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SubjectPatch "hrtimers: Move lock held region in hrtimer_interrupt()" has been added to the 3.0-stable tree
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Date

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

hrtimers: Move lock held region in hrtimer_interrupt()

to the 3.0-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:
hrtimers-move-lock-held-region-in-hrtimer_interrupt.patch
and it can be found in the queue-3.0 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 johnstul@us.ibm.com Tue Jul 17 15:26:26 2012
From: John Stultz <johnstul@us.ibm.com>
Date: Tue, 17 Jul 2012 13:33:55 -0400
Subject: hrtimers: Move lock held region in hrtimer_interrupt()
To: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>, John Stultz <johnstul@us.ibm.com>, Prarit Bhargava <prarit@redhat.com>, Linux Kernel <linux-kernel@vger.kernel.org>
Message-ID: <1342546438-17534-9-git-send-email-johnstul@us.ibm.com>


From: Thomas Gleixner <tglx@linutronix.de>

This is a backport of 196951e91262fccda81147d2bcf7fdab08668b40

We need to update the base offsets from this code and we need to do
that under base->lock. Move the lock held region around the
ktime_get() calls. The ktime_get() calls are going to be replaced with
a function which gets the time and the offsets atomically.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Link: http://lkml.kernel.org/r/1341960205-56738-6-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/hrtimer.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1263,11 +1263,10 @@ void hrtimer_interrupt(struct clock_even
cpu_base->nr_events++;
dev->next_event.tv64 = KTIME_MAX;

+ raw_spin_lock(&cpu_base->lock);
entry_time = now = ktime_get();
retry:
expires_next.tv64 = KTIME_MAX;
-
- raw_spin_lock(&cpu_base->lock);
/*
* We set expires_next to KTIME_MAX here with cpu_base->lock
* held to prevent that a timer is enqueued in our queue via
@@ -1344,6 +1343,7 @@ retry:
* interrupt routine. We give it 3 attempts to avoid
* overreacting on some spurious event.
*/
+ raw_spin_lock(&cpu_base->lock);
now = ktime_get();
cpu_base->nr_retries++;
if (++retries < 3)
@@ -1356,6 +1356,7 @@ retry:
*/
cpu_base->nr_hangs++;
cpu_base->hang_detected = 1;
+ raw_spin_unlock(&cpu_base->lock);
delta = ktime_sub(now, entry_time);
if (delta.tv64 > cpu_base->max_hang_time.tv64)
cpu_base->max_hang_time = delta;

Patches currently in stable-queue which might be from johnstul@us.ibm.com are

queue-3.0/timekeeping-fix-leapsecond-triggered-load-spike-issue.patch
queue-3.0/time-move-common-updates-to-a-function.patch
queue-3.0/timekeeping-fix-clock_monotonic-inconsistency-during-leapsecond.patch
queue-3.0/hrtimer-update-hrtimer-base-offsets-each-hrtimer_interrupt.patch
queue-3.0/timekeeping-add-missing-update-call-in-timekeeping_resume.patch
queue-3.0/hrtimers-move-lock-held-region-in-hrtimer_interrupt.patch
queue-3.0/hrtimer-provide-clock_was_set_delayed.patch
queue-3.0/ntp-fix-leap-second-hrtimer-livelock.patch
queue-3.0/timekeeping-provide-hrtimer-update-function.patch
queue-3.0/timekeeping-maintain-ktime_t-based-offsets-for-hrtimers.patch
queue-3.0/ntp-correct-tai-offset-during-leap-second.patch


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