新手求助

#include <ntddk.h>
VOID Unload(PDRIVER_OBJECT driver)
{
    DbgPrint("Unloading...\n");
}
NTSTATUS DriverEntry(PDRIVER_OBJECT driver, PUNICODE_STRING path)
{
    DEVICE_OBJECT newdevice;//过滤设备对象
    DEVICE_OBJECT targetdevice;//目标设备对象
    FILE_OBJECT fileobject;//过滤层文件对象
    UNICODE_STRING comname;//设备名称
    NTSTATUS status;
    PDEVICE_OBJECT poutdevice = NULL;

#if DBG
    _asm int 3
#endif
    DbgPrint("begin...\n");

    RtlInitUnicodeString(&comname, L"\\Device\\Serial0");//初始化设备名称字符串

    status = IoGetDeviceObjectPointer(&comname, FILE_ALL_ACCESS, &fileobject, &targetdevice);//获取设备对象
    if(status != STATUS_SUCCESS)
    {
        DbgPrint("获取串口设备对象失败！\n");
        return status;
    }

    status = IoCreateDevice(driver, 0, NULL, targetdevice.DeviceType, 0, FALSE, &newdevice);//创建过滤设备
    if(status != STATUS_SUCCESS)
    {
        DbgPrint("创建过滤设备失败！\n");
        return status;
    }

    if(targetdevice.Flags & DO_BUFFERED_IO)//拷贝重要标志位
        newdevice.Flags &=  DO_BUFFERED_IO;
    if(targetdevice.Flags & DO_DIRECT_IO)
        newdevice.Flags &= DO_DIRECT_IO;
    if(targetdevice.Characteristics & FILE_DEVICE_SECURE_OPEN)
        newdevice.Characteristics |= FILE_DEVICE_SECURE_OPEN;
    newdevice.Flags |= DO_POWER_PAGABLE;

    poutdevice = IoAttachDeviceToDeviceStack(&newdevice, &targetdevice);//绑定设备
    if(poutdevice == NULL)
    {
        DbgPrint("绑定设备失败！\n");
        IoDeleteDevice(&fileobject);
        return status;
    }

    IoDeleteDevice(&fileobject);
    driver->DriverUnload = Unload;
    return STATUS_SUCCESS;
}