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

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On 2016-09-27 20:03, Greg KH wrote:
> On Tue, Sep 27, 2016 at 05:12:12PM +0100, Marc Zyngier wrote:
>> Greg,
>> 
>> On Tue, 27 Sep 2016 16:27:57 +0200
>> <gregkh@xxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx> know about it.
>> > 
>> > 
>> > From 9c808765e88efb6fa6af7e2206ef89512f1840a7 Mon Sep 17 00:00:00 2001
>> > From: Marc Zyngier <marc.zyngier@xxxxxxx>
>> > Date: Fri, 15 Jan 2016 17:41:08 +0000
>> > Subject: hrtimer: Add support for CLOCK_MONOTONIC_RAW
>> > 
>> > From: Marc Zyngier <marc.zyngier@xxxxxxx>
>> > 
>> > 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@xxxxxxx>
>> > Cc: Tomasz Nowicki <tn@xxxxxxxxxxxx>
>> > Cc: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
>> > Link: http://lkml.kernel.org/r/1452879670-16133-2-git-send-email-marc.zyngier@xxxxxxx
>> > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> > Cc: Felix Fietkau <nbd@xxxxxxxx>
>> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>> 
>> 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?
I guess I can send a mac80211_hwpatch to switch to CLOCK_MONOTONIC
instead and add Cc: stable.

- Felix
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