diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 425b4ceb7cd0765346704ba24569ce87e358a9a1..206774ac69460af889af852598a5f14fad651a21 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -711,6 +711,21 @@ do {									\
 # define lockdep_assert_in_irq() do { } while (0)
 #endif
 
+#ifdef CONFIG_PROVE_RAW_LOCK_NESTING
+
+# define lockdep_assert_RT_in_threaded_ctx() do {			\
+		WARN_ONCE(debug_locks && !current->lockdep_recursion &&	\
+			  current->hardirq_context &&			\
+			  !(current->hardirq_threaded || current->irq_config),	\
+			  "Not in threaded context on PREEMPT_RT as expected\n");	\
+} while (0)
+
+#else
+
+# define lockdep_assert_RT_in_threaded_ctx() do { } while (0)
+
+#endif
+
 #ifdef CONFIG_LOCKDEP
 void lockdep_rcu_suspicious(const char *file, const int line, const char *s);
 #else
diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c
index f15e96164ff1ee3a5391225128a7a28a0b7cb673..a778554f9dad737a4afb248f671a428c791868fd 100644
--- a/kernel/sched/completion.c
+++ b/kernel/sched/completion.c
@@ -58,7 +58,7 @@ void complete_all(struct completion *x)
 {
 	unsigned long flags;
 
-	WARN_ON(irqs_disabled());
+	lockdep_assert_RT_in_threaded_ctx();
 
 	raw_spin_lock_irqsave(&x->wait.lock, flags);
 	x->done = UINT_MAX;