Re: Hmm.. WARN_ON_ONCE(cpuc->enabled)

From: Ingo Molnar
Date: Fri Feb 10 2012 - 01:11:10 EST



* David Ahern <dsahern@xxxxxxxxx> wrote:

> On 02/09/2012 04:46 PM, Linus Torvalds wrote:
> > Ok, so I get the appended on my Core i5 when I did a "perf record -f
> > -e cycles:pp make -j" on the kernel build.
> >
> > What's up, guys? I haven't tried that particular perf run in a while,
> > so it might have been going on for quite some time.
>
> Perhaps already fixed by
> https://lkml.org/lkml/2012/2/4/42
>
> It's not in your tree; but in tip/urgent.

That patch only fixed the symptom - there was an underlying bug
that is fixed in perf/urgent as well, via:

f39d47ff819e: perf: Fix double start/stop in x86_pmu_start()

I committed it two days ago - so it narrowly missed -rc3. Note
that no actual misbehavior is known to be caused by this bug,
beyond the annoying WARN_ONCE() messages and a potential slight
mis-measurement.

I'll send those fixes to Linus in a couple of hours.

Thanks,

Ingo
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