求助！一个简单驱动出现了问题（附带源码）

小弟在学习驱动，最近按照书，写了一个简单的驱动程序，不需要物理设备，是一个LoopBack程序（仿照那本2000驱动指南写的）
但是，在用DRIVERMONITOR 调试的时候，一运行"Start driver"  马上重启，郁闷中，希望高手解答。 源码如下

Driver.c

#include "Driver.h"



VOID DriverUnload(IN PDRIVER_OBJECT pDriverObject)
{
PDEVICE_OBJECT pDevObj;
UNICODE_STRING pLinkName;
pDevObj=pDriverObject->DeviceObject;
if(pDevObj!=NULL)
{
PDEVICE_EXTENSION pDevExt=(PDEVICE_EXTENSION)pDevObj->DeviceExtension;
        pLinkName=pDevExt->DeviceWin32Name;
if (pDevExt->DeviceBuffer!=NULL)
{
ExFreePool(pDevExt->DeviceBuffer);
pDevExt->DeviceBuffer=NULL;
pDevExt->DeviceBufferSize=0;
}
IoDeleteSymbolicLink(&pLinkName);
IoDeleteDevice(pDevExt->pDeviceObject);
}

}

NTSTATUS DispatchCreate(IN PDEVICE_OBJECT pDevObj,
IN PIRP pIrp)
{
pIrp->IoStatus.Status=STATUS_SUCCESS;
pIrp->IoStatus.Information=0;
IoCompleteRequest(pIrp,IO_NO_INCREMENT);
return STATUS_SUCCESS;
}

NTSTATUS DispatchClose(IN PDEVICE_OBJECT pDevObj,
  IN PIRP pIrp )
{
PDEVICE_EXTENSION pDevExt;
pDevExt=(PDEVICE_EXTENSION)pDevObj->DeviceExtension;
if (pDevExt->DeviceBuffer!=NULL)
{
ExFreePool(pDevExt->DeviceBuffer);
pDevExt->DeviceBuffer=NULL;
pDevExt->DeviceBufferSize=0;
}
pIrp->IoStatus.Status=STATUS_SUCCESS;
pIrp->IoStatus.Information=0;
IoCompleteRequest(pIrp,IO_NO_INCREMENT);
return STATUS_SUCCESS;
}

NTSTATUS DispatchRead(IN PDEVICE_OBJECT pDevObj,
 IN PIRP pIrp)
{
NTSTATUS status = STATUS_SUCCESS;
PDEVICE_EXTENSION pDevExt;
PVOID UserBuffer;
ULONG XferSize;
PIO_STACK_LOCATION pIrpStack;
pIrpStack = IoGetCurrentIrpStackLocation(pIrp);
UserBuffer = pIrp->AssociatedIrp.SystemBuffer;
XferSize = pIrpStack->Parameters.Read.Length;
pDevExt = (PDEVICE_EXTENSION)pDevObj->DeviceExtension;
XferSize = (XferSize < pDevExt->DeviceBufferSize) ? XferSize:pDevExt->DeviceBufferSize;
RtlCopyMemory(UserBuffer,pDevExt->DeviceBuffer,XferSize);
ExFreePool(pDevExt->DeviceBuffer);
pDevExt->DeviceBuffer = NULL;
pDevExt->DeviceBufferSize = 0;
pIrp->IoStatus.Status = status;
pIrp->IoStatus.Information = XferSize;
IoCompleteRequest(pIrp,IO_NO_INCREMENT);
return status;
}

NTSTATUS DispatchWrite(IN PDEVICE_OBJECT pDevObj,
  IN PIRP pIrp)
{
NTSTATUS status = STATUS_SUCCESS;
PDEVICE_EXTENSION pDevExt;
PVOID UserBuffer;
ULONG XferSize;
PIO_STACK_LOCATION pIrpStack;
pIrpStack = IoGetCurrentIrpStackLocation(pIrp);
UserBuffer = pIrp->AssociatedIrp.SystemBuffer;
XferSize = pIrpStack->Parameters.Write.Length;
pDevExt = (PDEVICE_EXTENSION)pDevObj->DeviceExtension;
if (pDevExt->DeviceBuffer != NULL)
{
ExFreePool(pDevExt->DeviceBuffer);
pDevExt->DeviceBuffer = NULL;
XferSize = 0;
}
pDevExt->DeviceBuffer = ExAllocatePool(PagedPool,XferSize);
if (pDevExt->DeviceBuffer == NULL)
{
status = STATUS_INSUFFICIENT_RESOURCES;
XferSize = 0;
}
else
{
pDevExt->DeviceBufferSize = XferSize;
RtlCopyMemory(pDevExt->DeviceBuffer,UserBuffer,XferSize);
}
pIrp->IoStatus.Status = status;
pIrp->IoStatus.Information = XferSize;
IoCompleteRequest(pIrp,IO_NO_INCREMENT);
return status;
}


NTSTATUS DriverEntry(PDRIVER_OBJECT pDriverObject,
PUNICODE_STRING pRegPath     )
{
NTSTATUS status;
UNICODE_STRING NtName;
UNICODE_STRING Win32Name;
PDEVICE_OBJECT pDevObj;
PDEVICE_EXTENSION pDevExt;
    
pDriverObject->DriverUnload=DriverUnload;
pDriverObject->MajorFunction [IRP_MJ_CREATE] = DispatchCreate;
pDriverObject->MajorFunction [IRP_MJ_CLOSE] = DispatchClose;
pDriverObject->MajorFunction [IRP_MJ_READ] = DispatchRead;
pDriverObject->MajorFunction [IRP_MJ_WRITE] = DispatchWrite;



RtlInitUnicodeString(&NtName,DeviceInterName);
RtlInitUnicodeString(&Win32Name,DeviceLinkName);
status = IoCreateDevice(  pDriverObject,
                     sizeof(DEVICE_EXTENSION),
     &NtName,
     FILE_DEVICE_UNKNOWN,
     0,
     TRUE,
     &pDevObj  );
if (status != STATUS_SUCCESS)
{
IoDeleteDevice(pDevObj);

                

return status;
}


   RtlZeroMemory(pDevObj->DeviceExtension,sizeof(DEVICE_EXTENSION));
   pDevObj->Flags |= DO_BUFFERED_IO;
   pDevExt=(PDEVICE_EXTENSION)(pDevObj)->DeviceExtension;
        pDevExt->pDeviceObject = pDevObj;
pDevExt->DeviceNTName=NtName;
   
pDevExt->DeviceBuffer = NULL;
pDevExt->DeviceBufferSize = 0;
pDevExt->DeviceWin32Name=Win32Name;
   status=IoCreateSymbolicLink(&Win32Name,&NtName);
return status;
}

Driver.h
#include "D:\NTDDK\inc\ddk\ntddk.h"
#include "stdlib.h"

#define DeviceInterName L"\\Device\\LoopBack"
#define DeviceLinkName L"\\??\\LoopBack"

typedef struct _DEVICE_EXTENSION
{
PDEVICE_OBJECT pDeviceObject;

PVOID DeviceBuffer;
ULONG DeviceBufferSize;
UNICODE_STRING DeviceNTName;
UNICODE_STRING DeviceWin32Name;
}DEVICE_EXTENSION,*PDEVICE_EXTENSION;