diff --git a/src/thread.cpp b/src/thread.cpp
index a6a2fb4..a392422 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -26,7 +26,7 @@ namespace sta
 				  running_{false}
 		{
 			STA_ASSERT(stack_size >= 0);
-			STA_ASSERT(stack_size >= 0);
+			STA_ASSERT(cb_size >= 0);
 		}
 
 		void TacosThread::entry_point(void* arg)