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-- 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: linux (Ubuntu)
     Importance: Undecided
     Assignee: Taco Screen team (taco-screen-team)
         Status: New


** Tags: architecture-ppc64le bugnameltc-146759 severity-critical 
targetmilestone-inin16041
-- 
ISST-LTE:pNV: ppc64_cpu command is hung w HDs, SSDs and NVMe
https://bugs.launchpad.net/bugs/1662666
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