Comment 9 for bug 96753

I tried your suggestion and that works (as in doesn't crash). I also discovered a simple workaround (at least if the unused interface is dhcp). I tried

$ sudo /etc/init.d/networking restart

after dhcp failed to find any leases and went to sleep, no more crash. I'd be curious if the same works for a connection set up for static.

I checked with the current upstream release and this still happens with it, so hopefully they'll do something with your suggestion.