Re: Viewing dmesg output after crash

[Leo Prasath <leo.prasath@xxxxxxxxx>]

I use netconsole which sends the kernel ring buffer updates to a
remote machine through UDP ..
And then you can use netcat command to dump the remote udp logs to a
file and view it.
I have never missed any log messages using this approach..

http://www.kernel.org/doc/Documentation/networking/netconsole.txt

My commands are :

in the client machine ( which crashes ):

modprobe netconsole netconsole=@/eth0,@128.105.102.217/

where the ip address "128.105.102.217" is the remote machine's ip
address. ( which captures logs )

in the remote machine I run the command :

netcat -u -l -p 6666 | tee crashlog

also, iptables --flush helped me remove the udp packet filters which
sometimes can filter out the netconsole udp messages.

thanks,
-Leo



On Tue, Apr 26, 2011 at 4:48 AM, Amit Virdi <amit.virdi@xxxxxx> wrote:
> Hi
>
> I'm debugging a system crash. I got OOPS message and found the buggy piece
> of code. I wish I had the output of dmesg just before the crash. In other
> words, I want to view the last messages collected by the ring buffer used by
> dmesg.
>
> The log messages are certainly being appended to some logfile in the RAM.
> How can I find the address where the logfile is being created or how can I
> extract the logfile?
>
> Thanks n Regards
> Amit Virdi
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