From 7959154b93d74aa29c14779c962c4bc82327c3ed Mon Sep 17 00:00:00 2001
From: JoelKatz <DavidJoelSchwartz@GMail.com>
Date: Wed, 6 Mar 2013 11:04:35 -0800
Subject: [PATCH] Fix a deadlock in the websocketpp code. data::get calls
 m_used.push_back(p) which can call intrusive_ptr_release. If
 intrusive_ptr_release discovers a use_count of 1 (due to the vector being
 resized) that can call recycle, which acquires the very same non-recursive
 lock we already hold from get.

---
 src/cpp/websocketpp/src/messages/data.hpp | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/cpp/websocketpp/src/messages/data.hpp b/src/cpp/websocketpp/src/messages/data.hpp
index 2848e522b..2a668a4d6 100644
--- a/src/cpp/websocketpp/src/messages/data.hpp
+++ b/src/cpp/websocketpp/src/messages/data.hpp
@@ -37,6 +37,7 @@
 #include <boost/function.hpp>
 #include <boost/intrusive_ptr.hpp>
 #include <boost/thread/mutex.hpp>
+#include <boost/thread/recursive_mutex.hpp>
 #include <boost/utility.hpp>
 
 #include <algorithm>
@@ -81,7 +82,7 @@ public:
      * pointer.
      */
     element_ptr get() {
-        boost::lock_guard<boost::mutex> lock(m_lock);
+        boost::lock_guard<boost::recursive_mutex> lock(m_lock);
         
         element_ptr p;
         
@@ -114,7 +115,7 @@ public:
         return p;
     }
     void recycle(element_ptr p) {
-        boost::lock_guard<boost::mutex> lock(m_lock);
+        boost::lock_guard<boost::recursive_mutex> lock(m_lock);
         
         if (p->get_index()+1 > m_used.size() || m_used[p->get_index()] != p) {
             //std::cout << "error tried to recycle a pointer we don't control" << std::endl;
@@ -139,7 +140,7 @@ public:
     
     // set a function that will be called when new elements are avaliable.
     void set_callback(callback_type fn) {
-        boost::lock_guard<boost::mutex> lock(m_lock);
+        boost::lock_guard<boost::recursive_mutex> lock(m_lock);
         m_callback = fn;
     }
     
@@ -152,7 +153,7 @@ private:
     
     callback_type   m_callback;
     
-    boost::mutex      m_lock;
+    boost::recursive_mutex      m_lock;
 };
 
 class data {