Fix two data races in QThread/QThreadData

* theMainThread is written by the main thread and read by
   QThreadData::~QThreadData() (any managed thread)

* QThreadData::thread is written by QThread::~QThread (in the parent thread)
  and read+written by QThreadData::~QThreadData (in the managed thread).
  This can happen because QThreadData is refcounted so the managed
  thread (which derefs it) races with the parent thread (which sets it to 0).

Change-Id: I72de793716391a0937254cda6b4328fcad5060c7
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/corelib/thread/qthread_unix.cpp b/src/corelib/thread/qthread_unix.cpp
index 77093c9cf1..5698a61326 100644
--- a/src/corelib/thread/qthread_unix.cpp
+++ b/src/corelib/thread/qthread_unix.cpp
@@ -225,7 +225,7 @@ QThreadData *QThreadData::current(bool createIfNecessary)
         data->isAdopted = true;
         data->threadId = (Qt::HANDLE)pthread_self();
         if (!QCoreApplicationPrivate::theMainThread)
-            QCoreApplicationPrivate::theMainThread = data->thread;
+            QCoreApplicationPrivate::theMainThread = data->thread.load();
     }
     return data;
 }