From ac984bd8768b3d7e6439e0ffd98fd8b53e16b922 Mon Sep 17 00:00:00 2001 From: Mike Achtelik Date: Tue, 28 Jun 2022 09:55:25 +0200 Subject: Android A11Y: Fix deadlock in QtAndroidAccessibility::runInObjectContext() On android the event loop is normally blocked, when the application is suspended, e.g. when it enters the background or when the screen is locked (see android.app.background_running). This leads to a problem when we try to process events after this happens, e.g. when android sends us an ACTION_CLEAR_ACCESSIBILITY_FOCUS event after the event loop is suspended. While handling it we eventually call QtAndroidAccessibility::runInObjectContext() which tries to do a blocking call on the object context, however, with the event loop being suspended we run into a deadlock which leads to an ANR. So we need to make sure to never make a blocking call while the event loop is suspended. Task-number: QTBUG-102594 Pick-to: 6.4 6.3 6.2 5.15 Change-Id: I33f0440a3da84fb4bdae5ab0fc10d514c73f23ad Reviewed-by: Assam Boudjelthia --- src/plugins/platforms/android/androidjniaccessibility.cpp | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'src') diff --git a/src/plugins/platforms/android/androidjniaccessibility.cpp b/src/plugins/platforms/android/androidjniaccessibility.cpp index 0523211196..38b1ed0952 100644 --- a/src/plugins/platforms/android/androidjniaccessibility.cpp +++ b/src/plugins/platforms/android/androidjniaccessibility.cpp @@ -61,7 +61,13 @@ namespace QtAndroidAccessibility template void runInObjectContext(QObject *context, Func &&func, Ret *retVal) { - QMetaObject::invokeMethod(context, func, Qt::BlockingQueuedConnection, retVal); + if (!QtAndroid::blockEventLoopsWhenSuspended() + || QGuiApplication::applicationState() != Qt::ApplicationSuspended) { + QMetaObject::invokeMethod(context, func, Qt::BlockingQueuedConnection, retVal); + } else { + __android_log_print(ANDROID_LOG_WARN, m_qtTag, + "Could not run accessibility call in object context, event loop suspended."); + } } void initialize() -- cgit v1.2.3