Help: Stack-overflow and tail-recursive functions

Hi I've written a function that is tail-recursive and takes a list(queue) as one of its arguments. However the function fails because of "Stack space overflow"(GHC) or "ERROR - Garbage collection fails to reclaim sufficient space"(hugs). For example (simplified), both of these results in stack-overflow: f1 100000 [0,1,2], and even f2 100000 [0,1,2], where, f1 0 l = l f1 n l = f (n-1) $ take 3 $ l ++ [0,1] f2 0 l = l f2 n l = f2 (n - 1) $! (take 3 $ l ++ [0,1]) Why f2 overflows? How to avoid this stack-overflow?