Message-ID: <543BC242.7020304@hurleysoftware.com>
Date: Mon, 13 Oct 2014 08:14:58 -0400
From: Peter Hurley <peter@hurleysoftware.com>
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To: Udo van den Heuvel <udovdh@xs4all.nl>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: CRASH during boot 3.16.3+
References: <543A88E4.4060707@xs4all.nl> <543ABD7D.5010308@hurleysoftware.com> <543BA610.8010001@xs4all.nl>
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Sender: linux-kernel-owner@vger.kernel.org

On 10/13/2014 06:14 AM, Udo van den Heuvel wrote:
> On 2014-10-12 19:42, Peter Hurley wrote:
>> On 10/12/2014 09:57 AM, Udo van den Heuvel wrote:
>>> The problem:
>>> During the first few seconds of bootup the kernel gets into some sort of
>>> loop and rapidly prints loads of register-like things and then a load of
>>> rubbish.
>>> I did `make clean` and then a rebuild etc but this did not help.
>>>
>>> How can I capture the logging to find the point where things go wrong?
>>> How can I find out what is wrong?
>>
>> Start with git bisect between good=3.16.2 and bad=3.16.3.
>> And dmesg from 3.16.2.
> 
> Incomplete dmesg attached for 3.16.2.

Why incomplete? No kernel command line, no version stamp, no CPU info,
no memory map, no IRQ routing info, etc.

And this is only going to be useful with a commit identified by git bisect.

>> What happens after the 'then a load of rubbish.'?
> 
> I press reset as this is unexpected and looks like it will not result in
> a succesfull boot.
> 
>> And rubbish is not
> very descriptive. Please include a sample, if you can't catch all the
> console prints.
> 
> How can I capture the output easily?

The bisect is preferred and will take you less time.

But if you _also_ want to try to capture the console output, I'd suggest
setting up netconsole if you can't setup a serial console.
Basic setup information is in Documentation/networking/netconsole.txt

Regards,
Peter Hurley
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