diff --git a/src/http/modules/proxy/ngx_http_proxy_upstream.c b/src/http/modules/proxy/ngx_http_proxy_upstream.c
index e6f27a2..3599f0a 100644
--- a/src/http/modules/proxy/ngx_http_proxy_upstream.c
+++ b/src/http/modules/proxy/ngx_http_proxy_upstream.c
@@ -623,7 +623,7 @@
         }
 
         output->free->buf = r->request_body->buf;
-        output->free->buf = NULL;
+        output->free->next = NULL;
         output->allocated = 1;
 
         r->request_body->buf->pos = r->request_body->buf->start;