Possible regression due to "hrtimer: Get rid of hrtimer softirq"

Simon Horman [off-list ref] writes:

Hi Thomas,

On Thu, May 07, 2015 at 02:35:59PM +0200, Thomas Gleixner wrote:

quoted

On Thu, 7 May 2015, Simon Horman wrote:

quoted

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kernel BUG at kernel/irq_work.c:135!

  BUG_ON(!irqs_disabled());

So something enables interrupts in the periodic tick handling
machinery. Seems you have high resolution timers disabled, but nohz
enabled. And that code path has a local_irq_disable/enable pair which
causes havoc. Patch below.

Thanks for your quick response. I have been able to confirm that
when applied on top of next-20150507 the problem I observed no longer
manifests. I have successfully tested it on all the boards
where I previously observed a problem.

If you are planning to formally submit the patch below feel free to add:

Tested-by: Simon Horman <redacted>

FWIW, I confirmed this fixed a boot hang on my kzm9d in next-20150507
also.

Tested-by: Kevin Hilman <redacted>