Re: + hrtimers-fix-reprogramming-smp-race.patch added to -mm tree

Re: + hrtimers-fix-reprogramming-smp-race.patch added to -mm tree

[Thomas Gleixner]

On Mon, 2007-03-26 at 12:46 -0700, akpm@linux-foundation.org wrote:
> The patch titled
>      hrtimers: fix reprogramming SMP race
> has been added to the -mm tree.  Its filename is
>      hrtimers-fix-reprogramming-smp-race.patch
> 
> *** Remember to use Documentation/SubmitChecklist when testing your code ***
> 
> See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
> out what to do about this
> 
> ------------------------------------------------------
> Subject: hrtimers: fix reprogramming SMP race
> From: Ingo Molnar <mingo@elte.hu>
> 
> hrtimer_start() incorrectly set the 'reprogram' flag to enqueue_hrtimer(),
> which should only be 1 if the hrtimer is queued to the current CPU.
> 
> Doing otherwise could result in a reprogramming of the current CPU's
> clockevents device, with a timer that is not queued to it - resulting in a
> bogus next expiry value.

Doh.

> Signed-off-by: Ingo Molnar <mingo@elte.hu>
> Cc: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Acked-by: Thomas Gleixner <tglx@linutronix.de>

Andrew, this should go into 2.6.21 as well.

	tglx