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From: Andrew Morton <akpm@linux-foundation.org>
To: Mel Gorman <mel@csn.ul.ie>
Cc: pacman@kosh.dhis.org, linux-mm@kvack.org,
	Christoph Lameter <cl@linux.com>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Yinghai Lu <yinghai@kernel.org>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: PROBLEM: memory corrupting bug, bisected to 6dda9d55
Date: Mon, 11 Oct 2010 14:00:39 -0700	[thread overview]
Message-ID: <20101011140039.15a2c78d.akpm@linux-foundation.org> (raw)
In-Reply-To: <20101011143022.GD30667@csn.ul.ie>

(cc linuxppc-dev@lists.ozlabs.org)

On Mon, 11 Oct 2010 15:30:22 +0100
Mel Gorman <mel@csn.ul.ie> wrote:

> On Sat, Oct 09, 2010 at 04:57:18AM -0500, pacman@kosh.dhis.org wrote:
> > (What a big Cc: list... scripts/get_maintainer.pl made me do it.)
> > 
> > This will be a long story with a weak conclusion, sorry about that, but it's
> > been a long bug-hunt.
> > 
> > With recent kernels I've seen a bug that appears to corrupt random 4-byte
> > chunks of memory. It's not easy to reproduce. It seems to happen only once
> > per boot, pretty quickly after userspace has gotten started, and sometimes it
> > doesn't happen at all.
> > 
> 
> A corruption of 4 bytes could be consistent with a pointer value being
> written to an incorrect location.

It's corruption of user memory, which is unusual.  I'd be wondering if
there was a pre-existing bug which 6dda9d55bf545013597 has exposed -
previously the corruption was hitting something harmless.  Something
like a missed CPU cache writeback or invalidate operation.

How sensitive/vulnerable is PPC32 to such things?

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  parent reply	other threads:[~2010-10-11 21:02 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-09  9:57 PROBLEM: memory corrupting bug, bisected to 6dda9d55 pacman
2010-10-11 12:52 ` Christoph Lameter
2010-10-11 14:30 ` Mel Gorman
2010-10-11 20:35   ` pacman
2010-10-11 21:00   ` Andrew Morton [this message]
2010-10-13 14:40     ` Mel Gorman
2010-10-13 17:52       ` pacman
2010-10-18 11:33         ` Mel Gorman
2010-10-18 19:10           ` pacman
2010-10-18 21:10             ` Benjamin Herrenschmidt
2010-10-18 21:33               ` pacman
2010-10-19 10:16                 ` Benjamin Herrenschmidt
2010-10-19 18:10                   ` pacman
2010-10-19 20:47                     ` Segher Boessenkool
2010-10-19 21:02                       ` Benjamin Herrenschmidt
2010-10-20  3:23                         ` pacman
2010-10-20 10:32                           ` Benjamin Herrenschmidt
2010-10-19 20:58                     ` Benjamin Herrenschmidt
2010-10-18 19:37           ` Andrew Morton
2010-10-18 21:02             ` Benjamin Herrenschmidt
2010-10-18 21:55             ` Thomas Gleixner
2010-10-19 16:24               ` Helmut Grohne
2010-10-19 16:42                 ` Thomas Gleixner
2010-10-18 20:59       ` Benjamin Herrenschmidt

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