Does anyone know when FUTEX_WAIT can fail with EAGAIN?

Hello,

I'm trying to debug a hangup where my program loops with FUTEX_WAIT (actually
FUTEX_WAIT_PRIVATE but same thing)  endlessly erring out with EAGAIN. I would
like to know if anyone on the mailing list knows when FUTEX_WAIT can fail with
EAGAIN.

Some info for people who are interested in what I'm working on.

I'm working on sand boxing my program at gitorious.org/linted with namespaces
and chroot.

The error only appeared after changing unshare then fork code into a direct
clone call.

| uname -a
Linux alonzo 3.13.0-24-generic #1trisquel1 SMP Tue May 13 15:17:50 UTC 2014

x86_64 x86_64 x86_64 GNU/Linux

Thank you,
Steven Stewart-Gallus