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From: Bouchard Louis <louis.bouchard@canonical.com>
To: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: kexec@lists.infradead.org
Subject: Re: makedumpfile --dump-dmesg option broken on 3.5 kernels and later
Date: Wed, 23 Jan 2013 09:49:15 +0100	[thread overview]
Message-ID: <50FFA40B.3020405@canonical.com> (raw)
In-Reply-To: <20130123101952.79072daf31bb30e217d38adf@mxc.nes.nec.co.jp>

Hi Kumagai-san,

Le 23/01/2013 02:19, Atsushi Kumagai a écrit :
> Hello Louis,
> 
> On Tue, 22 Jan 2013 14:52:09 +0100
> Bouchard Louis <louis.bouchard@canonical.com> wrote:
> 
>> Hello Kumagai-san,
>>
>> Following a suggestion from Dave Anderson, I have tested the
>> makedumpfile --dump-dmesg option. After some research, I realized that
>> the option was no longer working on 3.5 kernel and later. Here is an
>> example of the result (on Ubuntu Quantal) :
>>
>> # makedumpfile --dump-dmesg /proc/vmcore /tmp/dmesg
>> dump_dmesg: Can't find some symbols for log_buf.
>>
>> makedumpfile Failed.
>>
>> On 3.5 kernel and later, the log_end symbol no longer exists.
>>
>> This is caused by the change from byte-buffer structure to
>> variable-length record buffer of the kernel log buffer introduced by
>> this commit :
>> 	http://goo.gl/NCgLI
>>
>> I am curious to know if you were aware of this change and if you had
>> done some work on modifying dump_dmesg() accordingly ? Just so I don't
>> go off and try to work on something that you have already solved.
> 
> Thanks for your report.
> I haven't been aware of this, so could I ask you to help me ?
> 

I will be happy to do so. Dave Anderson has already fixed in for crash,
so I have an example to follow. I've already started work on a patch for
the post 3.5 kernels.

I might need to come back to you for some details about the code though.

Kind regards,

...Louis


-- 
Louis Bouchard
Backline Support Analyst
Canonical Ltd
Ubuntu support: http://landscape.canonical.com

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  reply	other threads:[~2013-01-23  8:49 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-22 13:52 makedumpfile --dump-dmesg option broken on 3.5 kernels and later Bouchard Louis
2013-01-23  1:19 ` Atsushi Kumagai
2013-01-23  8:49   ` Bouchard Louis [this message]
2013-01-30 13:45   ` Bouchard Louis
     [not found] <mailman.13964.1359561994.1038.kexec@lists.infradead.org>
2013-01-30 17:11 ` Dave Anderson

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