Hi Oleg, the ptrace-testsuite http://sourceware.org/systemtap/wiki/utrace/tests currently FAILs (also) on Fedora 12 kernel-2.6.31.1-48.fc12.x86_64 for: FAIL: detach-stopped FAIL: stopped-attach-transparency Do you agree with the testcases and is it planned to fix them for F12? Thanks, Jan