src/http/ngx_http_upstream.c:637: error: Integer Overflow L2
  ([0, `r->main->count` + 3] - 1):unsigned32 by call to `ngx_http_upstream_connect`.

src/http/ngx_http_upstream.c:505:1: Parameter `r->main->count`
503. 
504. 
505. static void
     ^
506. ngx_http_upstream_init_request(ngx_http_request_t *r)
507. {

src/http/ngx_http_upstream.c:637:13: Call
635.             }
636. 
637.             ngx_http_upstream_connect(r, u);
                 ^
638. 
639.             return;

src/http/ngx_http_upstream.c:1303:1: Parameter `r->main->count`
  1301. 
  1302. 
  1303. static void
        ^
  1304. ngx_http_upstream_connect(ngx_http_request_t *r, ngx_http_upstream_t *u)
  1305. {

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:3778:1: Parameter `r->main->count`
    3776. 
    3777. 
    3778. static void
          ^
    3779. ngx_http_upstream_next(ngx_http_request_t *r, ngx_http_upstream_t *u,
    3780.     ngx_uint_t ft_type)

src/http/ngx_http_upstream.c:3847:9: Call
    3845. 
    3846.     if (r->connection->error) {
    3847.         ngx_http_upstream_finalize_request(r, u,
                  ^
    3848.                                            NGX_HTTP_CLIENT_CLOSED_REQUEST);
    3849.         return;

src/http/ngx_http_upstream.c:3923:1: Parameter `r->main->count`
      3921. 
      3922. 
      3923. static void
            ^
      3924. ngx_http_upstream_finalize_request(ngx_http_request_t *r,
      3925.     ngx_http_upstream_t *u, ngx_int_t rc)

src/http/ngx_http_upstream.c:3934:9: Call
      3932.     if (u->cleanup == NULL) {
      3933.         /* the request was already finalized */
      3934.         ngx_http_finalize_request(r, NGX_DONE);
                    ^
      3935.         return;
      3936.     }

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. 
        2342.             if (!r->logged) {
