src/http/ngx_http_upstream.c:633: error: Integer Overflow L2
  ([0, `r->main->count` + 3] - 1):unsigned32 by call to `ngx_http_upstream_connect`.

src/http/ngx_http_upstream.c:501:1: Parameter `r->main->count`
499. 
500. 
501. static void
     ^
502. ngx_http_upstream_init_request(ngx_http_request_t *r)
503. {

src/http/ngx_http_upstream.c:633:13: Call
631.             }
632. 
633.             ngx_http_upstream_connect(r, u);
                 ^
634. 
635.             return;

src/http/ngx_http_upstream.c:1299:1: Parameter `r->main->count`
  1297. 
  1298. 
  1299. static void
        ^
  1300. ngx_http_upstream_connect(ngx_http_request_t *r, ngx_http_upstream_t *u)
  1301. {

src/http/ngx_http_upstream.c:1343:9: Call
  1341.     if (rc == NGX_BUSY) {
  1342.         ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "no live upstreams");
  1343.         ngx_http_upstream_next(r, u, NGX_HTTP_UPSTREAM_FT_NOLIVE);
                ^
  1344.         return;
  1345.     }

src/http/ngx_http_upstream.c:3753:1: Parameter `r->main->count`
    3751. 
    3752. 
    3753. static void
          ^
    3754. ngx_http_upstream_next(ngx_http_request_t *r, ngx_http_upstream_t *u,
    3755.     ngx_uint_t ft_type)

src/http/ngx_http_upstream.c:3822:9: Call
    3820. 
    3821.     if (r->connection->error) {
    3822.         ngx_http_upstream_finalize_request(r, u,
                  ^
    3823.                                            NGX_HTTP_CLIENT_CLOSED_REQUEST);
    3824.         return;

src/http/ngx_http_upstream.c:3898:1: Parameter `r->main->count`
      3896. 
      3897. 
      3898. static void
            ^
      3899. ngx_http_upstream_finalize_request(ngx_http_request_t *r,
      3900.     ngx_http_upstream_t *u, ngx_int_t rc)

src/http/ngx_http_upstream.c:4041:9: Call
      4039. 
      4040.     if (r->header_only) {
      4041.         ngx_http_finalize_request(r, rc);
                    ^
      4042.         return;
      4043.     }

src/http/ngx_http_request.c:2249:1: <LHS trace>
2247. 
2248. 
2249. void
      ^
2250. ngx_http_finalize_request(ngx_http_request_t *r, ngx_int_t rc)
2251. {

src/http/ngx_http_request.c:2249:1: Parameter `r->main->count`
        2247. 
        2248. 
        2249. void
              ^
        2250. ngx_http_finalize_request(ngx_http_request_t *r, ngx_int_t rc)
        2251. {

src/http/ngx_http_request.c:2340:13: Binary operation: ([0, r->main->count + 3] - 1):unsigned32 by call to `ngx_http_upstream_connect` 
        2338.         if (r == c->data) {
        2339. 
        2340.             r->main->count--;
                          ^
        2341.             r->main->subrequests++;
        2342. 
