diff --git a/src/kit/taosdemo/taosdemo.c b/src/kit/taosdemo/taosdemo.c
index 31a53ca4ddd73f76f052680f9f389ea797dc94a4..8b3f5743de3821fdf93e8b73f891ebd82c209975 100644
--- a/src/kit/taosdemo/taosdemo.c
+++ b/src/kit/taosdemo/taosdemo.c
@@ -4982,12 +4982,20 @@ static int64_t generateData(char *recBuf, char **data_type,
       bool b = rand_bool() & 1;
       pstr += sprintf(pstr, ",%s", b ? "true" : "false");
     } else if (strcasecmp(data_type[i % columnCount], "BINARY") == 0) {
-      char *s = malloc(lenOfBinary);
+      char *s = malloc(lenOfBinary + 1);
+      if (s == NULL) {
+          errorPrint("%s() LN%d, memory allocation %d bytes failed\n",
+                  __func__, __LINE__, lenOfBinary + 1);
+      }
       rand_string(s, lenOfBinary);
       pstr += sprintf(pstr, ",\"%s\"", s);
       free(s);
     } else if (strcasecmp(data_type[i % columnCount], "NCHAR") == 0) {
-      char *s = malloc(lenOfBinary);
+      char *s = malloc(lenOfBinary + 1);
+      if (s == NULL) {
+          errorPrint("%s() LN%d, memory allocation %d bytes failed\n",
+                  __func__, __LINE__, lenOfBinary + 1);
+      }
       rand_string(s, lenOfBinary);
       pstr += sprintf(pstr, ",\"%s\"", s);
       free(s);