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Date: Thu, 20 Jan 2011 02:10:26 +0100
From: Johannes Weiner <hannes@cmpxchg.org>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: werner <w.landgraf@ru.ru>, Borislav Petkov <bp@amd64.org>,
        Ilya Dryomov <idryomov@gmail.com>, linux-mm <linux-mm@kvack.org>,
        linux-kernel@vger.kernel.org
Subject: Re: 2.6.38-rc1 problems with khugepaged
Message-ID: <20110120011026.GJ2232@cmpxchg.org>
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On Thu, Jan 20, 2011 at 01:01:47AM +0100, Andrea Arcangeli wrote:
> On Wed, Jan 19, 2011 at 10:45:23PM +0100, Johannes Weiner wrote:
> > Hi,
> > 
> > On Wed, Jan 19, 2011 at 04:59:54PM +0100, Borislav Petkov wrote:
> > > Adding some more parties to CC.
> > > 
> > > On Wed, Jan 19, 2011 at 09:45:25AM -0400, werner wrote:
> > > > **  Help   Help Help ***
> > > > 
> > > > My computer crashs on booting  ...   :( :(
> > 
> > That sucks!
> > 
> > I cross-compiled for 32-bit and was able to match up the disassembly
> > against the code line from your oops report.  Apparently the pte was
> > an invalid pointer, and it makes perfect sense: we unmap the highpte
> > _before_ we access the pointer again for __collapse_huge_page_copy().
> > 
> > Can you test with this fix applied?  It is only compile-tested, I too
> > have no 32-bit installations anymore.
> 
> Thanks Johannes, I already sent the same fix a few minutes ago, it is
> also confirmed to work from Ilya in Message-ID:
> <20110119224950.GA3429@kwango.lan.net>

Actually, I sent it half an hour before you ;-) But good to see that
it fixes the problem.

	Hannes