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Date: Wed, 11 Jan 2006 08:58:43 -0800
From: Octavio Alvarez Piza <alvarezp@alvarezp.ods.org>
To: Hugh Dickins <hugh@veritas.com>
Cc: Dave Jones <davej@redhat.com>, Arjan van de Ven <arjan@infradead.org>,
       Andrew Morton <akpm@osdl.org>, nickpiggin@yahoo.com.au,
       linux-kernel@vger.kernel.org
Subject: Re: mm/rmap.c negative page map count BUG.
Message-ID: <20060111085843.1d79e045@octavio.alvarezp.pri>
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On Wed, 11 Jan 2006 16:12:54 +0000 (GMT)
Hugh Dickins <hugh@veritas.com> wrote:

> On Wed, 11 Jan 2006, Octavio Alvarez Piza wrote:
> > On Thu, 05 Jan 2006 11:00:41 -0800
> > "Octavio Alvarez" <alvarezp@alvarezp.ods.org> wrote:
> > 
> > I have found another instance of "bad_page_state" with mapcount:-1
> > before hitting BUG_ON().
> > 
> > Bad page state at free_hot_cold_page (in process 'X', page c1140c60)
> > flags:0x80010008 mapping:00000000 mapcount:-65536 count:0
> 
> No, that's mapcount -65536 not -1.
> 

That's right, this might be a different issue. Now that it was X and not
"kswap0d" and that Arjan has asked me, I've realized that I'm using the
binary nVidia driver. I had gotten pretty much the same issue with the
open driver, though. Still, since I changed kernels to 2.6.15, I'll try
again to catch the bad page state with the nv free driver.
 
> That means page->_mapcount contained 0xfffeffff when it should have
> contained 0xffffffff.  A single bit got cleared.  Probably bad memory,
> overheating, something of that kind.

BTW, what's the first 8 in flags:0x80010008? I can't find 1<<31 in
include/linux/page-flags.h

Octavio.