Re: [PATCH V2 1/1] lib/atomic64 using raw_spin_lock_irq[save|resotre]for atomicity

[Shan Hai]

On 09/01/2011 06:11 PM, Thomas Gleixner wrote:
> On Thu, 1 Sep 2011, Thomas Gleixner wrote:
>
> > On Thu, 1 Sep 2011, Shan Hai wrote:
> >
> > > The spin_lock_irq[save|restore] could break the atomicity of the
> > > atomic64_* operations in the PREEMPT-RT configuration, because
> > > the spin_lock_irq[save|restore] themselves are preemptable in the
> > > PREEMPT-RT, using raw variant of the spin lock could provide the
> > > atomicity that atomic64_* need.
> > Good catch. Queued for the next release.
> Though the changelog is misleading. The reason is not that they are
> preemtible.
>
> The reason for your OOPs is that the sleeping locks are not IRQ
> safe. And your system simply deadlocked due to that.

Will correct it in the V3 patch, thanks for the advice.

Cheers
Shan Hai

> Thanks,
>
> 	tglx
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