From db6f1440cbe78018e442c1fb961310a4e619e8fe Mon Sep 17 00:00:00 2001
From: J-P Nurmi <jpnurmi@qt.io>
Date: Fri, 9 Jun 2017 23:36:49 +0200
Subject: QQuickItemView: fix releaseItem() loops

Calling releaseItem() destroys the item, which emits childrenChanged
for the contentItem, and if at that point anything calls setFooMargin(),
setContentHeight(), returnToBounds(), or many other methods that
indirectly access the visibleItems list, it leads to a crash due to
read after free. Add a releaseVisibleItems() helper method that makes
a copy, clears the original list first, and then releases the items.

Task-number: QTBUG-48394
Task-number: QTBUG-61294
Change-Id: I29e4d3870d33549e8bf789de84c67ab1826fca7d
Reviewed-by: Robin Burchell <robin.burchell@crimson.no>
---
 tests/auto/quick/qquickgridview/data/releaseItems.qml  | 12 ++++++++++++
 tests/auto/quick/qquickgridview/tst_qquickgridview.cpp | 13 +++++++++++++
 tests/auto/quick/qquicklistview/data/releaseItems.qml  | 12 ++++++++++++
 tests/auto/quick/qquicklistview/tst_qquicklistview.cpp | 13 +++++++++++++
 4 files changed, 50 insertions(+)
 create mode 100644 tests/auto/quick/qquickgridview/data/releaseItems.qml
 create mode 100644 tests/auto/quick/qquicklistview/data/releaseItems.qml

(limited to 'tests')

diff --git a/tests/auto/quick/qquickgridview/data/releaseItems.qml b/tests/auto/quick/qquickgridview/data/releaseItems.qml
new file mode 100644
index 0000000000..19d58550a4
--- /dev/null
+++ b/tests/auto/quick/qquickgridview/data/releaseItems.qml
@@ -0,0 +1,12 @@
+import QtQuick 2.0
+
+GridView {
+    width: 400
+    height: 400
+    model: 100
+    delegate: Rectangle {
+        height: 100; width: 100
+        color: index % 2 ? "lightsteelblue" : "lightgray"
+    }
+    contentHeight: contentItem.children.length * 40
+}
diff --git a/tests/auto/quick/qquickgridview/tst_qquickgridview.cpp b/tests/auto/quick/qquickgridview/tst_qquickgridview.cpp
index 1acc36c9b0..b2d6584701 100644
--- a/tests/auto/quick/qquickgridview/tst_qquickgridview.cpp
+++ b/tests/auto/quick/qquickgridview/tst_qquickgridview.cpp
@@ -209,6 +209,7 @@ private slots:
     void QTBUG_48870_fastModelUpdates();
 
     void keyNavigationEnabled();
+    void releaseItems();
 
 private:
     QList<int> toIntList(const QVariantList &list);
@@ -6666,6 +6667,18 @@ void tst_QQuickGridView::QTBUG_48870_fastModelUpdates()
     }
 }
 
+void tst_QQuickGridView::releaseItems()
+{
+    QScopedPointer<QQuickView> view(createView());
+    view->setSource(testFileUrl("releaseItems.qml"));
+
+    QQuickGridView *gridview = qobject_cast<QQuickGridView *>(view->rootObject());
+    QVERIFY(gridview);
+
+    // don't crash (QTBUG-61294)
+    gridview->setModel(123);
+}
+
 QTEST_MAIN(tst_QQuickGridView)
 
 #include "tst_qquickgridview.moc"
diff --git a/tests/auto/quick/qquicklistview/data/releaseItems.qml b/tests/auto/quick/qquicklistview/data/releaseItems.qml
new file mode 100644
index 0000000000..de774e5e08
--- /dev/null
+++ b/tests/auto/quick/qquicklistview/data/releaseItems.qml
@@ -0,0 +1,12 @@
+import QtQuick 2.0
+
+ListView {
+    width: 400
+    height: 400
+    model: 100
+    delegate: Rectangle {
+        height: 40; width: 400
+        color: index % 2 ? "lightsteelblue" : "lightgray"
+    }
+    contentHeight: contentItem.children.length * 40
+}
diff --git a/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp b/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp
index ff06c1e1a4..98c628068d 100644
--- a/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp
+++ b/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp
@@ -254,6 +254,7 @@ private slots:
     void keyNavigationEnabled();
     void QTBUG_50097_stickyHeader_positionViewAtIndex();
     void itemFiltered();
+    void releaseItems();
 
 private:
     template <class T> void items(const QUrl &source);
@@ -8508,6 +8509,18 @@ void tst_QQuickListView::itemFiltered()
     model.setData(model.index(2), QStringLiteral("modified three"), Qt::DisplayRole);
 }
 
+void tst_QQuickListView::releaseItems()
+{
+    QScopedPointer<QQuickView> view(createView());
+    view->setSource(testFileUrl("releaseItems.qml"));
+
+    QQuickListView *listview = qobject_cast<QQuickListView *>(view->rootObject());
+    QVERIFY(listview);
+
+    // don't crash (QTBUG-61294)
+    listview->setModel(123);
+}
+
 QTEST_MAIN(tst_QQuickListView)
 
 #include "tst_qquicklistview.moc"
-- 
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