0xfe0难道有罪吗？？关于用ExAllocatePool分配内存的问题

我用Buffer = ExAllocatePool(PagedPool,WriteLen);分配内存，当writelen<4000多字节的时候，就ok，否则，就兰屏
谁有经验，帮助解决以下

是分配蓝屏还是，之后引用地址蓝屏。。。却别很大  :D :D :D

哦，准确地说应该是应用地址，感谢楼上的兄弟

那就是分配内存失败了，而你又没有检查这个分配的地址。。。看看关于内存分配的DDK说明吧，在低资源情况下会出现的。。。 :D :D :D

我在饮用这块内存的时候（IF BUFFER），应该是做了检测的
而且，我的内存肯定不是处于低资源状况！
还有，如果分配的直接只要少于0XFE0哪怕一个字节，就没有任何问题
我想应该是分页的问题，郁闷ING

分配和使用是否在同一个地方？ :D :D :D :D

if (WriteLen>BufferSize)//如果缓冲区不够大，从新分配内存
{
BufferSize=WriteLen;
if (Buffer!=NULL)
{
ExFreePool(Buffer);
Buffer=NULL;
}
Buffer = ExAllocatePool(PagedPool,WriteLen);


}


// Write to shared memory
if( BufferSize>0 && Buffer)
{
RtlCopyMemory( Buffer, Irp->AssociatedIrp.SystemBuffer, WriteLen);

}

if (WriteLen>BufferSize)//如果缓冲区不够大，从新分配内存
{
BufferSize=WriteLen;
if (Buffer!=NULL)
{
ExFreePool(Buffer);
Buffer=NULL;
}
Buffer = ExAllocatePool(PagedPool,WriteLen);


}


// Write to shared memory
if( BufferSize>0 && Buffer)
{
RtlCopyMemory( Buffer, Irp->AssociatedIrp.SystemBuffer, WriteLen);

}

我觉得问题不在分配内存上面。。。。如果分配失败也不会执行COPY了。。。。建议使用

NULL != Buffer

这样的形式来判断。。。 :D :D :D

我原来就是(!=null)这么用的，出了问题之后，看ddk中的sample就是if （buf）这么用的，就照着改了过来，问题依然存在

现在我都不知道问题出在哪儿了
如果分配内存没有错
有没有可能 DO_BUFFERED_IO方法不支持超过4k字节呢

哦，准确地说应该是应用地址，感谢楼上的兄弟

IRQL== PASSIVE_LEVEL for PagedPool.

我用Buffer = ExAllocatePool(NonPagedPool,WriteLen);
也是同样的错误啊！！！
我该怎么解决，拜托多写两句！

我用Buffer = ExAllocatePool(NonPagedPool,WriteLen);
也是同样的错误啊！！！
我该怎么解决，拜托多写两句！

不是拜托我多写两句，
是拜托你多给两行代码看看。

NTSTATUS
PtDispatch(
IN PDEVICE_OBJECT DeviceObject,
IN PIRP Irp
)
{
PIO_STACK_LOCATION irpStack;
NTSTATUS status = STATUS_SUCCESS;
//ULONG BytesTxd = 0;
LONGLONG FilePointer=0;
ULONG WriteLen=0;
ULONG NewBufferSize=0;
PVOID NewBuffer;
ULONG ControlCode;
ULONG InputLength;
ULONG OutputLength;
KIRQL irql;
PVOID Buff = NULL;


DBGPRINT((\"==>Pt Dispatch\\n\"));
irpStack = IoGetCurrentIrpStackLocation(Irp);

switch (irpStack->MajorFunction)
{
case IRP_MJ_CREATE:
break;
case IRP_MJ_CLOSE:
break;

case IRP_MJ_WRITE:

FilePointer = irpStack->Parameters.Write.ByteOffset.QuadPart;
WriteLen = irpStack->Parameters.Write.Length;
// Get call parameters

//DBGPRINT(\"Write %d bytes from file pointer %d\",(int)WriteLen,(int)FilePointer);

if( FilePointer<0)
status = STATUS_INVALID_PARAMETER;
else
{
// Get access to the shared buffer
//KIRQL irql;
KeAcquireSpinLock(&BufferLock,&irql);

if (WriteLen>BufferSize)//如果缓冲区不够大，从新分配内存
{
BufferSize=WriteLen;
if (Buffer!=NULL)
{
ExFreePool(Buffer);
Buffer=NULL;
}
Buffer = ExAllocatePool(PagedPool,WriteLen);


}


// Write to shared memory
if( BufferSize>0 && Buffer)
{

RtlCopyMemory( Buffer, Irp->AssociatedIrp.SystemBuffer, WriteLen);


}
else
{
KeReleaseSpinLock(&BufferLock,irql);
return STATUS_INSUFFICIENT_RESOURCES;    
}
// Release shared buffer
KeReleaseSpinLock(&BufferLock,irql);
}

// Complete IRP
return CompleteIrp(Irp,status,WriteLen);
break;

NTSTATUS
PtDispatch(
IN PDEVICE_OBJECT DeviceObject,
IN PIRP Irp
)
{
PIO_STACK_LOCATION irpStack;
NTSTATUS status = STATUS_SUCCESS;
//ULONG BytesTxd = 0;
LONGLONG FilePointer=0;
ULONG WriteLen=0;
ULONG NewBufferSize=0;
PVOID NewBuffer;
ULONG ControlCode;
ULONG InputLength;
ULONG OutputLength;
KIRQL irql;
PVOID Buff = NULL;


