simplest way to trap error in lua?

["Matthew Armstrong" <turkeypotpie@...>]

Giving a simple example:

function f1()
    local ohNoImNil = nil
    ohNoImNil()
end

function f2()
    f1()
end

f2()

What's the easiest way to trap the nil call and dump the stack?

easiest within lua?
easiest within c?

I can get the error description and line number from the c api, but I'd like to get the full stack where the error occured.

Thanks :)