no, it is not. labs also seems to just round up the length not adding the remainder of the unaligned va address. it would be a one line fix in the kernel.
the manpage sais this: Va and len specify the position of the segment in the process's address space. Va is rounded down to the nearest page boundary and va+len is rounded up. The system does not permit segments to overlap. If va is zero, the system will choose a suitable address. the question is, does the va in va+len mean before or after the rounding down. i'd say *before* because otherwise, theres no point in define it as va+len. -- cinap