Bug 259544

Summary:	[ macOS Debug WK2 ] ASSERT call in RenderVTTCue.cpp causing flaky crash (media/modern-media-controls/tracks-support/text-track-selected-via-media-api.html)
Product:	WebKit	Reporter:	Ben Schwartz <ben_schwartz>
Component:	WebCore Misc.	Assignee:	Eric Carlson <eric.carlson>
Status:	RESOLVED FIXED
Severity:	Normal	CC:	eric.carlson, jer.noble, webkit-bot-watchers-bugzilla, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified
See Also:	https://bugs.webkit.org/show_bug.cgi?id=259545 https://bugs.webkit.org/show_bug.cgi?id=259546

Description Ben Schwartz 2023-07-26 20:13:59 PDT

media/modern-media-controls/tracks-support/text-track-selected-via-media-api.html

This test is a flaky crash on macOS debug wk2 builds.

HISTORY:

https://results.webkit.org/?suite=layout-tests&test=media%2Fmodern-media-controls%2Ftracks-support%2Ftext-track-selected-via-media-api.html&style=debug

CRASH LOG TEXT:

ASSERTION FAILED: firstChild()
rendering/RenderVTTCue.cpp(380) : void WebCore::RenderVTTCue::repositionGenericCue()
1   0x34c189939 WTFCrash
2   0x2f35f572b WTFCrashWithInfo(int, char const*, char const*, int)
3   0x2f93e78cd WebCore::RenderVTTCue::repositionGenericCue()
4   0x2f93e7317 WebCore::RenderVTTCue::layout()
5   0x2f80c9f83 WebCore::RenderElement::layoutIfNeeded()
6   0x2f9130049 WebCore::RenderBlock::layoutPositionedObject(WebCore::RenderBox&, bool, bool)
7   0x2f912ec1f WebCore::RenderBlock::layoutPositionedObjects(bool, bool)
8   0x2f912e7f7 WebCore::RenderBlock::simplifiedLayout()
9   0x2f914908a WebCore::RenderBlockFlow::layoutBlock(bool, WebCore::LayoutUnit)
10  0x2f912cf78 WebCore::RenderBlock::layout()
11  0x2f84945c8 WebCore::LocalFrameViewLayoutContext::performLayout()
12  0x2f8472296 WebCore::LocalFrameViewLayoutContext::layout()
13  0x2f738c93d WebCore::Document::resolveStyle(WebCore::Document::ResolveStyleType)
14  0x2f738d71d WebCore::Document::updateStyleIfNeeded()
15  0x2f848daeb WebCore::LocalFrameView::updateLayoutAndStyleIfNeededRecursive()
16  0x2f84fe93c WebCore::Page::layoutIfNeeded()
17  0x2f84ff145 WebCore::Page::updateRendering()
18  0x3230e0d81 WebKit::WebPage::updateRendering()
19  0x322177e1c WebKit::TiledCoreAnimationDrawingArea::updateRendering(WebKit::TiledCoreAnimationDrawingArea::UpdateRenderingType)
20  0x32217c477 WebKit::TiledCoreAnimationDrawingArea::renderingUpdateRunLoopCallback()
21  0x32217e928 WebKit::TiledCoreAnimationDrawingArea::TiledCoreAnimationDrawingArea(WebKit::WebPage&, WebKit::WebPageCreationParameters const&)::$_0::operator()() const
22  0x32217e8c9 WTF::Detail::CallableWrapper<WebKit::TiledCoreAnimationDrawingArea::TiledCoreAnimationDrawingArea(WebKit::WebPage&, WebKit::WebPageCreationParameters const&)::$_0, void>::call()
23  0x2f3615442 WTF::Function<void ()>::operator()() const
24  0x2f8768ff2 WebCore::RunLoopObserver::runLoopObserverFired()
25  0x2f88755cd WebCore::RunLoopObserver::runLoopObserverFired(__CFRunLoopObserver*, unsigned long, void*)
26  0x7ff810883500 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__
27  0x7ff810883392 __CFRunLoopDoObservers
28  0x7ff810881e90 CFRunLoopRunSpecific
29  0x7ff8116e0d3a -[NSRunLoop(NSRunLoop) runMode:beforeDate:]
30  0x7ff81176b787 -[NSRunLoop(NSRunLoop) run]
31  0x7ff810505786 _xpc_objc_main
com.apple.WebKit.WebContent.Development terminated (pid 25405) for reason: crash
LEAK: 2 WebPageProxy

CRASH LOG LINK:

https://build.webkit.org/results/Apple-Monterey-Debug-WK2-Tests/266326@main%20(8297)/media/modern-media-controls/tracks-support/text-track-selected-via-media-api-crash-log.txt

CAUSE/PERMALINK:

This bug is caused by an ASSERT call not functioning properly. See: https://github.com/WebKit/WebKit/blame/0ef0801e78b627d421da475271e6f9385e18af4c/Source/WebCore/rendering/RenderVTTCue.cpp#L380

Comment 1 Radar WebKit Bug Importer 2023-07-26 20:14:09 PDT

<rdar://problem/112951082>

Comment 2 Ben Schwartz 2023-07-26 20:23:07 PDT

I have marked this test as a flaky crash while this issue is investigated. (Link: https://github.com/WebKit/WebKit/pull/16127)

Comment 3 EWS 2023-07-31 10:45:47 PDT

Test gardening commit 266431@main (ec91d98d727f): <https://commits.webkit.org/266431@main>

Reviewed commits have been landed. Closing PR #16127 and removing active labels.

Comment 4 Eric Carlson 2023-08-02 07:41:10 PDT

Pull request: https://github.com/WebKit/WebKit/pull/16315

Comment 5 EWS 2023-08-02 08:56:46 PDT

Committed 266513@main (83a6562ec0c7): <https://commits.webkit.org/266513@main>

Reviewed commits have been landed. Closing PR #16315 and removing active labels.