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?
WARNING: multiple messages have this Message-ID (diff)
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?
WARNING: multiple messages have this Message-ID (diff)
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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next prev parent reply other threads:[~2010-10-11 21:02 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-09 9:57 PROBLEM: memory corrupting bug, bisected to 6dda9d55 pacman
2010-10-09 9:57 ` pacman
2010-10-11 12:52 ` Christoph Lameter
2010-10-11 12:52 ` Christoph Lameter
2010-10-11 14:30 ` Mel Gorman
2010-10-11 14:30 ` Mel Gorman
2010-10-11 20:35 ` pacman
2010-10-11 20:35 ` pacman
2010-10-11 21:00 ` Andrew Morton [this message]
2010-10-11 21:00 ` Andrew Morton
2010-10-11 21:00 ` Andrew Morton
2010-10-13 14:40 ` Mel Gorman
2010-10-13 14:40 ` Mel Gorman
2010-10-13 14:40 ` Mel Gorman
2010-10-13 17:52 ` pacman
2010-10-13 17:52 ` pacman
2010-10-13 17:52 ` pacman
2010-10-18 11:33 ` Mel Gorman
2010-10-18 11:33 ` Mel Gorman
2010-10-18 11:33 ` Mel Gorman
2010-10-18 19:10 ` pacman
2010-10-18 19:10 ` pacman
2010-10-18 19:10 ` pacman
2010-10-18 21:10 ` Benjamin Herrenschmidt
2010-10-18 21:10 ` Benjamin Herrenschmidt
2010-10-18 21:33 ` pacman
2010-10-18 21:33 ` pacman
2010-10-18 21:33 ` pacman
2010-10-19 10:16 ` Benjamin Herrenschmidt
2010-10-19 10:16 ` Benjamin Herrenschmidt
2010-10-19 18:10 ` pacman
2010-10-19 18:10 ` pacman
2010-10-19 18:10 ` pacman
2010-10-19 20:47 ` Segher Boessenkool
2010-10-19 20:47 ` Segher Boessenkool
2010-10-19 20:47 ` Segher Boessenkool
2010-10-19 21:02 ` Benjamin Herrenschmidt
2010-10-19 21:02 ` Benjamin Herrenschmidt
2010-10-19 21:02 ` Benjamin Herrenschmidt
2010-10-20 3:23 ` pacman
2010-10-20 3:23 ` pacman
2010-10-20 3:23 ` pacman
2010-10-20 10:32 ` Benjamin Herrenschmidt
2010-10-20 10:32 ` Benjamin Herrenschmidt
2010-10-20 10:32 ` Benjamin Herrenschmidt
2010-10-20 18:33 ` pacman
2010-10-20 18:33 ` pacman
2010-10-20 20:56 ` Benjamin Herrenschmidt
2010-10-20 20:56 ` Benjamin Herrenschmidt
2010-10-22 9:15 ` pacman
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 8:57 ` pacman
2010-10-27 10:13 ` Olaf Hering
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 22:58 ` pacman
2010-10-27 23:33 ` Segher Boessenkool
2010-10-27 23:33 ` Segher Boessenkool
2010-10-28 1:11 ` pacman
2010-10-28 19:50 ` Segher Boessenkool
2010-10-28 19:50 ` Segher Boessenkool
2010-10-28 21:07 ` pacman
2010-10-29 0:16 ` Segher Boessenkool
2010-10-29 0:16 ` Segher Boessenkool
2010-11-05 6:43 ` pacman
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
2010-10-27 13:27 ` Benjamin Herrenschmidt
2010-10-19 20:58 ` PROBLEM: memory corrupting bug, bisected to 6dda9d55 Benjamin Herrenschmidt
2010-10-19 20:58 ` Benjamin Herrenschmidt
2010-10-18 19:37 ` Andrew Morton
2010-10-18 19:37 ` Andrew Morton
2010-10-18 19:37 ` Andrew Morton
2010-10-18 21:02 ` Benjamin Herrenschmidt
2010-10-18 21:02 ` Benjamin Herrenschmidt
2010-10-18 21:55 ` Thomas Gleixner
2010-10-18 21:55 ` Thomas Gleixner
2010-10-18 21:55 ` Thomas Gleixner
2010-10-19 16:24 ` Helmut Grohne
2010-10-19 16:24 ` Helmut Grohne
2010-10-19 16:24 ` Helmut Grohne
2010-10-19 16:42 ` Thomas Gleixner
2010-10-19 16:42 ` Thomas Gleixner
2010-10-19 16:42 ` Thomas Gleixner
2010-10-18 20:59 ` Benjamin Herrenschmidt
2010-10-18 20:59 ` Benjamin Herrenschmidt
2010-10-18 20:59 ` Benjamin Herrenschmidt
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