Bug 262681 – REGRESSION(267014@main): "ASSERTION FAILED: Unhandled message GPUConnectionToWebProcess_ReleaseGraphicsContextGL to 0" for fast/canvas/webgl/canvas-webgl-page-cache.html

• Status: RESOLVED
• Resolution: DUPLICATE
• Component: WebGL

[Fujii Hironori]

Windows port is observing an assertion failure.

> python.exe ./Tools/Scripts/run-webkit-tests --debug fast/canvas/webgl/canvas-webgl-page-cache.html

It is passing but crashing WebKitGPUProcess.exe.

ASSERTION FAILED: Unhandled message GPUConnectionToWebProcess_ReleaseGraphicsContextGL to 0
assertionFailureDueToUnreachableCode
C:\home\webkit\gc\WebKitBuild\Debug\WebKit\DerivedSources\GPUConnectionToWebProcessMessageReceiver.cpp(136) : didReceiveMessage
1   00007FFDE6331C19 WTFCrash
2   00007FFDDB9DA22F WebKit::GPUConnectionToWebProcess::didReceiveMessage
3   00007FFDDC6AB29A IPC::Connection::dispatchMessage
4   00007FFDDC6AB50E IPC::Connection::dispatchMessage
5   00007FFDDC6B148E IPC::Connection::SyncMessageState::ConnectionAndIncomingMessage::dispatch
6   00007FFDDC6A5FF2 IPC::Connection::SyncMessageState::dispatchMessagesAndResetDidScheduleDispatchMessagesForConnection
7   00007FFDDC6AB886 IPC::Connection::dispatchSyncStateMessages
8   00007FFDDC6AD41B IPC::Connection::SyncMessageState::processIncomingMessage::<lambda_3>::operator()
9   00007FFDDC6AD3B7 WTF::Detail::CallableWrapper<`lambda at C:\home\webkit\gc\Source\WebKit\Platform\IPC\Connection.cpp:224:31',void>::call
10  00007FFDE63481A4 WTF::Function<void ()>::operator()
11  00007FFDE63CAF2A WTF::RunLoop::performWork
12  00007FFDE649F220 WTF::RunLoop::wndProc
13  00007FFDE649F157 WTF::RunLoop::RunLoopWndProc
14  00007FFE3DEFE858 CallWindowProcW
15  00007FFE3DEFE299 DispatchMessageW
16  00007FFDE649F3ED WTF::RunLoop::run
17  00007FFDDB835413 WebKit::AuxiliaryProcessMainBase<WebKit::GPUProcess,0>::run
18  00007FFDDB8352C7 WebKit::AuxiliaryProcessMain<WebKit::GPUProcessMainWin>
19  00007FFDDB8351A3 WebKit::GPUProcessMain
20  00007FF63617124C main
21  00007FF6361718BC __scrt_common_main_seh
22  00007FFE3CBC7344 BaseThreadInitThunk
23  00007FFE3E7E26B1 RtlUserThreadStart
Exception thrown at 0x00007FFDE6331C1E (WTF.dll) in WebKitGPUProcess.exe: 0xC0000005: Access violation writing location 0x00000000BBADBEEF.

I don't know the regresion point. I'm testing with 268897@main.

[Fujii Hironori]

the assertion was added by 267014@main (bug#259552)?

[Fujii Hironori]

There is a race condition.
Web process sends Messages::GPUConnectionToWebProcess::ReleaseGraphicsContextGL when GraphicsContextGL is destroyed.
UI process sends Messages::GPUProcess::UpdatePreferencesForWebProcess to disable WebGL flag when all WebPageProxy is closed.
If UpdatePreferencesForWebProcess is dispatch before ReleaseGraphicsContextGL, the assertion fails.

Here is the callstack of updatePreferencesForWebProcess of UI process:

> WebKit2.dll!WebKit::GPUProcessProxy::updatePreferencesForWebProcess(WebKit::WebProcessProxy & webProcessProxy, const WebKit::GPUProcessPreferencesForWebProcess & preferences) Line 453	C++
> WebKit2.dll!WebKit::WebProcessProxy::updatePreferencesForGPUProcess() Line 2018	C++
> WebKit2.dll!WebKit::WebProcessProxy::removeWebPage(WebKit::WebPageProxy & webPage, WebKit::WebProcessProxy::EndsUsingDataStore endsUsingDataStore) Line 832	C++
> WebKit2.dll!WebKit::WebPageProxy::close() Line 1455	C++
> WebKit2.dll!WebKit::WebView::close() Line 781	C++
> WebKit2.dll!WebKit::WebView::wndProc(HWND__ * hWnd, unsigned int message, unsigned __int64 wParam, __int64 lParam) Line 114	C++
> WebKit2.dll!WebKit::WebView::WebViewWndProc(HWND__ * hWnd, unsigned int message, unsigned __int64 wParam, __int64 lParam) Line 89	C++
> [External Code]	
> WebKitTestRunner.exe!WTR::PlatformWebView::~PlatformWebView() Line 97	C++
> [External Code]	
> WebKitTestRunner.exe!WTR::TestController::~TestController() Line 205	C++
> WebKitTestRunner.exe!main(int argc, const char * * argv) Line 34	C++
> [External Code]	

Adding Sleep works around the crash.

diff --git a/Source/WebKit/UIProcess/GPU/GPUProcessProxy.cpp b/Source/WebKit/UIProcess/GPU/GPUProcessProxy.cpp
index 82e675719ae0..4e044bb593f5 100644
--- a/Source/WebKit/UIProcess/GPU/GPUProcessProxy.cpp
+++ b/Source/WebKit/UIProcess/GPU/GPUProcessProxy.cpp
@@ -450,6 +450,7 @@ std::optional<bool> GPUProcessProxy::s_hasVP9ExtensionSupport;
 
 void GPUProcessProxy::updatePreferencesForWebProcess(WebProcessProxy& webProcessProxy, const GPUProcessPreferencesForWebProcess& preferences)
 {
+    Sleep(1000);
     send(Messages::GPUProcess::UpdatePreferencesForWebProcess(webProcessProxy.coreProcessIdentifier(), preferences), 0);
 }

[Kimmo Kinnunen]

Thanks for the investigation. Let's continue fixing in the earlier bug.

*** This bug has been marked as a duplicate of bug 262401 ***