Details
P4: Low Description
Our app sometimes crashes on shutdown with the following stack:
Qt5Cored.dll!QScopedPointer<QObjectData,QScopedPointerDeleter<QObjectData> >::data() Line 143 C++ Qt5Cored.dll!qGetPtrHelper<QScopedPointer<QObjectData,QScopedPointerDeleter<QObjectData> > >() Line 919 C++ Qt5Cored.dll!QObject::d_func() Line 118 C++ Qt5Cored.dll!QMetaObject::activate() Line 3454 C++ Qt5Cored.dll!QMetaObject::activate() Line 3445 C++ Qt5Guid.dll!QClipboard::dataChanged() Line 175 C++ Qt5Guid.dll!QClipboard::emitChanged() Line 547 C++ Qt5Guid.dll!QPlatformClipboard::emitChanged() Line 127 C++ qwindowsd.dll!QWindowsClipboard::clipboardViewerWndProc() Line 242 C++ qwindowsd.dll!qClipboardViewerWndProc() Line 130 C++ user32.dll!UserCallWinProcCheckWow() user32.dll!DispatchClientMessage() user32.dll!__fnDWORD() ntdll.dll!KiUserCallbackDispatcherContinue() user32.dll!NtUserChangeClipboardChain() qwindowsd.dll!QWindowsClipboard::unregisterViewer() Line 176 C++ qwindowsd.dll!QWindowsClipboard::~QWindowsClipboard() Line 146 C++ qwindowsd.dll!QWindowsIntegrationPrivate::~QWindowsIntegrationPrivate() Line 365 C++ qwindowsd.dll!QWindowsIntegrationPrivate::`scalar deleting destructor'() C++ qwindowsd.dll!QScopedPointerDeleter<QWindowsIntegrationPrivate>::cleanup() Line 62 C++ qwindowsd.dll!QScopedPointer<QWindowsIntegrationPrivate,QScopedPointerDeleter<QWindowsIntegrationPrivate> >::~QScopedPointer<QWindowsIntegrationPrivate,QScopedPointerDeleter<QWindowsIntegrationPrivate> >() Line 110 C++ qwindowsd.dll!QWindowsIntegration::~QWindowsIntegration() Line 380 C++ qwindowsd.dll!QWindowsIntegration::`scalar deleting destructor'() C++ Qt5Guid.dll!QGuiApplicationPrivate::~QGuiApplicationPrivate() Line 1210 C++ Qt5Widgetsd.dll!QApplicationPrivate::~QApplicationPrivate() Line 174 C++ Qt5Widgetsd.dll!QApplicationPrivate::`vector deleting destructor'() C++ Qt5Cored.dll!QScopedPointerDeleter<QObjectData>::cleanup() Line 62 C++ Qt5Cored.dll!QScopedPointer<QObjectData,QScopedPointerDeleter<QObjectData> >::~QScopedPointer<QObjectData,QScopedPointerDeleter<QObjectData> >() Line 110 C++ Qt5Cored.dll!QObject::~QObject() Line 940 C++ Qt5Cored.dll!QCoreApplication::~QCoreApplication() Line 787 C++ > Qt5Guid.dll!QGuiApplication::~QGuiApplication() Line 526 C++ Qt5Widgetsd.dll!QApplication::~QApplication() Line 757 C++ QtSolutions_MFCMigrationFramework-2.8d.dll!000007fef3e53ec6() [Frames below may be incorrect and/or missing, no symbols loaded for QtSolutions_MFCMigrationFramework-2.8d.dll] unittest2.exe!QMfcApp::`scalar deleting destructor'() C++ unittest2.exe!std::default_delete<QMfcApp>::operator()() Line 2068 C++ unittest2.exe!std::unique_ptr<QMfcApp,std::default_delete<QMfcApp> >::_Delete() Line 2345 C++ unittest2.exe!std::unique_ptr<QMfcApp,std::default_delete<QMfcApp> >::~unique_ptr<QMfcApp,std::default_delete<QMfcApp> >() Line 2302 C++ unittest2.exe!main() Line 559 C++ unittest2.exe!__tmainCRTStartup() Line 555 C unittest2.exe!mainCRTStartup() Line 371 C kernel32.dll!BaseThreadInitThunk() ntdll.dll!RtlUserThreadStart()
This crash occurs because QGuiApplication::~QGuiApplication() (shallower on the stack) has already set QGuiApplicationPrivate::qt_clipboard to null, and now (deeper on the stack) QPlatformClipboard::emitChanged() is blindly dereferencing QGuiApplication::clipboard().
I believe the fix would be to have QPlatformClipboard::emitChanged() actually check for null rather than blindly dereferencing.