Private bug reported: The kernel patch(es) of LP 1743560 'KVM patches for s390x to provide facility bits 81 (ppa15) and 82 (bpb)' (accepted upstream) introduced a problem due to spurious zeroing of r0.
The following fix is addressing this: s390/entry.S: fix spurious zeroing of r0 https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git/commit/?h=fixes&id=d3f468963cd6fd6d2aa5e26aed8b24232096d0e1 If our X, A and B kernels are affected by the above issue (what is probably the case if the upstream patches got used), then the fix/patch (commit d3f468963cd6fd6d2aa5e26aed8b24232096d0e1) needs to be applied, too. ** Affects: ubuntu-z-systems Importance: Critical Assignee: Canonical Kernel Team (canonical-kernel-team) Status: New ** Affects: linux (Ubuntu) Importance: Undecided Status: New ** Tags: s390x ** Information type changed from Public to Private ** Also affects: ubuntu-z-systems Importance: Undecided Status: New ** Changed in: ubuntu-z-systems Importance: Undecided => Critical ** Changed in: ubuntu-z-systems Assignee: (unassigned) => Canonical Kernel Team (canonical-kernel-team) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1754047 Title: Fix spurious zeroing of r0 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1754047/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs