======================================
| [ 3966.423835][   T71] ==================================================================
| [ 3966.424319][ T71] 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
| [ 3966.424792][   T71] Read of size 8 at addr ffff88800ac48bd0 by task kworker/u8:1/71
| [ 3966.425182][   T71]
[ 3966.425706][   T71] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 3966.426322][   T71] Workqueue: netns cleanup_net
[ 3966.426577][   T71] Call Trace:
[ 3966.426746][   T71]  <TASK>
[ 3966.426902][ T71] dump_stack_lvl (lib/dump_stack.c:107) 
[ 3966.427135][ T71] print_address_description.constprop.0 (mm/kasan/report.c:378) 
[ 3966.427505][ T71] ? vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 3966.427825][ T71] print_report (mm/kasan/report.c:489) 
[ 3966.428052][ T71] ? 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) 
[ 3966.428307][ T71] kasan_report (mm/kasan/report.c:603) 
[ 3966.428525][ T71] ? vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 3966.428849][ T71] vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 3966.429162][ T71] ? __pfx_vlan_device_event (net/8021q/vlan.c:362) 8021q
[ 3966.429482][ T71] ? __pfx_vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4631) vxlan
[ 3966.429820][ T71] ? netconsole_netdev_event (drivers/net/netconsole.c:991) 
[ 3966.430108][ T71] notifier_call_chain (kernel/notifier.c:93) 
[ 3966.430369][ T71] unregister_netdevice_many_notify (net/core/dev.c:11095) 
[ 3966.430693][ T71] ? 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) 
[ 3966.430937][ T71] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11035) 
[ 3966.431278][ T71] ? vrf_dellink (drivers/net/vrf.c:1708) vrf
[ 3966.431545][ T71] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11019) 
[ 3966.431862][ T71] default_device_exit_batch (net/core/dev.c:11629) 
[ 3966.432144][ T71] ? __pfx_default_device_exit_batch (net/core/dev.c:11604) 
[ 3966.432454][ T71] ? 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) 
[ 3966.432697][ T71] ? 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) 
[ 3966.432997][ T71] cleanup_net (net/core/net_namespace.c:636 (discriminator 3)) 
[ 3966.433222][ T71] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 3966.433515][ T71] ? __pfx_cleanup_net (net/core/net_namespace.c:581) 
[ 3966.433763][ T71] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5725) 
[ 3966.434000][ T71] ? process_one_work (kernel/workqueue.c:2609) 
[ 3966.434261][ T71] process_one_work (kernel/workqueue.c:2633) 
[ 3966.434513][ T71] ? 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) 
[ 3966.434744][ T71] ? __pfx_process_one_work (kernel/workqueue.c:2542) 
[ 3966.435017][ T71] ? assign_work (kernel/workqueue.c:1101) 
[ 3966.435253][ T71] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[ 3966.435491][ T71] ? lockdep_hardirqs_on_prepare.part.0 (kernel/locking/lockdep.c:4300 kernel/locking/lockdep.c:4359) 
[ 3966.435821][ T71] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 3966.436081][ T71] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 3966.436339][ T71] kthread (kernel/kthread.c:388) 
[ 3966.436544][ T71] ? __pfx_kthread (kernel/kthread.c:341) 
[ 3966.436779][ T71] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 3966.437003][ T71] ? __pfx_kthread (kernel/kthread.c:341) 
[ 3966.437236][ T71] ret_from_fork_asm (arch/x86/entry/entry_64.S:250) 
| [ 3966.455861][   T71] ==================================================================
| [ 3966.457140][   T71] Disabling lock debugging due to kernel taint
| [ 3966.457549][   T71] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI
| [ 3966.458156][   T71] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
[ 3966.459042][   T71] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 3966.459650][   T71] Workqueue: netns cleanup_net
