From ec959b384ce02e438ed89968c4449b12d7e20f74 Mon Sep 17 00:00:00 2001
From: "Charles E. Rolke" <chug@apache.org>
Date: Wed, 27 Mar 2013 15:15:26 +0000
Subject: QPID-4672: C++ Broker deadlock in XmlExchange unbind Unbind functions
 get the Wlock directly and do not get Rlock first.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk/qpid@1461634 13f79535-47bb-0310-9956-ffa450edef68
---
 cpp/src/qpid/xml/XmlExchange.cpp | 13 ++++++++++---
 cpp/src/qpid/xml/XmlExchange.h   |  2 ++
 2 files changed, 12 insertions(+), 3 deletions(-)

(limited to 'cpp/src')

diff --git a/cpp/src/qpid/xml/XmlExchange.cpp b/cpp/src/qpid/xml/XmlExchange.cpp
index fb6c326327..29c00d9c12 100644
--- a/cpp/src/qpid/xml/XmlExchange.cpp
+++ b/cpp/src/qpid/xml/XmlExchange.cpp
@@ -178,6 +178,12 @@ bool XmlExchange::bind(Queue::shared_ptr queue, const std::string& bindingKey, c
 }
 
 bool XmlExchange::unbind(Queue::shared_ptr queue, const std::string& bindingKey, const FieldTable* args)
+{
+    RWlock::ScopedWlock l(lock);
+    return unbindLH(queue, bindingKey, args);
+}
+
+bool XmlExchange::unbindLH(Queue::shared_ptr queue, const std::string& bindingKey, const FieldTable* args)
 {
     /*
      *  When called directly, no qpidFedOrigin argument will be
@@ -185,11 +191,12 @@ bool XmlExchange::unbind(Queue::shared_ptr queue, const std::string& bindingKey,
      *
      *  This is a bit of a hack - the binding needs the origin, but
      *  this interface, as originally defined, would not supply one.
+     *
+     *  Note: caller must hold Wlock
      */
     std::string fedOrigin;
     if (args) fedOrigin = args->getAsString(qpidFedOrigin);
 
-    RWlock::ScopedWlock l(lock);
     if (bindingsMap[bindingKey].remove_if(MatchQueueAndOrigin(queue, fedOrigin))) {
         if (mgmtExchange != 0) {
             mgmtExchange->dec_bindingCount();
@@ -389,9 +396,9 @@ void XmlExchange::propagateFedOp(const std::string& bindingKey, const std::strin
 
 bool XmlExchange::fedUnbind(const std::string& fedOrigin, const std::string& fedTags, Queue::shared_ptr queue, const std::string& bindingKey, const FieldTable* args)
 {
-    RWlock::ScopedRlock l(lock);
+    RWlock::ScopedWlock l(lock);
 
-    if (unbind(queue, bindingKey, args)) {
+    if (unbindLH(queue, bindingKey, args)) {
         propagateFedOp(bindingKey, fedTags, fedOpUnbind, fedOrigin); 
         return true;
     }
diff --git a/cpp/src/qpid/xml/XmlExchange.h b/cpp/src/qpid/xml/XmlExchange.h
index 7b04781ad5..fd3f8d0278 100644
--- a/cpp/src/qpid/xml/XmlExchange.h
+++ b/cpp/src/qpid/xml/XmlExchange.h
@@ -107,6 +107,8 @@ class XmlExchange : public virtual Exchange {
         bool operator()(XmlBinding::shared_ptr b);
     };
 
+  private:
+    bool unbindLH(Queue::shared_ptr queue, const std::string& routingKey, const qpid::framing::FieldTable* args);
 };
 
 
-- 
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