Backport upstream bugfix in cpuidle to fix memory corruption

[bugproxy]

== Comment: #0 - Shilpasri G. Bhat <email address hidden> - 2015-04-10 14:35:43 ==
This is a request to backport upstream cpuidle bugfix for a memory corruption

d52356e7f48e powerpc: fix memory corruption by pnv_alloc_idle_core_states

Space allocated for paca is based off nr_cpu_ids, but pnv_alloc_idle_core_states()
iterates paca with cpu_nr_cores()*threads_per_core, which is using NR_CPUS.
This causes pnv_alloc_idle_core_states() to write over memory, which is outside
of paca array and may later lead to various panics.

Fixes: 7cba160ad789 (powernv/cpuidle: Redesign idle states management)

[Ubuntu Foundations Team Bug Bot (crichton)]

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[Chris J Arges (arges)]

This was already applied in Vivid.
$ git describe --contains 38fc1ab8c74ff9de5f779be9a985d0d9871458f3
Ubuntu-3.19.0-14.14~4