linux panic on 4.0.0-rc4

[Michael Ellerman]

On Mon, 2015-03-16 at 01:34 -0400, Pranith Kumar wrote:
> On Mon, Mar 16, 2015 at 1:11 AM, Pranith Kumar <bobby.prani at gmail.com> wrote:
> > Hello,
> >
> > I have a power mac mini 32-bit system.
> >
> ...
> > You can see the panic message here: http://imgur.com/s1lH15g. (there
> > is no log and I have no serial console).
> 
> There was some debug code in there when it hit. The actual hang seems
> to be in printk_late_init(). It does not return from this. May be this
> is a hint?

That is where the boot consoles get disabled and it switches to the "real"
console. It suggests that the system is not "hung" there but you just lost
output.

Try booting with "keep_bootcon" ?

If that doesn't help try booting with "udbg-immortal".

cheers