Mark vx and vxe as important hwcap to be able to provide differently tuned shared libraries.

Bug #1821200 reported by bugproxy
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Ubuntu on IBM z Systems
Canonical Foundations Team
glibc (Ubuntu)
Skipper Bug Screeners

Bug Description

Please pick the glibc commit "S390: Mark vx and vxe as important hwcap.". This commit is already cherry-picked to glibc 2.29 release branch:;a=commit;h=6eb48fe80cb6dd3ef536e86d005976d1c22b170e.
Note: This commit is also cherry-picked to glibc 2.27, 2.28 release branches.

This commit allows to have a library (e.g. libatlas) with different tunings, e.g. one with vx- and another one with vxe-instructions. With this patch, glibc chooses the "best" available version depending on the hwcaps reported by the kernel.

The correct locations for the different tuned libraries are:
-for z14 with vxe-support: /usr/lib/s390x-linux-gnu/vxe/
-for z13 with vx-support: /usr/lib/s390x-linux-gnu/vx/
-for all without vector-support: /usr/lib/s390x-linux-gnu/

As information:
One could also place the libraries into z13 or z14 subfolders. But e.g. if you run on a z13 and vector support is disabled (e.g. by specified kernel-parameter), the "z13" library with vector instructions is chosen - which is NOT allowed!

Contact Information =

---uname output---

Machine Type =

---Steps to Reproduce---
 see "problem description"

Userspace tool common name: glibc

Userspace rpm: libc6

The userspace tool has the following bit modes: both

Userspace tool obtained from project website: na

*Additional Instructions for :
-Attach ltrace and strace of userspace application.

bugproxy (bugproxy)
tags: added: architecture-s39064 bugnameltc-176286 severity-medium targetmilestone-inin1904
Changed in ubuntu:
assignee: nobody → Skipper Bug Screeners (skipper-screen-team)
affects: ubuntu → glibc (Ubuntu)
Changed in ubuntu-z-systems:
assignee: nobody → Canonical Foundations Team (canonical-foundations)
importance: Undecided → Medium
tags: added: id-5c93c113804f71397d34da01
Revision history for this message
Frank Heimes (fheimes) wrote :

Just for completeness reasons - this ticket derived from discussions at LP 1814796.

Changed in glibc (Ubuntu):
status: New → Fix Committed
Changed in ubuntu-z-systems:
status: New → Fix Committed
Revision history for this message
Dimitri John Ledkov (xnox) wrote :

submitted for consideration to be included in Disco.

Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package glibc - 2.29-0ubuntu2

glibc (2.29-0ubuntu2) disco; urgency=medium

  * debian/patches/git-updates.diff: Update from upstream stable branch,
    including "S390: Mark vx and vxe as important hwcap" (LP: #1821200)
  * debian/ XFAIL new tst-nss-test3 for disco.
  * debian/ Only restart services once each.
  * debian/patches/arm/unsubmitted-ldso-abi-check.diff: Fix rtld segv in
    dl_open() introduced via merge with upstream at 2.28 (LP: #1821677)
  * debian/ XFAIL new tst-support_descriptors.

 -- Adam Conrad <email address hidden> Sun, 07 Apr 2019 14:12:24 -0600

Changed in glibc (Ubuntu):
status: Fix Committed → Fix Released
Frank Heimes (fheimes)
Changed in ubuntu-z-systems:
status: Fix Committed → Fix Released
Revision history for this message
bugproxy (bugproxy) wrote : Comment bridged from LTC Bugzilla

------- Comment From <email address hidden> 2019-04-13 05:12 EDT-------
IBM Bugzilla status -> closed, Fix Released with Disco

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