From: Peter Zijlstra <peterz@infradead.org>
To: Jiri Olsa <jolsa@redhat.com>
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: Mon, 3 Aug 2015 23:54:17 +0200 [thread overview]
Message-ID: <20150803215417.GG25159@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20150803213228.GC14481@krava.redhat.com>
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.
next prev parent reply other threads:[~2015-08-03 21:54 UTC|newest]
Thread overview: 5+ 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 21:54 ` Peter Zijlstra [this message]
2015-08-04 5:52 ` Jiri Olsa
2015-08-04 7:46 ` Peter Zijlstra
2015-08-04 13:57 ` Don Zickus
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150803215417.GG25159@twins.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=dong.su@ericsson.com \
--cc=dzickus@redhat.com \
--cc=hbabu@us.ibm.com \
--cc=jolsa@redhat.com \
--cc=kexec@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=vgoyal@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox