Comment 24 for bug 1640547

stress-ng was at 0.05.23-1ubuntu2 for the above tests.

I have now upgraded stress-ng from the package in Xenial to that from Zesty:

$ sudo apt-cache policy stress-ng
stress-ng:
  Installed: 0.07.08-1
  Candidate: 0.07.08-1
  Version table:
 *** 0.07.08-1 500
        500 http://ports.ubuntu.com/ubuntu-ports zesty/universe ppc64el Packages
        100 /var/lib/dpkg/status
     0.05.23-1ubuntu2 500
        500 http://ports.ubuntu.com/ubuntu-ports xenial-updates/universe ppc64el Packages
     0.05.23-1 500
        500 http://ports.ubuntu.com/ubuntu-ports xenial/universe ppc64el Packages

$ sudo stress-ng --sync-file 1
stress-ng: info: [2626] defaulting to a 86400 second run per stressor
stress-ng: info: [2626] dispatching hogs: 1 sync-file
stress-ng: info: [2626] cache allocate: using built-in defaults as unable to determine cache details
stress-ng: info: [2626] cache allocate: default cache size: 2048K
stress-ng: info: [2627] stress-ng-sync-file: this stressor is not implemented on this system: ppc64le Linux 4.4.0-51-generic
stress-ng: info: [2626] successful run completed in 0.00s

Mind you, this sync-file stressor is more of a red herring and isn't the cause of the system lockups.

I have also found that this bug shows up on all 3 open power servers running petitboot that I have access to at the moment. If I had access to a Tuleta, I'm going to guess this would also affect that as well. I have a good feeling this is just like the memory test[0] (still not resolved). As of now, the stress_ng memory and disk tests both fail with really similar results (system/session lockup).

[0] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1573062