Let's assume I want to add support for this to the glibc dynamic loader, while still being able to run on older kernels. Is it safe to try the open call first, with O_MAYEXEC, and if that fails with EINVAL, try again without O_MAYEXEC? Or do I risk disabling this security feature if I do that? Do we need a different way for recognizing kernel support. (Note that we cannot probe paths in /proc for various reasons.) Thanks, Florian