Patchwork [03/11] 2.6.32.x: timekeeping: Fix CLOCK_MONOTONIC inconsistency during leapsecond

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Submitter Luis Henriques
Date July 23, 2012, 5:24 p.m.
Message ID <1343064279-28091-4-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/172718/
State New
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Luis Henriques - July 23, 2012, 5:24 p.m.
From: John Stultz <john.stultz@linaro.org>

BugLink: http://bugs.launchpad.net/bugs/1020285

This is a backport of fad0c66c4bb836d57a5f125ecd38bed653ca863a
which resolves a bug the previous commit.

Commit 6b43ae8a61 (ntp: Fix leap-second hrtimer livelock) broke the
leapsecond update of CLOCK_MONOTONIC. The missing leapsecond update to
wall_to_monotonic causes discontinuities in CLOCK_MONOTONIC.

Adjust wall_to_monotonic when NTP inserted a leapsecond.

Reported-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Tested-by: Richard Cochran <richardcochran@gmail.com>
Link: http://lkml.kernel.org/r/1338400497-12420-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 kernel/time/timekeeping.c |    1 +
 1 file changed, 1 insertion(+)

Patch

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 00e2fae..6d19a00 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -780,6 +780,7 @@  void update_wall_time(void)
 			xtime.tv_sec++;
 			leap = second_overflow(xtime.tv_sec);
 			xtime.tv_sec += leap;
+			wall_to_monotonic.tv_sec -= leap;
 		}
 
 		raw_time.tv_nsec += timekeeper.raw_interval;