diff -Naur a/options.c b/options.c
--- a/options.c	2025-10-20 11:21:06.429267402 +0800
+++ b/options.c	2025-10-20 11:23:04.599552277 +0800
@@ -1487,6 +1487,9 @@
 	struct thread_data *td = cb_data_to_td(data);
 	int ret;
 
+	if (!input)
+	    return 1;
+
 	/* FIXME: for now buffer pattern does not support formats */
 	ret = parse_and_fill_pattern(input, strlen(input), td->o.buffer_pattern,
 				     MAX_PATTERN_SIZE, NULL, NULL, NULL);