   T71]  process_one_work (kernel/workqueue.c:3268)
[   28.159453][   T71]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   28.159461][   T71]  ? assign_work (kernel/workqueue.c:1206)
[   28.159468][   T71]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   28.159477][   T71]  ? rescuer_thread (kernel/workqueue.c:3373)
[   28.159483][   T71]  kthread (kernel/kthread.c:463)
[   28.159490][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   28.159494][   T71]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   28.159503][   T71]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   28.159512][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   28.159517][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   28.159524][   T71]  ret_from_fork (arch/x86/kernel/process.c:164)
[   28.159529][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   28.159534][   T71]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   28.186059][   T71] refcount_t: underflow; use-after-free.
| [   28.186445][   T71] WARNING: CPU: 3 PID: 71 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   28.186874][   T71] Modules linked in: sctp ip6_udp_tunnel udp_tunnel xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nft_compat nf_tables x_tables sch_netem cls_u32 sch_htb veth
| [   28.188205][   T71] Tainted: [B]=BAD_PAGE
[   28.188390][   T71] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   28.188683][   T71] Workqueue: netns cleanup_net
[   28.188935][   T71] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   28.189240][   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 c5 9f 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 c5 9f 	mov    $0xffffffff9fc5dea0,%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
[   28.190077][   T71] RSP: 0018:ffffc900004c7a08 EFLAGS: 00010282
[   28.190396][   T71] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   28.190741][   T71] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   28.191116][   T71] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff40be220
[   28.191478][   T71] R10: 0000000000000003 R11: ffffc900004c7580 R12: 0000000000000001
[   28.191847][   T71] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   28.192202][   T71] FS:  0000000000000000(0000) GS:ffff88809496c000(0000) knlGS:0000000000000000
[   28.192598][   T71] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   28.192905][   T71] CR2: 000056323a19b0f0 CR3: 0000000008ea1001 CR4: 0000000000772ef0
[   28.193286][   T71] PKRU: 55555554
[   28.193477][   T71] Call Trace:
[   28.193651][   T71]  <TASK>
[   28.193781][   T71]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   28.194028][   T71]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   28.194293][   T71]  ? generic_xdp_install (net/core/dev.c:11630)
[   28.194533][   T71]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   28.194784][   T71]  ? netns_get (net/core/net_namespace.c:223)
[   28.195025][   T71]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   28.195254][   T71]  cleanup_net (net/core/net_namespace.c:698)
[   28.195497][   T71]  ? net_passive_dec (net/core/net_namespace.c:660)
[   28.195730][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   28.195981][   T71]  process_one_work (kernel/workqueue.c:3268)
[   28.196229][   T71]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   28.196482][   T71]  ? assign_work (kernel/workqueue.c:1206)
[   28.196720][   T71]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   28.196966][   T71]  ? rescuer_thread (kernel/workqueue.c:3373)
[   28.197235][   T71]  kthread (kernel/kthread.c:463)
[   28.197426][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   28.197665][   T71]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   28.197907][   T71]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   28.198153][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   28.198415][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   28.198661][   T71]  ret_from_fork (arch/x86/kernel/process.c:164)
[   28.198901][   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