[arch-general] valgrind - memory exclusion files on the fritz?

[Chi-Hsuan Yen]

On Wed, Nov 23, 2016 at 2:46 PM, David C. Rankin
<drankinatty at suddenlinkmail.com> wrote:
> On 11/23/2016 12:31 AM, Chi-Hsuan Yen via arch-general wrote:
>> In glibc, printf calls malloc. See
>> http://stackoverflow.com/questions/6743034/does-fprintf-use-malloc-under-the-hood
>
> Yes,
>
>   That's not the point. There is generally a know exclusion file that covers
> the memory used by fprintf, etc.. The reporting of the allocation and free by
> fprintf (if that is indeed the case here) should not be reported by valgrind.
>
>   The same code run on 4.8.7-1-ARCH #1 SMP PREEMPT Thu Nov 10 17:22:48 CET
> 2016 x86_64 GNU/Linux and on SuSE:
>
>
> valgrind ./bin/valgrindchk
> ==1974== Memcheck, a memory error detector
> ==1974== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
> ==1974== Using Valgrind-3.10.1 and LibVEX; rerun with -h for copyright info
> ==1974== Command: ./bin/valgrindchk
> ==1974==
>  s : 0123456789
> ==1974==
> ==1974== HEAP SUMMARY:
> ==1974==     in use at exit: 0 bytes in 0 blocks
> ==1974==   total heap usage: 1 allocs, 1 frees, 11 bytes allocated
> ==1974==
> ==1974== All heap blocks were freed -- no leaks are possible
> ==1974==
> ==1974== For counts of detected and suppressed errors, rerun with: -v
> ==1974== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 1 from 1)
>
>   Something is wrong with the Arch package.
>
> --
> David C. Rankin, J.D.,P.E.

As far as I know it's impossible (yet) to skip specific functions in
memory usage counters. Only memory leak reports can be filtered. And
things may be different on SuSE and Arch as they ship with different
glibc versions and/or patches.

Best,

Yen, Chi-Hsuan