======================================
| [   27.948890][  T240] ==================================================================
| [   27.949229][  T240] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   27.949602][  T240] Read of size 1 at addr ffff888001e9c69c by task kworker/u16:2/240
| [   27.949883][  T240]
[   27.949981][  T240] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   27.949985][  T240] Workqueue: netns cleanup_net
[   27.949994][  T240] Call Trace:
[   27.949997][  T240]  <TASK>
[   27.949999][  T240]  dump_stack_lvl (lib/dump_stack.c:123)
[   27.950006][  T240]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   27.950018][  T240]  ? kobject_put (lib/kobject.c:733)
[   27.950023][  T240]  print_report (mm/kasan/report.c:483)
[   27.950025][  T240]  ? kobject_put (lib/kobject.c:733)
[   27.950028][  T240]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   27.950031][  T240]  ? kobject_put (lib/kobject.c:733)
[   27.950034][  T240]  kasan_report (mm/kasan/report.c:597)
[   27.950037][  T240]  ? kobject_put (lib/kobject.c:733)
[   27.950042][  T240]  kobject_put (lib/kobject.c:733)
[   27.950045][  T240]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   27.950051][  T240]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   27.950054][  T240]  ? generic_xdp_install (net/core/dev.c:11630)
[   27.950057][  T240]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   27.950064][  T240]  ? bond_net_exit_rtnl (./include/linux/rcupdate.h:341 ./include/linux/rcupdate.h:897 ./include/net/netns/generic.h:48 drivers/net/bonding/bond_main.c:6462)
[   27.950073][  T240]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   27.950078][  T240]  ? netns_get (net/core/net_namespace.c:223)
[   27.950081][  T240]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   27.950086][  T240]  cleanup_net (net/core/net_namespace.c:698)
[   27.950090][  T240]  ? net_passive_dec (net/core/net_namespace.c:660)
[   27.950095][  T240]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   27.950102][  T240]  process_one_work (kernel/workqueue.c:3268)
[   27.950110][  T240]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   27.950116][  T240]  ? assign_work (kernel/workqueue.c:1206)
[   27.950120][  T240]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   27.950126][  T240]  ? rescuer_thread (kernel/workqueue.c:3373)
[   27.950129][  T240]  kthread (kernel/kthread.c:463)
[   27.950134][  T240]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   27.950137][  T240]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   27.950144][  T240]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   27.950148][  T240]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   27.950150][  T240]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   27.950154][  T240]  ret_from_fork (arch/x86/kernel/process.c:164)
[   27.950157][  T240]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   27.950160][  T240]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   27.971093][  T240] refcount_t: underflow; use-after-free.
| [   27.971294][  T240] WARNING: CPU: 3 PID: 240 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   27.971629][  T240] Modules linked in:
| [   27.972143][  T240] Tainted: [B]=BAD_PAGE
[   27.972273][  T240] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   27.972498][  T240] Workqueue: netns cleanup_net
[   27.972925][  T240] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   27.973128][  T240] Code: a2 b5 02 80 fb 01 0f 87 db 6e d8 fe 83 e3 01 0f 85 51 ff ff ff c6 05 c2 a2 b5 02 01 90 48 c7 c7 60 a8 45 91 e8 72 c3 17 ff 90 <0f> 0b 90 90 e9 33 ff ff ff 48 89 df e8 20 69 a0 ff e9 ba fe ff ff
All code
========
   0:	a2 b5 02 80 fb 01 0f 	movabs %al,0xdb870f01fb8002b5
   7:	87 db 
   9:	6e                   	outsb  %ds:(%rsi),(%dx)
   a:	d8 fe                	fdivr  %st(6),%st
   c:	83 e3 01             	and    $0x1,%ebx
   f:	0f 85 51 ff ff ff    	jne    0xffffffffffffff66
  15:	c6 05 c2 a2 b5 02 01 	movb   $0x1,0x2b5a2c2(%rip)        # 0x2b5a2de
  1c:	90                   	nop
  1d:	48 c7 c7 60 a8 45 91 	mov    $0xffffffff9145a860,%rdi
  24:	e8 72 c3 17 ff       	call   0xffffffffff17c39b
  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 20 69 a0 ff       	call   0xffffffffffa0695b
  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 20 69 a0 ff       	call   0xffffffffffa06931
  11:	e9 ba fe ff ff       	jmp    0xfffffffffffffed0
[   27.973708][  T240] RSP: 0018:ffffc90000a97a08 EFLAGS: 00010282
[   27.973898][  T240] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   27.974139][  T240] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   27.974374][  T240] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff23be134
[   27.974596][  T240] R10: 0000000000000003 R11: ffffc90000a97580 R12: 0000000000000001
[   27.974869][  T240] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   27.975110][  T240] FS:  0000000000000000(0000) GS:ffff8880a3101000(0000) knlGS:0000000000000000
[   27.975384][  T240] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   27.975622][  T240] CR2: 000055c824f66dec CR3: 0000000008987004 CR4: 0000000000772ef0
[   27.975854][  T240] PKRU: 55555554
[   27.975970][  T240] Call Trace:
[   27.976086][  T240]  <TASK>
[   27.976172][  T240]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   27.976334][  T240]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   27.976492][  T240]  ? generic_xdp_install (net/core/dev.c:11630)
[   27.976672][  T240]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   27.976852][  T240]  ? bond_net_exit_rtnl (./include/linux/rcupdate.h:341 ./include/linux/rcupdate.h:897 ./include/net/netns/generic.h:48 drivers/net/bonding/bond_main.c:6462)
[   27.977020][  T240]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   27.977180][  T240]  ? netns_get (net/core/net_namespace.c:223)
[   27.977338][  T240]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   27.977499][  T240]  cleanup_net (net/core/net_namespace.c:698)
[   27.977675][  T240]  ? net_passive_dec (net/core/net_namespace.c:660)
[   27.977835][  T240]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   27.977995][  T240]  process_one_work (kernel/workqueue.c:3268)
[   27.978152][  T240]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   27.978306][  T240]  ? assign_work (kernel/workqueue.c:1206)
[   27.978458][  T240]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   27.978617][  T240]  ? rescuer_thread (kernel/workqueue.c:3373)
[   27.978768][  T240]  kthread (kernel/kthread.c:463)
[   27.978885][  T240]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   27.979046][  T240]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   27.979219][  T240]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   27.979376][  T240]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   27.979543][  T240]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   27.979704][  T240]  ret_from_fork (arch/x86/kernel/process.c:164)
[   27.979858][  T240]  ? 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