unregister_netdevice: waiting for batadv_slave_1 to become free. Usage count = 2
ref_tracker: netdev@ffff8881bc6b0658 has 1/1 users at
     netdev_get_by_index+0x79/0xb0
     fib6_nh_init+0x285/0x1e30
     ip6_route_info_create_nh+0x16a/0xad0
     ip6_route_add+0x6e/0x1b0
     ipv6_route_ioctl+0x3ac/0x4f0
     inet6_ioctl+0x246/0x2e0
     sock_do_ioctl+0x101/0x320
     sock_ioctl+0x5c6/0x7f0
     __se_sys_ioctl+0xfc/0x170
     do_syscall_64+0x15f/0xf80
     entry_SYSCALL_64_after_hwframe+0x77/0x7f

