From: Viresh Kumar <viresh.kumar(a)linaro.org>
This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.
===============
commit 27630532ef5ead28b98cfe28d8f95222ef91c2b7 upstream.
Since commit d689fe222 (NOHZ: Check for nohz active instead of nohz
enabled) the tick_nohz_switch_to_nohz() function returns because it
checks for the tick_nohz_active flag. This can't be set, because the
function itself sets it.
Undo the change in tick_nohz_switch_to_nohz().
Signed-off-by: Viresh Kumar <viresh.kumar(a)linaro.org>
Cc: linaro-kernel(a)lists.linaro.org
Cc: fweisbec(a)gmail.com
Cc: Arvind.Chauhan(a)arm.com
Cc: linaro-networking(a)linaro.org
Cc: <stable(a)vger.kernel.org> # 3.13+
Link: http://lkml.kernel.org/r/40939c05f2d65d781b92b20302b02243d0654224.139753798…
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Signed-off-by: Jiri Slaby <jslaby(a)suse.cz>
---
kernel/time/tick-sched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index ea20f7d1ac2c..29b063b32ff0 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -970,7 +970,7 @@ static void tick_nohz_switch_to_nohz(void)
struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
ktime_t next;
- if (!tick_nohz_active)
+ if (!tick_nohz_enabled)
return;
local_irq_disable();
--
2.0.0
3.8.13.25 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Viresh Kumar <viresh.kumar(a)linaro.org>
commit 84ea7fe37908254c3bd90910921f6e1045c1747a upstream.
switch_hrtimer_base() calls hrtimer_check_target() which ensures that
we do not migrate a timer to a remote cpu if the timer expires before
the current programmed expiry time on that remote cpu.
But __hrtimer_start_range_ns() calls switch_hrtimer_base() before the
new expiry time is set. So the sanity check in hrtimer_check_target()
is operating on stale or even uninitialized data.
Update expiry time before calling switch_hrtimer_base().
[ tglx: Rewrote changelog once again ]
Signed-off-by: Viresh Kumar <viresh.kumar(a)linaro.org>
Cc: linaro-kernel(a)lists.linaro.org
Cc: linaro-networking(a)linaro.org
Cc: fweisbec(a)gmail.com
Cc: arvind.chauhan(a)arm.com
Link: http://lkml.kernel.org/r/81999e148745fc51bbcd0615823fbab9b2e87e23.139988225…
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Signed-off-by: Kamal Mostafa <kamal(a)canonical.com>
---
kernel/hrtimer.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 9873816..20e88af 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -980,11 +980,8 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
/* Remove an active timer from the queue: */
ret = remove_hrtimer(timer, base);
- /* Switch the timer base, if necessary: */
- new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
-
if (mode & HRTIMER_MODE_REL) {
- tim = ktime_add_safe(tim, new_base->get_time());
+ tim = ktime_add_safe(tim, base->get_time());
/*
* CONFIG_TIME_LOW_RES is a temporary way for architectures
* to signal that they simply return xtime in
@@ -999,6 +996,9 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
hrtimer_set_expires_range_ns(timer, tim, delta_ns);
+ /* Switch the timer base, if necessary: */
+ new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
+
timer_stats_hrtimer_set_start_info(timer);
leftmost = enqueue_hrtimer(timer, new_base);
--
1.9.1