Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 70e39a01ecebf7473ac1a3f4670b47f1222c65ce
https://github.com/WebKit/WebKit/commit/70e39a01ecebf7473ac1a3f4670b47f1222c65ce
Author: zbleyen <[email protected]>
Date: 2026-02-09 (Mon, 09 Feb 2026)
Changed paths:
M Source/WebKit/UIProcess/Cocoa/WKScreenTimeConfigurationObserver.mm
Log Message:
-----------
Concurrent XPC configuration updates in WKScreenTimeConfigurationObserver can
cause crash
https://bugs.webkit.org/show_bug.cgi?id=303024
Reviewed by Aditya Keerthi.
The bug occurred because the private method `[STScreenTimeConfigurationObserver
setConfiguration:]` could be called
concurrently from multiple XPC connection callbacks. Even though the
`configuration` property itself is atomic,
the Key-Value Observing (KVO) process for notifying observers is not
thread-safe. Concurrent modifications from
multiple threads could cause internal inconsistency and crashes within the KVO
machinery.
To fix this, we now create a dedicated static serial dispatch queue
(`screenTimeUpdateQueueSingleton`) within
`WKScreenTimeConfigurationObserver`. All XPC communication and configuration
updates are dispatched to this queue,
ensuring that the entire process of modifying the configuration and sending KVO
notifications is serialized and
thread-safe. This matches the pattern used elsewhere in WebKit for serializing
access to shared resources from
asynchronous callbacks.
* Source/WebKit/UIProcess/Cocoa/WKScreenTimeConfigurationObserver.mm:
(screenTimeUpdateQueueSingleton): Added.
(-[WKScreenTimeConfigurationObserver startObserving]): Use shared queue.
Canonical link: https://commits.webkit.org/307131@main
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