On Sat, 20 Aug 2022 20:18:24 +0900 Masami Hiramatsu (Google) mhiramat@kernel.org wrote:
Do not assume that comm is a string. Not to mention, it currently forces comm fields to fault, as string processing for event probes is currently broken.
Indeed. There should be an event argument which names "comm". Eprobe might refer it. BTW, does eprobe use any special common fields? I originally introduced "$" variable for such special variables.
I used the '$' for denoting the fields, as it was the easiest way to integrate with trace_probe.c. There's no special variables, but this patch series now allows '@' as well as if $comm (or $COMM) is not a field, it acts the same as $comm for kprobes. Filtering and histograms do the same thing (use 'comm' as the event field, or has the current->comm if the event does not have 'comm' as a field). I should probably make "$common_comm" used too.
-- Steve