why RtlCompareUnicodeString cause page error?

when I call
RtlCompareUnicodeString((PUNICODE_STRING)filename,&targetName, TRUE )

a page error occurs, why?
I noticed that both filename and targetName has valid unicode string,
and RtlCompareUnicodeString must running on PASSIVE_LEVEL.

I call this function in IRP_MJ_SET_INFORMATION dispatch function,
is there any problem?

thanks!

你想做什么？把代码贴上来看看才知道，估计你访问了无效的地址