Bug 127916

Summary:	fast/events/page-visibility-iframe-move-test.html asserts under RenderLayer::paintBackgroundForFragments
Product:	WebKit	Reporter:	Alexey Proskuryakov <ap>
Component:	Layout and Rendering	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	abucur, barraclough, kling, koivisto, simon.fraser, thorton
Priority:	P1	Keywords:	MakingBotsRed, Regression
Version:	528+ (Nightly build)
Hardware:	Unspecified
OS:	Unspecified
See Also:	https://bugs.webkit.org/show_bug.cgi?id=207303

Description Alexey Proskuryakov 2014-01-30 09:56:33 PST

Bot says that this started in this range <http://trac.webkit.org/log/?verbose=on&rev=163079&stop_rev=163074>, which probably implicates <http://trac.webkit.org/changeset/163079>.

Note that this test was crashing about a week ago as well, but that was for an entirely different reason.

Sample crash: <http://build.webkit.org/results/Apple%20MountainLion%20Debug%20WK2%20(Tests)/r163080%20(15681)/fast/events/page-visibility-iframe-move-test-crash-log.txt>

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   com.apple.JavaScriptCore      	0x000000010d81b75a WTFCrash + 42 (Assertions.cpp:333)
1   com.apple.WebCore             	0x00000001101d647b WebCore::RenderView::paint(WebCore::PaintInfo&, WebCore::LayoutPoint const&) + 91 (RenderView.cpp:479)
2   com.apple.WebCore             	0x0000000110032924 WebCore::RenderLayer::paintBackgroundForFragments(WTF::Vector<WebCore::LayerFragment, 1ul, WTF::CrashOnOverflow> const&, WebCore::GraphicsContext*, WebCore::GraphicsContext*, WebCore::LayoutRect const&, bool, WebCore::RenderLayer::LayerPaintingInfo const&, unsigned int, WebCore::RenderObject*) + 708 (RenderLayer.cpp:4302)
3   com.apple.WebCore             	0x000000011002fcc3 WebCore::RenderLayer::paintLayerContents(WebCore::GraphicsContext*, WebCore::RenderLayer::LayerPaintingInfo const&, unsigned int) + 1875 (RenderLayer.cpp:4051)
4   com.apple.WebCore             	0x000000011005dcd7 WebCore::RenderLayerBacking::paintIntoLayer(WebCore::GraphicsLayer const*, WebCore::GraphicsContext*, WebCore::IntRect const&, unsigned int, unsigned int) + 551 (RenderLayerBacking.cpp:2203)
5   com.apple.WebCore             	0x000000011005e000 WebCore::RenderLayerBacking::paintContents(WebCore::GraphicsLayer const*, WebCore::GraphicsContext&, unsigned int, WebCore::IntRect const&) + 608 (RenderLayerBacking.cpp:2248)

Comment 1 Alexey Proskuryakov 2014-01-30 10:02:51 PST

Hmm, two iterations in a row crashed, but the third one didn't, so it's possible that another recent change made the test flaky.

Comment 2 Alexey Proskuryakov 2014-01-30 17:11:41 PST

So, it only happened twice, and is green since. Can't blame this revision I guess.

Comment 3 Andrei Bucur 2014-01-31 00:12:50 PST

Thanks for the heads up! I'm taking a look anyway, maybe I spot something fishy.