[nginx] Upstream: ngx_post_event() instead of upgraded call (tic...

[Maxim Dounin]

details:   http://hg.nginx.org/nginx/rev/7586e7b2dbe9
branches:  
changeset: 5579:7586e7b2dbe9
user:      Maxim Dounin <mdounin at mdounin.ru>
date:      Tue Feb 18 17:30:40 2014 +0400
description:
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.

diffstat:

 src/http/ngx_http_upstream.c |  2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diffs (13 lines):

diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -2557,7 +2557,9 @@ ngx_http_upstream_upgrade(ngx_http_reque
     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);