======================================
| xx__-> [   32.622419][   T71] ==================================================================
| [   32.622953][   T71] BUG: KASAN: slab-use-after-free in kobject_put (lib/kobject.c:733)
| [   32.623282][   T71] Read of size 1 at addr ffff888008e3c69c by task kworker/u16:1/71
| [   32.623573][   T71]
[   32.623693][   T71] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   32.623698][   T71] Workqueue: netns cleanup_net
[   32.623714][   T71] Call Trace:
[   32.623719][   T71]  <TASK>
[   32.623722][   T71]  dump_stack_lvl (lib/dump_stack.c:123)
[   32.623733][   T71]  print_address_description.constprop.0 (mm/kasan/report.c:379)
[   32.623752][   T71]  ? kobject_put (lib/kobject.c:733)
[   32.623756][   T71]  print_report (mm/kasan/report.c:483)
[   32.623759][   T71]  ? kobject_put (lib/kobject.c:733)
[   32.623762][   T71]  ? kasan_addr_to_slab (./include/linux/mm.h:1245 mm/kasan/../slab.h:191 mm/kasan/common.c:47)
[   32.623766][   T71]  ? kobject_put (lib/kobject.c:733)
[   32.623768][   T71]  kasan_report (mm/kasan/report.c:597)
[   32.623772][   T71]  ? kobject_put (lib/kobject.c:733)
[   32.623778][   T71]  kobject_put (lib/kobject.c:733)
[   32.623781][   T71]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   32.623790][   T71]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   32.623794][   T71]  ? generic_xdp_install (net/core/dev.c:11630)
[   32.623800][   T71]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   32.623805][   T71]  ? netns_get (net/core/net_namespace.c:223)
[   32.623808][   T71]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   32.623815][   T71]  cleanup_net (net/core/net_namespace.c:698)
[   32.623819][   T71]  ? net_passive_dec (net/core/net_namespace.c:660)
[   32.623823][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   32.623837][   T71]  process_one_work (kernel/workqueue.c:3268)
[   32.623851][   T71]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   32.623859][   T71]  ? assign_work (kernel/workqueue.c:1206)
[   32.623864][   T71]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   32.623870][   T71]  ? rescuer_thread (kernel/workqueue.c:3373)
[   32.623874][   T71]  kthread (kernel/kthread.c:463)
[   32.623878][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   32.623881][   T71]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   32.623895][   T71]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   32.623900][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   32.623904][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   32.623908][   T71]  ret_from_fork (arch/x86/kernel/process.c:164)
[   32.623910][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   32.623914][   T71]  ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
| [   32.644991][   T71] refcount_t: underflow; use-after-free.
| [   32.645579][   T71] WARNING: CPU: 3 PID: 71 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
| [   32.645969][   T71] Modules linked in:
| [   32.646589][   T71] Tainted: [B]=BAD_PAGE
[   32.646749][   T71] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   32.647007][   T71] Workqueue: netns cleanup_net
[   32.647234][   T71] RIP: 0010:refcount_warn_saturate (lib/refcount.c:28 (discriminator 3))
[   32.647474][   T71] 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 85 a8 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 85 a8 	mov    $0xffffffffa8858d60,%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
[   32.648182][   T71] RSP: 0018:ffffc900004c7a08 EFLAGS: 00010282
[   32.648441][   T71] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   32.648739][   T71] RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000001
[   32.649054][   T71] RBP: 0000000000000003 R08: 0000000000000000 R09: fffffbfff5242934
[   32.649350][   T71] R10: 0000000000000003 R11: ffffc900004c7580 R12: 0000000000000001
[   32.649649][   T71] R13: dffffc0000000000 R14: dead000000000122 R15: dead000000000100
[   32.649955][   T71] FS:  0000000000000000(0000) GS:ffff88808bd04000(0000) knlGS:0000000000000000
[   32.650304][   T71] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   32.650547][   T71] CR2: 0000563d8b3ea6a8 CR3: 0000000004fd2005 CR4: 0000000000772ef0
[   32.650869][   T71] PKRU: 55555554
[   32.651020][   T71] Call Trace:
[   32.651174][   T71]  <TASK>
[   32.651284][   T71]  netdev_run_todo (./include/linux/list.h:381 net/core/dev.c:11670)
[   32.651486][   T71]  ? dev_ingress_queue_create (net/core/dev.c:12299)
[   32.651680][   T71]  ? generic_xdp_install (net/core/dev.c:11630)
[   32.651889][   T71]  ops_undo_list (net/core/net_namespace.c:190 net/core/net_namespace.c:248)
[   32.652089][   T71]  ? netns_get (net/core/net_namespace.c:223)
[   32.652285][   T71]  ? cleanup_net (./include/linux/list.h:191 net/core/net_namespace.c:693)
[   32.652469][   T71]  cleanup_net (net/core/net_namespace.c:698)
[   32.652670][   T71]  ? net_passive_dec (net/core/net_namespace.c:660)
[   32.652900][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   32.653101][   T71]  process_one_work (kernel/workqueue.c:3268)
[   32.653305][   T71]  ? pwq_dec_nr_in_flight (kernel/workqueue.c:3165)
[   32.653491][   T71]  ? assign_work (kernel/workqueue.c:1206)
[   32.653683][   T71]  worker_thread (kernel/workqueue.c:3340 kernel/workqueue.c:3427)
[   32.653900][   T71]  ? rescuer_thread (kernel/workqueue.c:3373)
[   32.654097][   T71]  kthread (kernel/kthread.c:463)
[   32.654254][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   32.654440][   T71]  ? ret_from_fork (arch/x86/kernel/process.c:157)
[   32.654634][   T71]  ? __lock_release (kernel/locking/lockdep.c:5536)
[   32.654836][   T71]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   32.655044][   T71]  ? kthread_is_per_cpu (kernel/kthread.c:412)
[   32.655236][   T71]  ret_from_fork (arch/x86/kernel/process.c:164)
[   32.655426][   T71]  ? 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