Red Hat warns that “The next leap second insertion is scheduled for June 30th, 2015 at 23:59:60 UTC.” Red Hat has further advised that kernel crashes or hangs may occur in out-of-date systems because of this leap second insertion. As a result Red Hat is recommending that system administrators insure that their systems are on the latest kernel update available for the distribution.
A leap second vulnerability detector script has been published by Red Hat for use in diagnosing whether a system running a Red Hat distribution is at risk. It is available to anyone who has an account on Red Hat’s customer portal (you do not need to have an active Red Hat subscription). The script is designed to check Red Hat systems by checking to see if the installed tzdata packages (tzdata and tzdata-java) are up to date (they need to be from 2015 and not 2014 or earlier).