Re: [PATCH 02/31] perf tools: Don't set cmdline_group_boundary if no evsel is collected

From: Jiri Olsa
Date: Tue Sep 01 2015 - 06:38:56 EST

On Mon, Aug 31, 2015 at 04:20:03PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Sat, Aug 29, 2015 at 04:21:36AM +0000, Wang Nan escreveu:
> > If parse_events__scanner() collects no entry, perf_evlist__last(evlist)
> > is invalid. Then setting of cmdline_group_boundary touches invalid.
> >
> > It could happend in currect BPF implementation. See [1]. Although it
> > can be fixed, for safety reason it whould be better to introduce this
> > check.
> >
> > Instead of checking number of entries, check data.list instead, so we
> > can add dummy evsel here.
> Event parsing fixes should have Jiri Olsa on the CC list, Jiri, is this
> ok?
> From what I can see it looks Ok, my question, just from looking at this
> patch, is if it is valid to get to this point with an empty data.list,
> i.e. was it ever possible and this is a bug irrespective of eBPF?

good point, I believe it's either fail or event(s) added to the list
I haven't checked how's eBPF connected with event parsing, is there a
git tree I could check?

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