Date: Thu, 16 Aug 2012 19:53:24 +0100
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Tomas Racek <tracek@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@linux.intel.com>,
        Alan Cox <alan@linux.intel.com>, linux-kernel@vger.kernel.org,
        qemu-devel@nongnu.org
Subject: Re: x86, nops settings result in kernel crash
Message-ID: <20120816195324.5356cba0@pyramind.ukuu.org.uk>
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On Thu, 16 Aug 2012 14:45:15 -0400 (EDT)
Tomas Racek <tracek@redhat.com> wrote:

> ----- Original Message -----
> > On Thu, Aug 16, 2012 at 09:35:12AM -0400, Tomas Racek wrote:
> > > Hi,
> > > 
> > > I am writing a file system test which I execute in qemu with kernel
> > > compiled from latest git sources and running it causes this error:
> > > 
> > > https://bugzilla.kernel.org/show_bug.cgi?id=45971
> > > 
> > > It works with v3.5, so I ran git bisect which pointed me to:
> > > 
> > > d6250a3f12edb3a86db9598ffeca3de8b4a219e9 x86, nops: Missing break
> > > resulting in incorrect selection on Intel
> > > 
> > > To be quite honest, I don't understand this stuff much but I tried
> > > to do some debugging and I figured out (I hope) that the crash is
> > > caused by setting ideal_nops to p6_nops (k8_nops was used before
> > > the break statement was added).
> > 
> > Maybe I overlooked it or maybe it was implied but did you try
> > reverting
> > the patch and rerunning your test? Does it work ok then?
> > 
> 
> Yes, if I remove the break statement (introduced by this commit), it works fine.

What version of qemu is this - do we have qemu bug here I wonder.

Alan
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