1 files changed, 27 insertions, 2 deletions

diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
index 2b0484a5dc28..9cb1ae4aabdd 100644
--- a/kernel/rcutiny_plugin.h
+++ b/kernel/rcutiny_plugin.h
@@ -312,8 +312,8 @@ static int rcu_boost(void)
         rt_mutex_lock(&mtx);
         rt_mutex_unlock(&mtx);  /* Keep lockdep happy. */
 
-        return rcu_preempt_ctrlblk.boost_tasks != NULL ||
-               rcu_preempt_ctrlblk.exp_tasks != NULL;
+        return ACCESS_ONCE(rcu_preempt_ctrlblk.boost_tasks) != NULL ||
+               ACCESS_ONCE(rcu_preempt_ctrlblk.exp_tasks) != NULL;
 }
 
 /*
@@ -885,6 +885,19 @@ static void invoke_rcu_callbacks(void)
         wake_up(&rcu_kthread_wq);
 }
 
+#ifdef CONFIG_RCU_TRACE
+
+/*
+ * Is the current CPU running the RCU-callbacks kthread?
+ * Caller must have preemption disabled.
+ */
+static bool rcu_is_callbacks_kthread(void)
+{
+        return rcu_kthread_task == current;
+}
+
+#endif /* #ifdef CONFIG_RCU_TRACE */
+
 /*
  * This kthread invokes RCU callbacks whose grace periods have
  * elapsed.  It is awakened as needed, and takes the place of the
@@ -938,6 +951,18 @@ void invoke_rcu_callbacks(void)
         raise_softirq(RCU_SOFTIRQ);
 }
 
+#ifdef CONFIG_RCU_TRACE
+
+/*
+ * There is no callback kthread, so this thread is never it.
+ */
+static bool rcu_is_callbacks_kthread(void)
+{
+        return false;
+}
+
+#endif /* #ifdef CONFIG_RCU_TRACE */
+
 void rcu_init(void)
 {
         open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);