Re: [patch 2/2] x86: mce: Implement cmci poll mode for intel machines

[Chen Gong]

ä 2012/6/6 22:46, Thomas Gleixner åé:
> On Wed, 6 Jun 2012, Thomas Gleixner wrote:
>
> > On Wed, 6 Jun 2012, Chen Gong wrote:
> > > ä 2012/6/6 18:23, Thomas Gleixner åé:
> > > I think you mean
> > >
> > > -               del_timer_sync(t);
> > >                  smp_call_function_single(cpu, mce_disable_cpu,&action, 1);
> > > +		del_timer_sync(t);
> > >                  break;
> >
> > No I meant it the way I wrote, but as you don't execute hotplug it's
> > irrelevant.
> >
> > So the obvious candidate is the mce-injection code, which was
> > obviously never tested with DEBUG_PREEMPT enabled.
> >
> > raise_local() can be called with preemption enabled from
> > raise_mce(). Fix for that below.
> >
> > Though I can't see how that would do anything with the timer.
>
> I think I found it. Do you have CONFIG_NO_HZ enabled? Then mod_timer()
> will try to move the timer to a different cpu, when the cpu which is
> running that code is idle. Bloody obvious :(

Oh, yes, it works! mod_timer is really a naughty baby :-).
Now it passes the basic test, and then I will use your latest
patch series to test more scenarios.

> I'll send out a combo patch with all changes so far later.
>
> Thanks,
> 	
> 	tglx
>
> Index: linux-2.6/arch/x86/kernel/cpu/mcheck/mce.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/cpu/mcheck/mce.c
> +++ linux-2.6/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -1307,7 +1307,7 @@ void mce_timer_kick(unsigned long interv
>
>   	if (timer_pending(t)) {
>   		if (time_before(when, t->expires))
> -			mod_timer(t, when);
> +			mod_timer_pinned(t, when);
>   	} else {
>   		t->expires = round_jiffies(when);
>   		add_timer_on(t, smp_processor_id());

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