======================================
| [ 1214.341487][   T12] ==================================================================
| [ 1214.341799][   T12] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [ 1214.342083][   T12] Read of size 1 at addr ffff88800b7fc6ac by task kworker/u16:0/12
| [ 1214.342321][   T12]
[ 1214.342419][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 1214.342424][   T12] Workqueue: netns cleanup_net
[ 1214.342434][   T12] Call Trace:
[ 1214.342437][   T12]  <TASK>
[ 1214.342441][   T12]  dump_stack_lvl (lib/dump_stack.c:123)
[ 1214.342448][   T12]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[ 1214.342455][   T12]  ? kobject_put (lib/kobject.c:733)
[ 1214.342459][   T12]  print_report (mm/kasan/report.c:483)
[ 1214.342462][   T12]  ? kobject_put (lib/kobject.c:733)
[ 1214.342466][   T12]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[ 1214.342469][   T12]  ? kobject_put (lib/kobject.c:733)
[ 1214.342472][   T12]  kasan_report (mm/kasan/report.c:597)
[ 1214.342476][   T12]  ? kobject_put (lib/kobject.c:733)
[ 1214.342481][   T12]  kobject_put (lib/kobject.c:733)
[ 1214.342485][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[ 1214.342489][   T12]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[ 1214.342495][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[ 1214.342498][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[ 1214.342504][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[ 1214.342509][   T12]  ? netns_get (net/core/net_namespace.c:223)
[ 1214.342512][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[ 1214.342517][   T12]  cleanup_net (net/core/net_namespace.c:698)
[ 1214.342521][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[ 1214.342525][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[ 1214.342533][   T12]  process_one_work (kernel/workqueue.c:3268)
[ 1214.342542][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[ 1214.342548][   T12]  ? assign_work (kernel/workqueue.c:1206)
[ 1214.342552][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[ 1214.342557][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[ 1214.342561][   T12]  kthread (kernel/kthread.c:463)
[ 1214.342565][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[ 1214.342568][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[ 1214.342572][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[ 1214.342579][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[ 1214.342583][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[ 1214.342590][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[ 1214.342593][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[ 1214.342597][   T12]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [ 1214.362163][   T12] refcount_t: underflow; use-after-free.
| [ 1214.362375][   T12] WARNING: CPU: 3 PID: 12 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [ 1214.362726][   T12] Modules linked in: act_gact cls_flower vxlan ip6_udp_tunnel udp_tunnel bridge stp llc 8021q sch_ingress vrf veth
| [ 1214.363569][   T12] Tainted: [B]=BAD_PAGE
[ 1214.363702][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 1214.363912][   T12] Workqueue: netns cleanup_net
[ 1214.364099][   T12] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[ 1214.364318][   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 c5 89 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 c5 89 	mov    $0xffffffff89c58d60,%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
[ 1214.364957][   T12] RSP: 0000:ffffc900000c7a08 EFLAGS: 00010282
[ 1214.365169][   T12] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[ 1214.365421][   T12] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[ 1214.365697][   T12] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff14be134
[ 1214.365965][   T12] R10: 0000000000000003 R11: ffffc900000c7580 R12: 0000000000000001
[ 1214.366214][   T12] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[ 1214.366471][   T12] FS:  0000000000000000(0000) GS:ffff8880aa972000(0000) knlGS:0000000000000000
[ 1214.366803][   T12] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1214.367040][   T12] CR2: 00007fac5991fc38 CR3: 000000000fcaf003 CR4: 0000000000772ef0
[ 1214.367292][   T12] PKRU: 55555554
[ 1214.367423][   T12] Call Trace:
[ 1214.367572][   T12]  <TASK>
[ 1214.367675][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[ 1214.367861][   T12]  ? rtnl_is_locked (net/core/rtnetlink.c:169)
[ 1214.368044][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[ 1214.368210][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[ 1214.368371][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[ 1214.368560][   T12]  ? netns_get (net/core/net_namespace.c:223)
[ 1214.368729][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[ 1214.368919][   T12]  cleanup_net (net/core/net_namespace.c:698)
[ 1214.369103][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[ 1214.369263][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[ 1214.369430][   T12]  process_one_work (kernel/workqueue.c:3268)
[ 1214.369630][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[ 1214.369797][   T12]  ? assign_work (kernel/workqueue.c:1206)
[ 1214.369998][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[ 1214.370186][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[ 1214.370358][   T12]  kthread (kernel/kthread.c:463)
[ 1214.370511][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[ 1214.370694][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[ 1214.370862][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[ 1214.371034][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[ 1214.371203][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[ 1214.371362][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[ 1214.371549][   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