======================================
| [   28.497070][   T12] ==================================================================
| [   28.497445][   T12] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   28.497768][   T12] Read of size 1 at addr ffff88800906469c by task kworker/u16:0/12
| [   28.498067][   T12]
[   28.498202][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   28.498206][   T12] Workqueue: netns cleanup_net
[   28.498223][   T12] Call Trace:
[   28.498227][   T12]  <TASK>
[   28.498230][   T12]  dump_stack_lvl (lib/dump_stack.c:123)
[   28.498243][   T12]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   28.498256][   T12]  ? kobject_put (lib/kobject.c:733)
[   28.498260][   T12]  print_report (mm/kasan/report.c:483)
[   28.498263][   T12]  ? kobject_put (lib/kobject.c:733)
[   28.498266][   T12]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   28.498270][   T12]  ? kobject_put (lib/kobject.c:733)
[   28.498273][   T12]  kasan_report (mm/kasan/report.c:597)
[   28.498277][   T12]  ? kobject_put (lib/kobject.c:733)
[   28.498282][   T12]  kobject_put (lib/kobject.c:733)
[   28.498285][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   28.498291][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   28.498295][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   28.498301][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   28.498306][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   28.498309][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   28.498314][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   28.498318][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   28.498322][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   28.498337][   T12]  process_one_work (kernel/workqueue.c:3268)
[   28.498355][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   28.498361][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   28.498366][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   28.498372][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   28.498375][   T12]  kthread (kernel/kthread.c:463)
[   28.498380][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   28.498383][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   28.498391][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   28.498399][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   28.498402][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   28.498406][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   28.498409][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   28.498412][   T12]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   28.524590][   T12] refcount_t: underflow; use-after-free.
| [   28.524893][   T12] WARNING: CPU: 0 PID: 12 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   28.525341][   T12] Modules linked in:
| [   28.525931][   T12] Tainted: [B]=BAD_PAGE
[   28.526131][   T12] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   28.526516][   T12] Workqueue: netns cleanup_net
[   28.526832][   T12] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   28.527204][   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 9d 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 9d 	mov    $0xffffffff9da58d60,%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
[   28.528345][   T12] RSP: 0018:ffffc900000c7a08 EFLAGS: 00010282
[   28.528718][   T12] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   28.529149][   T12] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   28.529528][   T12] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff3c82934
[   28.529957][   T12] R10: 0000000000000003 R11: ffffc900000c7580 R12: 0000000000000001
[   28.530362][   T12] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   28.530812][   T12] FS:  0000000000000000(0000) GS:ffff888096984000(0000) knlGS:0000000000000000
[   28.531299][   T12] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   28.531697][   T12] CR2: 00007fca2564d000 CR3: 0000000023f59002 CR4: 0000000000772ef0
[   28.532083][   T12] PKRU: 55555554
[   28.532318][   T12] Call Trace:
[   28.532536][   T12]  <TASK>
[   28.532667][   T12]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   28.532927][   T12]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   28.533219][   T12]  ? generic_xdp_install (net/core/dev.c:11630)
[   28.533475][   T12]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   28.533742][   T12]  ? netns_get (net/core/net_namespace.c:223)
[   28.534040][   T12]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   28.534309][   T12]  cleanup_net (net/core/net_namespace.c:698)
[   28.534568][   T12]  ? net_passive_dec (net/core/net_namespace.c:660)
[   28.534860][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   28.535116][   T12]  process_one_work (kernel/workqueue.c:3268)
[   28.535399][   T12]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   28.535668][   T12]  ? assign_work (kernel/workqueue.c:1206)
[   28.535949][   T12]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   28.536260][   T12]  ? rescuer_thread (kernel/workqueue.c:3373)
[   28.536532][   T12]  kthread (kernel/kthread.c:463)
[   28.536770][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   28.537016][   T12]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   28.537281][   T12]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   28.537581][   T12]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   28.537886][   T12]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   28.538125][   T12]  ret_from_fork (arch/x86/kernel/process.c:164)
[   28.538410][   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