I have a machine with 4GB of memory.  After it's done ten or twenty minutes
of heavy disk activity, pages in the cache get corrupted.  This is
with -current as of yesterday.  If I build a kernel that only "sees" 2GB,
everything works fine.

The disk device driver I'm using does, AFAICT, use bus_dma correctly; user
processes' memory does *not* seem to get corrupted.  Eventually, the system
crashes in the filesystem code, unsurprisingly enough; where in the filesystem
code is pretty much random.

I suspect signedness problems in the i386 bus_dma or in UBC/UVM.  Is anyone
else successfully running a 32-bit machine with more than 2GB of physical
memory?  How about an x86?

-- 
Thor Lancelot Simon	                                      tls@rek.tjls.com
    And now he couldn't remember when this passion had flown, leaving him so
  foolish and bewildered and astray: can any man?
						   William Styron