[ 3966.459897][ T71] RIP: 0010:vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 3966.460252][ T71] 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
[ 3966.461220][   T71] RSP: 0018:ffffc9000051f980 EFLAGS: 00010246
[ 3966.461524][   T71] RAX: 0000000000000000 RBX: ffffffffffffffd0 RCX: dffffc0000000000
[ 3966.461924][   T71] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88800ac48c24
[ 3966.462319][   T71] RBP: 1ffff920000a3f33 R08: 1ffff11000e9581a R09: ffffc9000051f9b8
[ 3966.462770][   T71] R10: ffffffffb153ca07 R11: 205d313754202020 R12: ffffed1000e9581a
[ 3966.463161][   T71] R13: ffff88800ac48ba0 R14: ffff888006884000 R15: ffff8880074ac000
[ 3966.463598][   T71] FS:  0000000000000000(0000) GS:ffff88802e800000(0000) knlGS:0000000000000000
[ 3966.464045][   T71] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3966.464380][   T71] CR2: 00007f1658881270 CR3: 000000000941e002 CR4: 0000000000770ef0
[ 3966.464777][   T71] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 3966.465179][   T71] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 3966.465582][   T71] PKRU: 55555554
[ 3966.465761][   T71] Call Trace:
[ 3966.465927][   T71]  <TASK>
[ 3966.466079][ T71] ? die_addr (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:460) 
[ 3966.466292][ T71] ? exc_general_protection (arch/x86/kernel/traps.c:701 arch/x86/kernel/traps.c:643) 
[ 3966.466579][ T71] ? asm_exc_general_protection (./arch/x86/include/asm/idtentry.h:564) 
[ 3966.466873][ T71] ? vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4613 drivers/net/vxlan/vxlan_core.c:4636) vxlan
[ 3966.467199][ T71] ? __pfx_vxlan_netdevice_event (drivers/net/vxlan/vxlan_core.c:4631) vxlan
[ 3966.467537][ T71] ? netconsole_netdev_event (drivers/net/netconsole.c:991) 
[ 3966.467829][ T71] notifier_call_chain (kernel/notifier.c:93) 
[ 3966.468086][ T71] unregister_netdevice_many_notify (net/core/dev.c:11095) 
[ 3966.468411][ T71] ? 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) 
[ 3966.468654][ T71] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11035) 
[ 3966.468993][ T71] ? vrf_dellink (drivers/net/vrf.c:1708) vrf
[ 3966.469261][ T71] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11019) 
[ 3966.469581][ T71] default_device_exit_batch (net/core/dev.c:11629) 
[ 3966.469863][ T71] ? __pfx_default_device_exit_batch (net/core/dev.c:11604) 
[ 3966.470171][ T71] ? 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) 
[ 3966.470417][ T71] ? 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) 
[ 3966.470716][ T71] cleanup_net (net/core/net_namespace.c:636 (discriminator 3)) 
[ 3966.470946][ T71] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 3966.471229][ T71] ? __pfx_cleanup_net (net/core/net_namespace.c:581) 
[ 3966.471480][ T71] ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5725) 
[ 3966.471723][ T71] ? process_one_work (kernel/workqueue.c:2609) 
[ 3966.471981][ T71] process_one_work (kernel/workqueue.c:2633) 
[ 3966.472237][ T71] ? 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) 
[ 3966.472468][ T71] ? __pfx_process_one_work (kernel/workqueue.c:2542) 
[ 3966.472739][ T71] ? assign_work (kernel/workqueue.c:1101) 
[ 3966.472977][ T71] worker_thread (kernel/workqueue.c:2700 kernel/workqueue.c:2787) 
[ 3966.473213][ T71] ? lockdep_hardirqs_on_prepare.part.0 (kernel/locking/lockdep.c:4300 kernel/locking/lockdep.c:4359) 
[ 3966.473556][ T71] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 3966.473814][ T71] ? __pfx_worker_thread (kernel/workqueue.c:2733) 
[ 3966.474071][ T71] kthread (kernel/kthread.c:388) 
[ 3966.474279][ T71] ? __pfx_kthread (kernel/kthread.c:341) 
[ 3966.474511][ T71] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 3966.474742][ T71] ? __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