On Thu, Jan 13, 2011 at 8:32 PM, Richard Cochran
[off-list ref] wrote:

This patch adds a new mode bit into the timex structure. When set, the bit
instructs the kernel to add the given time value to the current time.

The unix time is a nonlinear timescale and there's no way to predict
how many leap seconds will be inserted/deleted during the given time
interval.  So it is impossible to convert relative time to absolute
time and thus your patch is broken. (More specifically, the
timekeeping_inject_offset function is broken.)

My proposal: Limit the adjustable range of the offset so that leap
seconds will never occur more than once. (2147.5 seconds would be the
best choice. :-)