unregister_netdevice: waiting for syz_tun to become free. Usage count = 2
leaked reference.
 __netdev_tracker_alloc include/linux/netdevice.h:4005 [inline]
 netdev_tracker_alloc include/linux/netdevice.h:4017 [inline]
 fib6_nh_init+0x664/0x1c84 net/ipv6/route.c:3621
 ip6_route_info_create+0x7ac/0xf14 net/ipv6/route.c:3799
 ip6_route_add+0x38/0x168 net/ipv6/route.c:3843
 addrconf_add_mroute net/ipv6/addrconf.c:2489 [inline]
 addrconf_add_dev+0x2b8/0x458 net/ipv6/addrconf.c:2507
 addrconf_dev_config net/ipv6/addrconf.c:3382 [inline]
 addrconf_init_auto_addrs+0x708/0xc9c net/ipv6/addrconf.c:3469
 addrconf_notify+0x7d0/0xc94 net/ipv6/addrconf.c:3642
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:455
 __dev_notify_flags+0x2ac/0x534
 dev_change_flags+0xc8/0x154 net/core/dev.c:8624
 do_setlink+0xc70/0x3334 net/core/rtnetlink.c:2788
 __rtnl_newlink net/core/rtnetlink.c:3547 [inline]
 rtnl_newlink+0x13b8/0x1b04 net/core/rtnetlink.c:3594
 rtnetlink_rcv_msg+0x72c/0xd94 net/core/rtnetlink.c:6091
 netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2524
 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6109
 netlink_unicast_kernel net/netlink/af_netlink.c:1328 [inline]
 netlink_unicast+0x660/0x8d4 net/netlink/af_netlink.c:1354
 netlink_sendmsg+0x834/0xb18 net/netlink/af_netlink.c:1902