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From: Ingo Molnar <mingo@kernel.org>
To: John Stultz <john.stultz@linaro.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Prarit Bhargava <prarit@redhat.com>,
	Richard Cochran <richardcochran@gmail.com>,
	stable <stable@vger.kernel.org>
Subject: Re: [RFC][PATCH 4/5] timekeeping: Fix CLOCK_TAI timer/nanosleep delays
Date: Thu, 12 Dec 2013 14:25:18 +0100	[thread overview]
Message-ID: <20131212132518.GB16360@gmail.com> (raw)
In-Reply-To: <1386789098-17391-5-git-send-email-john.stultz@linaro.org>


* John Stultz <john.stultz@linaro.org> wrote:

> 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.

Hm, it looks like the whole CLOCK_TAI feature was rushed in, with not 
enough testing done.

If the bugs extend to more than this two-liner then for -stable it 
might be better to just disable CLOCK_TAI (userspace can deal with it 
just fine), and queue up the right fixes for the next merge window or 
so.

Thanks,

	Ingo

  reply	other threads:[~2013-12-12 13:25 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-11 19:11 [RFC][PATCH 0/5] Timekeeping fixes v2 John Stultz
2013-12-11 19:11 ` [RFC][PATCH 1/5] timekeeping: Fix lost updates to tai adjustment John Stultz
2013-12-11 19:11 ` [RFC][PATCH 2/5] timekeeping: Fix potential lost pv notification of time change John Stultz
2013-12-11 19:11 ` [RFC][PATCH 3/5] timekeeping: Avoid possible deadlock from clock_was_set_delayed John Stultz
2013-12-12 13:23   ` Ingo Molnar
2013-12-12 18:53     ` John Stultz
2013-12-12 16:34   ` Sasha Levin
2013-12-12 18:32     ` Sasha Levin
2013-12-12 18:59       ` John Stultz
2013-12-12 19:05         ` Sasha Levin
2013-12-12 19:13           ` John Stultz
2013-12-17  5:15             ` John Stultz
2013-12-17  6:41               ` Sasha Levin
2013-12-17 16:34                 ` John Stultz
2013-12-11 19:11 ` [RFC][PATCH 4/5] timekeeping: Fix CLOCK_TAI timer/nanosleep delays John Stultz
2013-12-12 13:25   ` Ingo Molnar [this message]
2013-12-12 18:31     ` John Stultz
2013-12-13 14:10       ` Ingo Molnar
2013-12-11 19:11 ` [RFC][PATCH 5/5] timekeeping: Fix missing timekeeping_update in suspend path John Stultz

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