Re: kvm: RCU warning in async pf

From: Gleb Natapov
Date: Mon Apr 16 2012 - 06:29:11 EST


On Sat, Apr 14, 2012 at 11:44:53AM +0200, Peter Zijlstra wrote:
> On Wed, 2012-04-04 at 15:30 +0300, Gleb Natapov wrote:
> >
> > @@ -253,7 +254,10 @@ do_async_page_fault(struct pt_regs *regs, unsigned long error_code)
> > kvm_async_pf_task_wait((u32)read_cr2());
> > break;
> > case KVM_PV_REASON_PAGE_READY:
> > + rcu_irq_enter();
> > + exit_idle();
> > kvm_async_pf_task_wake((u32)read_cr2());
> > + rcu_irq_exit();
> > break;
> > }
> > }
>
> Wouldn't irq_enter() / irq_exit() be more appropriate? You're basically
> taking an interrupt/exception from idle, irq_enter() will fix up
> everything that needs fixing up, including time sources (which the
> scheduler expects to be up-to-date).
>
You are right. Will send a patch.

--
Gleb.
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