From 256cad898045eb63036a70d90c2fc827be85fd08 Mon Sep 17 00:00:00 2001
From: Andy Wilkinson <awilkinson@pivotal.io>
Date: Thu, 3 Dec 2015 10:57:14 +0000
Subject: [PATCH] Fix inconsistent synchronization in
 HttpTunnelServer.ServerThread

Previously, ServerThread.lastHttpRequestTime was written while
synchronized on this.httpConnections but was read without
synchronization. This could lead to a read of the field producing the
wrong value and cause premature connection timeout.

This commit moves the call to checkNotDisconnected into a block that
sychronizes on this.httpConnections, thereby ensuring that
lastHttpRequestTime can be read safely.

Closes gh-4668
---
 .../boot/devtools/tunnel/server/HttpTunnelServer.java           | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/tunnel/server/HttpTunnelServer.java b/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/tunnel/server/HttpTunnelServer.java
index 829e87bf5f6..fe1ee9673c2 100644
--- a/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/tunnel/server/HttpTunnelServer.java
+++ b/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/tunnel/server/HttpTunnelServer.java
@@ -274,8 +274,8 @@ public class HttpTunnelServer {
 		}
 
 		private void closeStaleHttpConnections() throws IOException {
-			checkNotDisconnected();
 			synchronized (this.httpConnections) {
+				checkNotDisconnected();
 				Iterator<HttpConnection> iterator = this.httpConnections.iterator();
 				while (iterator.hasNext()) {
 					HttpConnection httpConnection = iterator.next();