linux-kernel - Re: kdump broken on 2.6.37-rc4

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Message-ID: <4D0BC067.90507@zytor.com>
Date:	Fri, 17 Dec 2010 11:56:23 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Vivek Goyal <vgoyal@...hat.com>
CC:	Yinghai Lu <yinghai@...nel.org>,
	Stanislaw Gruszka <sgruszka@...hat.com>,
	Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>,
	Maxim Uvarov <muvarov@...il.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Neil Horman <nhorman@...hat.com>
Subject: Re: kdump broken on 2.6.37-rc4

On 12/17/2010 11:50 AM, Vivek Goyal wrote:
> On Fri, Dec 17, 2010 at 11:46:08AM -0800, Yinghai Lu wrote:
>> On 12/17/2010 11:39 AM, H. Peter Anvin wrote:
>>> On 12/17/2010 10:21 AM, Yinghai Lu wrote:
>>>>>>
>>>>>> Do we have actual testing for how high the 64-bit kernel will load?
>>>>>
>>>>> I will do some experiments on my box today and let you know.
>>>>
>>>> if bzImage is used, it is 896M.
>>>>
>>>
>>> Why?  896 MiB is a 32-bit kernel limitation which doesn't have anything
>>> to do with the bzImage format.
>>>
>>> So unless there is something going on here, I suspect you're just plain
>>> flat wrong.
>>
>> kexec-tools have some checking when it loads bzImage.
>>
> 
> Yinghai,
> 
> I think x86_64 might have just inherited the settings of 32bit without
> giving it too much of thought. At that point of time nobody bothered
> to load the kernel from high addresses. So these might be artificial
> limits.
> 

Can we do this in the meantime, just so we fix the immediate problem?

	-hpa

View attachment "0001-x86-kexec-Limit-the-crashkernel-address-to-768-MiB.patch" of type "text/x-patch" (2015 bytes)