According the lwn comments it should be sufficient (and the post by perception-point suggests that it would at least make things more difficult), but I haven't the hardware to test for myself.
EDIT:
[chris@f23m cve20160728]$ ./cve_2016_0728 PP_KEY
uid=1000, euid=1000
Increfing...
finished increfing
forking...
finished forking
caling revoke...
uid=1000, euid=1000
sh-4.3$