diff --git a/ChangeLog b/ChangeLog
index 0c9a4e885b..c074128b1b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2019-02-04  Matthew Malcomson  <matthew.malcomson@arm.com>
+
+	* Makefile (testrun.sh): Exit in case of incorrect argument.
+
 2019-02-04  Florian Weimer  <fweimer@redhat.com>
 
 	* time/tzfile.c (__tzfile_read): Reorder suballocations to avoid
diff --git a/Makefile b/Makefile
index 4a014d6eff..1bfe7fefe1 100644
--- a/Makefile
+++ b/Makefile
@@ -137,6 +137,7 @@ GCONV_PATH="$${builddir}/iconvdata"
 usage () {
   echo "usage: $$0 [--tool=strace] PROGRAM [ARGUMENTS...]" 2>&1
   echo "       $$0 --tool=valgrind PROGRAM [ARGUMENTS...]" 2>&1
+  exit 1
 }
 
 toolname=default