From b0cf92fd173d5fe96095f9ebb1feaf13d7526cfd Mon Sep 17 00:00:00 2001
From: Michael Insel <michael@insel.email>
Date: Mon, 12 Nov 2018 19:09:44 +0000
Subject: [PATCH] Fix deadlock in GraphiteWriter

This fixes a deadlock in the GraphiteWriter feature, which is visible
during the reload process. The reload thread waits for the
GraphiteWriter to finish, but the GraphiteWriter can't finish because
it's stuck in `SendMetric()` waiting for a lock which is hold by the
reload thread.
---
 lib/perfdata/graphitewriter.cpp | 2 +-
 lib/perfdata/graphitewriter.hpp | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/perfdata/graphitewriter.cpp b/lib/perfdata/graphitewriter.cpp
index a01f6c48b..1b6461d51 100644
--- a/lib/perfdata/graphitewriter.cpp
+++ b/lib/perfdata/graphitewriter.cpp
@@ -299,7 +299,7 @@ void GraphiteWriter::SendMetric(const String& prefix, const String& name, double
 	msgbuf << "\n";
 	String metric = msgbuf.str();
 
-	ObjectLock olock(this);
+	boost::mutex::scoped_lock lock(m_StreamMutex);
 
 	if (!GetConnected())
 		return;
diff --git a/lib/perfdata/graphitewriter.hpp b/lib/perfdata/graphitewriter.hpp
index 6934d13b3..ec4c5bbfe 100644
--- a/lib/perfdata/graphitewriter.hpp
+++ b/lib/perfdata/graphitewriter.hpp
@@ -27,6 +27,7 @@
 #include "base/timer.hpp"
 #include "base/workqueue.hpp"
 #include <fstream>
+#include <boost/thread/mutex.hpp>
 
 namespace icinga
 {
@@ -54,6 +55,7 @@ protected:
 
 private:
 	Stream::Ptr m_Stream;
+	boost::mutex m_StreamMutex;
 	WorkQueue m_WorkQueue{10000000, 1};
 
 	Timer::Ptr m_ReconnectTimer;