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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andi Kleen <ak@suse.de>, Zachary Amsden <zach@vmware.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] i386: For debugging, make the initial page table setup less forgiving.
Date: Wed, 25 Apr 2007 11:18:12 -0700	[thread overview]
Message-ID: <462F9B64.3020107@goop.org> (raw)
In-Reply-To: <m1irbks5qa.fsf@ebiederm.dsl.xmission.com>

Eric W. Biederman wrote:
> "H. Peter Anvin" <hpa@zytor.com> writes:
>
>   
>> Andrew Morton wrote:
>>
>>     
>>> This patch causes oopses after a minute or so running LTP's
>>>
>>> ./testcases/bin/growfiles -W gf16 -b -e 1 -i 0 -L 120 -u -g 4090 -T 100 -t
>>>       
>> 408990 -l -C 10 -c 1000 -S 10 -f Lgf02_
>>     
>>> on everyone's favoutite Vaio, configured with
>>> http://userweb.kernel.org/~akpm/config-sony.txt
>>>
>>>       
>> *BLINK*
>>
>> This patch only affects the initial page tables, which should have been
>> thrown out *way* long ago at this point.
>>     
>
> Yes.  I noticed this was happening a few days ago.
> I must not have mentioned it loudly enough.
>   

I might have introduced it as part of the paravirt_ops patches.  When
setting up pagetables under Xen, we need to make sure we preserve the
initial mappings Xen put in place (it starts the VM with paging enabled,
and a sane initial pagetable).  This may have leaked over into native if
it doesn't replace an existing entry.

Hm, but it should be overwriting small mappings with large ones.  Maybe
I overlooked that.

> I'm halfway through putting together a patchset to address a
> bunch of these.
>
> I haven't yet resolved how I want to allocate the pages for the
> identity mapping of the page table yet.  I can't use the bootmem
> allocate as it exists because that assumes the page is mapped
> into the address space already.
>   

Are you going to clash horribly with the paravirt pagetable setup?  We
should probably coordinate if so.

    J

  parent reply	other threads:[~2007-04-25 18:17 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-04-13 21:49 H. Peter Anvin
2007-04-13 22:18 ` Zachary Amsden
2007-04-13 22:26   ` H. Peter Anvin
2007-04-13 22:40     ` Zachary Amsden
2007-04-13 22:26   ` Jeremy Fitzhardinge
2007-04-25 11:48 ` Andrew Morton
2007-04-25 15:28   ` H. Peter Anvin
2007-04-25 17:50     ` Eric W. Biederman
2007-04-25 17:56       ` H. Peter Anvin
2007-04-25 18:23         ` Eric W. Biederman
2007-04-25 18:18       ` Jeremy Fitzhardinge [this message]
2007-04-25 19:01         ` Eric W. Biederman
2007-04-25 19:19           ` Jeremy Fitzhardinge
2007-04-25 22:08           ` Jeremy Fitzhardinge
2007-04-25 22:27             ` Eric W. Biederman
2007-04-25 23:08               ` Jeremy Fitzhardinge
2007-04-25 23:45                 ` Eric W. Biederman
2007-04-26  0:14                   ` Jeremy Fitzhardinge
2007-04-27  5:02                     ` Eric W. Biederman
2007-04-26  3:27                   ` Zachary Amsden

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