Lock subscription mutex around optional trace logs (#1260)

- The _subscribers vector was utilized in the trace function without
obtaining a lock.  This vector could change size and lead to a segfault.

Co-authored-by: Bill Stoffel <bstoffel@belvederetrading.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/cpp/src/IceStorm/TopicI.cpp b/cpp/src/IceStorm/TopicI.cpp
index badd3ec8435..0b1cf1f0b31 100644
--- a/cpp/src/IceStorm/TopicI.cpp
+++ b/cpp/src/IceStorm/TopicI.cpp
@@ -527,6 +527,8 @@ TopicImpl::subscribeAndGetPublisher(const QoS& qos, const Ice::ObjectPrx& obj)
     Ice::Identity id = obj->ice_getIdentity();
 
     TraceLevelsPtr traceLevels = _instance->traceLevels();
+
+    IceUtil::Mutex::Lock sync(_subscribersMutex);
     if(traceLevels->topic > 0)
     {
         Ice::Trace out(traceLevels->logger, traceLevels->topicCat);
@@ -549,8 +551,6 @@ TopicImpl::subscribeAndGetPublisher(const QoS& qos, const Ice::ObjectPrx& obj)
         }
     }
 
-    IceUtil::Mutex::Lock sync(_subscribersMutex);
-
     SubscriberRecord record;
     record.id = id;
     record.obj = obj;
@@ -621,6 +621,7 @@ TopicImpl::unsubscribe(const Ice::ObjectPrx& subscriber)
 
     Ice::Identity id = subscriber->ice_getIdentity();
 
+    IceUtil::Mutex::Lock sync(_subscribersMutex);
     if(traceLevels->topic > 0)
     {
         Ice::Trace out(traceLevels->logger, traceLevels->topicCat);
@@ -633,7 +634,6 @@ TopicImpl::unsubscribe(const Ice::ObjectPrx& subscriber)
         }
     }
 
-    IceUtil::Mutex::Lock sync(_subscribersMutex);
     Ice::IdentitySeq ids;
     ids.push_back(id);
     removeSubscribers(ids);