Created attachment 449911 [details] the html that trigger crash 1. build a debug webkit 2. open the html 3. crash ASSERTION FAILED: x2 >= x1 ../../Source/WebCore/rendering/RenderElement.cpp(1945) : void WebCore::RenderElement::drawLineForBoxSide(WebCore::GraphicsContext&, const WebCore::FloatRect&, WebCore::BoxSide, WebCore ::Color, WebCore::BorderStyle, float, float, bool) const 1 0x7f4fdf61b964 WTFReportBacktrace 2 0x7f4fdf61bc01 WTFCrash 3 0x7f4ff9112ba1 WTF::CrashOnOverflow::overflowed() 4 0x7f5002a66924 WebCore::RenderElement::drawLineForBoxSide(WebCore::GraphicsContext&, WebCore::FloatRect const&, WebCore::BoxSide, WebCore::Color, WebCore::BorderStyle, float, float , bool) const 5 0x7f5002b51fae WebCore::RenderInline::paintOutlineForLine(WebCore::GraphicsContext&, WebCore::LayoutPoint const&, WebCore::LayoutRect const&, WebCore::LayoutRect const&, WebCore::LayoutRect const&, WebCore::Color const&) 6 0x7f5002b4ec86 WebCore::RenderInline::paintOutline(WebCore::PaintInfo&, WebCore::LayoutPoint const&) 7 0x7f5002c8d856 WebCore::RenderLineBoxList::paint(WebCore::RenderBoxModelObject*, WebCore::PaintInfo&, WebCore::LayoutPoint const&) const 8 0x7f500294d072 WebCore::RenderBlockFlow::paintInlineChildren(WebCore::PaintInfo&, WebCore::LayoutPoint const&) 9 0x7f5002852925 WebCore::RenderBlock::paintContents(WebCore::PaintInfo&, WebCore::LayoutPoint const&) 10 0x7f500285535e WebCore::RenderBlock::paintObject(WebCore::PaintInfo&, WebCore::LayoutPoint const&) 11 0x7f5002852563 WebCore::RenderBlock::paint(WebCore::PaintInfo&, WebCore::LayoutPoint const&) 12 0x7f5002ca1a3d WebCore::RenderListItem::paint(WebCore::PaintInfo&, WebCore::LayoutPoint const&) 13 0x7f50028535f7 WebCore::RenderBlock::paintChild(WebCore::RenderBox&, WebCore::PaintInfo&, WebCore::LayoutPoint const&, WebCore::PaintInfo&, bool, WebCore::RenderBlock::PaintBlockType) 14 0x7f5002852d82 WebCore::RenderBlock::paintChildren(WebCore::PaintInfo&, WebCore::LayoutPoint const&, WebCore::PaintInfo&, bool) 15 0x7f5002852c91 WebCore::RenderBlock::paintContents(WebCore::PaintInfo&, WebCore::LayoutPoint const&) 16 0x7f500285535e WebCore::RenderBlock::paintObject(WebCore::PaintInfo&, WebCore::LayoutPoint const&) 17 0x7f5002852563 WebCore::RenderBlock::paint(WebCore::PaintInfo&, WebCore::LayoutPoint const&) 18 0x7f50028535f7 WebCore::RenderBlock::paintChild(WebCore::RenderBox&, WebCore::PaintInfo&, WebCore::LayoutPoint const&, WebCore::PaintInfo&, bool, WebCore::RenderBlock::PaintBlockType) 19 0x7f5002852d82 WebCore::RenderBlock::paintChildren(WebCore::PaintInfo&, WebCore::LayoutPoint const&, WebCore::PaintInfo&, bool) 20 0x7f5002852c91 WebCore::RenderBlock::paintContents(WebCore::PaintInfo&, WebCore::LayoutPoint const&) 21 0x7f500285535e WebCore::RenderBlock::paintObject(WebCore::PaintInfo&, WebCore::LayoutPoint const&) 22 0x7f5002852563 WebCore::RenderBlock::paint(WebCore::PaintInfo&, WebCore::LayoutPoint const&) 23 0x7f5002b7d527 WebCore::RenderLayer::paintForegroundForFragmentsWithPhase(WebCore::PaintPhase, WTF::Vector<WebCore::LayerFragment, 1ul, WTF::CrashOnOverflow, 16ul, WTF::FastMalloc> const&, WebCore::GraphicsContext&, WebCore::RenderLayer::LayerPaintingInfo const&, WTF::OptionSet<WebCore::PaintBehavior>, WebCore::RenderObject*) 24 0x7f5002b7cdcf WebCore::RenderLayer::paintForegroundForFragments(WTF::Vector<WebCore::LayerFragment, 1ul, WTF::CrashOnOverflow, 16ul, WTF::FastMalloc> const&, WebCore::GraphicsContext&, WebCore::GraphicsContext&, WebCore::LayoutRect const&, bool, WebCore::RenderLayer::LayerPaintingInfo const&, WTF::OptionSet<WebCore::PaintBehavior>, WebCore::RenderObject*) 25 0x7f5002b7671c WebCore::RenderLayer::paintLayerContents(WebCore::GraphicsContext&, WebCore::RenderLayer::LayerPaintingInfo const&, WTF::OptionSet<WebCore::RenderLayer::PaintLayerFlag>)
<rdar://problem/88322002>