Re: [PATCH -tip 1/4] perf/probe: Improve error message for unknown member of data structure

[Patrick Palka]

On Fri, Jun 6, 2014 at 3:13 AM, Masami Hiramatsu
<masami.hiramatsu.pt@xxxxxxxxxxx> wrote:
> Improve the error message if we can not find given member in
> the given structure. Currently perf probe shows a wrong error
> message as below.
>
>   -----
>   # perf probe getname_flags:65 "result->BOGUS"
>   result(type:filename) has no member BOGUS.
>   Failed to find 'result' in this function.
>     Error: Failed to add events. (-22)
>   -----
>
> The first message is correct, but the second one is not, since
> we didn't fail to find a variable but fails to find the member
> of given variable.
>
>   -----
>   # perf probe getname_flags:65 "result->BOGUS"
>   result(type:filename) has no member BOGUS.
>     Error: Failed to add events. (-22)
>   -----
>
> With this patch, the error message shows only the first one.
> And if we really failed to find given variable, it tells us so.
>
>   -----
>   # perf probe getname_flags:65 "BOGUS"
>   Failed to find 'BOGUS' in this function.
>     Error: Failed to add events. (-2)
>   -----
>
> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
> Reported-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
>  tools/perf/util/probe-finder.c |    5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index 9d8eb26..ce8faf4 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -573,14 +573,13 @@ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
>         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
>                 /* Search again in global variables */
>                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
> +                       pr_warning("Failed to find '%s' in this function.\n",
> +                                  pf->pvar->var);
>                         ret = -ENOENT;

It looks like you're missing a pair of braces here.
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