Merge commit '8700c95adb03' into timers/nohz

The full dynticks tree needs the latest RCU and sched
upstream updates in order to fix some dependencies.

Merge a common upstream merge point that has these
updates.

Conflicts:
	include/linux/perf_event.h
	kernel/rcutree.h
	kernel/rcutree_plugin.h

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

1 files changed, 15 insertions, 3 deletions

diff --git a/kernel/smpboot.c b/kernel/smpboot.c
index b9bde57..02fc5c9 100644
--- a/kernel/smpboot.c
+++ b/kernel/smpboot.c
@@ -131,7 +131,7 @@ static int smpboot_thread_fn(void *data)
 			continue;
 		}
 
-		//BUG_ON(td->cpu != smp_processor_id());
+		BUG_ON(td->cpu != smp_processor_id());
 
 		/* Check for state change setup */
 		switch (td->status) {
@@ -185,8 +185,18 @@ __smpboot_create_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
 	}
 	get_task_struct(tsk);
 	*per_cpu_ptr(ht->store, cpu) = tsk;
-	if (ht->create)
-		ht->create(cpu);
+	if (ht->create) {
+		/*
+		 * Make sure that the task has actually scheduled out
+		 * into park position, before calling the create
+		 * callback. At least the migration thread callback
+		 * requires that the task is off the runqueue.
+		 */
+		if (!wait_task_inactive(tsk, TASK_PARKED))
+			WARN_ON(1);
+		else
+			ht->create(cpu);
+	}
 	return 0;
 }
 
@@ -209,6 +219,8 @@ static void smpboot_unpark_thread(struct smp_hotplug_thread *ht, unsigned int cp
 {
 	struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
 
+	if (ht->pre_unpark)
+		ht->pre_unpark(cpu);
 	kthread_unpark(tsk);
 }