Re: [PATCH 1/2] perf diff: Fix segfault on perf diff -o N option

[Jiri Olsa <jolsa@redhat.com>]

On Wed, Jan 18, 2017 at 02:14:56PM +0900, Namhyung Kim wrote:
> The -o/--order option is to select column number to sort a diff result.
> It does the job by adding a hpp field at the beginning of the sort list.
> But it should not be added to the output field list as it has no
> callbacks required by a output field.
> 
> During the setup_sorting(), the perf_hpp__setup_output_field() appends
> given sort keys to the output field if it's not there already.
> 
> Originally it was checked by the fmt->list being non-empty.  But commit
> 3f931f2c4274 changed it to check the ->equal callback.  Anyway we don't
> need to add the pseudo hpp field to the output field list since it won't
> be used for output.  So just skip fields if they have no ->color or
>  ->entry callbacks.
> 
> Fixes: 3f931f2c4274 ("perf hists: Make hpp setup function generic")
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Acked-by: Jiri Olsa <jolsa@kernel.org>

thanks,
jirka

> ---
>  tools/perf/ui/hist.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/tools/perf/ui/hist.c b/tools/perf/ui/hist.c
> index 37388397b5bc..4ec79b2f9416 100644
> --- a/tools/perf/ui/hist.c
> +++ b/tools/perf/ui/hist.c
> @@ -560,6 +560,10 @@ void perf_hpp__setup_output_field(struct perf_hpp_list *list)
>  	perf_hpp_list__for_each_sort_list(list, fmt) {
>  		struct perf_hpp_fmt *pos;
>  
> +		/* skip sort-only fields ("sort_compute" in perf diff) */
> +		if (!fmt->entry && !fmt->color)
> +			continue;
> +
>  		perf_hpp_list__for_each_format(list, pos) {
>  			if (fmt_equal(fmt, pos))
>  				goto next;
> -- 
> 2.11.0
>