diff --git a/bench-all b/bench-all
index bbcac98..845c22f 100755
--- a/bench-all
+++ b/bench-all
@@ -71,7 +71,7 @@ mkdir "$new_dir"
 do_bench_buildroot_build() (
   arch="$default_arch"
   build_id=bench
-  if [ "$1" = baseline ]; then
+  if [ "${1:-}" = baseline ]; then
     baseline=--baseline
     baseline_suffix=-baseline
   else