[PATCH RT 1/8] timer/hrtimer: check properly for a running timer

[Steven Rostedt <rostedt@goodmis.org>]

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4.4.97-rt111-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

hrtimer_callback_running() checks only whether a timmer is running on a
CPU in hardirq-context. This is okay for !RT. For RT environment we move
most timers to the timer-softirq and therefore we therefore need to
check if the timer is running in the softirq context.

Cc: stable-rt@vger.kernel.org
Reported-by: Alexander Gerasiov <gq@cs.msu.su>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/hrtimer.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 8fbcdfa5dc77..ff317006d3e8 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -455,7 +455,13 @@ static inline int hrtimer_is_queued(struct hrtimer *timer)
  */
 static inline int hrtimer_callback_running(const struct hrtimer *timer)
 {
-	return timer->base->cpu_base->running == timer;
+	if (timer->base->cpu_base->running == timer)
+		return 1;
+#ifdef CONFIG_PREEMPT_RT_BASE
+	if (timer->base->cpu_base->running_soft == timer)
+		return 1;
+#endif
+	return 0;
 }
 
 /* Forward a hrtimer so it expires after now: */
-- 
2.13.2