strace hung at setup

[Donuvi Tanoga]

Hi,

I'm using strace -p <pid> on a hung process and I get the following:

Process 1234 attached - interrupt to quit
setup(

That's it, it doesn't print nothing else.

Any idea what that is ? Is it really a system call ? or an strace problem ?
How should I further debug this ?

Thank you all
donuvi