From owner-freebsd-stable@FreeBSD.ORG  Tue Oct  5 06:07:50 2010
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
Delivered-To: freebsd-stable@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 0AF68106564A
	for <freebsd-stable@freebsd.org>; Tue,  5 Oct 2010 06:07:50 +0000 (UTC)
	(envelope-from alc@rice.edu)
Received: from mh8.mail.rice.edu (mh8.mail.rice.edu [128.42.201.24])
	by mx1.freebsd.org (Postfix) with ESMTP id D6B918FC24
	for <freebsd-stable@freebsd.org>; Tue,  5 Oct 2010 06:07:49 +0000 (UTC)
Received: from mh8.mail.rice.edu (localhost.localdomain [127.0.0.1])
	by mh8.mail.rice.edu (Postfix) with ESMTP id BAFC228F825;
	Tue,  5 Oct 2010 00:51:58 -0500 (CDT)
X-Virus-Scanned: by amavis-2.6.4 at mh8.mail.rice.edu, auth channel
Received: from mh8.mail.rice.edu ([127.0.0.1])
	by mh8.mail.rice.edu (mh8.mail.rice.edu [127.0.0.1]) (amavis,
	port 10026)
	with ESMTP id XPx598wzAhxq; Tue,  5 Oct 2010 00:51:58 -0500 (CDT)
Received: from adsl-216-63-78-18.dsl.hstntx.swbell.net
	(adsl-216-63-78-18.dsl.hstntx.swbell.net [216.63.78.18])
	(using TLSv1 with cipher RC4-MD5 (128/128 bits))
	(No client certificate requested) (Authenticated sender: alc)
	by mh8.mail.rice.edu (Postfix) with ESMTPSA id 42D6628F824;
	Tue,  5 Oct 2010 00:51:58 -0500 (CDT)
Message-ID: <4CAABCFD.6050709@rice.edu>
Date: Tue, 05 Oct 2010 00:51:57 -0500
From: Alan Cox <alc@rice.edu>
User-Agent: Thunderbird 2.0.0.24 (X11/20100725)
MIME-Version: 1.0
To: Dave Hayes <dave@jetcafe.org>
References: <201010030211.o932Bd4C048116@hugeraid.jetcafe.org>
	<AANLkTikenQoA7UBo_N3bzQJ9ABJSTGL89_Qda_Tu7Wa0@mail.gmail.com>
	<201010040512.o945CTor092854@hugeraid.jetcafe.org>
In-Reply-To: <201010040512.o945CTor092854@hugeraid.jetcafe.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Cc: alc@freebsd.org, freebsd-stable <freebsd-stable@freebsd.org>
Subject: Re: Panic: attempted pmap_enter on 2MB page
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Production branch of FreeBSD source code <freebsd-stable.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>, 
	<mailto:freebsd-stable-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-stable>
List-Post: <mailto:freebsd-stable@freebsd.org>
List-Help: <mailto:freebsd-stable-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
	<mailto:freebsd-stable-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 05 Oct 2010 06:07:50 -0000

Dave Hayes wrote:
> Alan Cox <alan.l.cox@gmail.com> writes:
>   
>> I'm afraid that I can't offer much insight without a stack trace.  At
>> initialization time, we map the kernel with 2MB pages.  I suspect that
>> something within the kernel is later trying to change one those mappings.
>> If I had to guess, it's related to the mfs root.
>>     
>
> Here is the stack trace. The machine is sitting here in KDB if you
> need me to extract any information from it. I
>
>   db> bt
>   Tracing pid 0 tid 0 td 0xffffffff80c67140
>   kdb_enter() at kdbenter+0x3d
>   panic() at panic+0x17b
>   pmap_enter() at pmap_enter+0x641
>   kmem_malloc() at kmem_malloc+0x1b5
>   uma_large_malloc() at uma_large_malloc+0x4a
>   malloc() at malloc+0xd7
>   acpi_alloc_wakeup_handler() at acpi_alloc_wakeup_handler+0x82
>   mi_startup() at mi_startup+0x59
>   btext() at btext+0x2c
>   db>
>
>   

Thanks.

There are two pieces of information that might be helpful: the value of 
the global variable "kernel_vm_end" and the virtual address that was 
passed to pmap_enter().

Is this problem reproducible?  I don't recall if you mentioned that earlier.

Can you take a crash dump?

Alan