WebView2 memory leak

[tj-jyk]

Description

WebView2 (and old WebView) exhibits a memory leak when creating and deleting the control in a loop. In my application, the user can change the content every (x) seconds and with a WebView/WebView2 control the user will get a memory leak. I opened already 2 Issues in WindowsAppSDK repo and in WinUI repo

Version
SDK: 1.0.902.49
Runtime: 92.0.902.62
Framework: UWP
OS: Win10 10.0.19042 Build 19042

Repro Steps
UWP Project GitHub repo

1. Start a loop / a timer var timer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(1) }; timer.Tick += Timer_Tick; timer.Start();
2. In a loop logic find the old WebView/WebView2 control in a DOM VisualTreeHelper.GetChildrenCount(parent); ..... VisualTreeHelper.GetChild(parent, i) ...)
3. Remove the old WebView from the DOM (VisualTreeHelper.DisconnectChildrenRecursive(rootGrid);)
4. For a WebView call webViewToRemove.Navigate(new Uri("about:blank")); For a WebView2: webViewToRemove.Close();
5. Add a new WebView/WebView2 control to the DOM rootGrid.Children.Add(newWebView);
6. Application crashes after 15 minutes.

Screenshots

Additional context

AB#35385513

[champnic]

Thanks for the bug report @tj-jyk! I've added it to our backlog to take a look.

In the meantime do you need to remove and create a new WebView2 every time? Can you reuse the WebView2 when you need to change content?

[tj-jyk]

Hi @champnic.
Yes, it's possible and its work. But if the component has a memory leak, will be better to get an update, otherwise you will have to spend a lot of time rewriting the existing code. I found many articles in the internet and nobody has a right answer.

[champnic]

I completely agree we should try and fix this memory leak - I just wanted to make sure that your app wasn't blocked by this issue :)

[AdamCaviness]

In my case it appears a leak stems from the HwndSourceKeyboardInputSite. I am calling Dispose() but the WebView2 instance remains in memory.

[champnic]

Hey @AdamCaviness - Can you share how you are hooking up to the WebView2 and how/when you are calling Dispose?

[AdamCaviness]

@champnic Gladly. In my scenario, the WebView2 component is not placed in a dedicated window but is instead shown directly in the MainWindow with an active screen approach. The sample (WpfWebView2Leak) demonstrates the same single window app approach. The WebView2 component is disposed in the WebScreen Close button handler. The derived WebView2 approach is intended to address a Windows sleep issue with WebView2. I used dotMemory to profile the sample. Thanks.

[champnic]

Thanks for sharing. I've verified that the WebView2 processes and most of the WebView2 code is being cleaned up at least, as those are where most of the memory usage would be. I wonder if there's a bug in WPF around making sure the HwndSourceKeyboardInputSite gets removed from the list. We'll take a closer look. Thanks!

[MatevzRopret]

I'd just like to report that we have found the same issue: attaching the Webview to the UI is what causes the leak.
If the webview is not attached to the UI it won't leak.

Here is an example project (VS solution)

Webview2MemoryLeakTest.zip

EDIT:
This memory leak happens also if you create just eg 10 webviews and pool them and add/remove the cyclicaly.
Though it seems that the leak is less severe in this case, but it's still there.

[fabioparodi]

I have the same problem.
I've modified a very old and stable C++/MFC application to use WebVIew2. Then scripted to create-show-hide-dispose the WebVIew2 window in a cycle every 10 seconds. I can see the proces private bytes increase, it is very regular.
I am going to pool and reuse the WebView2 windows - never ever dispose.
Still an open bug

[fabioparodi]

[juipinjao]

fanioparoid
I face the same problem on a MFC app. too. Just wonder if you find any solution? Thanks

[fabioparodi]

Hello I have a workaround: never delete the webview2 object. If you do not need the browser anymore, keep it around for next usage. Fabio Da: juipinjao ***@***.***> Inviato: giovedì 6 ottobre 2022 16:37 A: MicrosoftEdge/WebView2Feedback ***@***.***> Cc: Fabio Parodi ***@***.***>; Comment ***@***.***> Oggetto: Re: [MicrosoftEdge/WebView2Feedback] WebView2 memory leak (#1633) fanioparoid I face the same problem on a MFC app. too. Just wonder if you find any solution? Thanks — Reply to this email directly, view it on GitHub<#1633 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ACA6FUXNYPENIHRBXOXLQ53WB3PYFANCNFSM5B3R2DSA>. You are receiving this because you commented.Message ID: ***@***.******@***.***>>

[agenne]

The original issue posted by @tj-jyk (my colleague) seems to be solved.
Updated the WebView2 version to WinUI 2.8.1.
It is still necessary to cleanup, but it is sufficient to call Close on the webview which is much better than navigate to about:blank and call Gc.Collect

[champnic]

Glad to hear it's working now @agenne!

For others on this thread - if you are still seeing the issue and it's not in WinUI 2.8.1 or WindowsAppSDK, please open a separate issue for us to track. Thanks!