Phil Oester [off-list ref] wrote:

At Andrew's suggestion, I tested the latest 2.6.12-rc5-gitx, and am still
 hitting an oops on a gateway box under load.  From comparing the various
 oops, it seems like a dev is disappearing while one CPU is in the middle
 of processing traffic.  At least that's what my naive analysis leads
 me to believe.

Are you _sure_ the hardware is good?

Are you running anything which would cause netdevs to be destroyed? 
Bringing virtual devices up and down?  TUN/TAP driver?  Bonding driver? 
Anything like that?

Have you tried CONFIG_DEBUG_SLAB and/or CONFIG_DEBUG_PAGEALLOC?