This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: Reverting the s390 jmp_buf/ucontext_t ABI change
- From: Florian Weimer <fweimer at redhat dot com>
- To: Dan Horák <dan at danny dot cz>, libc-alpha at sourceware dot org
- Date: Fri, 01 Aug 2014 09:11:42 +0200
- Subject: Re: Reverting the s390 jmp_buf/ucontext_t ABI change
- Authentication-results: sourceware.org; auth=none
- References: <20140801085035 dot 092c19d0e758cc59d119a0d0 at danny dot cz>
On 08/01/2014 08:50 AM, Dan Horák wrote:
I'm the main person behind Fedora for s390x and I have some objections
regarding this change. We had to cope with the breakage in 2.19 early
this year, it took some time to realize what's wrong and we found a
solution how to make it work. After some rebootstrapping work we have
used the planned mass rebuild to clean everything. Due some nasty gcc
4.9 bugs the rebuild on s390 finishes during these days. And you are
telling we should do it again? Sorry, but it is not possible, there is
only one mass rebuild planned in Fedora per release and now it's also
too late when we are approaching Fedora 21 Alpha deadline.
For the benefit of those reading along: s390 is a secondary architecture
in Fedora, which means that its release engineering is decoupled from
the primary architectures (which are i386, x86_64, armhfp). However,
all builds on secondary architectures exactly reproduce the builds on
primary architectures, both in terms of source code and installed build
dependencies in the build root. As a result, a mass rebuild on a
secondary architecture (with the proper tooling, see below) is only
possible if it happens on primary architectures as well.
I wonder if another mass rebuild will be scheduled on the primary
architectures to make sure that everything is built with a fixed GCC
because PR61801 seems to affect a lot of programs using inline assembly
(not just glibc).
> Fortunately I
still have the notes for the rebootstrap, so it can be done again (for
Fedora 22), but not now.
It should be considerably easier if you start with Fedora 20 because the
ABIs are fully compatible. In fact, if you revert the koji-shadow
database to its Fedora 20 state, and the mass rebuild in primary
happens, it should be mostly automatic. You could do the same for the
Fedora 22 bring-up, but due to the larger jump in versions, problematic
packages with tightly versioned cyclic build dependencies are more
likely to break.
This could perform a mass rebuild on s390x for Fedora 21 even without
one on primary, but it will result in RPM packages with the same
name/epoch/version/release/architecture which implement different ABIs,
which is rather undesirable.
--
Florian Weimer / Red Hat Product Security