unregister_netdevice: waiting for wpan4 to become free. Usage count = 2
ref_tracker: wpan4@ffff88807ac745b8 has 1/1 users at
     dev_ifsioc+0xbef/0xe60 net/core/dev_ioctl.c:408
     dev_ioctl+0x6f7/0x1300 net/core/dev_ioctl.c:605
     sock_do_ioctl+0x26f/0x460 net/socket.c:1204
     sock_ioctl+0x5dd/0x850 net/socket.c:1307
     vfs_ioctl fs/ioctl.c:51 [inline]
     __do_sys_ioctl fs/ioctl.c:870 [inline]
     __se_sys_ioctl+0xf8/0x170 fs/ioctl.c:856
     do_syscall_x64 arch/x86/entry/common.c:50 [inline]
     do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
     entry_SYSCALL_64_after_hwframe+0x63/0xcd