The Linux Kernel Is Still Rectifying The Year 2038 Problem
If you somehow are not familiar with the Year 2038 "Y2038" problem, you can learn more via Wikipedia.
The Linux kernel has been receiving fixes and workarounds for years now through many Y2038 commits to work through the many different areas of the kernel that are relying upon 32-bit signed ints for storing time values. With Linux 4.15, this work has continued.
The security updates for the Linux 4.15 kernel merge window adds Y2038 fixes on top of Smack support for OverlayFS, audit subsystem changes, and more. The Year 2038 work in the security subsystem for 4.15 includes timestamping fixes for TOMOYO, the security module implementing mandatory access control.
The timer updates for Linux 4.15 also include more Year 2038 fixes. "More year 2038 work from Arnd slowly reaching the point where we need to think about the syscalls themself."
These fixes are mostly dropping the use of the deprecated do_gettimeofday() function to instead use the safer ktime_get_real_ts64() or ktime_get_seconds().