Re: [PATCH] x86/mce: fix failed to reenable cmci when swiching to interrupt mode

[Xie XiuQi]

On 2015/8/11 22:46, Borislav Petkov wrote:
> On Tue, Aug 11, 2015 at 06:09:37PM +0800, Xie XiuQi wrote:
> > Zhang Liguang report a bug as bellow:
> > 1) system detected cmci storm on current cpu
> > 2) disable cmci interrupt on banks ownd by current cpu, then swiching to poll mode
> > 3) a few minites later, system swiching to interrupt mode on current cpu
> > 4) we expect system to reenable cmci interrupt on banks ownd by current cpu
> >     mce_intel_adjust_timer
> >     |-> cmci_reenable
> >         |-> cmci_discover     # but, ownd banks is ignore here
> >
> > > static void cmci_discover(int banks)
> > > 	...
> > > 	for (i = 0; i < banks; i++) {
> > > 		...
> > > 		if (test_bit(i, owned))	# ownd banks is ignore here
> > > 			continue;
> >
> > In this patch, we add a func cmci_storm_enable_banks(), just to enable banks
> > which ownd by current cpu without clean the ownd flags. We call this func
> > instead of cmci_reenble() when swiching to interrupt mode.
>
> Hmm, and we cannot clear the owned bit because those banks won't be
> polled otherwise, see:
>
> 27f6c573e0f7 ("x86, CMCI: Add proper detection of end of CMCI storms")

OK, thanks.

> Yuck.
>
> Well, ok, but do it differently, please: rename
> cmci_storm_disable_banks() to cmci_storm_switch_banks(bool on) which
> turns them on and off. Unless Tony has a better suggestion...
>
> > Reported-by: Zhang Liguang <zhangliguang@xxxxxxxxxx>
> > Cc: stable@xxxxxxxxxxxxxxx  # v4.1+
>
> Why 4.1 only?

My fault, it's v3.15+.

Thanks,
Xie XiuQi

>

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