Why Does the Leap Second Cause Problems?

Question

So at this moment (but most likely not for long) Reddit, Meetup, Fark, LinkedIn, Yelp, 4Chan are all down. Netflix apparently was out for a while too.

According to R

Answer 1

Certain Linux kernels (versions before 2.6.29) have issues handling leap seconds, to the point where it can cause a kernel panic. Other Linux kernels can suffer from a livelock. This obviously has detrimental effects for the system, given that it requires a reboot.

Here's the related ServerFault question on this topic, since it's really a Linux server issue.