What are the general causes of frozen system?

[Larry Finger <Larry.Finger@lwfinger.net>]

I am trying to help the bcm43xx project develop a driver for the 
Broadcom 43xx wireless chips, using my Linksys WPC54G card. 
Unfortunately, since the group got far enough to turn on RX DMA, my 
system has frozen whenever I load the driver. TX DMA was OK. It seems to 
correlate with the receipt of a beacon from my AP, but that cannot be 
proven. When the freeze happens, I cannot do anything more and have to 
power the system off.

What should I consider as a cause of the freeze? I have reviewed the 
code and do not find any obvious out-of-bounds memory references. I have 
tried various 'printk' statements, but none of them in the bottom-half 
interrupt routine make it to the logs. Are there any tricks that I 
should try?

Thanks,

Larry