unregister_netdevice: waiting for syz_tun to become free. Usage count = 3 ref_tracker: netdev@ffff88807e58c700 has 1/2 users at __netdev_tracker_alloc include/linux/netdevice.h:4499 [inline] netdev_tracker_alloc include/linux/netdevice.h:4511 [inline] netdev_get_by_index+0x79/0xb0 net/core/dev.c:1027 fib6_nh_init+0x285/0x1e40 net/ipv6/route.c:3615 ip6_route_info_create_nh+0x16a/0xad0 net/ipv6/route.c:3914 addrconf_f6i_alloc+0x3b7/0x630 net/ipv6/route.c:4706 ipv6_add_addr+0x59c/0x1110 net/ipv6/addrconf.c:1132 inet6_addr_add+0x43c/0xb50 net/ipv6/addrconf.c:3073 inet6_rtm_newaddr+0x9f3/0xdf0 net/ipv6/addrconf.c:5094 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7076 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775 __sock_sendmsg net/socket.c:790 [inline] __sys_sendto+0x408/0x5a0 net/socket.c:2252 __do_sys_sendto net/socket.c:2259 [inline] __se_sys_sendto net/socket.c:2255 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2255 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f ref_tracker: netdev@ffff88807e58c700 has 1/2 users at __netdev_tracker_alloc include/linux/netdevice.h:4499 [inline] netdev_hold include/linux/netdevice.h:4528 [inline] ipv6_add_dev+0x50f/0x13a0 net/ipv6/addrconf.c:411 addrconf_notify+0x771/0x1050 net/ipv6/addrconf.c:3685 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2288 [inline] call_netdevice_notifiers net/core/dev.c:2302 [inline] register_netdevice+0x18a4/0x1eb0 net/core/dev.c:11478 tun_set_iff+0x814/0xec0 drivers/net/tun.c:2877 __tun_chr_ioctl+0x7bb/0x1e10 drivers/net/tun.c:3158 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+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f