[Debian-med-packaging] Bug#906980: kmer: autopkgtest fails with segfault in testing/unstable while it passes in stable

[Andreas Tille]

Hi Liubov,

On Wed, Aug 22, 2018 at 09:42:13PM +0200, Liubov Chuprikova wrote:
> An autopkgtest fails with segfault in testing and unstable [1].
> 
> ```
> /usr/bin/../lib/atac/bin/statsGenerator -a /tmp/autopkgtest-lxc.epng5fx9/downtmp/autopkgtest_tmp/results/EcolivsSent.atac
> -p /tmp/autopkgtest-lxc.epng5fx9/downtmp/autopkgtest_tmp/results/stats/EcolivsSent
> -g A > /tmp/autopkgtest-lxc.epng5fx9/downtmp/autopkgtest_tmp/results/stats/EcolivsSent.stats
> 
> Segmentation fault
> Failed to ganerate statistics.
> ```
> 
> Notably, that building and testing in stable were successful (I tested
> it in clean chroot). JFI, I tried installing an older version of gcc on
> testing, the one that is used in stable (4:6.3.0-4), and this eliminated
> the segfault.

Thanks for this good catch which proves how important your Outreachy
project is for providing stable and working packages in Debian Med.
Thanks also for verifying that older compilers seem to produce working
code while newer don't.

I wonder whether you feel able to do some debugging what position of
code causes the issue.  My first shout would be to grep for
   "Failed to ganerate statistics"
which is probably in a wrapper around some code and than use some
debugging techniques (either you are comfortable with gdb / want to
become comfortable with gdb or simply use some 
    printf("DEBUG %s(%i): ...", __FILE__, __LINE__, ...);
statements in the code to watch what's happening.

It might be helpful to lower / switch off optimisation options to see
whether some optimisation feature of some later gcc will deal
differently with some not properly specified code part.

Please let me know if you need further advise.

Kind regards

        Andreas.

-- 
http://fam-tille.de