I have noticed the following line in the local log mochitst of locally created DEBUG version of C-C TB executed lately. ERROR psutil not available! Will wait 30s before attempting to kill parent process. This should not occur in mozilla automation. See bug 1143547. This is printed when a timeout occurs. (We need to figure out why timeout occurs and fix the cause, but that is another story.) Reading bug 1143547, I have a feeling we really should install python's psutil module. Since python3 seems to be the favorite these days, we should install python3's psutil module. I am usin Debian GNU/Linux and its package name is python3-psutil. I installed its debug module, python3-psutil-dbg. I wonder if this requirement of psutil module should be written in the prerequisite section of the necessary build and test tools in the documentation site. Chiaki PS: Earlier this year, when we switched to mochitest from |make mozmill| test, I seem to have had psutil module for python2.7 or some such version. But during the shuffle to switch to python3. psutil package for python3 was not installed. This is why I did not notice it. Also the particular code where psutil is invoked is only executed when a timeout occurs cleanly, it seems. Not always, that is. That is why it took me so long to realize it? OR, maybe because I have a few local patches that avoid strange crash of TB at the termination, thus TB may proceed a bit more now during shutdown without hitting the previously triggered assertions/aborts and the code hitherto unexecuted before may be executed now.