Comment 1 for bug 1662666

Steve,

Can Foundations take a look at this request, please.

                  Michael

On 02/07/2017 12:39 PM, Launchpad Bug Tracker wrote:
> bugproxy (bugproxy) has assigned this bug to you for Ubuntu:
>
> -- Problem Description --
> The following upstream patches are needed for Ubuntu to fix a hang situation reported when executing ppc64_cpu --smt=on that occurs with various disk types. We need whichever ones have not yet been pulled into the base.
>
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=e57690fe009b2ab0cee8a57f53be634540e49c9d
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=0e87e58bf60edb6bb28e493c7a143f41b091a5e5
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=135e8c9250dd5c8c9aae5984fde6f230d0cbfeaf
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c02ebfdddbafa9a6a0f52fbd715e6bfa229af9d3
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d1b1cea1e58477dad88ff769f54c0d2dfa56d923
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=36e1f3d107867b25c616c2fd294f5a1c9d4e5d09
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=71f79fb3179e69b0c1448a2101a866d871c66e7f
>
> The hang problem can be reproduced with the following shell script using
> an NVMe device executed on kernel versions 4.4.0-45 and 4.4.0-59 within
> 30 minutes. It was also reproduced on a 4.8.0-32-generic kernel,
> although it took over 3 hours to manifest.
>
> #!/bin/bash
>
> if [[ ${#} -eq 0 ]]; then
> ${0} breaker &
> while true; do
> dd if=/dev/nvme0n1 bs=1024k of=/dev/null
> done
> elif [[ ${1} == "breaker" ]]; then
> while true; do
> ppc64_cpu --smt=off
> sleep 5
> ppc64_cpu --smt=on
> sleep 5
> done
> fi
>
> ** Affects: ubuntu
> Importance: Undecided
> Assignee: Taco Screen team (taco-screen-team)
> Status: New
>
>
> ** Tags: architecture-ppc64le bugnameltc-146759 severity-critical targetmilestone-inin16041

--
Michael Hohnbaum
OIL Program Manager
Power (ppc64el) Development Project Manager
Canonical, Ltd.