src/http/modules/ngx_http_charset_filter_module.c:653: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned64 by call to `ngx_utf8_decode`.

src/http/modules/ngx_http_charset_filter_module.c:608:1: Parameter `*buf->last`
606. 
607. 
608. static ngx_chain_t *
     ^
609. ngx_http_charset_recode_from_utf8(ngx_pool_t *pool, ngx_buf_t *buf,
610.     ngx_http_charset_ctx_t *ctx)

src/http/modules/ngx_http_charset_filter_module.c:650:17: Assignment
648.                 out->next = NULL;
649. 
650.                 size = buf->last - src;
                     ^
651. 
652.                 saved = src;

src/http/modules/ngx_http_charset_filter_module.c:653:21: Call
651. 
652.                 saved = src;
653.                 n = ngx_utf8_decode(&saved, size);
                         ^
654. 
655.                 if (n == 0xfffffffe) {

src/core/ngx_string.c:1081:1: <LHS trace>
1079.  */
1080. 
1081. uint32_t
      ^
1082. ngx_utf8_decode(u_char **p, size_t n)
1083. {

src/core/ngx_string.c:1081:1: Parameter `n`
  1079.  */
  1080. 
  1081. uint32_t
        ^
  1082. ngx_utf8_decode(u_char **p, size_t n)
  1083. {

src/core/ngx_string.c:1112:9: Binary operation: ([0, +oo] - 1):unsigned64 by call to `ngx_utf8_decode` 
  1110.     }
  1111. 
  1112.     if (n - 1 < len) {
                ^
  1113.         return 0xfffffffe;
  1114.     }
