The problem reported there is slightly different; the program linked in the OP operates recursively, building a larger and larger graph of 'in flight' FDs, while the earlier report simply allocates a bunch of pairs and sends FDs to them. The earlier report is apparently fixable by triggering the GC in this case (as mentioned in the lkml followup), but that fix does not address the exploit in the OP.

The one I linked to is exactly the same as the one in this HN submission (on an alternate mailing list archive site, because the one used in the submission seemed to have failed under the load at the time).