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Re: Porter roll call for Debian Stretch



Hello,

On 30 August 2016 at 23:07, Lucas Nussbaum <lucas@debian.org> wrote:
> On 22/08/16 at 19:12 +0200, Bálint Réczey wrote:
>> Hi Guillem,
>>
>> 2016-08-21 14:02 GMT+02:00 Guillem Jover <guillem@debian.org>:
>> > Hi!
>> >
>> > On Sun, 2016-08-21 at 10:24:42 +0200, Bálint Réczey wrote:
>> >> I'm testing a set of patches [2] for gcc and dpkg which enable bindnow for all
>> >> arches and PIE for amd64, ppc64el and s390x in sync with Ubuntu.
>> >>
>> >> My assumption was that this set of architectures need the least amount of
>> >> additional work since they are tested already in Ubuntu, but I would be happy
>> >> if more ports would opt in for PIE.
>> >>
>> >> I plan filing wishlist bugs against dpkg and gcc with the patches
>> >> after I rebuilt a
>> >> few packages with the defaults.
>> >
>> > TBH I think PIE should in fact be safer to enable globally than
>> > bindnow, because the latter changes the run-time behavior and things
>> > might break (perhaps even silently) when failing to load plugins
>> > or similar.
>>
>> Yes, in that sense enabling PIE is safer indeed. Regarding bindnow
>> I don't expect too many surprises either, since other distributions
>> already tested enabling bindnow and probably they found
>> most issues.
>>
>> >
>> > From dpkg PoV enabling both, would at least require a full-archive
>> > rebuild, for bindnow ideally also a full autopkgtest run (as the
>> > updated dpkg FAQ states now, after Lucas Nussbaum approached me some
>> > weeks ago mentioning he was willing to do such archive-wide rebuild).
>>
>> The patches at [2] seem to work well and since you expressed that you would
>> prefer changing both toolchain and dpkg, too, I would like to suggest running
>> the rebuild with those patches.
>>
>> I think Matthias would be OK with the patch since it is very small and brings
>> Debian's gcc closer to Ubuntu's.
>>
>> Lucas, could you please run the rebuild with the three patches?
>
> Hi,
>
> Results are available at
> https://people.debian.org/~lucas/logs/2016/08/30/pie-bindnow-20160830/
>
> I did a full rebuild with bindnow and PIE enabled, then rebuilt all
> failed packages with a pristine unstable chroot.
>
> You can take a look at
> https://people.debian.org/~lucas/logs/2016/08/30/pie-bindnow-20160830/diff.txt
> and grep for "OK Failed" (failed with PIE+bindnow, built fine in
> unstable). (There are 1188 packages failing to build)
>
> Logs for both builds are available in the respective subdirectories.
>
> Lucas
>

Are you sure these are correct? The numbers for PIE+bindnow are a lot
higher than what we see in Ubuntu, for same unmodified packages.

E.g. looking at http://qa.ubuntuwire.org/ftbfs/

amd64/ppc64el/s390x have PIE+bindnow enabled, and
i386/armhf/arm64/powerpc do not. here is nothing in the thousands
range. There might be a dozen packages with PIE+bindnow fixes in
ubuntu, that's not in debian, but that amount cannot be more than a
dozen or two.

Looking at e.g. ace buildlog the PIE+bindnow has this:
-fno-PIE -no-pie -Wl,-z,relro -Wl,-z,now

Which is bindnow without pie, instead of with pie.

And same ace build fine in Ubuntu, with PIE+bindnow on the relevant
arches. https://launchpad.net/ubuntu/+source/ace/6.3.3+dfsg-1.1

-- 
Regards,

Dimitri.


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