Bug 196739 – [GTK][GStreamer] Flaky ASSERTION FAILED: m_lock.isHeld() in TextureMapperPlatformLayerProxy

• Component: WebKitGTK
• Status: RESOLVED FIXED

[Alicia Boya García]

I got this while running imported/w3c/web-platform-tests/media-source/mediasource-timestamp-offset.html, but it's timing dependent.

ASSERTION FAILED: m_lock.isHeld()
../../Source/WebCore/platform/graphics/texmap/TextureMapperPlatformLayerProxy.cpp(109) : bool WebCore::TextureMapperPlatformLayerProxy::isActive()
1   0x7f834ac08299 /webkit/WebKitBuild/Debug/lib/libjavascriptcoregtk-4.0.so.18(WTFCrash+0x9) [0x7f834ac08299]
2   0x7f8356f67fc7 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::TextureMapperPlatformLayerProxy::isActive()+0x47) [0x7f8356f67fc7]
3   0x7f835979eb9d /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(+0xd544b9d) [0x7f835979eb9d]
4   0x7f835979ed27 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::MediaPlayerPrivateGStreamerBase::flushCurrentBuffer()+0x15f) [0x7f835979ed27]
5   0x7f835979c05d /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::MediaPlayerPrivateGStreamerBase::~MediaPlayerPrivateGStreamerBase()+0x4f) [0x7f835979c05d]
6   0x7f835977b31a /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::MediaPlayerPrivateGStreamer::~MediaPlayerPrivateGStreamer()+0x9da) [0x7f835977b31a]
7   0x7f83597ae187 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::MediaPlayerPrivateGStreamerMSE::~MediaPlayerPrivateGStreamerMSE()+0x2f5) [0x7f83597ae187]
8   0x7f83597ae1b0 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::MediaPlayerPrivateGStreamerMSE::~MediaPlayerPrivateGStreamerMSE()+0x18) [0x7f83597ae1b0]
9   0x7f8358c79504 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(std::default_delete<WebCore::MediaPlayerPrivateInterface>::operator()(WebCore::MediaPlayerPrivateInterface*) const+0x2e) [0x7f8358c79504]
10  0x7f8358c78a7d /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(std::unique_ptr<WebCore::MediaPlayerPrivateInterface, std::default_delete<WebCore::MediaPlayerPrivateInterface> >::~unique_ptr()+0x49) [0x7f8358c78a7d]
11  0x7f8358c70f2f /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::MediaPlayer::~MediaPlayer()+0xb7) [0x7f8358c70f2f]
12  0x7f8358c70f6a /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::MediaPlayer::~MediaPlayer()+0x18) [0x7f8358c70f6a]
13  0x7f835858a95c /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WTF::RefCounted<WebCore::MediaPlayer>::deref() const+0x48) [0x7f835858a95c]
14  0x7f83585861d8 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(void WTF::derefIfNotNull<WebCore::MediaPlayer>(WebCore::MediaPlayer*)+0x2c) [0x7f83585861d8]
15  0x7f8358581cf5 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WTF::RefPtr<WebCore::MediaPlayer, WTF::DumbPtrTraits<WebCore::MediaPlayer> >::operator=(decltype(nullptr))+0x33) [0x7f8358581cf5]
16  0x7f835856b8d2 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::HTMLMediaElement::clearMediaPlayer()+0xf8) [0x7f835856b8d2]
17  0x7f835856b69f /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::HTMLMediaElement::userCancelledLoad()+0x43) [0x7f835856b69f]
18  0x7f835856ba5b /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::HTMLMediaElement::stopWithoutDestroyingMediaPlayer()+0xad) [0x7f835856ba5b]
19  0x7f835856bc21 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::HTMLMediaElement::stop()+0x2b) [0x7f835856bc21]
20  0x7f835835fc53 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(+0xc105c53) [0x7f835835fc53]
21  0x7f835835fc8a /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(+0xc105c8a) [0x7f835835fc8a]
22  0x7f8358362b1a /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WTF::Function<WebCore::ScriptExecutionContext::ShouldContinue (WebCore::ActiveDOMObject&)>::operator()(WebCore::ActiveDOMObject&) const+0x78) [0x7f8358362b1a]
23  0x7f8358357b85 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::ScriptExecutionContext::forEachActiveDOMObject(WTF::Function<WebCore::ScriptExecutionContext::ShouldContinue (WebCore::ActiveDOMObject&)> const&) const+0xc3) [0x7f8358357b85]
24  0x7f8358357d36 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::ScriptExecutionContext::stopActiveDOMObjects()+0x58) [0x7f8358357d36]
25  0x7f8358211a40 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::Document::stopActiveDOMObjects()+0x1e) [0x7f8358211a40]
26  0x7f835821157a /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::Document::prepareForDestruction()+0x292) [0x7f835821157a]
27  0x7f83589d13d7 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::Frame::setView(WTF::RefPtr<WebCore::FrameView, WTF::DumbPtrTraits<WebCore::FrameView> >&&)+0xaf) [0x7f83589d13d7]
28  0x7f83589d3915 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::Frame::createView(WebCore::IntSize const&, WTF::Optional<WebCore::Color> const&, WebCore::IntSize const&, WebCore::IntRect const&, bool, WebCore::ScrollbarMode, bool, WebCore::ScrollbarMode, bool)+0xed) [0x7f83589d3915]
29  0x7f8356e4fcd3 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebKit::WebFrameLoaderClient::transitionToCommittedForNewPage()+0x2ab) [0x7f8356e4fcd3]
30  0x7f8358867534 /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::FrameLoader::transitionToCommitted(WebCore::CachedPage*)+0x4be) [0x7f8358867534]
31  0x7f835886686a /webkit/WebKitBuild/Debug/lib/libwebkit2gtk-4.0.so.37(WebCore::FrameLoader::commitProvisionalLoad()+0x4b4) [0x7f835886686a]

[Philippe Normand]

What's your platform video decoder? The trace indicates the flush is done from the player destructor, that means a v4l2 is used. Can you  confirm?

[Alicia Boya García]

(In reply to Philippe Normand from comment #1)
> What's your platform video decoder? The trace indicates the flush is done
> from the player destructor, that means a v4l2 is used. Can you  confirm?

I don't think so. According to pipeline dumps a decoder has not even been added to the pipeline at all in this test.

[Philippe Normand]

🤨

[Philippe Normand]

Oh I know, m_videoDecoderPlatform likely is initialized to the first enum value be default, that's no good.

[Philippe Normand]

(In reply to Philippe Normand from comment #4)
> Oh I know, m_videoDecoderPlatform likely is initialized to the first enum
> value be default, that's no good.

It could become a WTF::Optional<T>. I'll write a patch tomorrow if no one else does it first.

[Philippe Normand]

Created attachment 368118 [details]
Patch

[Xabier Rodríguez Calvar]

Comment on attachment 368118 [details]
Patch

I tend to think that the proper solution would be:

enum class WebKitGstVideoDecoderPlatform { Other, ImxVPU, Video4Linux };

WebKitGstVideoDecoderPlatform m_videoDecoderPlatform { Other }

[Philippe Normand]

Seems to me like a clear case for Optional.

[Xabier Rodríguez Calvar]

Comment on attachment 368118 [details]
Patch

(In reply to Philippe Normand from comment #8)
> Seems to me like a clear case for Optional.

I don't have a strong opinion so r+

[Philippe Normand]

Committed r244587: <https://trac.webkit.org/changeset/244587>