diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index da796e2dc4f5..c7c96bc7654a 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -360,6 +360,10 @@ static int ddebug_parse_query(char *words[], int nwords,
 				if (parse_lineno(last, &query->last_lineno) < 0)
 					return -EINVAL;
 
+				/* special case for last lineno not specified */
+				if (query->last_lineno == 0)
+					query->last_lineno = UINT_MAX;
+
 				if (query->last_lineno < query->first_lineno) {
 					pr_err("last-line:%d < 1st-line:%d\n",
 						query->last_lineno,