On 12/1/13, 10:59 PM, Masami Hiramatsu wrote:
> (2013/12/02 9:07), David Ahern wrote:
>> When requesting a function from a userspace library the error message to
>> the user is less than helpful. e.g.,
>>
>> perf probe -x /lib64/libpthread-2.14.90.so -a
>> 'lock_full=__pthread_mutex_lock_full'
>> no symbols found in /lib64/libpthread-2.14.90.so, maybe install a debug
>> package?
>> Failed to load map.
>> Error: Failed to add events. (-22)
>>
>> In this cae the symbol really does exist but is a local symbol which is
>> filtered:
>>
>> nm /lib64/libpthread-2.14.90.so | grep __pthread_mutex_lock_full
>> 0000000000005700 t __pthread_mutex_lock_full
>>
>> With this patch:
>> perf probe -x /lib64/libpthread-2.14.90.so -a
>> 'lock_full=__pthread_mutex_lock_full'
>>
>> no symbols found in /lib64/libpthread-2.14.90.so, maybe install a debug
>> package?
>> Failed to find function in /lib64/libpthread-2.14.90.so. Perhaps it is
>> a local variable?
>
> Hmm, indeed current message is too less information, but your message looks
> wired. I think just showing "Failed to find requested symbol in %s" is
> enough. :)
I disagree. perf-probe filters non-global variables:
if (sym->binding == STB_GLOBAL &&
strfilter__compare(available_func_filter, sym->name))
return 0;
That needs to be explicitly stated in the error message -- only global
symbols may be given.
Between the 2 original error messages I wasted 2 hours strace'ing perf
looking at files -- including all the debuginfo variants -- that perf
opens. nm/objdump and every other tool sees the symbols yet perf throws
out bizarre error messages -- "no symbols found in ..." and "Failed to
load map". Let's fix those messages with something meaningful.
David
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
