1 files changed, 15 insertions, 3 deletions

diff --git a/kernel/smpboot.c b/kernel/smpboot.c
index b9bde5727829..02fc5c933673 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);
 }