Patch "timekeeping: Fix CLOCK_TAI timer/nanosleep delays" has been added to the 3.12-stable tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



This is a note to let you know that I've just added the patch titled

    timekeeping: Fix CLOCK_TAI timer/nanosleep delays

to the 3.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     timekeeping-fix-clock_tai-timer-nanosleep-delays.patch
and it can be found in the queue-3.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 04005f6011e3b504cd4d791d9769f7cb9a3b2eae Mon Sep 17 00:00:00 2001
From: John Stultz <john.stultz@xxxxxxxxxx>
Date: Tue, 10 Dec 2013 17:13:35 -0800
Subject: timekeeping: Fix CLOCK_TAI timer/nanosleep delays

From: John Stultz <john.stultz@xxxxxxxxxx>

commit 04005f6011e3b504cd4d791d9769f7cb9a3b2eae upstream.

A think-o in the calculation of the monotonic -> tai time offset
results in CLOCK_TAI timers and nanosleeps to expire late (the
latency is ~2x the tai offset).

Fix this by adding the tai offset from the realtime offset instead
of subtracting.

Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Richard Cochran <richardcochran@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/time/timekeeping.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -77,7 +77,7 @@ static void tk_set_wall_to_mono(struct t
 	tk->wall_to_monotonic = wtm;
 	set_normalized_timespec(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
 	tk->offs_real = timespec_to_ktime(tmp);
-	tk->offs_tai = ktime_sub(tk->offs_real, ktime_set(tk->tai_offset, 0));
+	tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
 }
 
 static void tk_set_sleep_time(struct timekeeper *tk, struct timespec t)
@@ -595,7 +595,7 @@ s32 timekeeping_get_tai_offset(void)
 static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
 {
 	tk->tai_offset = tai_offset;
-	tk->offs_tai = ktime_sub(tk->offs_real, ktime_set(tai_offset, 0));
+	tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
 }
 
 /**


Patches currently in stable-queue which might be from john.stultz@xxxxxxxxxx are

queue-3.12/3.13.y-timekeeping-fix-clock_set-clock_was_set-think-o.patch
queue-3.12/timekeeping-fix-potential-lost-pv-notification-of-time-change.patch
queue-3.12/timekeeping-fix-lost-updates-to-tai-adjustment.patch
queue-3.12/timekeeping-fix-clock_tai-timer-nanosleep-delays.patch
queue-3.12/timekeeping-avoid-possible-deadlock-from-clock_was_set_delayed.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]