unregister_netdevice: waiting for syz_tun to become free. Usage count = 2
ref_tracker: syz_tun@ffff888068bcc5b8 has 1/1 users at
     __netdev_tracker_alloc include/linux/netdevice.h:4110 [inline]
     netdev_hold include/linux/netdevice.h:4139 [inline]
     fib_check_nh_nongw net/ipv4/fib_semantics.c:1239 [inline]
     fib_check_nh+0xd23/0x1a70 net/ipv4/fib_semantics.c:1259
     fib_create_info+0x142c/0x2460 net/ipv4/fib_semantics.c:1557
     fib_table_insert+0xc6/0x1b20 net/ipv4/fib_trie.c:1217
     fib_magic+0x2e5/0x3c0 net/ipv4/fib_frontend.c:1118
     fib_add_ifaddr+0x3fb/0x5e0 net/ipv4/fib_frontend.c:1162
     fib_netdev_event+0x389/0x490 net/ipv4/fib_frontend.c:1500
     notifier_call_chain+0x197/0x380 kernel/notifier.c:93
     call_netdevice_notifiers_extack net/core/dev.c:2090 [inline]
     call_netdevice_notifiers net/core/dev.c:2104 [inline]
     __dev_notify_flags+0x1aa/0x310 net/core/dev.c:8755
     dev_change_flags+0xe8/0x1a0 net/core/dev.c:8793
     do_setlink+0xc58/0x4130 net/core/rtnetlink.c:2905
     __rtnl_newlink net/core/rtnetlink.c:3703 [inline]
     rtnl_newlink+0x17da/0x20a0 net/core/rtnetlink.c:3750
     rtnetlink_rcv_msg+0x869/0xfa0 net/core/rtnetlink.c:6472
     netlink_rcv_skb+0x241/0x4d0 net/netlink/af_netlink.c:2545
     netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
     netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346
     netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1894
     sock_sendmsg_nosec net/socket.c:730 [inline]
     __sock_sendmsg net/socket.c:745 [inline]
     __sys_sendto+0x4a9/0x6b0 net/socket.c:2200