diff --git a/test/regress_main.c b/test/regress_main.c
index ad337427..4d518b24 100644
--- a/test/regress_main.c
+++ b/test/regress_main.c
@@ -96,7 +96,7 @@ regress_make_tmpfile(const void *data, size_t datalen)
 #ifndef WIN32
 	char tmpfilename[32];
 	int fd;
-	strcpy(tmpfilename, "/tmp/eventtmp.XXXX");
+	strcpy(tmpfilename, "/tmp/eventtmp.XXXXXX");
 	fd = mkstemp(tmpfilename);
 	if (fd == -1)
 		return (-1);