src/http/ngx_http_upstream.c:1735: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned32 by call to `ngx_http_file_cache_free`.

src/http/ngx_http_upstream.c:1735:17: Call
1733.                 }
1734. 
1735.                 ngx_http_file_cache_free(r->cache, u->pipe->temp_file);
                      ^
1736.             }
1737. #endif

src/http/ngx_http_file_cache.c:907:1: <LHS trace>
905. 
906. 
907. void
     ^
908. ngx_http_file_cache_free(ngx_http_cache_t *c, ngx_temp_file_t *tf)
909. {

src/http/ngx_http_file_cache.c:907:1: Parameter `c->node->count`
  905. 
  906. 
  907. void
       ^
  908. ngx_http_file_cache_free(ngx_http_cache_t *c, ngx_temp_file_t *tf)
  909. {

src/http/ngx_http_file_cache.c:925:5: Binary operation: ([0, +oo] - 1):unsigned32 by call to `ngx_http_file_cache_free` 
  923. 
  924.     fcn = c->node;
  925.     fcn->count--;
           ^
  926. 
  927.     if (c->updating) {
