question about circular locking dependency

question about circular locking dependency

[Udo van den Heuvel]

Hello,

While shutting down 2.6.25 on my VIA EK8000, just before turning off the
encrypted swap, I noticed messages about a circular locking dependency
rolling over the screen. The messages were not in /var/log/messages
after reboot.
The machine did shut down and restart without further problems.

I assume a serial console is the only way to capture the error messages
of this circular locking dependency.
Or are there alternatice methods?

Is this specific circular locking dependency a known issue?

Kind regards,
Udo

Re: question about circular locking dependency

[Dan Noé]

Udo van den Heuvel wrote:
> I assume a serial console is the only way to capture the error messages
> of this circular locking dependency.
> Or are there alternatice methods?

You can try netconsole: see Documentation/networking/netconsole.txt for 
details on how to set it up.  It may not always work.  Obviously a 
failure in the networking code may not be reported correctly.  But it 
will try its best.

I just use netcat on a separate system to listen on a specific port and 
redirect to a file:

netcat -lu -p 6666 > logfile

This tells netcat to listen, UDP, port 6666.

Then, on the test system, I load the netconsole module with option:

netconsole=@/,@192.168.4.60/00:17:31:98:77:2f

on boot.  After this point every kernel message is logged to the logfile 
via netcat.  You can also build netconsole in and specify the options on 
the boot command line.  But if you do this obviously you need to build 
in your network card driver, as well :)

Hope that helps.

Cheers,
Dan

-- 
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