timekeeping: Fix CLOCK_MONOTONIC inconsistency during leapsecond

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>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit c33f2424c3941986d402c81d380d4e805870a20f)
Conflicts:
	kernel/time/timekeeping.c

Signed-off-by: Joe Jin <joe.jin@oracle.com>

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index bd056f01ccf9bbf6c2ea1f222120a35ac1fd79dd..4e6cd20a1683d8b83c036f1ab6d3ce594f4145fc 100644 (file)
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -833,6 +833,7 @@ static cycle_t logarithmic_accumulation(cycle_t offset, int shift)
                xtime.tv_sec++;
                leap = second_overflow(xtime.tv_sec);
                xtime.tv_sec += leap;
+               wall_to_monotonic.tv_sec -= leap;
        }
 
        /* Accumulate raw time */
@@ -943,6 +944,7 @@ static void update_wall_time(void)
                xtime.tv_sec++;
                leap = second_overflow(xtime.tv_sec);
                xtime.tv_sec += leap;
+               wall_to_monotonic.tv_sec -= leap;
        }
 
        /* check to see if there is a new clocksource to use */