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

From: Dave Jones
Date: Fri Jun 12 2015 - 11:00:20 EST


On Fri, Jun 12, 2015 at 10:55:57AM -0400, Prarit Bhargava wrote:

> > > 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 ?
>
> Likely occurs in any kernel after NOHZ was introduced.

At least on 3.14, it seems to happen even if NOHZ is disabled.

# ./leap -i 5 -s
Setting time to speed up testing
Running for 5 iterations. Press ctrl-c to stop

Setting time to Sat Jun 13 23:59:50 2015
Scheduling leap second for Sun Jun 14 00:00:00 2015
Setting timer for Sun Jun 14 00:00:00 2015
Sat Jun 13 23:59:57 2015 + 55 us (1) TIME_INS
Sat Jun 13 23:59:57 2015 + 500127 us (1) TIME_INS
Sat Jun 13 23:59:58 2015 + 189 us (1) TIME_INS
Sat Jun 13 23:59:58 2015 + 500250 us (1) TIME_INS
Sat Jun 13 23:59:59 2015 + 312 us (1) TIME_INS
Sat Jun 13 23:59:59 2015 + 500372 us (1) TIME_INS
Sun Jun 14 00:00:00 2015 + 3 us (1) TIME_INS - TIMER FIRED
Error: Incorrect NTP state?
Sun Jun 14 00:00:00 2015 + 12 us (1) TIME_INS
Sat Jun 13 23:59:59 2015 + 500068 us (2) TIME_OOP
Sun Jun 14 00:00:00 2015 + 130 us (2) TIME_OOP
Sun Jun 14 00:00:00 2015 + 500190 us (2) TIME_WAIT
Sun Jun 14 00:00:01 2015 + 256 us (2) TIME_WAIT
Sun Jun 14 00:00:01 2015 + 500315 us (2) TIME_WAIT
Sun Jun 14 00:00:02 2015 + 376 us (2) TIME_WAIT
Leap complete
Errors observed



Dave
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