linux-kernel - Re: 2.6.34-rc2 - crash on shutdown

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Date:	Wed, 24 Mar 2010 00:27:33 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Stephane Eranian <eranian@...gle.com>
Cc:	Clemens Ladisch <clemens@...isch.de>,
	David R <david@...olicited.net>, linux-kernel@...r.kernel.org
Subject: Re: 2.6.34-rc2 - crash on shutdown

On Tuesday 23 March 2010, Stephane Eranian wrote:
> On Tue, Mar 23, 2010 at 11:18 PM, Rafael J. Wysocki <rjw@...k.pl> wrote:
> > On Tuesday 23 March 2010, Clemens Ladisch wrote:
> >> Stephane Eranian wrote:
> >> > On Tue, Mar 23, 2010 at 1:02 PM, Clemens Ladisch <clemens@...isch.de> wrote:
> >> > > The only pointer access in this function is cpuhw->amd_nb, but
> >> > > I don't see any obvious bugs.
> >> >
> >> > I reported a problem with the AMD initialization just last week.
> >> > There is an issue with amd_pmu_cpu_online() which gets called
> >> > too early, and thus fails. That leaves some bogus state and causes
> >> > a crash in amd_pmu_cpu_offline().
> >> >
> >> > I proposed a fix which was rejected. The alternative involves moving
> >> > some the of CPU initialization code (on AMD) to an earlier position,i.e.,
> >> > which would be executed before the CPU_STARTED notifier. Nobody
> >> > has proposed anything else so far.
> >>
> >> I don't know about the early bootmem stuff, but regardless of this issue,
> >> if amd_pmu_cpu_online() can fail, then amd_pmu_cpu_offline() must be able
> >> to handle this without blowing up.  Something like this (untested):
> >
> > I guess we handle that already:
> >
> > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=a90110c61073eab95d1986322693c2b9a8a6a5f6
> >
> Ok, the fix avoids the crash but perf_events support for AMD is still broken.
> 
> The root of the problem is elsewhere as I pointed out last week. Peter proposed
> a patch today and I think this would be enough to avoid the crash and have
> perf_events working again on AMD.

Yes, I saw the Peter's patch.

Thanks,
Rafael
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