winrt: Do not use CoTaskMemFree as image cleanup function

CoTaskMemFree is declared __stdcall. This declaration causes a stack
maintenance behavior (called function pops its own arguments from the
stack) that breaks release builds and leads to crashes. By wrapping that
function into our own function (which is by default __cdecl) we get the
wanted stack maintenance behavior (calling function pops arguments from
the stack) and thus avoid these crashes.

Task-number: QTBUG-63016
Change-Id: Ibd36f4fc2680351bf41c2991e9b3f1723bb19eab
Reviewed-by: Andre de la Rocha <andre.rocha@qt.io>
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@qt.io>
Reviewed-by: VaL Doroshchuk <valentyn.doroshchuk@qt.io>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/plugins/winrt/qwinrtcameraimagecapturecontrol.cpp b/src/plugins/winrt/qwinrtcameraimagecapturecontrol.cpp
index 54f4b103b..f4903c5a1 100644
--- a/src/plugins/winrt/qwinrtcameraimagecapturecontrol.cpp
+++ b/src/plugins/winrt/qwinrtcameraimagecapturecontrol.cpp
@@ -106,6 +106,12 @@ struct CaptureRequest
     ComPtr<IAsyncAction> op;
 };
 
+// Do not use CoTaskMemFree directly for image cleanup as it leads to crashes in release
+static void freeImageData(void *data)
+{
+    CoTaskMemFree(data);
+}
+
 class QWinRTCameraImageCaptureControlPrivate
 {
 public:
@@ -296,7 +302,7 @@ HRESULT QWinRTCameraImageCaptureControl::onCaptureCompleted(IAsyncAction *asyncI
     hr = frame->get_PixelWidth(&pixelWidth);
     Q_ASSERT_SUCCEEDED(hr);
     const QImage image(pixelData, pixelWidth, pixelHeight, QImage::Format_RGBA8888,
-                       reinterpret_cast<QImageCleanupFunction>(&CoTaskMemFree), pixelData);
+                       reinterpret_cast<QImageCleanupFunction>(&freeImageData), pixelData);
     emit imageCaptured(request.id, image);
 
     QWinRTImageEncoderControl *imageEncoderControl = static_cast<QWinRTImageEncoderControl*>(d->cameraControl->imageEncoderControl());