[Debian-med-packaging] Bug#907624: Help for SIGSEGV in test suite needed when built with gcc 8.2 what works nicely with gcc 6.3

[Andreas Tille]

Hi,

On Thu, Jan 10, 2019 at 02:14:14AM +0500, Andrey Rahmatullin wrote:
> On Wed, Jan 09, 2019 at 09:42:43PM +0100, Andreas Tille wrote:
> > to find the exact code line[2] where the SIGSEGV is thrown.  It turns out
> > that the elements of a structure are not accessible:
> > 
> >    (gdb) print entry->offset
> >    Cannot access memory at address 0x7
> It's because entry is 0x7.

When I was running the code with some more debugging info activated[1]
I had pretty valid looking adresses 0x555666 (or something in that line
just remembering by heart - can activate the patch if needed).  I have
no idea why the address is this without that extra debug code.
 
> > The values of the structure are set in line 350[3] and are OK there.
> The problem is not about the structure fields but about the structure
> pointer itself though.
> ...
> You need to find out why one of the tree nodes has an invalid address.

Can you propose any means to find this out?  I have no idea about
specific compiler differences.  BTW, I also tried to set -O0 but this
did not avoided the SIGSEGV.

Thanks for your hint anyway

      Andreas.

[1] https://salsa.debian.org/med-team/ffindex/blob/master/debian/patches/debug_segfault

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