Hi all, glibc 2.19 has changed the libc ABI on s390, more specifically the setjmp/longjmp functions [1] [2]. Symbol versioning is used to handle some cases, but it doesn't work when a jmp_buf variable is embedded into a structure, as it changes the size of the structure. The result is that mixing programs or libraries built with 2.18 with ones built with 2.19 do not work anymore, usually they end up with a segmentation fault. Some persons from this list have experienced that with perl. We first thought it was limited to a few packages (even if all perl is already more than that), but as time goes more and more issues are found. libpng and gauche are also affected, the issue with mono is also likely due to this ABI change. According to upstream [3], the problem is that Debian doesn't do a mass rebuild, which is the strategy chosen by Red Hat to handle^Wworkaround this issue. This means some programs might segfault during the upgrade, or on partially upgraded systems. Now we have to chose a strategy for Debian. I see multiple options: 1) Ignore the issue and just rebuild (binNMU) the packages that seems affected when we discover them. This means partial upgrades will likely be broken, and that we might discover some broken packages only after the jessie release. 2) Rebuild (binNMU) all packages. This means partial upgrades will likely be broken. 3) Bump the soname of affected packages and rebuild their reverse dependencies. It is the solution that is currently being implemented for perl. It clearly won't scale if more broken packages (and even for libpng) are discovered as it requires a source upload and a transition handled by the release team. It also means breaking the ABI compatibility with other distributions. 4) Bump the libc soname to libc.so.6.1 and do a libc transition. This is probably what upstream should have done instead of breaking the ABI. This is a huge work though, and this also means breaking the ABI compatibility with other distributions. 5) Revert the ABI change. This is likely just postponing the problem as the change is required to support future hardware. This also means breaking the ABI compatibility with other distributions. 6) simply drop the s390x port and tell users to either use an other distribution or use Debian on other hardware. Any opinion? Any other ideas how to handle that? Regards, Aurelien [1] http://sourceware.org/git/?p=glibc.git;a=commitdiff;h=ee4ec1d7f9bdbdfc87117133478cfb2f6653e65c [2] https://sourceware.org/glibc/wiki/Release/2.19#Packaging_Changes [3] https://sourceware.org/ml/libc-alpha/2014-07/msg00316.html -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurelien@aurel32.net http://www.aurel32.net
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