From 5cbc7b16c04331599f382fa71bdc73f4aed476c7 Mon Sep 17 00:00:00 2001
From: sledgehammer999 <hammered999@gmail.com>
Date: Sun, 30 Oct 2016 00:43:53 +0300
Subject: [PATCH] Guard the flag used for deferred session configure.

---
 src/base/bittorrent/session.cpp | 13 +++++++++----
 src/base/bittorrent/session.h   |  3 +++
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/base/bittorrent/session.cpp b/src/base/bittorrent/session.cpp
index 40b8cd28d..758ef3663 100644
--- a/src/base/bittorrent/session.cpp
+++ b/src/base/bittorrent/session.cpp
@@ -911,6 +911,9 @@ void Session::adjustLimits()
 void Session::configure()
 {
     qDebug("Configuring session");
+    if (!m_deferredConfigureScheduled) return; // Obtaining the lock is expensive, let's check early
+    QWriteLocker locker(&m_lock);
+    if (!m_deferredConfigureScheduled) return; // something might have changed while we were getting the lock
 #if LIBTORRENT_VERSION_NUM < 10100
     libt::session_settings sessionSettings = m_nativeSession->settings();
     configure(sessionSettings);
@@ -2957,10 +2960,12 @@ void Session::initResumeFolder()
 
 void Session::configureDeferred()
 {
-    if (!m_deferredConfigureScheduled) {
-        QMetaObject::invokeMethod(this, "configure", Qt::QueuedConnection);
-        m_deferredConfigureScheduled = true;
-    }
+    if (m_deferredConfigureScheduled) return; // Obtaining the lock is expensive, let's check early
+    QWriteLocker locker(&m_lock);
+    if (m_deferredConfigureScheduled) return; // something might have changed while we were getting the lock
+
+    QMetaObject::invokeMethod(this, "configure", Qt::QueuedConnection);
+    m_deferredConfigureScheduled = true;
 }
 
 // Enable IP Filtering
diff --git a/src/base/bittorrent/session.h b/src/base/bittorrent/session.h
index 847447edf..82fd6f00c 100644
--- a/src/base/bittorrent/session.h
+++ b/src/base/bittorrent/session.h
@@ -41,6 +41,7 @@
 #endif
 #include <QNetworkConfigurationManager>
 #include <QPointer>
+#include <QReadWriteLock>
 #include <QStringList>
 #include <QVector>
 #include <QWaitCondition>
@@ -604,6 +605,8 @@ namespace BitTorrent
 
         QNetworkConfigurationManager m_networkManager;
 
+        mutable QReadWriteLock m_lock;
+
         static Session *m_instance;
     };
 }