Re: [PATCH 2/5] perf tools: Fix segfault on dynamic entries

[Jiri Olsa <jolsa@redhat.com>]

On Sun, Feb 21, 2016 at 11:22:35PM +0900, Namhyung Kim wrote:
> The dynamic entry is created for each tracepoint event.  When it sets up
> the sort key, it checks with existing keys using ->equal() callback.
> But it missed to set the ->equal for dynamic entries.  The following
> segfault was due to the missing ->equal() callback.
> 
>   (gdb) bt
>   #0  0x0000000000140003 in ?? ()
>   #1  0x0000000000537769 in fmt_equal (b=0x2106980, a=0x21067a0) at ui/hist.c:548
>   #2  perf_hpp__setup_output_field (list=0x8c6d80 <perf_hpp_list>) at ui/hist.c:560
>   #3  0x00000000004e927e in setup_sorting (evlist=<optimized out>) at util/sort.c:2642
>   #4  0x000000000043cf50 in cmd_report (argc=<optimized out>, argv=<optimized out>, prefix=<optimized out>)
>       at builtin-report.c:932
>   #5  0x00000000004865a1 in run_builtin (p=p@entry=0x8bbce0 <commands+192>, argc=argc@entry=7,
>       argv=argv@entry=0x7ffd24d56ce0) at perf.c:390
>   #6  0x000000000042dc1f in handle_internal_command (argv=0x7ffd24d56ce0, argc=7) at perf.c:451
>   #7  run_argv (argv=0x7ffd24d56a70, argcp=0x7ffd24d56a7c) at perf.c:495
>   #8  main (argc=7, argv=0x7ffd24d56ce0) at perf.c:620
> 
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>

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

thanks,
jirka

> ---
>  tools/perf/util/sort.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
> index de715756f281..7daea71691df 100644
> --- a/tools/perf/util/sort.c
> +++ b/tools/perf/util/sort.c
> @@ -1835,6 +1835,20 @@ bool perf_hpp__is_dynamic_entry(struct perf_hpp_fmt *fmt)
>  	return fmt->cmp == __sort__hde_cmp;
>  }
>  
> +static bool __sort__hde_equal(struct perf_hpp_fmt *a, struct perf_hpp_fmt *b)
> +{
> +	struct hpp_dynamic_entry *hde_a;
> +	struct hpp_dynamic_entry *hde_b;
> +
> +	if (!perf_hpp__is_dynamic_entry(a) || !perf_hpp__is_dynamic_entry(b))
> +		return false;
> +
> +	hde_a = container_of(a, struct hpp_dynamic_entry, hpp);
> +	hde_b = container_of(b, struct hpp_dynamic_entry, hpp);
> +
> +	return hde_a->field == hde_b->field;
> +}
> +
>  static void hde_free(struct perf_hpp_fmt *fmt)
>  {
>  	struct hpp_dynamic_entry *hde;
> @@ -1867,6 +1881,7 @@ __alloc_dynamic_entry(struct perf_evsel *evsel, struct format_field *field)
>  	hde->hpp.cmp = __sort__hde_cmp;
>  	hde->hpp.collapse = __sort__hde_cmp;
>  	hde->hpp.sort = __sort__hde_cmp;
> +	hde->hpp.equal = __sort__hde_equal;
>  	hde->hpp.free = hde_free;
>  
>  	INIT_LIST_HEAD(&hde->hpp.list);
> -- 
> 2.7.1
>