Re: [PATCH V9 02/13] ntp: add ADJ_SETOFFSET mode bit

From: Kuwahara,T.
Date: Thu Jan 13 2011 - 15:40:19 EST


On Thu, Jan 13, 2011 at 8:32 PM, Richard Cochran
<richardcochran@xxxxxxxxx> 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. :-)
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