src/http/ngx_http_upstream.c:2767: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32 by call to `ngx_http_file_cache_free`.

src/http/ngx_http_upstream.c:2767:13: Call
2765. 
2766.         if (r->cache) {
2767.             ngx_http_file_cache_free(r->cache, u->pipe->temp_file);
                  ^
2768.         }
2769. 

src/http/ngx_http_file_cache.c:1606:1: <LHS trace>
1604. 
1605. 
1606. void
      ^
1607. ngx_http_file_cache_free(ngx_http_cache_t *c, ngx_temp_file_t *tf)
1608. {

src/http/ngx_http_file_cache.c:1606:1: Parameter `c->node->count`
  1604. 
  1605. 
  1606. void
        ^
  1607. ngx_http_file_cache_free(ngx_http_cache_t *c, ngx_temp_file_t *tf)
  1608. {

src/http/ngx_http_file_cache.c:1624:5: Binary operation: ([0, +oo] - 1):unsigned32 by call to `ngx_http_file_cache_free` 
  1622. 
  1623.     fcn = c->node;
  1624.     fcn->count--;
            ^
  1625. 
  1626.     if (c->updating && fcn->lock_time == c->lock_time) {
