unregister_netdevice: waiting for wpan4 to become free. Usage count = 2
ref_tracker: wpan4@ffff88802ca38620 has 1/1 users at
     __netdev_tracker_alloc include/linux/netdevice.h:4064 [inline]
     netdev_hold include/linux/netdevice.h:4093 [inline]
     dev_ifsioc+0x91c/0x10b0 net/core/dev_ioctl.c:590
     dev_ioctl+0x224/0x10a0 net/core/dev_ioctl.c:787
     sock_do_ioctl+0x19e/0x280 net/socket.c:1236
     sock_ioctl+0x22e/0x6c0 net/socket.c:1341
     vfs_ioctl fs/ioctl.c:51 [inline]
     __do_sys_ioctl fs/ioctl.c:904 [inline]
     __se_sys_ioctl fs/ioctl.c:890 [inline]
     __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:890
     do_syscall_x64 arch/x86/entry/common.c:52 [inline]
     do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
     entry_SYSCALL_64_after_hwframe+0x77/0x7f