From d485dfe7ef1910a7f6652610388ae2d93cdec29f Mon Sep 17 00:00:00 2001 From: David Edmundson Date: Thu, 13 Sep 2018 10:19:12 +0100 Subject: [PATCH] Avoid crash with on scripted window teardown with threaded quick render loop Summary: Qt render loops behave quite differently to each other. KWin scripting as a workaround for another situation cleans (17553e5a1fb72a92dbbff3fa6bc7d55b8f1a0123) handles tracking of script windows by deleting the underlying window handle on hide. This currently happens before the window gets the hideEvent. Arguably this is a quirk with Qt, but in the current state: - QSGThreadedRenderLoop deletes the platform window and cleans up - We then get the hide() event. This no-ops because there's no window. (else branch of case WM_TryRelease in qsgthreadedrenderloop.cpp) - We carry on rendering animations despite having no platform - undefined behaviour Normally this isn't a problem as typically destruction of the platform window happens only when a window is being deleted, we're messing with Qt internals here. If we make sure the QHideEvent is processed by the render loop first, things seem fine. BUG: 397767 Test Plan: Ran QSG_RENDER_LOOP=threaded Read output with scenegraph logging rules on Reviewers: #kwin, broulik Reviewed By: broulik Subscribers: kwin Tags: #kwin Differential Revision: https://phabricator.kde.org/D15025 --- scripting/scripting.cpp | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/scripting/scripting.cpp b/scripting/scripting.cpp index 4522ac81a..b1c6a98c2 100644 --- a/scripting/scripting.cpp +++ b/scripting/scripting.cpp @@ -628,11 +628,11 @@ QVariant KWin::JSEngineGlobalMethodsWrapper::readConfig(const QString &key, QVar void KWin::JSEngineGlobalMethodsWrapper::registerWindow(QQuickWindow *window) { - connect(window, &QWindow::visibilityChanged, [window](QWindow::Visibility visibility) { + connect(window, &QWindow::visibilityChanged, this, [window](QWindow::Visibility visibility) { if (visibility == QWindow::Hidden) { window->destroy(); } - }); + }, Qt::QueuedConnection); } bool KWin::JSEngineGlobalMethodsWrapper::registerShortcut(const QString &name, const QString &text, const QKeySequence& keys, QJSValue function) -- GitLab