For a few weeks now I'm experiencing random console lockups.
I could not exactly find a reason why this is happening,
but it is usually triggered by a session switch in GNU screen,
or by some rapid output of a program (like ls), or it happened
to me three times while I was typing some text on IRC and at
the same time a new message arrived. The console locks up
completely, no output, no input. But it seems like the system
is otherwise still ok because if I'm downloading something
at the time the download process continues just fine, and I
guess if I had an opportunity to login remotely I could work
just fine.

Could anybody please suggest how I could go about debugging
this?

At the time the lockups started to occur I upgraded to a
newer version of screen, but I changed that back to the
old version and the lockups still occur. I don't quite
remember what I was doing to the kernel at that time but
just to be on the safe side I removed all my private patches
and was running a stock -current kernel for a few days,
until the console locked up again. So currently I'm
out of ideas.

The lockups don't happen like every second day. I noticed
that there is usually some modem activity when the console
locks up, so this could be related.

This is NetBSD/amiga running a kernel around July 6th.

Thanks for any help in advance.

-- 
  Blaz Zupan, Ljubljanska 19/b, 62000 Maribor, Slovenia
     blaz.zupan@uni-mb.si, 2:380/104.40, GMIZO::BLAZ