On Wed, Jul 16, 2014 at 21:17:32 +0200,
  Dietmar Eggemann <dietmar.eggemann@arm.com> wrote:
>Hi Bruno and Josh,
>
>From the issue, I see that the machine making trouble is an Xeon (2 
>processors w/ hyper-threading).
>
>Could you please share:
>
> cat /proc/cpuinfo and

I have attached it to the bug and to this message.

> cat /proc/schedstat (kernel config w/ CONFIG_SCHEDSTATS=y)

It looks like that isn't set for my previous builds and I'll need to 
set it for my next test build.

>Could you also put the two BUG_ON lines into build_sched_groups() 
>[kernel/sched/core.c] wo/ the cpumask_clear() and setting 
>sg->sgc->capacity to 0 and share the possible crash output as well?

I can try a new build with this. I can probably get results back tomorrow 
before I leave for work. The crashes happen too early in the boot process 
for me to easily capture output as text. I can slow things down to take 
pictures though.