From: Jiri Olsa <jolsa@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Don Zickus <dzickus@redhat.com>,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
Ingo Molnar <mingo@kernel.org>, Haren Myneni <hbabu@us.ibm.com>,
dong.su@ericsson.com, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [RFC] perf: Clear MSRs on kexec
Date: Tue, 4 Aug 2015 07:52:29 +0200 [thread overview]
Message-ID: <20150804055229.GD14481@krava.redhat.com> (raw)
In-Reply-To: <20150803215417.GG25159@twins.programming.kicks-ass.net>
On Mon, Aug 03, 2015 at 11:54:17PM +0200, Peter Zijlstra wrote:
> On Mon, Aug 03, 2015 at 11:32:28PM +0200, Jiri Olsa wrote:
> > hi,
> > I'm getting following message on the kdump kernel start
> >
> > Broken BIOS detected, complain to your hardware vendor.\
> > [Firmware Bug]: the BIOS has corrupted hw-PMU resources (MSR 38d is b0)
> >
> > it seems to be caused by NMI watchdog being configured
> > and fixed counter values stays in MSRs, which triggers
> > warning in check_hw_exists and disables perf support
> > in kdump kernel.. which probably does not hurt ;-)
> >
> > zeroing MSRs during kdump shutdown seems to work (attached)
> > but I'm not sure thats correct place for kdump perf callback
>
> Right, but why bother? All that kernel needs to do is write a memory
> dump to someplace and reboot, right? The less you do, the less can go
> wrong.
well, I was hunting that 'Broken BIOS..' message which is wrong
I wouldn't think anyone wants to use perf under kdump kernel,
but you never know ;-)
jirka
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WARNING: multiple messages have this Message-ID (diff)
From: Jiri Olsa <jolsa@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
Ingo Molnar <mingo@kernel.org>,
dong.su@ericsson.com, Vivek Goyal <vgoyal@redhat.com>,
Haren Myneni <hbabu@us.ibm.com>, Don Zickus <dzickus@redhat.com>
Subject: Re: [RFC] perf: Clear MSRs on kexec
Date: Tue, 4 Aug 2015 07:52:29 +0200 [thread overview]
Message-ID: <20150804055229.GD14481@krava.redhat.com> (raw)
In-Reply-To: <20150803215417.GG25159@twins.programming.kicks-ass.net>
On Mon, Aug 03, 2015 at 11:54:17PM +0200, Peter Zijlstra wrote:
> On Mon, Aug 03, 2015 at 11:32:28PM +0200, Jiri Olsa wrote:
> > hi,
> > I'm getting following message on the kdump kernel start
> >
> > Broken BIOS detected, complain to your hardware vendor.\
> > [Firmware Bug]: the BIOS has corrupted hw-PMU resources (MSR 38d is b0)
> >
> > it seems to be caused by NMI watchdog being configured
> > and fixed counter values stays in MSRs, which triggers
> > warning in check_hw_exists and disables perf support
> > in kdump kernel.. which probably does not hurt ;-)
> >
> > zeroing MSRs during kdump shutdown seems to work (attached)
> > but I'm not sure thats correct place for kdump perf callback
>
> Right, but why bother? All that kernel needs to do is write a memory
> dump to someplace and reboot, right? The less you do, the less can go
> wrong.
well, I was hunting that 'Broken BIOS..' message which is wrong
I wouldn't think anyone wants to use perf under kdump kernel,
but you never know ;-)
jirka
next prev parent reply other threads:[~2015-08-04 5:52 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-03 21:32 [RFC] perf: Clear MSRs on kexec Jiri Olsa
2015-08-03 21:32 ` Jiri Olsa
2015-08-03 21:54 ` Peter Zijlstra
2015-08-03 21:54 ` Peter Zijlstra
2015-08-04 5:52 ` Jiri Olsa [this message]
2015-08-04 5:52 ` Jiri Olsa
2015-08-04 7:46 ` Peter Zijlstra
2015-08-04 7:46 ` Peter Zijlstra
2015-08-04 13:57 ` Don Zickus
2015-08-04 13:57 ` Don Zickus
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