under it while running. Note that this is still not perfect:
- Try to do something intelligent if kvm_read() fails to read a routing
table structure such as an rtentry, radix_node, or ifnet.
- Don't follow left and right node pointers in radix_nodes unless
RNF_ACTIVE is set in rn_flags. This avoids walking through freed
radix_nodes.
MFC after: 1 week