Fixed premature background subrequest finalization.
When "aio" or "aio threads" is used while processing the response body of an
in-memory background subrequest, the subrequest could be finalized with an aio
operation still in progress. Upon aio completion either parent request is
woken or the old r->write_event_handler is called again. The latter may result
in request errors. In either case post_subrequest handler is never called with
the full response body, which is typically expected when using in-memory
subrequests.
Currently in nginx background subrequests are created by the upstream module
and the mirror module. The issue does not manifest itself with these
subrequests because they are header-only. But it can manifest itself with
third-party modules which create in-memory background subrequests.
diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index bb69e71..5fcaa2c 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -2490,6 +2490,15 @@
if (r != r->main) {
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
+ if (r->buffered || r->postponed) {
+
+ if (ngx_http_set_write_handler(r) != NGX_OK) {
+ ngx_http_terminate_request(r, 0);
+ }
+
+ return;
+ }
+
if (r->background) {
if (!r->logged) {
if (clcf->log_subrequest) {
@@ -2509,15 +2518,6 @@
return;
}
- if (r->buffered || r->postponed) {
-
- if (ngx_http_set_write_handler(r) != NGX_OK) {
- ngx_http_terminate_request(r, 0);
- }
-
- return;
- }
-
pr = r->parent;
if (r == c->data) {
