IMHO that's code smell. Modules shouldn't depend on each other, because that creates a web of tangled dependency where you have to understand everything before you can understand one of them. Circular dependency is to modules what goto is to control flow.
Besides, if you are in a "well, fuck it, deadline is tomorrow" mode, you can always do something horrible like:
I think bad code gives raise to more dependencies in general and so circular dependencies.
But the truth is sometimes it has happened to me and the only solution I found was creating an small module with maybe one or two functions which is not exactly ideal.
Besides, if you are in a "well, fuck it, deadline is tomorrow" mode, you can always do something horrible like: