Kernel panic in 7.0-RELEASE with fatm driver

[Sean Thomas Caron]

Hi folks,

I've been running FreeBSD 6.x on a number of Ultrasparc based systems  
using the Cranor NATM driver with a bunch of Fore PCA-200E cards. It  
generally worked but as the machines got hit with higher and higher  
network load I would get kernel panics at fairly random intervals on  
"sbdrop" and "sbflush". Sometimes I would get two per day, sometimes I  
wouldn't get any for two weeks.

So after a while at this I decided to try 7.0-RELEASE out hoping  
whatever bug was causing these random kernel panics might have gotten  
fixed.

Test system is Sun Fire v120, 550 MHz, 1 GB RAM, PCA-200e installed in  
PCI slot.

I pruned a bunch of stuff from GENERIC and added the usual Cranor NATM  
stuff that I was using in 6.x. In particular -

# ATM

options         NATM
device          atm
device          fatm
device          utopia

Kernel does have multiprocessing enabled (as GENERIC did) even though  
it's a uniprocessor machine.

I built the new kernel then reboot and it panics immediately after  
touching the ATM card -

fatm0: <FORE PCA200E> mem 0x200000-0x3fffff at device 5.0 on pci2
panic: bus_dma_tag_create: parent DMA tag NULL
cpuid = 0
Uptime: 1s
Automatic reboot in 15 seconds - press a key on the console to abort
--> Press a key on the console to reboot,
--> or switch off the system now.

I'm hoping maybe someone has seen this before and has a patch laying  
around somewhere, or if nothing else, it might get passed along to the  
fatm maintainer eventually?

If anyone wants to see any further information e.g. full kernel  
configuration file, I will be happy to pass along. I can also procure  
a backtrace if someone can tell me how to hardcode a dump path into  
the kernel; I can't find a procedure documented anywhere.

Thanks!

-Sean