Details
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Bug
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Status: Reported
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P2: Important
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Resolution: Unresolved
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5.12.12
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None
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None
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macOS
Description
I can't reproduce it, but one of our users says that our application crashes under certain conditions. Sounds like some sort of a race condition bug.
Here is the stack trace and exception info:
"exception" : {"codes":"0x000000000000000d, 0x0000000000000000","rawCodes":[13,0],"type":"EXC_BAD_ACCESS","signal":"SIGSEGV","subtype":"UNKNOWN_0xD at 0x0000000000000000"}
typeinfo name for QMetaCallEvent QAccessible::setActive(bool) NSAccessibilityGetObjectForAttributeUsingLegacyAPI NSAccessibilityGetObjectValueForAttribute -[NSView accessibilityParent] -[NSAccessibilityAttributeAccessorInfo getAttributeValue:forObject:] ___NSAccessibilityEntryPointValueForAttribute_block_invoke.818 NSAccessibilityPerformEntryPointObject _NSAccessibilityEntryPointValueForAttribute NSAccessibilityGetObjectForAttributeUsingLegacyAPI ___NSAccessibilityEntryPointValueForAttribute_block_invoke.818 NSAccessibilityPerformEntryPointObject _NSAccessibilityEntryPointValueForAttribute -[NSWindow(NSWindowAccessibility) accessibilityFocusedUIElement] NSAccessibilityHandleFocusChangedForce -[NSWindow _realMakeFirstResponder:] QWindowPrivate::destroy() QWidgetPrivate::deleteTLSysExtra() QWidget::destroy(bool, bool) QWidget::~QWidget() QMessageBox::~QMessageBox() QObjectPrivate::deleteChildren() QObject::~QObject() QQuickItem::~QQuickItem() QObjectPrivate::deleteChildren() QObject::~QObject() QQuickItem::~QQuickItem() QObject::event(QEvent*) QApplicationPrivate::notify_helper(QObject*, QEvent*) QApplication::notify(QObject*, QEvent*) QCoreApplication::notifyInternal2(QObject*, QEvent*) QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ __CFRunLoopDoSource0 __CFRunLoopDoSources0 __CFRunLoopRun CFRunLoopRunSpecific RunCurrentEventLoopInMode ReceiveNextEventCommon _BlockUntilNextEventMatchingListInModeWithFilter _DPSNextEvent -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] -[NSApplication run] QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) QCoreApplication::exec() App::runImpl() App::run(bool) main start
I've checked the code of QAccessible::setActive function. It seems that list of observers inside of qAccessibleActivationObservers can change while the code is calling observers' accessibilityActiveChanged callback. Thus it's getting invalid pointers and tries to call invalid objects then.
Can anything be done to work around this?
