unregister_netdevice: waiting for syz_tun to become free. Usage count = 3
ref_tracker: netdev@ffff8880662c8618 has 1/2 users at
     __netdev_tracker_alloc include/linux/netdevice.h:4400 [inline]
     netdev_tracker_alloc include/linux/netdevice.h:4412 [inline]
     netdev_get_by_index+0x79/0xb0 net/core/dev.c:1021
     fib6_nh_init+0x1f7/0x2060 net/ipv6/route.c:3601
     ip6_route_info_create_nh+0x16a/0xad0 net/ipv6/route.c:3901
     addrconf_f6i_alloc+0x3b7/0x630 net/ipv6/route.c:4693
     fixup_permanent_addr net/ipv6/addrconf.c:3583 [inline]
     addrconf_permanent_addr+0x1e0/0x740 net/ipv6/addrconf.c:3622
     addrconf_notify+0x864/0x1050 net/ipv6/addrconf.c:3694
     notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
     call_netdevice_notifiers_extack net/core/dev.c:2281 [inline]
     call_netdevice_notifiers net/core/dev.c:2295 [inline]
     __dev_notify_flags+0x1a9/0x310 net/core/dev.c:9788
     netif_change_flags+0xe8/0x1a0 net/core/dev.c:9817
     do_setlink+0xf82/0x4590 net/core/rtnetlink.c:3158
     rtnl_changelink net/core/rtnetlink.c:3776 [inline]
     __rtnl_newlink net/core/rtnetlink.c:3935 [inline]
     rtnl_newlink+0x15a9/0x1be0 net/core/rtnetlink.c:4072
     rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958
     netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
     netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
     netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344
     netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
     sock_sendmsg_nosec net/socket.c:727 [inline]
     __sock_sendmsg net/socket.c:742 [inline]
     __sys_sendto+0x709/0x7a0 net/socket.c:2206

ref_tracker: netdev@ffff8880662c8618 has 1/2 users at
     __netdev_tracker_alloc include/linux/netdevice.h:4400 [inline]
     netdev_hold include/linux/netdevice.h:4429 [inline]
     ipv6_add_dev+0x50f/0x13a0 net/ipv6/addrconf.c:411
     addrconf_notify+0x771/0x1050 net/ipv6/addrconf.c:3650
     notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
     call_netdevice_notifiers_extack net/core/dev.c:2281 [inline]
     call_netdevice_notifiers net/core/dev.c:2295 [inline]
     register_netdevice+0x171a/0x1cd0 net/core/dev.c:11444
     tun_set_iff+0x844/0xf00 drivers/net/tun.c:2807
     __tun_chr_ioctl+0x7bb/0x1e10 drivers/net/tun.c:3088
     vfs_ioctl fs/ioctl.c:51 [inline]
     __do_sys_ioctl fs/ioctl.c:597 [inline]
     __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
     do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
     do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
     entry_SYSCALL_64_after_hwframe+0x77/0x7f