[SRU] lscpu reports incorrect number of NUMA nodes on systems with discontinuous NUMA nodes

[Matt Ezell]

[Impact]
Running 'lscpu' on a system with discontinuous NUMA nodes (such as some IBM Power 8 hardware) will only display the continuous NUMA nodes. Users may be confused due to incorrect information.

[Test Case]
On a system with discontinuous NUMA nodes, just run the lscpu command
# ls -d /sys/devices/system/node/node*
/sys/devices/system/node/node0 /sys/devices/system/node/node1 /sys/devices/system/node/node16 /sys/devices/system/node/node17
# lscpu|grep NUMA
NUMA node(s): 2
NUMA node0 CPU(s): 0-39
NUMA node1 CPU(s): 40-79

[Regression Potential]
Since this is an informational command, anything relying on its output may experience new behavior.

This affects Trusty, but Utopic and Vivid are based on newer upstream releases that don't include this error.

[Matt Ezell (ezellma)]

This was fixed upstream (http://git.kernel.org/cgit/utils/util-linux/util-linux.git/) by commit e9074a167cb485fea91be2cb20f68e137b6d3246. There have been many changes, so I don't think updating to the new version is appropriate for a SRU. To backport this, I had to also pull in code from 416c43a9a5519ae0e4c91e075cf42c5cf0b5cbcb and dd3bc51a539ffdd5c6c6b7d0b20acd1f61bdd337.

[Thomas Ward (teward)]

Nominated for Trusty. Since this is not affecting Utopic or Vivid, I've marked the master bug "Fix Released" as it's already fixed.

[Chris J Arges (arges)]

@ezellma:

Thanks for your contribution, bug report, and patch. I've reviewed and sponsored this for Trusty.

[Brian Murray (brian-murray)]

Hello Matt, or anyone else affected,

Accepted util-linux into trusty-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/util-linux/2.20.1-5.1ubuntu20.4 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Matt Ezell (ezellma)]

Verified that the update package produces the expected results on Trusty:

root@crest4:~# dpkg -l util-linux
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-==================================-======================-======================-=========================================================================
ii util-linux 2.20.1-5.1ubuntu20.3 ppc64el Miscellaneous system utilities
root@crest4:~# lscpu|grep NUMA
NUMA node(s): 2
NUMA node0 CPU(s): 0-39
NUMA node1 CPU(s): 40-79
root@crest4:~# apt-get install util-linux=2.20.1-5.1ubuntu20.4
...
root@crest4:~# lscpu|grep NUMA
NUMA node(s): 4
NUMA node0 CPU(s): 0-39
NUMA node1 CPU(s): 40-79
NUMA node16 CPU(s): 80-119
NUMA node17 CPU(s): 120-159

[Launchpad Janitor (janitor)]

This bug was fixed in the package util-linux - 2.20.1-5.1ubuntu20.4

---------------
util-linux (2.20.1-5.1ubuntu20.4) trusty; urgency=medium

  * Backport from util-linux upstream commit e9074a16 to support discontinuous
    NUMA nodes. This also pulls in code from upstream 416c43a9 and dd3bc51a to
    support the backport. (LP: #1419503)
 -- Matt Ezell <email address hidden> Tue, 10 Feb 2015 08:56:56 -0600

[Adam Conrad (adconrad)]

The verification of the Stable Release Update for util-linux has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.