1 files changed, 7 insertions, 1 deletions
diff --git a/src/corelib/thread/qmutex_win.cpp b/src/corelib/thread/qmutex_win.cpp
index a810000..c278f04 100644
--- a/src/corelib/thread/qmutex_win.cpp
+++ b/src/corelib/thread/qmutex_win.cpp
@@ -60,7 +60,13 @@ QMutexPrivate::~QMutexPrivate()
 
 bool QMutexPrivate::wait(int timeout)
 {
-    return WaitForSingleObject(event, timeout < 0 ? INFINITE : timeout) ==  WAIT_OBJECT_0;
+    if (contenders.fetchAndAddAcquire(1) == 0) {
+        // lock acquired without waiting
+        return true;
+    }
+    bool returnValue = (WaitForSingleObject(event, timeout < 0 ? INFINITE : timeout) ==  WAIT_OBJECT_0);
+    contenders.deref();
+    return returnValue;
 }
 
 void QMutexPrivate::wakeUp()