In message <20021219215608.GC744@drowsy.duskware.de>, you write: 

-> On Thu, Dec 19, 2002 at 01:43:50PM -0800, Andrew Gillham wrote:
-> 
-> > I would like to have this machine stable, but I haven't had much luck so
-> > far.  Anyone have any suggestions on stable kernels?
-> 
-> What CPU is that? My U5 @ 270 MHz is realy stable running -current, but my
-> U60 @ 360 MHz has problems. Sometimes these show up as RED state exceptions
-> on the serial console - but then firmware is hosed, so maybe with a real
-> console it wouldn't even get to printing the message.
-> 
-> Both run pretty stable on 1.6.

Let me second Martin's assesment that it does seem timing related.  My U5
which has this issue has a 360Mhz CPU, and ran months at a time all the
way from the 1.6 release cycle to ~ mid-to-end of September (I think my
choice of a cutoff date of 9/21 was due to Chuq's rototill of the pmap,
which seems to have exposed this problem).

--rafal

----
Rafal Boni                                                     rafal@attbi.com
  We are all worms.  But I do believe I am a glowworm.  -- Winston Churchill