diff --git a/repos/base/src/lib/base/heap.cc b/repos/base/src/lib/base/heap.cc
index 8cf9e45ed8..13a7e93305 100644
--- a/repos/base/src/lib/base/heap.cc
+++ b/repos/base/src/lib/base/heap.cc
@@ -291,7 +291,7 @@ void Heap::free(void *addr, size_t)
 			break;
 
 	if (!ds) {
-		warning("heap could not free memory block: invalid address");
+		warning("heap could not free memory block: invalid address ", addr);
 		return;
 	}