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

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

(2014/06/22 3:18), Patrick Palka wrote:
> On Fri, Jun 6, 2014 at 3:13 AM, Masami Hiramatsu
> <masami.hiramatsu.pt@hitachi.com> 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@hitachi.com>
>> Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
>> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
>> Cc: Paul Mackerras <paulus@samba.org>
>> Cc: Ingo Molnar <mingo@redhat.com>
>> Cc: Namhyung Kim <namhyung@kernel.org>
>> Cc: Jiri Olsa <jolsa@redhat.com>
>> ---
>>  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.

Oops, right! Thank you very much!

-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com