From: Ingo Molnar <mingo@elte.hu>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: [git pull] timer fixes
Date: Thu, 4 Dec 2008 21:52:43 +0100 [thread overview]
Message-ID: <20081204205243.GA6565@elte.hu> (raw)
Linus,
Please pull the latest timers-fixes-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers-fixes-for-linus
Thanks,
Ingo
------------------>
John Stultz (1):
time: catch xtime_nsec underflows and fix them
Petr Tesarik (1):
posix-cpu-timers: fix clock_gettime with CLOCK_PROCESS_CPUTIME_ID
kernel/posix-cpu-timers.c | 2 +-
kernel/time/timekeeping.c | 22 ++++++++++++++++++++++
2 files changed, 23 insertions(+), 1 deletions(-)
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 895337b..4e5288a 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -311,7 +311,7 @@ static int cpu_clock_sample_group(const clockid_t which_clock,
struct task_cputime cputime;
thread_group_cputime(p, &cputime);
- switch (which_clock) {
+ switch (CPUCLOCK_WHICH(which_clock)) {
default:
return -EINVAL;
case CPUCLOCK_PROF:
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index e7acfb4..fa05e88 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -518,6 +518,28 @@ void update_wall_time(void)
/* correct the clock when NTP error is too big */
clocksource_adjust(offset);
+ /*
+ * Since in the loop above, we accumulate any amount of time
+ * in xtime_nsec over a second into xtime.tv_sec, its possible for
+ * xtime_nsec to be fairly small after the loop. Further, if we're
+ * slightly speeding the clocksource up in clocksource_adjust(),
+ * its possible the required corrective factor to xtime_nsec could
+ * cause it to underflow.
+ *
+ * Now, we cannot simply roll the accumulated second back, since
+ * the NTP subsystem has been notified via second_overflow. So
+ * instead we push xtime_nsec forward by the amount we underflowed,
+ * and add that amount into the error.
+ *
+ * We'll correct this error next time through this function, when
+ * xtime_nsec is not as small.
+ */
+ if (unlikely((s64)clock->xtime_nsec < 0)) {
+ s64 neg = -(s64)clock->xtime_nsec;
+ clock->xtime_nsec = 0;
+ clock->error += neg << (NTP_SCALE_SHIFT - clock->shift);
+ }
+
/* store full nanoseconds into xtime after rounding it up and
* add the remainder to the error difference.
*/
next reply other threads:[~2008-12-04 20:53 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-04 20:52 Ingo Molnar [this message]
-- strict thread matches above, loose matches on Subject: below --
2024-04-14 8:42 [GIT PULL] timer fixes Ingo Molnar
2024-04-14 18:48 ` pr-tracker-bot
2024-04-07 8:03 Ingo Molnar
2024-04-07 16:44 ` pr-tracker-bot
2023-01-12 14:44 Ingo Molnar
2023-01-12 23:01 ` pr-tracker-bot
2022-08-13 10:25 Ingo Molnar
2022-08-13 16:25 ` Borislav Petkov
2022-08-13 20:27 ` Linus Torvalds
2022-08-14 8:57 ` Ingo Molnar
2022-08-14 12:41 ` Borislav Petkov
2022-08-14 17:24 ` Paul E. McKenney
2022-08-14 17:42 ` Borislav Petkov
2022-08-13 21:48 ` pr-tracker-bot
2020-12-27 9:26 Ingo Molnar
2020-12-27 17:27 ` pr-tracker-bot
2019-12-17 11:55 Ingo Molnar
2019-12-17 19:14 ` Linus Torvalds
2019-12-17 19:30 ` Peter Zijlstra
2019-12-17 20:16 ` Linus Torvalds
2019-12-17 20:35 ` Peter Zijlstra
2019-12-17 20:43 ` Linus Torvalds
2019-12-17 20:54 ` Peter Zijlstra
2019-12-17 19:20 ` pr-tracker-bot
2019-05-16 16:09 Ingo Molnar
2019-05-16 18:20 ` pr-tracker-bot
2019-04-20 7:45 Ingo Molnar
2019-04-20 19:25 ` pr-tracker-bot
2018-07-13 20:01 Ingo Molnar
2017-03-07 20:36 Ingo Molnar
2016-10-28 8:38 Ingo Molnar
2016-08-18 20:46 Ingo Molnar
2016-08-12 19:43 Ingo Molnar
2016-01-14 10:12 Ingo Molnar
2015-10-03 10:20 Ingo Molnar
2015-09-17 8:13 Ingo Molnar
2015-03-28 13:50 Ingo Molnar
2015-03-17 16:50 Ingo Molnar
2015-03-01 17:06 Ingo Molnar
2013-12-17 13:52 Ingo Molnar
2013-09-28 18:19 Ingo Molnar
2013-08-19 9:41 Ingo Molnar
2013-02-26 11:32 Ingo Molnar
2012-09-21 19:12 Ingo Molnar
2012-08-03 16:47 Ingo Molnar
2011-12-20 19:25 Ingo Molnar
2011-12-05 19:00 Ingo Molnar
2011-06-19 8:51 Ingo Molnar
2011-06-13 9:55 Ingo Molnar
2011-06-06 19:10 [GIT pull] " Thomas Gleixner
2011-05-20 17:52 Thomas Gleixner
2011-04-19 16:03 [GIT PULL] " Ingo Molnar
2011-04-16 10:09 Ingo Molnar
2011-04-07 17:42 Ingo Molnar
2011-02-06 12:06 Ingo Molnar
2011-01-24 13:24 Ingo Molnar
2010-11-26 13:40 Ingo Molnar
2010-03-26 15:34 Ingo Molnar
2009-12-18 18:49 Ingo Molnar
2009-10-08 18:35 Ingo Molnar
2009-08-25 18:04 Ingo Molnar
2009-06-26 19:03 Ingo Molnar
2009-04-09 15:43 Ingo Molnar
2009-01-30 23:07 [git pull] " Ingo Molnar
2009-01-26 17:21 Ingo Molnar
2009-01-06 16:18 Ingo Molnar
2008-11-11 18:47 Ingo Molnar
2008-09-23 19:41 Ingo Molnar
2008-09-17 9:59 Ingo Molnar
2008-08-25 17:52 Ingo Molnar
2008-08-22 12:24 Ingo Molnar
2008-07-24 15:18 Ingo Molnar
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