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Re: Distributions still suffering from s390 ABI change problems.


"Carlos O'Donell" <carlos@redhat.com> writes:

> Should we bump the soname for glibc on s390?

I think it's clear in retrospect that this is what should have happened
when the structure size changed.  Now, the situation is more muddled
because there are binaries with the current SONAME out in the wild with
both structure sizes.  In essence, there are two different libc ABIs with
the same SONAME, both of which are to some extent deployed.

That said, I think it still makes sense to change the SONAME at this
point.

The primary benefit of doing so is that we then have a stable SONAME that
is interoperable across distributions, namely the new one.  Binaries built
with that SONAME will work with any libc with that SONAME, which is the
situation that we want to get back into.  Unfortunately, the current
SONAME is something of a loss; we won't be able to return to a world in
which the same property is true of that SONAME since there are now two
ABIs in the wild.  But we can at least create a stable situation looking
forward.

The drawback of this approach is that it forces everyone to do a libc
SONAME migration for s390, even if they think that they could have dealt
with this change via a mass rebuild.  So it potentially means more work
for everyone.  But I'm dubious that you really *can* deal with this
situation with a mass rebuild.  That only gets the binaries that are part
of the distribution; locally-built Perl on s390, for example, is still
going to fail with the new libc, and distribution Perl is still going to
fail with the old libc.  So even a mass rebuild doesn't clear up the two
ABI problem.

The only way that not changing the ABI makes sense to me is if people feel
that they can just rebuild everything on s390 and redefine the current
SONAME as meaning the new ABI, and just be content with old binaries that
use that structure not working.  But that doesn't feel right to me.

-- 
Russ Allbery (eagle@eyrie.org)              <http://www.eyrie.org/~eagle/>


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