DBGPRINT((\"==>Pt Dispatch\\n\"));
irpStack = IoGetCurrentIrpStackLocation(Irp);

switch (irpStack->MajorFunction)
{
case IRP_MJ_CREATE:
break;
case IRP_MJ_CLOSE:
break;

case IRP_MJ_WRITE:

FilePointer = irpStack->Parameters.Write.ByteOffset.QuadPart;
WriteLen = irpStack->Parameters.Write.Length;
// Get call parameters

//DBGPRINT(\"Write %d bytes from file pointer %d\",(int)WriteLen,(int)FilePointer);

if( FilePointer<0)
status = STATUS_INVALID_PARAMETER;
else
{
// Get access to the shared buffer
//KIRQL irql;
KeAcquireSpinLock(&BufferLock,&irql);

if (WriteLen>BufferSize)//如果缓冲区不够大，从新分配内存
{
BufferSize=WriteLen;
if (Buffer!=NULL)
{
ExFreePool(Buffer);
Buffer=NULL;
}
Buffer = ExAllocatePool(PagedPool,WriteLen);


}


// Write to shared memory
if( BufferSize>0 && Buffer)
{

RtlCopyMemory( Buffer, Irp->AssociatedIrp.SystemBuffer, WriteLen);


}
else
{
KeReleaseSpinLock(&BufferLock,irql);
return STATUS_INSUFFICIENT_RESOURCES;    
}
// Release shared buffer
KeReleaseSpinLock(&BufferLock,irql);
}

// Complete IRP
return CompleteIrp(Irp,status,WriteLen);
break;

1.
IoCreateDevice后是否
DeviceObject->Flags |= DO_BUFFER_IO?
2.
KeAcquireSpinLock(&BufferLock,&irql);
后，IRQL提升到DISPATCH_LEVEL,在Release前不能使用Unlock Paged
Memory,当然在锁定前也必须要Passive_level.
所以改buffer = ExAllocatePool(NonPagedPool,WriteLen);
3.
出错时RETURN时，请IoCompleteRequest结束请求




[编辑 -  9/29/02 by  gjpland]

逻辑:
看了半天
KeAcquireSpinLock(&BufferLock,&irql);
和
KeReleaseSpinLock(&BufferLock,irql);
之间都是涉及局部变量。为什么要用锁呢？

1.
IoCreateDevice后是否
DeviceObject->Flags |= DO_BUFFER_IO?,当然，否则，,小于0xfe0的数据应该也会非法
2.
KeAcquireSpinLock(&BufferLock,&irql);
后，IRQL提升到DISPATCH_LEVEL,在Release前不能使用Unlock Paged
Memory,当然在锁定前也必须要Passive_level.
所以改buffer = ExAllocatePool(NonPagedPool,WriteLen);
我最开始就是这样做的，结果还是非法
3.
出错时RETURN时，请IoCompleteRequest结束请求
这句话，我不怎么明白
因为buffer是全局变量，所以枷锁
麻烦兄台再帮我看看




[编辑 -  9/29/02 by  gjpland] [/quote]

试一下，下面我改的代码。
NTSTATUS
PtDispatch(
IN PDEVICE_OBJECT DeviceObject,
IN PIRP Irp
)
{
PIO_STACK_LOCATION irpStack;
NTSTATUS status = STATUS_SUCCESS;
//ULONG BytesTxd = 0;
LONGLONG FilePointer=0;
ULONG WriteLen=0;
ULONG NewBufferSize=0;
PVOID NewBuffer;
ULONG ControlCode;
ULONG InputLength;
ULONG OutputLength;
KIRQL irql;
PVOID Buff = NULL;


DBGPRINT((\"==>Pt Dispatch\\n\"));
irpStack = IoGetCurrentIrpStackLocation(Irp);

switch (irpStack->MajorFunction)
{
case IRP_MJ_CREATE:
break;
case IRP_MJ_CLOSE:
break;

case IRP_MJ_WRITE:

FilePointer = irpStack->Parameters.Write.ByteOffset.QuadPart;
WriteLen = irpStack->Parameters.Write.Length;
// Get call parameters

//DBGPRINT(\"Write %d bytes from file pointer %d\",(int)WriteLen,(int)FilePointer);

if( FilePointer<0)
status = STATUS_INVALID_PARAMETER;
else
{
char *tmpBuffer = NULL;
tmpBuffer = ExAllocatePool(NonPagedPool,WriteLen);
if( tmpBuffer == NULL )
{
CompleteIrp(Irp,STATUS_INSUFFICIENT_RESOURCES,0);
return STATUS_INSUFFICIENT_RESOURCES;    
}

memcpy(tmpBuffer,Irp->AssociatedIrp.SystemBuffer,WriteLen);

// Get access to the shared buffer
//KIRQL irql;
KeAcquireSpinLock(&BufferLock,&irql);

BufferSize=WriteLen;
if (Buffer!=NULL)
{
ExFreePool(Buffer);
Buffer=NULL;
}
Buffer = tmpBuffer;

KeReleaseSpinLock(&BufferLock,irql);
}

// Complete IRP
return CompleteIrp(Irp,status,WriteLen);
break;

多谢两位兄台援手，问题已经解决，分如数奉上，请笑纳