diff --git a/tools/testing/ktest/ktest.pl b/tools/testing/ktest/ktest.pl
index 10b3c5b25b69..964a531e1a65 100755
--- a/tools/testing/ktest/ktest.pl
+++ b/tools/testing/ktest/ktest.pl
@@ -1280,7 +1280,10 @@ sub __eval_option {
 	# If a variable contains itself, use the default var
 	if (($var eq $name) && defined($opt{$var})) {
 	    $o = $opt{$var};
-	    $retval = "$retval$o";
+	    # Only append if the default doesn't contain itself
+	    if ($o !~ m/\$\{$var\}/) {
+		$retval = "$retval$o";
+	    }
 	} elsif (defined($opt{$o})) {
 	    $o = $opt{$o};
 	    $retval = "$retval$o";