OverlayFS SELinux Support For Linux 4.9 Kernel
A notable addition to the security updates in Linux 4.9 is OverlayFS SELinux/LSM support. This support is needed for container file-systems. Vivek Goyal of Red Hat has been working on the OverlayFS SELinux effort for being able to better security this union file-system.
This Overlayfs SELinux support is now in place plus a variety of other security fixes/enhancements (LSM, Smack, TPM, Audit, etc) for 4.9, a full run-down via this pull request.