* mod_http2: a regression in v1.15.24 of the modules was fixed that

    could lead to httpd child processes not being terminated on a
    graceful reload or when reaching MaxConnectionsPerChild.
    When unprocessed h2 requests were queued at the time, these could stall.
    See <icing/mod_h2#212>.
    [@hansborr, @famzah, Stefan Eissing]

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1894728 13f79535-47bb-0310-9956-ffa450edef68
(cherry picked from commit 81595a3)

changes-entries/h2_graceful_stall.txt

@@ -0,0 +1,6 @@
+  * mod_http2: a regression in v1.15.24 of the modules was fixed that
+    could lead to httpd child processes not being terminated on a
+    graceful reload or when reaching MaxConnectionsPerChild.
+    When unprocessed h2 requests were queued at the time, these could stall.
+    See <https://github.com/icing/mod_h2/issues/212>.
+    [@hansborr, @famzah, Stefan Eissing]

modules/http2/h2_session.c

@@ -277,7 +277,7 @@ static int on_begin_headers_cb(nghttp2_session *ngh2,
                                const nghttp2_frame *frame, void *userp)
 {
     h2_session *session = (h2_session *)userp;
-    h2_stream *s;
+    h2_stream *s = NULL;
 
     /* We may see HEADERs at the start of a stream or after all DATA
      * streams to carry trailers. */
@@ -286,7 +286,7 @@ static int on_begin_headers_cb(nghttp2_session *ngh2,
     if (s) {
         /* nop */
     }
-    else {
+    else if (session->local.accepting) {
         s = h2_session_open_stream(userp, frame->hd.stream_id, 0);
     }
     return s? 0 : NGHTTP2_ERR_START_STREAM_NOT_ALLOWED;

modules/http2/h2_workers.c

@@ -461,8 +461,6 @@ apr_status_t h2_workers_unregister(h2_workers *workers, struct h2_mplx *m)
 void h2_workers_graceful_shutdown(h2_workers *workers)
 {
     workers->shutdown = 1;
-    workers->min_workers = 1;
     workers->max_idle_duration = apr_time_from_sec(1);
-    h2_fifo_term(workers->mplxs);
     wake_non_essential_workers(workers);
 }