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From: Andrew Morton <akpm@linux-foundation.org>
To: Mel Gorman <mel@csn.ul.ie>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, pacman@kosh.dhis.org,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Christoph Lameter <cl@linux.com>, Yinghai Lu <yinghai@kernel.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?

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

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20101009095718.1775.qmail@kosh.dhis.org>
     [not found] ` <20101011143022.GD30667@csn.ul.ie>
2010-10-11 21:00   ` Andrew Morton [this message]
2010-10-13 14:40     ` PROBLEM: memory corrupting bug, bisected to 6dda9d55 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
2010-10-20 18:33                             ` pacman
2010-10-20 20:56                               ` Benjamin Herrenschmidt
2010-10-22  9:15                                 ` pacman
2010-10-27  8:57                                 ` Pegasos OHCI bug (was Re: PROBLEM: memory corrupting bug, bisected to 6dda9d55) pacman
2010-10-27 10:13                                   ` Olaf Hering
2010-10-27 21:04                                     ` Pegasos OHCI bug (was Re: PROBLEM: memory corrupting bug, pacman
2010-10-27 22:05                                       ` Segher Boessenkool
2010-10-27 22:58                                         ` pacman
2010-10-27 23:33                                           ` Segher Boessenkool
2010-10-28  1:11                                             ` pacman
2010-10-28 19:50                                               ` Segher Boessenkool
2010-10-28 21:07                                                 ` pacman
2010-10-29  0:16                                                   ` Segher Boessenkool
2010-11-05  6:43                                                     ` pacman
2010-11-29  5:44                                                       ` Benjamin Herrenschmidt
2010-10-27 13:27                                   ` Pegasos OHCI bug (was Re: PROBLEM: memory corrupting bug, bisected to 6dda9d55) Benjamin Herrenschmidt
2010-10-19 20:58                     ` PROBLEM: memory corrupting bug, bisected to 6dda9d55 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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