Re: [PATCH 0/5 v2] Fixes for leapsecond expiring early ABS_TIME CLOCK_REALTIME timers

From: Dave Jones
Date: Fri Jun 12 2015 - 10:52:33 EST


On Thu, Jun 11, 2015 at 03:54:52PM -0700, John Stultz wrote:
> So this is a second round at trying to address the issue, trying
> to integrate feedback from Ingo and Thomas, trying to simplify
> what I can. I've also split out the changes so each can be
> more easily reviewed. Its still not tiny, but its simpler.
>
> This series is against tip/timers/core, and the first patch isn't
> strictly related but is a fix that is needed in tip/timers/core.
>
> As Prarit reported here:
> https://lkml.org/lkml/2015/5/27/458
>
> Since the leapsecond is applied at timer tick time, and not
> the actual second edge, ABS_TIME CLOCK_REALTIME timers set for
> right after the leapsecond could fire a second early, since
> some timers may be expired before we trigger the timekeeping
> timer, which then applies the leapsecond.
>
> Thus this patch series tries to address this issue, including
> extending the leap-a-day test to catch this problem, as well
> as other relevant fixups I found while working on the code.
>
> This series has only had limited testing, so I wanted to send
> it out for initial review and comment. Folks can grab this tree
> via git for testing here:
> https://git.linaro.org/people/john.stultz/linux.git dev/early-leap-timer

Any idea how far back this reaches ? Ie, which longterm stable releases
might be affected by this ?

(It really creeps me out that we're still changing this code so close
to the next leap second event).

Dave

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