QtConcurrent::run crashes on program exit

When an application is about to be closed and all the
destructors are called, if there isQtConcurrent::run on
the way, it crashes as the internal threadpool pointer
is nullptr.

Fixes: QTBUG-98901
Pick-to: 6.2 6.3
Change-Id: Idd84d1518fc6a225263e6666a0f1de2ccef79c82
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/concurrent/qtconcurrentrunbase.h b/src/concurrent/qtconcurrentrunbase.h
index 6038d0e60c..4870362146 100644
--- a/src/concurrent/qtconcurrentrunbase.h
+++ b/src/concurrent/qtconcurrentrunbase.h
@@ -93,7 +93,13 @@ public:
         promise.setRunnable(this);
         promise.reportStarted();
         QFuture<T> theFuture = promise.future();
-        parameters.threadPool->start(this, parameters.priority);
+
+        if (parameters.threadPool) {
+            parameters.threadPool->start(this, parameters.priority);
+        } else {
+            promise.reportCanceled();
+            promise.reportFinished();
+        }
         return theFuture;
     }