gdb 6.7.1 still failed (it was however very easily reproductible once I understood what was happening).
I finally find an external and better description and a fix for this problem: http://sourceware.org/ml/gdb-patches/2007-11/msg00136.html ... Upgrading to 6.7.1 and patching gdb with the patch file mentioned on the email thread fixed this for me. It's merged upstream, and further revisions should no longer be a problem.
