======================================
| [  644.998462][   T11] ==================================================================
| [ 644.998988][ T11] BUG: KASAN: slab-use-after-free in vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
| [  644.999523][   T11] Read of size 8 at addr ffff888004bf8bf0 by task kworker/u8:0/11
| [  644.999932][   T11]
[  645.000489][   T11] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  645.001142][   T11] Workqueue: netns cleanup_net
[  645.001411][   T11] Call Trace:
[  645.001598][   T11]  <TASK>
[ 645.001756][ T11] dump_stack_lvl (lib/dump_stack.c:107) 
[ 645.002007][ T11] print_address_description.constprop.0 (mm/kasan/report.c:378) 
[ 645.002363][ T11] ? vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 645.002706][ T11] print_report (mm/kasan/report.c:489) 
[ 645.002948][ T11] ? kasan_addr_to_slab (./arch/x86/include/asm/bitops.h:206 ./arch/x86/include/asm/bitops.h:238 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 ./include/linux/page-flags.h:481 mm/kasan/../slab.h:206 mm/kasan/common.c:38) 
[ 645.003216][ T11] kasan_report (mm/kasan/report.c:603) 
[ 645.003454][ T11] ? vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 645.003811][ T11] vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 645.004146][ T11] ? __pfx_vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4631) vxlan
[ 645.004509][ T11] ? nft_offload_netdev_event (net/netfilter/nf_tables_offload.c:677) nf_tables
[ 645.004964][ T11] ? mirred_device_event (./include/linux/spinlock.h:392 net/sched/act_mirred.c:543) act_mirred
[ 645.005372][ T11] notifier_call_chain (kernel/notifier.c:93) 
[ 645.005650][ T11] unregister_netdevice_many_notify (net/core/dev.c:11095) 
[ 645.006040][ T11] ? mutex_is_locked (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2569 ./include/linux/atomic/atomic-long.h:38 ./include/linux/atomic/atomic-instrumented.h:3161 kernel/locking/mutex.c:81 kernel/locking/mutex.c:91) 
[ 645.006337][ T11] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11035) 
[ 645.006742][ T11] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11019) 
[ 645.007122][ T11] default_device_exit_batch (net/core/dev.c:11629) 
[ 645.007450][ T11] ? __pfx_default_device_exit_batch (net/core/dev.c:11604) 
[ 645.007798][ T11] ? mutex_is_locked (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2569 ./include/linux/atomic/atomic-long.h:38 ./include/linux/atomic/atomic-instrumented.h:3161 kernel/locking/mutex.c:81 kernel/locking/mutex.c:91) 
[ 645.008115][ T11] ? nexthop_net_exit_batch_rtnl (net/ipv4/nexthop.c:569 net/ipv4/nexthop.c:1918 net/ipv4/nexthop.c:2426 net/ipv4/nexthop.c:3754) 
[ 645.008491][ T11] cleanup_net (net/core/net_namespace.c:636 (discriminator 3)) 
[ 645.008767][ T11] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 645.009084][ T11] ? __pfx_cleanup_net (net/core/net_namespace.c:581) 
[ 645.009400][ T11] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5725) 
[ 645.009651][ T11] ? process_one_work (kernel/workqueue.c:2609) 
[ 645.009969][ T11] process_one_work (kernel/workqueue.c:2633) 
[ 645.010261][ T11] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228) 
[ 645.010495][ T11] ? __pfx_process_one_work (kernel/workqueue.c:2542) 
[ 645.010795][ T11] ? assign_work (kernel/workqueue.c:1101) 
[ 645.011066][ T11] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[ 645.011358][ T11] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 645.011622][ T11] kthread (kernel/kthread.c:388) 
[ 645.011863][ T11] ? __pfx_kthread (kernel/kthread.c:341) 
[ 645.012122][ T11] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 645.012354][ T11] ? __pfx_kthread (kernel/kthread.c:341) 
[ 645.012624][ T11] ret_from_fork_asm (arch/x86/entry/entry_64.S:250) 
| [  645.032588][   T11] ==================================================================
| [  645.033906][   T11] Disabling lock debugging due to kernel taint
| [  645.034317][   T11] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI
| [  645.035004][   T11] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
[  645.036092][   T11] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  645.036809][   T11] Workqueue: netns cleanup_net
[ 645.037103][ T11] RIP: 0010:vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 645.037507][ T11] Code: 00 00 00 48 b9 00 00 00 00 00 fc ff df 49 89 c0 48 89 44 24 08 49 c1 e8 03 4d 8d 24 08 eb 2c 48 8d 53 30 48 89 d0 48 c1 e8 03 <80> 3c 08 00 0f 85 e0 00 00 00 48 8b 43 30 49 89 dd 48 83 e8 30 49
All code
========
   0:	00 00                	add    %al,(%rax)
   2:	00 48 b9             	add    %cl,-0x47(%rax)
   5:	00 00                	add    %al,(%rax)
   7:	00 00                	add    %al,(%rax)
   9:	00 fc                	add    %bh,%ah
   b:	ff                   	(bad)
   c:	df 49 89             	fisttps -0x77(%rcx)
   f:	c0 48 89 44          	rorb   $0x44,-0x77(%rax)
  13:	24 08                	and    $0x8,%al
