Re: [2.6.27] early exception - lockdep related?

[Peter Zijlstra <peterz@infradead.org>]

On Wed, 2008-09-03 at 10:54 +0200, Luca Tettamanti wrote:
> On Wed, Sep 3, 2008 at 10:37 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> > On Wed, 2008-09-03 at 10:28 +0200, Luca Tettamanti wrote:
> >> On Wed, Sep 3, 2008 at 8:52 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> >> > On Tue, 2008-09-02 at 23:06 +0200, Luca Tettamanti wrote:
> >> >> Hello,
> >> >> I'm seeing an early exception (0e) - which seems related to lockdep - at
> >> >> boot with many 2.6.27 kernels and I'm having troubles to track it down.
> >> >
> >> > Does it print one of these nice stack traces?
> >>
> >> Of course not ;-) It dies before dumping the stack trace (or at least
> >> it doesn't make to the console - that machine has a serial port, but
> >> my notebook does not... I've ordered a usb-to-serial adapter).
> >
> > Until it arrives, you could try poking at netconsole..
> 
> Hum, I forgot to mention that it dies very early, just after:
> 
> Kernel is alive
> Kernel is really alive
> <exception>
> <dead>
> 
> Is netconsole already up at that point?

Another thing you could try is booting this kernel in qemu and try
attaching to its gdb stub.

I've had varying levels of success doing that, you need a very recent
(might still be svn snapshot) of qemu to get x86_64 gdb to work iirc.