Re: Patch "hrtimer: Add support for CLOCK_MONOTONIC_RAW" has been added to the 4.4-stable tree

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Sep 27, 2016 at 05:12:12PM +0100, Marc Zyngier wrote:
> Greg,
> 
> On Tue, 27 Sep 2016 16:27:57 +0200
> <gregkh@linuxfoundation.org> wrote:
> 
> > This is a note to let you know that I've just added the patch titled
> > 
> >     hrtimer: Add support for CLOCK_MONOTONIC_RAW
> > 
> > to the 4.4-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:
> >      hrtimer-add-support-for-clock_monotonic_raw.patch
> > and it can be found in the queue-4.4 subdirectory.
> > 
> > If you, or anyone else, feels it should not be added to the stable tree,
> > please let <stable@vger.kernel.org> know about it.
> > 
> > 
> > From 9c808765e88efb6fa6af7e2206ef89512f1840a7 Mon Sep 17 00:00:00 2001
> > From: Marc Zyngier <marc.zyngier@arm.com>
> > Date: Fri, 15 Jan 2016 17:41:08 +0000
> > Subject: hrtimer: Add support for CLOCK_MONOTONIC_RAW
> > 
> > From: Marc Zyngier <marc.zyngier@arm.com>
> > 
> > commit 9c808765e88efb6fa6af7e2206ef89512f1840a7 upstream.
> > 
> > The KVM/ARM timer implementation arms a hrtimer when a vcpu is
> > blocked (usually because it is waiting for an interrupt)
> > while its timer is going to kick in the future.
> > 
> > It is essential that this timer doesn't get adjusted, or the
> > guest will end up being woken-up at the wrong time (NTP running
> > on the host seems to confuse the hell out of some guests).
> > 
> > In order to allow this, let's add CLOCK_MONOTONIC_RAW support
> > to hrtimer (it is so far only supported for posix timers). It also
> > has the (limited) benefit of fixing de0421d53bfb ("mac80211_hwsim:
> > shuffle code to prepare for dynamic radios"), which already uses
> > this functionnality without realizing wasn't implemented (just being
> > lucky...).
> > 
> > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> > Cc: Tomasz Nowicki <tn@semihalf.com>
> > Cc: Christoffer Dall <christoffer.dall@linaro.org>
> > Link: http://lkml.kernel.org/r/1452879670-16133-2-git-send-email-marc.zyngier@arm.com
> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> > Cc: Felix Fietkau <nbd@nbd.name>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> Please drop that patch. It is utterly broken, and was reverted in
> mainline with commit 82e88ff1ea94 ("hrtimer: Revert CLOCK_MONOTONIC_RAW
> support").
> 

Ok, will do.

Felix, this kind of means this isn't the fix you were looking for, any
other ideas?

thanks,

greg k-h