On Wed, Oct 09, 2024 at 10:41:42PM +0200, Jiri Olsa wrote: > > AFAICS we'd need to do roughly: > > - for each tracepoint we'd need to interpret one of the functions > > where TP_fast_assign macro gets unwinded: > > perf_trace_##call > > trace_custom_event_raw_event_##call > > trace_event_raw_event_##call > > - we can't tell at this point which argument is kernel object, > > so we'd need to check all arguments (assuming we can get their count) > > - store argument info (if it has null check) into some elf tables and > > use those later in bpf verifier > > - it's all arch specific > > > > on first look it seems hard and fragile (given it's arch specific) > > but I might be easily wrong with above.. do you have an idea on how > > this could work? > > Hi Josh, > we'd like to have information on which of tracepoint's arguments can be NULL > > Steven had an idea that objtool could help with that by doing something like > what's described above.. would you have any thoughts on that? Objtool doesn't know anything about function arguments, I'm not sure how this could be done unless I'm missing something. -- Josh
