Title: [246064] trunk/Source/WebKit
- Revision
- 246064
- Author
- [email protected]
- Date
- 2019-06-04 08:46:45 -0700 (Tue, 04 Jun 2019)
Log Message
[iOS] UIProcess' background task expiration handler may get called after the app is foreground again
https://bugs.webkit.org/show_bug.cgi?id=198380
<rdar://problem/49762471>
Reviewed by Geoff Garen.
UIProcess' background task expiration handler may get called after the app is foreground again. When
this happens, we already have a foreground assertion on behalf of the WebContent process, and the view
is visible. We would send the WillSuspendImminently IPC to the WebContent process, which would freeze
its layers, even though it is visible on screen.
To address the issue, we now check if the app is visible in the expiration handler. If it is visible,
we do not notify clients of imminent suspension. Instead, we end the background task right away and
call _updateBackgroundTask asynchronously to start a new background task if necessary.
* UIProcess/ios/ProcessAssertionIOS.mm:
(-[WKProcessAssertionBackgroundTaskManager _updateBackgroundTask]):
Modified Paths
Diff
Modified: trunk/Source/WebKit/ChangeLog (246063 => 246064)
--- trunk/Source/WebKit/ChangeLog 2019-06-04 15:26:04 UTC (rev 246063)
+++ trunk/Source/WebKit/ChangeLog 2019-06-04 15:46:45 UTC (rev 246064)
@@ -1,3 +1,23 @@
+2019-06-04 Chris Dumez <[email protected]>
+
+ [iOS] UIProcess' background task expiration handler may get called after the app is foreground again
+ https://bugs.webkit.org/show_bug.cgi?id=198380
+ <rdar://problem/49762471>
+
+ Reviewed by Geoff Garen.
+
+ UIProcess' background task expiration handler may get called after the app is foreground again. When
+ this happens, we already have a foreground assertion on behalf of the WebContent process, and the view
+ is visible. We would send the WillSuspendImminently IPC to the WebContent process, which would freeze
+ its layers, even though it is visible on screen.
+
+ To address the issue, we now check if the app is visible in the expiration handler. If it is visible,
+ we do not notify clients of imminent suspension. Instead, we end the background task right away and
+ call _updateBackgroundTask asynchronously to start a new background task if necessary.
+
+ * UIProcess/ios/ProcessAssertionIOS.mm:
+ (-[WKProcessAssertionBackgroundTaskManager _updateBackgroundTask]):
+
2019-06-04 Carlos Garcia Campos <[email protected]>
[GTK] Crash when re-entering AC mode after r245957
Modified: trunk/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm (246063 => 246064)
--- trunk/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm 2019-06-04 15:26:04 UTC (rev 246063)
+++ trunk/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm 2019-06-04 15:46:45 UTC (rev 246064)
@@ -197,6 +197,7 @@
- (void)_backgroundTaskExpired
{
RELEASE_LOG_ERROR(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager - _backgroundTaskExpired", self);
+ ASSERT(_applicationIsBackgrounded);
[self _cancelTimeoutTask];
// Tell our child processes they will suspend imminently.
@@ -222,6 +223,17 @@
RELEASE_LOG(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager - beginBackgroundTaskWithName", self);
_backgroundTask = [[UIApplication sharedApplication] beginBackgroundTaskWithName:@"com.apple.WebKit.ProcessAssertion" expirationHandler:^{
RELEASE_LOG_ERROR(ProcessSuspension, "Background task expired while holding WebKit ProcessAssertion (isMainThread? %d, _applicationIsBackgrounded? %d).", RunLoop::isMain(), _applicationIsBackgrounded);
+ if (!_applicationIsBackgrounded) {
+ // We've received the invalidation warning after the app has become foreground again. In this case, we should not
+ // warn clients of imminent suspension. To be safe (avoid potential killing), we end the task right away and call
+ // _updateBackgroundTask asynchronously to start a new task if necessary.
+ [self _releaseBackgroundTask];
+ dispatch_async(dispatch_get_main_queue(), ^{
+ [self _updateBackgroundTask];
+ });
+ return;
+ }
+
[self _backgroundTaskExpired];
}];
} else if (_assertionsNeedingBackgroundTask.isEmpty())
_______________________________________________
webkit-changes mailing list
[email protected]
https://lists.webkit.org/mailman/listinfo/webkit-changes
