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From: Roland Dreier <rdreier@cisco.com>
To: "Dan Upton" <upton.dan.linux@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: debugging an oops that kills the system
References: <ba7d8f720810211014g472c3e83oba511c24e1c2eb97@mail.gmail.com>
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Date: Tue, 21 Oct 2008 11:39:27 -0700
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	(Dan Upton's message of "Tue, 21 Oct 2008 13:14:02 -0400")
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 > I'm hoping for some pointers on debugging an oops that ultimately
 > hangs the system.  I'm doing some scheduler work and I can fairly
 > reliably duplicate the error on my machine, but the output is too
 > large for one screen and the system becomes unresponsive after the
 > crash so I can't scroll the console.  I tried purchasing a  USB->DB9
 > cable to log to a remote terminal, but so far I haven't had any luck
 > getting that to work.  Using kdump/kexec doesn't work either--I got
 > the second kernel to boot successfully using the magic sysrq example
 > in the documentation, but the second kernel doesn't boot with my
 > actual crash.  Any other suggestions for what I might do?

If you have two machines (it sounds like you do) and serial console is
not working for you (could be a setup problem -- do you have a
"console=" line on your kernel command line?), then netconsole might be
a good way to debug: Documentation/networking/netconsole.txt

 - R.