From: Dave Jones <davej@redhat.com>
To: Hugh Dickins <hugh@veritas.com>
Cc: Chris Wright <chrisw@osdl.org>, Andi Kleen <ak@suse.de>,
"Sergey S. Kostyliov" <rathamahata@ehouse.ru>,
Clem Taylor <clem.taylor@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: x86-64 bad pmds in 2.6.11.6 II
Date: Fri, 15 Apr 2005 14:07:03 -0400 [thread overview]
Message-ID: <20050415180703.GA26289@redhat.com> (raw)
In-Reply-To: <Pine.LNX.4.61.0504151833020.29919@goblin.wat.veritas.com>
On Fri, Apr 15, 2005 at 06:58:20PM +0100, Hugh Dickins wrote:
> > > If there was a fix for the bad pmd problem it might be a candidate
> > > for stable, but so far we dont know what causes it yet.
> > If I figure a way to trigger here, I'll report back.
>
> Dave, earlier on you were quite able to reproduce the problem on 2.6.11,
> finding it happened the first time you ran X. Do you have any time to
> reverify that, then try to reproduce with the load_cr3 in leave_mm patch?
>
> But please don't waste your time on this unless you think it's plausible.
I used to be able to reproduce it 100% by doing this on an vanilla
upstream kernel. Then it changed behaviour so I only saw it happening
on the Fedora kernel. For the latest Fedora update kernel I backported
this change..
- x86_64: Only free PMDs and PUDs after other CPUs have been flushed
as a 'try it and see'. At first I thought it killed the bug, but
a day or so later, it started doing it again.
In the Fedora kernel we have a patch which restricts /dev/mem reading,
so I got suspicious about this interacting with any of the changes
that had happened to drivers/char/mem.c
Out of curiousity, I backported the 3-4 patches from .12rc to
the Fedora .11 kernel, and haven't seen the problem since.
The bizarre thing is I can't explain why any of those patches would
make such a difference. Given the bug seems to be coming and going
for me, its possible its just masked the problem.
Dave
next prev parent reply other threads:[~2005-04-15 18:07 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-30 21:44 x86-64 bad pmds in 2.6.11.6 Dave Jones
2005-03-31 10:41 ` Andi Kleen
2005-03-31 21:52 ` Dave Jones
2005-04-01 11:52 ` Sergey S. Kostyliov
2005-04-07 2:49 ` Dave Jones
2005-04-07 6:29 ` Andi Kleen
2005-04-14 13:54 ` Hugh Dickins
2005-04-14 17:01 ` Andi Kleen
2005-04-14 17:34 ` Hugh Dickins
2005-04-14 18:10 ` Andi Kleen
2005-04-14 18:11 ` x86-64 bad pmds in 2.6.11.6 II Andi Kleen
2005-04-14 18:27 ` Chris Wright
2005-04-15 17:24 ` Andi Kleen
2005-04-15 17:28 ` Chris Wright
2005-04-15 17:58 ` Hugh Dickins
2005-04-15 18:07 ` Dave Jones [this message]
2005-04-22 17:37 ` Debugging patch was " Andi Kleen
2005-04-27 14:23 ` New debugging " Andi Kleen
2005-04-27 17:37 ` Dave Jones
2005-04-29 11:07 ` Hans Kristian Rosbach
2005-04-19 13:35 ` Andi Kleen
2005-04-19 15:52 ` Hugh Dickins
2005-04-29 11:12 ` Christopher Warner
2005-04-29 16:13 ` Chris Wright
2005-04-29 17:32 ` Dave Jones
2005-05-02 17:00 ` Andi Kleen
2005-05-02 15:28 ` Christopher Warner
2005-05-02 20:33 ` Chris Wright
2005-05-02 21:08 ` Dave Jones
2005-05-03 14:28 ` Andi Kleen
2005-05-03 15:15 ` Dave Jones
2005-05-10 9:36 ` Christopher Warner
2005-05-10 16:26 ` Chris Wright
2005-05-10 12:03 ` Christopher Warner
2005-05-10 16:38 ` Dave Jones
2005-05-10 16:46 ` Andi Kleen
2005-05-10 16:59 ` Dave Jones
2005-05-10 20:32 ` Andi Kleen
2005-05-10 20:43 ` Chris Wright
2005-05-12 21:23 ` Andi Kleen
2005-05-13 21:51 ` Peter J. Stieber
2005-05-14 17:29 ` Peter J. Stieber
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