Re: [PATCHSET] timer: clean up initializers and implement irqsafetimers

From: Thomas Gleixner
Date: Tue Aug 14 2012 - 04:32:09 EST


On Mon, 13 Aug 2012, Tejun Heo wrote:
> Hello,
>
> On Wed, Aug 08, 2012 at 11:10:24AM -0700, Tejun Heo wrote:
> > Timer internals are protected by irqsafe lock but the lock is
> > naturally dropped and irq enabled while a timer is executed. This
> > makes dequeueing timer for execution and the actual execution
> > non-atomic against IRQs. No matter what the timer function does, IRQs
> > can occur between timer dispatch and execution. This means that an
> > IRQ handler could interrupt any timer in progress and it's impossible
> > for an IRQ handler to cancel and drain a timer.
>
> If nobody objects, I'll route this through wq/for-3.7 together with
> "workqueue: use irqsafe timer in delayed_work" patchset. If you
> object, please scream.

SCREAM!

I'll reply to the original posting later - still processing my
vacation backlog.

Thanks,

tglx
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