EngProbeForRead

Hi, I’m trying to use this function along with EngProbeForReadAndWrite,
but they keep throwing exceptions(even though the addresses are valid).
I’m using the functions inside my DrvEscape routine, which is an io entry
point to user land, so I’m curious if this could be causing a problem, as
the addresses are basically from user mode. How else should I be checking
for buffer validity though? If anyone can help, I’d really appreciate it!
thanks!
benjamin