diff --git a/include/ardix/mutex.h b/include/ardix/mutex.h
index 7e621b9..6238876 100644
--- a/include/ardix/mutex.h
+++ b/include/ardix/mutex.h
@@ -97,11 +97,7 @@ extern void _mutex_unlock(uint8_t *lock);
  *
  * @param mutex Mutex to initialize
  */
-__always_inline void mutex_init(struct mutex *mutex)
-{
-	mutex->lock = 0;
-	list_init(&mutex->wait_queue);
-}
+void mutex_init(struct mutex *mutex);
 
 /**
  * @brief Acquire an exclusive lock on a mutex.
diff --git a/kernel/mutex.c b/kernel/mutex.c
index 300e429..ead5f59 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -10,6 +10,13 @@
 #include <errno.h>
 #include <stddef.h>
 
+void mutex_init(struct mutex *mutex)
+{
+	mutex->lock = 0;
+	spin_init(&mutex->wait_queue_lock);
+	list_init(&mutex->wait_queue);
+}
+
 void mutex_lock(struct mutex *mutex)
 {
 	if (mutex_trylock(mutex) != 0) {