From b2ba55c42b563418e7be4adb38cdbf1852e6c78d Mon Sep 17 00:00:00 2001
From: Gavin Andresen <gavinandresen@gmail.com>
Date: Tue, 15 Oct 2013 15:30:20 +1000
Subject: [PATCH] Avoid core dump if rpc port is in use.

The cleanup code needs to check for NULL rpcworkers thread group.
---
 src/bitcoinrpc.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/bitcoinrpc.cpp b/src/bitcoinrpc.cpp
index b0df9c5e..ae988a76 100644
--- a/src/bitcoinrpc.cpp
+++ b/src/bitcoinrpc.cpp
@@ -881,7 +881,8 @@ void StopRPCThreads()
 
     deadlineTimers.clear();
     rpc_io_service->stop();
-    rpc_worker_group->join_all();
+    if (rpc_worker_group != NULL)
+        rpc_worker_group->join_all();
     delete rpc_worker_group; rpc_worker_group = NULL;
     delete rpc_ssl_context; rpc_ssl_context = NULL;
     delete rpc_io_service; rpc_io_service = NULL;