timekeeping: Fix CLOCK_MONOTONIC inconsistency during leapsecond
John Stultz [Wed, 30 May 2012 17:54:57 +0000 (10:54 -0700)]
commit fad0c66c4bb836d57a5f125ecd38bed653ca863a upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel/time/timekeeping.c

index d66b213..d42574d 100644 (file)
@@ -964,6 +964,7 @@ static cycle_t logarithmic_accumulation(cycle_t offset, int shift)
                timekeeper.xtime.tv_sec++;
                leap = second_overflow(timekeeper.xtime.tv_sec);
                timekeeper.xtime.tv_sec += leap;
+               timekeeper.wall_to_monotonic.tv_sec -= leap;
        }
 
        /* Accumulate raw time */
@@ -1079,6 +1080,7 @@ static void update_wall_time(void)
                timekeeper.xtime.tv_sec++;
                leap = second_overflow(timekeeper.xtime.tv_sec);
                timekeeper.xtime.tv_sec += leap;
+               timekeeper.wall_to_monotonic.tv_sec -= leap;
        }
 
        timekeeping_update(false);