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

[Jiri Olsa]

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@xxxxxxxxxx>
> Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>

with that checkpatch changes

Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>

thanks,
jirka