ticket 1782

• behavior: worker process segmentation fault

• description: set error_page for proxy server and make a conditional client request for a cached response

• sketch:

  • ngx_http_internal_redirect at src/http/ngx_http_core_module.c:2436

    r->cache = NULL;

  • ngx_http_upstream_cache_background_update at src/http/ngx_http_upstream.c:1100

    if (!r->cached || !r->cache->background) {

  r->cached is not necessarily reset to 0 though r->cache becomes NULL

• patch: unresovled