======================================
| xx__-> [  126.419426][   T69] ==================================================================
| [  126.419853][   T69] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [  126.420255][   T69] Read of size 1 at addr ffff8880049bc69c by task kworker/u16:1/69
| [  126.420629][   T69]
[  126.420776][   T69] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  126.420782][   T69] Workqueue: netns cleanup_net
[  126.420793][   T69] Call Trace:
[  126.420796][   T69]  <TASK>
[  126.420800][   T69]  dump_stack_lvl (lib/dump_stack.c:123)
[  126.420809][   T69]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[  126.420820][   T69]  ? kobject_put (lib/kobject.c:733)
[  126.420826][   T69]  print_report (mm/kasan/report.c:483)
[  126.420832][   T69]  ? kobject_put (lib/kobject.c:733)
[  126.420837][   T69]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[  126.420843][   T69]  ? kobject_put (lib/kobject.c:733)
[  126.420848][   T69]  kasan_report (mm/kasan/report.c:597)
[  126.420855][   T69]  ? kobject_put (lib/kobject.c:733)
[  126.420864][   T69]  kobject_put (lib/kobject.c:733)
[  126.420870][   T69]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[  126.420879][   T69]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[  126.420885][   T69]  ? generic_xdp_install (net/core/dev.c:11630)
[  126.420897][   T69]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[  126.420906][   T69]  ? netns_get (net/core/net_namespace.c:223)
[  126.420911][   T69]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[  126.420921][   T69]  cleanup_net (net/core/net_namespace.c:698)
[  126.420928][   T69]  ? net_passive_dec (net/core/net_namespace.c:660)
[  126.420936][   T69]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  126.420947][   T69]  process_one_work (kernel/workqueue.c:3268)
[  126.420961][   T69]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[  126.420972][   T69]  ? assign_work (kernel/workqueue.c:1206)
[  126.420980][   T69]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[  126.420992][   T69]  ? rescuer_thread (kernel/workqueue.c:3373)
[  126.420999][   T69]  kthread (kernel/kthread.c:463)
[  126.421005][   T69]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  126.421010][   T69]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[  126.421016][   T69]  ? __lock_release (kernel/locking/lockdep.c:5536)
[  126.421023][   T69]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  126.421029][   T69]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  126.421036][   T69]  ret_from_fork (arch/x86/kernel/process.c:164)
[  126.421040][   T69]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  126.421046][   T69]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [  126.442773][   T69] refcount_t: underflow; use-after-free.
| [  126.443101][   T69] WARNING: CPU: 2 PID: 69 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [  126.443654][   T69] Modules linked in:
| [  126.444595][   T69] Tainted: [B]=BAD_PAGE
[  126.444852][   T69] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  126.445209][   T69] Workqueue: netns cleanup_net
[  126.445421][   T69] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[  126.445681][   T69] 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 25 bc 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 25 bc 	mov    $0xffffffffbc258d60,%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
[  126.446382][   T69] RSP: 0018:ffffc900004a7a08 EFLAGS: 00010282
[  126.446626][   T69] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[  126.446904][   T69] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[  126.447190][   T69] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff7982934
[  126.447469][   T69] R10: 0000000000000003 R11: ffffc900004a7580 R12: 0000000000000001
[  126.447731][   T69] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[  126.448009][   T69] FS:  0000000000000000(0000) GS:ffff888078284000(0000) knlGS:0000000000000000
[  126.448321][   T69] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  126.448556][   T69] CR2: 00007f9d70187000 CR3: 000000000b159002 CR4: 0000000000772ef0
[  126.448824][   T69] PKRU: 55555554
[  126.448980][   T69] Call Trace:
[  126.449125][   T69]  <TASK>
[  126.449238][   T69]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[  126.449451][   T69]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[  126.449636][   T69]  ? generic_xdp_install (net/core/dev.c:11630)
[  126.449818][   T69]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[  126.450057][   T69]  ? netns_get (net/core/net_namespace.c:223)
[  126.450245][   T69]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[  126.450430][   T69]  cleanup_net (net/core/net_namespace.c:698)
[  126.450620][   T69]  ? net_passive_dec (net/core/net_namespace.c:660)
[  126.450802][   T69]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  126.451003][   T69]  process_one_work (kernel/workqueue.c:3268)
[  126.451199][   T69]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[  126.451375][   T69]  ? assign_work (kernel/workqueue.c:1206)
[  126.451572][   T69]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[  126.451752][   T69]  ? rescuer_thread (kernel/workqueue.c:3373)
[  126.451937][   T69]  kthread (kernel/kthread.c:463)
[  126.452078][   T69]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  126.452258][   T69]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[  126.452453][   T69]  ? __lock_release (kernel/locking/lockdep.c:5536)
[  126.452653][   T69]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[  126.452834][   T69]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[  126.453022][   T69]  ret_from_fork (arch/x86/kernel/process.c:164)
[  126.453205][   T69]  ? 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