unregister_netdevice: waiting for syz_tun to become free. Usage count = 2
leaked reference.
 __netdev_tracker_alloc include/linux/netdevice.h:3974 [inline]
 netdev_tracker_alloc include/linux/netdevice.h:3986 [inline]
 fib6_nh_init+0x5c6/0x1be0 net/ipv6/route.c:3621
 ip6_route_info_create+0x125b/0x1aa0 net/ipv6/route.c:3799
 ip6_route_add+0x24/0x150 net/ipv6/route.c:3843
 addrconf_add_mroute+0x1e1/0x310 net/ipv6/addrconf.c:2489
 addrconf_add_dev+0x156/0x1c0 net/ipv6/addrconf.c:2507
 addrconf_dev_config+0x1ec/0x410 net/ipv6/addrconf.c:3382
 addrconf_notify+0xf36/0x1c10 net/ipv6/addrconf.c:3635
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1945
 call_netdevice_notifiers_extack net/core/dev.c:1983 [inline]
 call_netdevice_notifiers net/core/dev.c:1997 [inline]
 __dev_notify_flags+0x110/0x2b0 net/core/dev.c:8594
 dev_change_flags+0x112/0x170 net/core/dev.c:8632
 do_setlink+0x961/0x3bb0 net/core/rtnetlink.c:2780
 __rtnl_newlink+0xd6a/0x17e0 net/core/rtnetlink.c:3546
 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3593
 rtnetlink_rcv_msg+0x43a/0xca0 net/core/rtnetlink.c:6090
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2501