Re: [PATCH v5 2/2] perf parse: Copy string to perf_evsel_config_term

[Leo Yan <leo.yan@linaro.org>]

On Tue, Jan 14, 2020 at 10:12:28AM +0100, Jiri Olsa wrote:
> On Mon, Jan 13, 2020 at 11:18:06PM +0800, Leo Yan wrote:
> > perf with CoreSight fails to record trace data with command:
> > 
> >   perf record -e cs_etm/@tmc_etr0/u --per-thread ls
> >   failed to set sink "" on event cs_etm/@tmc_etr0/u with 21 (Is a
> >   directory)/perf/
> > 
> > This failure is root caused with the commit 1dc925568f01 ("perf
> > parse: Add a deep delete for parse event terms").
> > 
> > The log shows, cs_etm fails to parse the sink attribution; cs_etm event
> > relies on the event configuration to pass sink name, but the event
> > specific configuration data cannot be passed properly with flow:
> > 
> >   get_config_terms()
> >     ADD_CONFIG_TERM(DRV_CFG, term->val.str);
> >       __t->val.str = term->val.str;
> >         `> __t->val.str is assigned to term->val.str;
> > 
> >   parse_events_terms__purge()
> >     parse_events_term__delete()
> >       zfree(&term->val.str);
> >         `> term->val.str is freed and assigned to NULL pointer;
> > 
> >   cs_etm_set_sink_attr()
> >     sink = __t->val.str;
> >       `> sink string has been freed.
> > 
> > To fix this issue, in the function get_config_terms(), this patch
> > changes to use strdup() for allocation a new duplicate string rather
> > than directly assignment string pointer.
> > 
> > This patch addes a new field 'free_str' in the data structure
> > perf_evsel_config_term; 'free_str' is set to true when the union is used
> > as a string pointer; thus it can tell perf_evsel__free_config_terms() to
> > free the string.
> > 
> > Fixes: 1dc925568f01 ("perf parse: Add a deep delete for parse event terms")
> > Suggested-by: Jiri Olsa <jolsa@kernel.org>
> > Signed-off-by: Leo Yan <leo.yan@linaro.org>
> 
> with that checkpatch changes
> 
> Acked-by: Jiri Olsa <jolsa@kernel.org>

Will fix checkpath warnings and resend patch v6.

Thanks you/Mathieu/Andi's reviewing.

Leo