Re: Confusing behaviour with /proc/sys/kernel/nmi_watchdog

From: Anton Blanchard
Date: Tue Jan 20 2015 - 22:39:48 EST


Hi Andrew,

> On Wed, Nov 05, 2014 at 09:34:20AM +1100, Anton Blanchard wrote:
> > commit 9919e39a1738 ("kvm: ensure hard lockup detection is disabled
> > by default") provided a way for the kernel to disable the hard
> > lockup detector at runtime.
> >
> > I'm using it on ppc64 but notice some weird behaviour with the
> > nmi_watchdog procfs variable. At boot, that the hard lockup
> > detector appears to be enabled even when we disable it via
> > watchdog_enable_hardlockup_detector(false):
> >
> > # cat /proc/sys/kernel/nmi_watchdog
> > 1
> >
> > I have to echo 0 to it then echo 1 again to enable it.
> >
> > Anton
>
> Hi Anton,
>
> Yes, the nmi watchdog proc variables are currently a bit
> confusing. Uli has posted a series to clear all that up
> though. Please see
>
> https://lkml.org/lkml/2014/10/17/340

Any progress on this? I'm rebasing our hardware NMI patch for ppc64 and
notice the strange behaviour is still in mainline.

Anton
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