Here is a patch for the 2.6.1 kernel that fixes an oops that occurs when
the sunrpc module is unloaded.
The problem was the RPC cache_register() call was not saving entry pointers
to the procfs entries it was creating. So when it came time to dismantle
the entires, a BUG_ON() was tripped in remove_proc_entry() since the tree
was not broken down completely.