枚举端口时IoCallDriver返回STATUS_CANCELLED

           代码是枚举通信端口用的，但是不知道为什么IoCallDriver返回STATUS_CANCELLED，不知道此代码有啥问题，我弄了一晚上了也没弄出名堂，希望各位帮忙看看，谢谢各位了

#define IOCTL_TCP_QUERY_INFORMATION_EX 0x00120003
LONG GetPortCount()       //获取端口信息和个数，保存之
{
  LONG PortCount = 0;
  UNICODE_STRING DeviceName = RTL_CONSTANT_STRING(L"\\Device\\Tcp");
  PFILE_OBJECT FileObject = NULL;
  PDEVICE_OBJECT DeviceObject = NULL;
  PTCP_REQUEST_QUERY_INFORMATION_EX pRequestInformationEx ;
  PVOID pOutputBuff;
  IO_STATUS_BLOCK StatusBlock;
  PIO_STACK_LOCATION StackLocation ;
  PIRP pIrp;
  KEVENT Event;
  NTSTATUS ntStatus = IoGetDeviceObjectPointer(&DeviceName, GENERIC_READ|GENERIC_WRITE, &FileObject, &DeviceObject);
  if(!NT_SUCCESS(ntStatus))
    return 0;
  pRequestInformationEx = (PTCP_REQUEST_QUERY_INFORMATION_EX)ExAllocatePool(PagedPool, sizeof(TCP_REQUEST_QUERY_INFORMATION_EX));
     if (NULL == pRequestInformationEx)
     {
         return 0;
     }
    RtlZeroMemory(pRequestInformationEx, sizeof(TCP_REQUEST_QUERY_INFORMATION_EX));
  pOutputBuff = ExAllocatePool(PagedPool, PAGE_SIZE);
  RtlZeroMemory(pOutputBuff, PAGE_SIZE);


  //查看TCP端口
    pRequestInformationEx->ID.toi_entity.tei_instance = 0;
    pRequestInformationEx->ID.toi_class = INFO_CLASS_PROTOCOL;
    pRequestInformationEx->ID.toi_type = INFO_TYPE_PROVIDER;
    pRequestInformationEx->ID.toi_id = 0x102;
    pRequestInformationEx->ID.toi_entity.tei_entity = CO_TL_ENTITY;
  KeInitializeEvent(&Event, NotificationEvent, FALSE);
  pIrp = IoBuildDeviceIoControlRequest(IOCTL_TCP_QUERY_INFORMATION_EX , DeviceObject, (PVOID)&pRequestInformationEx, sizeof(TCP_REQUEST_QUERY_INFORMATION_EX), pOutputBuff, PAGE_SIZE, FALSE, &Event, &StatusBlock);
  if(!pIrp)
  {
    return 0;
  }
  StackLocation = IoGetNextIrpStackLocation(pIrp);
    StackLocation->FileObject = FileObject;
    pIrp->Tail.Overlay.Thread = PsGetCurrentThread();
    StackLocation->DeviceObject = DeviceObject;
  
  ntStatus  = IoCallDriver(DeviceObject, pIrp);       //////////////////////////就是此处返回STATUS_CANCELLED，郁闷
  if(ntStatus == STATUS_BUFFER_TOO_SMALL)
  {
    return 0;
  }
  else if(ntStatus == STATUS_PENDING)
  {
    ntStatus = KeWaitForSingleObject(&Event, Executive, 0, 0, 0);
  }
  PMIB_TCPROW_OWNER_PID pTcpInfo = (PMIB_TCPROW_OWNER_PID)pOutputBuff;
  for(; pTcpInfo->OwningPid; pTcpInfo++)
  {
    PPORT_INFO_LIST pInfoNode = (PPORT_INFO_LIST)ExAllocatePool(PagedPool, sizeof(PORT_INFO_LIST));
    pInfoNode->info.Flag = 0;
    pInfoNode->info.LocalAddr = pTcpInfo->LocalAddr;
    pInfoNode->info.LocalPort = pTcpInfo->LocalPort;
    pInfoNode->info.OwnPid = pTcpInfo->OwningPid;
    pInfoNode->info.RemoteAddr = pTcpInfo->RemoteAddr;
    pInfoNode->info.RemotePort = pTcpInfo->RemotePort;
    pInfoNode->info.State = pTcpInfo->State;
    pInfoNode->next = g_pMyPortInfoListHead;
    g_pMyPortInfoListHead = pInfoNode;
    ++PortCount;
  }
                if(pRequestInformationEx)
    ExFreePool(pRequestInformationEx);
  if(pOutputBuff)
    ExFreePool(pOutputBuff);
  if(FileObject)
    ObDereferenceObject(FileObject);
  if(DeviceObject)
    ObDereferenceObject(DeviceObject);
  return PortCount;
}

麻烦各位驻足稍微看看，再次感谢 ！！