初编的驱动，为什么一访问硬件，就马上重启

void PCIS5920Device::SerialRead(KIrp I)
{         NTSTATUS status = STATUS_SUCCESS;

// Declare a memory object
KMemory Mem(I.Mdl());
PUCHAR pBuffer = (PUCHAR)Mem.MapToSystemSpace();
// Requested read size
ULONG   dwTotalSize = I.ReadSize(CURRENT); ULONG   dwBytesRead = 0;// Count of bytes read
         char   buff;
  buff=m_MemoryRange0.inb(0X60);//读s5920的一个配置寄存器
  strcpy((char *)pBuffer,&buff);
  dwBytesRead=strlen(&buff);
  I.Information() = dwBytesRead;
  m_DriverManagedQueue.PnpNextIrp(I);
}
其中m_MemoryRange0的定义为
 KMemoryRange m_MemoryRange0;
初始化为：
status = m_MemoryRange0.Initialize(
pResListTranslated,
pResListRaw,
PciConfig.BaseAddressIndexToOrdinal(0)
);

这是测试程序test中的函数:
void doRead(int n)
{
char *buf;
ULONG nRead;
int i;
// int j;

buf = (char *) malloc(n);
if (buf == NULL)
{
printf("Failed to allocate buffer for read");
Exit(1);
}

// Read data from driver
printf("Reading from device - ");
ReadFile(hDevice, buf, n, &nRead, NULL);
           printf("%c, ",buf[0]);
free(buf);
}

可是每次用测试程序(test)一访问，test r 1,马上重启，小弟才开始学习驱动，实在不知道是什么原因555555.....，请各位大侠帮助呀!

配置或硬件有问题！ :P

在PCIS5920Device::SerialRead(KIrp I)
下断点,看看是哪一步出的问题.