Hi Satoru, I think you also meant to attach the stplog.c (and its own Makefile?) to your post? Is the format of the trace data used by systemtap always the same? I.e., is it always a kernel buffer filled with ASCII data? You mention that the command makes a file in a subdirectory of the running crash session. Wouldn't it be more flexible to dump the output to the terminal? And then if you want to save it to a file, just do something like this: crash> stplog -m mod_name > outputfile