shm_open() is failing for multiple applications. So far, I see this in gnome-builder (which crashes) and gitg (which spews a never-ending log of messages to stderr and doesn't function properly). I do not have selinux enabled. This problem did not exist in F23. The easiest way to reproduce is to run gitg from a terminal.
*** This bug has been marked as a duplicate of bug 1282981 ***