Kernel panics, one starting with r248508

I've been helping Adrian test the new ath improvements that support the 
chipset I have.  The first kernel panic is on my system if I have the cd 
driver loaded into the kernel, I would get a panic on boot.  While 
"Mounting local file systems:" it would panic with "Memory modified 
after free."  Removing the driver solved it.  I'd rather have wireless 
than cd for right now anyway.  But a couple days ago a new build would 
always panic, a couple seconds after getty is spawned.  All I get is 
"panic: Bio too short 0xfffffe000b1395d0."  Before that, the builds 
worked other than occasional issues due to cleaning.  The only place 
that panic can be generated is geom_io.c so I'm guessing I can't just 
remove the driver.  What needs done so I can get a working kernel again?