There exists a dependency of psmisc that is not included in the portage tree. The command killall aborts with "stack smashing attack in function kill_all" When psmisc is recompiled the problem goes away. Reproducible: Didn't try Steps to Reproduce: 1. 2. 3.
are you using -fstack-protector or hardened-gcc?
we really need more information before we can help you ... `emerge info` would be needed per the bug report page as for 'dependency in psmisc', i have no idea what that means