diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 5b8328a99b2a..07b527dca996 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -472,7 +472,11 @@ extern int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
 				 bool state);
 
 #ifdef CONFIG_IRQ_FORCED_THREADING
+# ifdef CONFIG_PREEMPT_RT
+#  define force_irqthreads	(true)
+# else
 extern bool force_irqthreads;
+# endif
 #else
 #define force_irqthreads	(0)
 #endif
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index e8f7f179bf77..97de1b7d43af 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -23,7 +23,7 @@
 
 #include "internals.h"
 
-#ifdef CONFIG_IRQ_FORCED_THREADING
+#if defined(CONFIG_IRQ_FORCED_THREADING) && !defined(CONFIG_PREEMPT_RT)
 __read_mostly bool force_irqthreads;
 EXPORT_SYMBOL_GPL(force_irqthreads);