diff options
| author | VaL Doroshchuk <valentyn.doroshchuk@qt.io> | 2020-02-04 13:18:31 +0100 |
|---|---|---|
| committer | VaL Doroshchuk <valentyn.doroshchuk@qt.io> | 2020-02-05 11:05:24 +0100 |
| commit | 9ecc595d7185ad3d072f3d811d7aa52fc6992cca (patch) | |
| tree | 5bb1dc10f0b57f41ac76385bbe8f2b21a567ef83 /src/widgets | |
| parent | e5408b62bdcee1abbc595eb581abcb540396ca4c (diff) | |
widgets: Don't create winId when the widget is being destroyed
When QWidget is being destroyed, its winId is cleared, and
a QEvent::WinIdChange is sent. If a listener of this event
reacted by calling winId() again, we might crash.
A crash can be observed when this child widget is destroyed in dtor of its parent.
E.g. here is a hierarchy of widgets:
1:QWidget
2:QObject
3:QWidget
4:QWidget
If a listener subscribed for WinIdChange events from (4),
and there is a connection to destroy (4) when (2) is destroyed.
This will lead to infinite loop:
1. QWidget::~QWidget
2. QWidget::destroy
3. QWidgetPrivate::setWinId(0)
4. QCoreApplication::sendEvent(q, QEvent::WinIdChange);
5. eventFilter
6. QWidget::winId
7. QWidgetPrivate::createWinId (this=0x555555957600) at kernel/qwidget.cpp:2380
8. QWidgetPrivate::createWinId (this=0x55555596b040) at kernel/qwidget.cpp:2387
9. QWidget::create (this=0x5555558f2010, window=0, initializeWindow=true, destroyOldWindow=true) at kernel/qwidget.cpp:1163
10. QWidgetPrivate::createWinId (this=0x55555596b040) at kernel/qwidget.cpp:2387
11. QWidget::create (this=0x5555558f2010, window=0, initializeWindow=true, destroyOldWindow=true) at kernel/qwidget.cpp:1163
12. QWidgetPrivate::createWinId (this=0x55555596b040) at kernel/qwidget.cpp:2387
Fixes: QTBUG-81849
Change-Id: Ib4c33ac97d9a79c701431ae107bddfb22720ba0d
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Diffstat (limited to 'src/widgets')
| -rw-r--r-- | src/widgets/kernel/qwidget.cpp | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp index 8ec7f7e072..e7f95ecf4d 100644 --- a/src/widgets/kernel/qwidget.cpp +++ b/src/widgets/kernel/qwidget.cpp @@ -2350,7 +2350,9 @@ QWidget *QWidget::find(WId id) */ WId QWidget::winId() const { - if (!testAttribute(Qt::WA_WState_Created) || !internalWinId()) { + if (!data->in_destructor + && (!testAttribute(Qt::WA_WState_Created) || !internalWinId())) + { #ifdef ALIEN_DEBUG qDebug() << "QWidget::winId: creating native window for" << this; #endif |