  15:	49 c1 e8 03          	shr    $0x3,%r8
  19:	4d 8d 24 08          	lea    (%r8,%rcx,1),%r12
  1d:	eb 2c                	jmp    0x4b
  1f:	48 8d 53 30          	lea    0x30(%rbx),%rdx
  23:	48 89 d0             	mov    %rdx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
  2a:*	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1)		<-- trapping instruction
  2e:	0f 85 e0 00 00 00    	jne    0x114
  34:	48 8b 43 30          	mov    0x30(%rbx),%rax
  38:	49 89 dd             	mov    %rbx,%r13
  3b:	48 83 e8 30          	sub    $0x30,%rax
  3f:	49                   	rex.WB

Code starting with the faulting instruction
===========================================
   0:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1)
   4:	0f 85 e0 00 00 00    	jne    0xea
   a:	48 8b 43 30          	mov    0x30(%rbx),%rax
   e:	49 89 dd             	mov    %rbx,%r13
  11:	48 83 e8 30          	sub    $0x30,%rax
  15:	49                   	rex.WB
[  645.038663][   T11] RSP: 0018:ffffc900000bf980 EFLAGS: 00010246
[  645.039027][   T11] RAX: 0000000000000000 RBX: ffffffffffffffd1 RCX: dffffc0000000000
[  645.039493][   T11] RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff888004bf8c44
[  645.039950][   T11] RBP: 1ffff92000017f33 R08: 1ffff1100160321a R09: ffffc900000bf9b8
[  645.040423][   T11] R10: ffffffffa9034a07 R11: 205d313154202020 R12: ffffed100160321a
[  645.040898][   T11] R13: ffff888004bf8bc0 R14: ffff888009d81000 R15: ffff88800b019000
[  645.041370][   T11] FS:  0000000000000000(0000) GS:ffff88802ea00000(0000) knlGS:0000000000000000
[  645.041926][   T11] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  645.042283][   T11] CR2: 00007f563e468000 CR3: 000000003c134001 CR4: 0000000000770ef0
[  645.042718][   T11] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  645.043142][   T11] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  645.043584][   T11] PKRU: 55555554
[  645.043783][   T11] Call Trace:
[  645.043957][   T11]  <TASK>
[ 645.044127][ T11] ? die_addr (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:460) 
[ 645.044358][ T11] ? exc_general_protection (arch/x86/kernel/traps.c:701 arch/x86/kernel/traps.c:643) 
[ 645.044667][ T11] ? asm_exc_general_protection (./arch/x86/include/asm/idtentry.h:564) 
[ 645.044989][ T11] ? vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 645.045325][ T11] ? __pfx_vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4631) vxlan
[ 645.045673][ T11] ? nft_offload_netdev_event (net/netfilter/nf_tables_offload.c:677) nf_tables
[ 645.046067][ T11] ? mirred_device_event (./include/linux/spinlock.h:392 net/sched/act_mirred.c:543) act_mirred
[ 645.046433][ T11] notifier_call_chain (kernel/notifier.c:93) 
[ 645.046771][ T11] unregister_netdevice_many_notify (net/core/dev.c:11095) 
[ 645.047176][ T11] ? mutex_is_locked (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2569 ./include/linux/atomic/atomic-long.h:38 ./include/linux/atomic/atomic-instrumented.h:3161 kernel/locking/mutex.c:81 kernel/locking/mutex.c:91) 
[ 645.047456][ T11] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11035) 
[ 645.047838][ T11] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11019) 
[ 645.048192][ T11] default_device_exit_batch (net/core/dev.c:11629) 
[ 645.048511][ T11] ? __pfx_default_device_exit_batch (net/core/dev.c:11604) 
[ 645.048903][ T11] ? mutex_is_locked (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2569 ./include/linux/atomic/atomic-long.h:38 ./include/linux/atomic/atomic-instrumented.h:3161 kernel/locking/mutex.c:81 kernel/locking/mutex.c:91) 
[ 645.049182][ T11] ? nexthop_net_exit_batch_rtnl (net/ipv4/nexthop.c:569 net/ipv4/nexthop.c:1918 net/ipv4/nexthop.c:2426 net/ipv4/nexthop.c:3754) 
[ 645.049488][ T11] cleanup_net (net/core/net_namespace.c:636 (discriminator 3)) 
[ 645.049722][ T11] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 645.050011][ T11] ? __pfx_cleanup_net (net/core/net_namespace.c:581) 
[ 645.050268][ T11] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5725) 
[ 645.050512][ T11] ? process_one_work (kernel/workqueue.c:2609) 
[ 645.050781][ T11] process_one_work (kernel/workqueue.c:2633) 
[ 645.051040][ T11] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:228) 
[ 645.051274][ T11] ? __pfx_process_one_work (kernel/workqueue.c:2542) 
[ 645.051552][ T11] ? assign_work (kernel/workqueue.c:1101) 
[ 645.051789][ T11] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[ 645.052035][ T11] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 645.052344][ T11] kthread (kernel/kthread.c:388) 
[ 645.052594][ T11] ? __pfx_kthread (kernel/kthread.c:341) 
[ 645.052862][ T11] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 645.053129][ T11] ? __pfx_kthread (kernel/kthread.c:341) 


Finger prints:
dump_stack_lvl:print_report:kasan_report:vxlan_netdevice_event
vxlan_netdevice_event:notifier_call_chain:unregister_netdevice_many_notify:default_device_exit_batch