diff --git a/src/cpp/ripple/JobQueue.cpp b/src/cpp/ripple/JobQueue.cpp
index cc2aadb40b..3dc9386d0e 100644
--- a/src/cpp/ripple/JobQueue.cpp
+++ b/src/cpp/ripple/JobQueue.cpp
@@ -256,16 +256,18 @@ void JobQueue::threadEntry()
 			break;
 
 		std::set<Job>::iterator it = mJobSet.begin();
-		Job job(*it);
-		mJobSet.erase(it);
-		--mJobCounts[job.getType()];
+		{
+			Job job(*it);
+			mJobSet.erase(it);
+			--mJobCounts[job.getType()];
 
-		if (job.getType() == jtDEATH)
-			break;
+			if (job.getType() == jtDEATH)
+				break;
 
-		sl.unlock();
-		cLog(lsTRACE) << "Doing " << Job::toString(job.getType()) << " job";
-		job.doJob();
+			sl.unlock();
+			cLog(lsTRACE) << "Doing " << Job::toString(job.getType()) << " job";
+			job.doJob();
+		} // must destroy job without holding lock
 		sl.lock();
 	}
 	--mThreadCount;
diff --git a/src/cpp/ripple/NetworkOPs.cpp b/src/cpp/ripple/NetworkOPs.cpp
index 728d18d278..dcd526c842 100644
--- a/src/cpp/ripple/NetworkOPs.cpp
+++ b/src/cpp/ripple/NetworkOPs.cpp
@@ -1696,12 +1696,14 @@ bool NetworkOPs::subLedger(InfoSub::ref isrListener, Json::Value& jvResult)
 	jvResult["reserve_base"]	= Json::UInt(lpClosed->getReserve(0));
 	jvResult["reserve_inc"]		= Json::UInt(lpClosed->getReserveInc());
 
+	boost::recursive_mutex::scoped_lock	sl(mMonitorLock);
 	return mSubLedger.insert(std::make_pair(isrListener->getSeq(), isrListener)).second;
 }
 
 // <-- bool: true=erased, false=was not there
 bool NetworkOPs::unsubLedger(uint64 uSeq)
 {
+	boost::recursive_mutex::scoped_lock	sl(mMonitorLock);
 	return !!mSubLedger.erase(uSeq);
 }
 
@@ -1722,36 +1724,42 @@ bool NetworkOPs::subServer(InfoSub::ref isrListener, Json::Value& jvResult)
 	jvResult["load_base"]		= theApp->getFeeTrack().getLoadBase();
 	jvResult["load_factor"]		= theApp->getFeeTrack().getLoadFactor();
 
+	boost::recursive_mutex::scoped_lock	sl(mMonitorLock);
 	return mSubServer.insert(std::make_pair(isrListener->getSeq(), isrListener)).second;
 }
 
 // <-- bool: true=erased, false=was not there
 bool NetworkOPs::unsubServer(uint64 uSeq)
 {
+	boost::recursive_mutex::scoped_lock	sl(mMonitorLock);
 	return !!mSubServer.erase(uSeq);
 }
 
 // <-- bool: true=added, false=already there
 bool NetworkOPs::subTransactions(InfoSub::ref isrListener)
 {
+	boost::recursive_mutex::scoped_lock	sl(mMonitorLock);
 	return mSubTransactions.insert(std::make_pair(isrListener->getSeq(), isrListener)).second;
 }
 
 // <-- bool: true=erased, false=was not there
 bool NetworkOPs::unsubTransactions(uint64 uSeq)
 {
+	boost::recursive_mutex::scoped_lock	sl(mMonitorLock);
 	return !!mSubTransactions.erase(uSeq);
 }
 
 // <-- bool: true=added, false=already there
 bool NetworkOPs::subRTTransactions(InfoSub::ref isrListener)
 {
+	boost::recursive_mutex::scoped_lock	sl(mMonitorLock);
 	return mSubTransactions.insert(std::make_pair(isrListener->getSeq(), isrListener)).second;
 }
 
 // <-- bool: true=erased, false=was not there
 bool NetworkOPs::unsubRTTransactions(uint64 uSeq)
 {
+	boost::recursive_mutex::scoped_lock	sl(mMonitorLock);
 	return !!mSubTransactions.erase(uSeq);
 }