HTTP/2: fixed the "http request count is zero" alert.

When the stream is terminated the HEADERS frame can still wait in the output
queue.  This frame can't be removed and must be sent to the client anyway,
since HTTP/2 uses stateful compression for headers.  So in order to postpone
closing and freeing memory of such stream the special close stream handler
is set to the write event.  After the HEADERS frame is sent the write event
is called and the stream will be finally closed.

Some events like receiving a RST_STREAM can trigger the read handler of such
stream in closing state and cause unexpected processing that can result in
another attempt to finalize the request.  To prevent it the read handler is
now set to ngx_http_empty_handler.

Thanks to Amazon.

diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c
index 342c307ef375e7e4ce3b47953358973d95d4bbd4..19e5f3a0975fa2ae66a1c99948b21cefdc18275e 100644 (file)
--- a/src/http/v2/ngx_http_v2.c
+++ b/src/http/v2/ngx_http_v2.c
@@ -3935,6 +3935,7 @@ ngx_http_v2_close_stream(ngx_http_v2_stream_t *stream, ngx_int_t rc)
 
     if (stream->queued) {
         fc->write->handler = ngx_http_v2_close_stream_handler;
+        fc->read->handler = ngx_http_empty_handler;
         return;
     }