different result on cross-compile on fc12 and fc13

[Frank Ch. Eigler]

Zhiwei Ying <zhiwei.ying@gmail.com> writes:

> [...]  If I compiled the trace.ko on fc13, then everything is
> fine. The trace log is generated correctly. But if I compiled the
> trace.ko on fc12, whatever I use the stap on fc12 or compile a
> systemtap 1.4 myself, I cannot see correct trace log on the board
> after running. [...]

One possibility is a mismatch between the version of stap on the host,
and the version of staprun installed on the board.  There was a
module<->staprun interface change in commit #3abb860f (in stap 1.4)
that was unfortunately not done in a cross-compatible manner.  You'd
see target kernel error (dmesg) messages of the form

    STP_RELOCATE message size mismatch (%lu vs %lu)

If you upgrade your staprun on the target, and your development stap,
it should work again.  We could change the next version of stap to
have its modules tolerate much older stapruns, if that's important.

- FChE