Subject: Re: netconsole system freeze when cable unplugged

From: Andi Kleen <[email-masked]>
Date: Sun, 11 Mar 2007 08:50:13 +0100

On Sat, Mar 10, 2007 at 02:06:28PM +0000, Simon Arlott wrote:
> On 10/03/07 13:38, Andi Kleen wrote:
> >Simon Arlott <[email-masked]> writes:
> >
> >>On 09/03/07 20:42, Francois Romieu wrote:
> >>>Simon Arlott <[email-masked]> :
> >>>>When I unplug the cable the system just stops responding to
> >>>>anything, at all. No message is printed to the console when the
> >>>>cable is plugged back in.
> >>>rtl8139_interrupt (spin_lock(&tp->lock))
> >>>-> rtl8139_weird_interrupt
> >>>   -> rtl_check_media
> >>>      -> mii_check_media (printk(KERN_INFO "%s: link down\n", ...))
> >>>         [netpoll stuff here]
> >>>         -> rtl8139_poll_controller
> >>>            -> rtl8139_interrupt
> >>>               *deadlock*
> >>>See below for my random stuff of the day. Feel free to open a PR at
> >>>bugzilla.kernel.org if the issue does not go away.
> >>The patch doesn't fix it, nothing changes. I'm not sure how this can
> >>be debugged if printk won't work...
> >
> >earlyprintk can be called directly (early_printk()) and should
> >work. It won't log over the network of course.
> 
> It also won't log over the serial console either :(

It does, you just have to configure it properly.

earlyprintk=serial,ttySx,baud

-Andi