packet一问

MyPacket->Private.Head = Packet->Private.Head;
MyPacket->Private.Tail = Packet->Private.Tail;
NdisUnchainBufferAtFront(MyPacket....);
调用NdisReturnPackets(Packet....)时死机
这是为什么?

MyPacket->Private.Head = Packet->Private.Head;
MyPacket->Private.Tail = Packet->Private.Tail;
这两行代码的效果是不是跟
NdisQueryPacket(Packet...,buffer,..);
NdisChainBufferAtFront(MyPacket,buffer);一样