Linux – /proc/net/dev and /sys/class/net/ bogus network interface names

I am constructing a list of network interfaces to monitor based on the contents of /proc/net/dev. But I am getting some bogus interfaces in the list:

__tmp1104705027
__tmp974528607

Where do those come from?

They also show up in /sys/class/net/:

# ls -1 /sys/class/net/
eth0
eth1
eth2
eth3
lo
sit0
__tmp1104705027
__tmp974528607

For now, I think I'll just ignore anything starting with __tmp, but I'd like to know what they are and where they come from.

This is on a recompiled CentOS 5.3 kernel: 2.6.18-128.7.1.el5.tvh.7PAE #1 SMP PREEMPT