Re: [PATCH] perf symbol: Fix kernel symbol address display

From: Thomas Richter
Date: Fri Apr 24 2020 - 08:37:20 EST


On 4/20/20 10:46 PM, Arnaldo Carvalho de Melo wrote:
> Em Wed, Apr 15, 2020 at 09:07:44AM +0200, Thomas Richter escreveu:
>> Running commands
>>
>> ./perf record -e rb0000 -- find .
>> ./perf report -v
>
> Or when pressing 'V' in the TUI.
>
>> reveals symbol names and its addresses. There is a mismatch between
>
> Yeah, an address that at some point was put there to help with debugging
> the symbol resolution, IIRC how it looked like when looking at
>
> readelf -sW vmlinux
>
> Or any other DSO, for instance, for a glibc symbol here:
>
> Using 'perf report -s pid,dso,sym' then pressing 'V':
>
> 1.55% 20325:perf /usr/lib64/libc-2.30.so 0x161825 B [.] __strlen_avx2
>
> [acme@five perf]$ readelf -sW /usr/lib64/libc-2.30.so | grep strlen_avx2
> 24371: 0000000000161810 414 FUNC LOCAL DEFAULT 15 __strlen_avx2
> [acme@five perf]$
>
> Can you check if doing in /lib/modules/.../build/vmlinux produces what
> appears when 'V' is in place?
>
> And perhaps we can also show the DSO offset and the rip as it gets laid
> out in memory in the end? So we have all the informations?
>
> - Arnaldo
>

Arnaldo,

having verified this also works in the TUI mode using 'V', are you going to pick
this patch?

Thanks


--
Thomas Richter, Dept 3252, IBM s390 Linux Development, Boeblingen, Germany
--
Vorsitzender des Aufsichtsrats: Matthias Hartmann
GeschÃftsfÃhrung: Dirk Wittkopp
Sitz der Gesellschaft: BÃblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294