diff --git a/src/cuda/causal_softmax/kernel.h b/src/cuda/causal_softmax/kernel.h
index 7c7ac87..cffa071 100644
--- a/src/cuda/causal_softmax/kernel.h
+++ b/src/cuda/causal_softmax/kernel.h
@@ -7,6 +7,7 @@
 #include "base/causal_softmax.h"
 #include "cuda/causal_softmax/kernel.cuh"
 #include "cuda/kernel_commons.cuh"
+#include "cuda/runtime_utils.h"
 #include "data_type.h"
 #include "dispatcher.h"