QProcess: Fix crash when calling closeWriteChannel on Windows

We must deleteLater the pipe writer in closeChannel, because if you
call closeWriteChannel() from a slot that is connected to a signal
emitted from QWindowsPipeWriter, we'd operate on a deleted object.

For consistency, we're calling QWindowsPipeWriter::stop before
deleteLater and deduplicate the code.

Fixes: QTBUG-73778
Change-Id: I61d3dedf57e9fd02517a108d13ffc85e006330f6
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

1 files changed, 14 insertions, 8 deletions

diff --git a/src/corelib/io/qprocess_win.cpp b/src/corelib/io/qprocess_win.cpp
index cb4b2f9f91..3ba86063e3 100644
--- a/src/corelib/io/qprocess_win.cpp
+++ b/src/corelib/io/qprocess_win.cpp
@@ -362,16 +362,22 @@ void QProcessPrivate::destroyPipe(Q_PIPE pipe[2])
     }
 }
 
+template <class T>
+void deleteWorker(T *&worker)
+{
+    if (!worker)
+        return;
+    worker->stop();
+    worker->deleteLater();
+    worker = nullptr;
+}
+
 void QProcessPrivate::closeChannel(Channel *channel)
 {
-    if (channel == &stdinChannel) {
-        delete stdinChannel.writer;
-        stdinChannel.writer = 0;
-    } else if (channel->reader) {
-        channel->reader->stop();
-        channel->reader->deleteLater();
-        channel->reader = 0;
-    }
+    if (channel == &stdinChannel)
+        deleteWorker(channel->writer);
+    else
+        deleteWorker(channel->reader);
     destroyPipe(channel->pipe);
 }