======================================
| [ 3848.255108][   T11] ==================================================================
| [ 3848.255604][ 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
| [ 3848.256106][   T11] Read of size 8 at addr ffff888009598bd0 by task kworker/u8:0/11
| [ 3848.256503][   T11]
[ 3848.257034][   T11] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 3848.257697][   T11] Workqueue: netns cleanup_net
[ 3848.257954][   T11] Call Trace:
[ 3848.258139][   T11]  <TASK>
[ 3848.258314][ T11] dump_stack_lvl (lib/dump_stack.c:107) 
[ 3848.258553][ T11] print_address_description.constprop.0 (mm/kasan/report.c:378) 
[ 3848.258922][ T11] ? vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 3848.259249][ T11] print_report (mm/kasan/report.c:489) 
[ 3848.259493][ 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) 
[ 3848.259783][ T11] kasan_report (mm/kasan/report.c:603) 
[ 3848.260063][ T11] ? vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 3848.260389][ T11] vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 3848.260751][ T11] ? __pfx_vlan_device_event (net/8021q/vlan.c:362) 8021q
[ 3848.261117][ T11] ? __pfx_vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4631) vxlan
[ 3848.261498][ T11] ? netconsole_netdev_event (drivers/net/netconsole.c:991) 
[ 3848.261835][ T11] notifier_call_chain (kernel/notifier.c:93) 
[ 3848.262151][ T11] unregister_netdevice_many_notify (net/core/dev.c:11095) 
[ 3848.262489][ 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) 
[ 3848.262753][ T11] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11035) 
[ 3848.263098][ T11] ? vrf_dellink (drivers/net/vrf.c:1708) vrf
[ 3848.263408][ T11] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11019) 
[ 3848.263756][ T11] default_device_exit_batch (net/core/dev.c:11629) 
[ 3848.264074][ T11] ? __pfx_default_device_exit_batch (net/core/dev.c:11604) 
[ 3848.264417][ 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) 
[ 3848.264726][ 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) 
[ 3848.265073][ T11] cleanup_net (net/core/net_namespace.c:636 (discriminator 3)) 
[ 3848.265301][ T11] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 3848.265592][ T11] ? __pfx_cleanup_net (net/core/net_namespace.c:581) 
[ 3848.265846][ T11] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5725) 
[ 3848.266085][ T11] ? process_one_work (kernel/workqueue.c:2609) 
[ 3848.266350][ T11] process_one_work (kernel/workqueue.c:2633) 
[ 3848.266605][ 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) 
[ 3848.266840][ T11] ? __pfx_process_one_work (kernel/workqueue.c:2542) 
[ 3848.267116][ T11] ? assign_work (kernel/workqueue.c:1101) 
[ 3848.267364][ T11] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[ 3848.267608][ T11] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 3848.267870][ T11] kthread (kernel/kthread.c:388) 
[ 3848.268079][ T11] ? __pfx_kthread (kernel/kthread.c:341) 
[ 3848.268317][ T11] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 3848.268545][ T11] ? __pfx_kthread (kernel/kthread.c:341) 
[ 3848.268782][ T11] ret_from_fork_asm (arch/x86/entry/entry_64.S:250) 
| [ 3848.288230][   T11] ==================================================================
| [ 3848.288733][   T11] Disabling lock debugging due to kernel taint
| [ 3848.289078][   T11] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI
| [ 3848.289733][   T11] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
[ 3848.290745][   T11] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 3848.291407][   T11] Workqueue: netns cleanup_net
[ 3848.291695][ T11] RIP: 0010:vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 3848.292050][ 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
[ 3848.293103][   T11] RSP: 0018:ffffc900000bf980 EFLAGS: 00010246
[ 3848.293439][   T11] RAX: 0000000000000000 RBX: ffffffffffffffd0 RCX: dffffc0000000000
[ 3848.293867][   T11] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff888009598c24
[ 3848.294289][   T11] RBP: 1ffff92000017f33 R08: 1ffff110015eb21a R09: ffffc900000bf9b8
[ 3848.294732][   T11] R10: ffffffff9853ca07 R11: 205d313154202020 R12: ffffed10015eb21a
[ 3848.295164][   T11] R13: ffff888009598ba0 R14: ffff888007144000 R15: ffff88800af59000
[ 3848.295619][   T11] FS:  0000000000000000(0000) GS:ffff88802ec00000(0000) knlGS:0000000000000000
[ 3848.296135][   T11] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3848.296509][   T11] CR2: 00005628dc3ce828 CR3: 000000000957e003 CR4: 0000000000770ef0
[ 3848.296942][   T11] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 3848.297374][   T11] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 3848.297851][   T11] PKRU: 55555554
[ 3848.298086][   T11] Call Trace:
[ 3848.298256][   T11]  <TASK>
[ 3848.298464][ T11] ? die_addr (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:460) 
[ 3848.298712][ T11] ? exc_general_protection (arch/x86/kernel/traps.c:701 arch/x86/kernel/traps.c:643) 
[ 3848.299046][ T11] ? asm_exc_general_protection (./arch/x86/include/asm/idtentry.h:564) 
[ 3848.299405][ T11] ? vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 3848.299754][ T11] ? __pfx_vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4631) vxlan
[ 3848.300124][ T11] ? netconsole_netdev_event (drivers/net/netconsole.c:991) 
[ 3848.300410][ T11] notifier_call_chain (kernel/notifier.c:93) 
[ 3848.300679][ T11] unregister_netdevice_many_notify (net/core/dev.c:11095) 
[ 3848.301003][ 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) 
[ 3848.301249][ T11] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11035) 
[ 3848.301589][ T11] ? vrf_dellink (drivers/net/vrf.c:1708) vrf
[ 3848.301854][ T11] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11019) 
[ 3848.302175][ T11] default_device_exit_batch (net/core/dev.c:11629) 
[ 3848.302463][ T11] ? __pfx_default_device_exit_batch (net/core/dev.c:11604) 
[ 3848.302777][ 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) 
[ 3848.303020][ 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) 
[ 3848.303346][ T11] cleanup_net (net/core/net_namespace.c:636 (discriminator 3)) 
[ 3848.303617][ T11] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 3848.303924][ T11] ? __pfx_cleanup_net (net/core/net_namespace.c:581) 
[ 3848.304209][ T11] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5725) 
[ 3848.304470][ T11] ? process_one_work (kernel/workqueue.c:2609) 
[ 3848.304765][ T11] process_one_work (kernel/workqueue.c:2633) 
[ 3848.305043][ 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) 
[ 3848.305307][ T11] ? __pfx_process_one_work (kernel/workqueue.c:2542) 
[ 3848.305606][ T11] ? assign_work (kernel/workqueue.c:1101) 
[ 3848.305863][ T11] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[ 3848.306106][ T11] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 3848.306421][ T11] kthread (kernel/kthread.c:388) 
[ 3848.306643][ T11] ? __pfx_kthread (kernel/kthread.c:341) 
[ 3848.306904][ T11] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 3848.307161][ 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