From: Ruediger Pluem <rpluem@apache.org>
Date: Tue, 5 Apr 2022 14:18:09 +0000 (+0000)
Subject: * Report a broken backend in case reading the response line failed on the
X-Git-Tag: 2.5.0-alpha2-ci-test-only~412
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4e6d9a6618e223b7177c93d4669b01341f24c652;p=thirdparty%2Fapache%2Fhttpd.git

* Report a broken backend in case reading the response line failed on the
  first request on this connection otherwise we assume we have just run
  into a keepalive race and the backend is still healthy.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1899584 13f79535-47bb-0310-9956-ffa450edef68
---

diff --git a/modules/proxy/mod_proxy_http.c b/modules/proxy/mod_proxy_http.c
index 0d335961291..97900b1d448 100644
--- a/modules/proxy/mod_proxy_http.c
+++ b/modules/proxy/mod_proxy_http.c
@@ -1162,8 +1162,23 @@ int ap_proxy_http_process_response(proxy_http_req_t *req)
                 ap_pass_brigade(r->output_filters, bb);
                 /* Mark the backend connection for closing */
                 backend->close = 1;
-                /* Need to return OK to avoid sending an error message */
-                return OK;
+                if (origin->keepalives) {
+                    /* We already had a request on this backend connection and
+                     * might just have run into a keepalive race. Hence we
+                     * think positive and assume that the backend is fine and
+                     * we do not need to signal an error on backend side.
+                     */
+                    return OK;
+                }
+                /*
+                 * This happened on our first request on this connection to the
+                 * backend. This indicates something fishy with the backend.
+                 * Return HTTP_INTERNAL_SERVER_ERROR to signal an unrecoverable
+                 * server error. We do not worry about r->status code and a
+                 * possible error response here as the ap_http_outerror_filter
+                 * will fix all of this for us.
+                 */
+                return HTTP_INTERNAL_SERVER_ERROR;
             }
             if (!c->keepalives) {
                 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01105)