commit d5da8fa776ff62ea3ccb81f8438a4bfe340d364b
author Maxim Dounin <mdounin@mdounin.ru> Tue Feb 18 17:30:40 2014 +0400
committer Maxim Dounin <mdounin@mdounin.ru> Tue Feb 18 17:30:40 2014 +0400
tree 6e45c4be8fda689d6f1f6876ee7496ce96dc9c24
parent d08e51c2da86e93a2b375078677b9c430b723019

Upstream: ngx_post_event() instead of upgraded call (ticket #503).

If a request is finalized in the first call to the
ngx_http_upstream_process_upgraded() function, e.g., because upstream
server closed the connection for some reason, in the second call
the u->peer.connection pointer will be null, resulting in segmentation
fault.

Fix is to avoid second direct call, and post event instead.  This ensures
that ngx_http_upstream_process_upgraded() won't be called again if
a request is finalized.

src/http/ngx_http_upstream.c

diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index ffdffcf..d99d854 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -2456,7 +2456,9 @@
     if (u->peer.connection->read->ready
         || u->buffer.pos != u->buffer.last)
     {
+        ngx_post_event(c->read, &ngx_posted_events);
         ngx_http_upstream_process_upgraded(r, 1, 1);
+        return;
     }
 
     ngx_http_upstream_process_upgraded(r, 0, 1);