Bug 57487 – chrome.dll!WebCore::RenderBlock::findNextLineBreak ReadAV@NULL (bb0085b7cdfcb99eb1362265d1fea9f0)

• Component: CSS
• Status: RESOLVED WORKSFORME

[Berend-Jan Wever]

Created attachment 87583 [details]
Repro

Chromium: http://code.google.com/p/chromium/issues/detail?id=77933
Repro:
<details><style>:first-line{ -webkit-perspective-origin:3;}</style>

webcore\rendering\renderblocklinelayout.cpp:
InlineIterator RenderBlock::findNextLineBreak(InlineBidiResolver& resolver, bool firstLine, bool& isLineEmpty, LineBreakIteratorInfo& lineBreakIteratorInfo, bool& previousLineBrokeCleanly, 
                                              bool& hyphenated, EClear* clear, FloatingObject* lastFloatFromPreviousLine, Vector<RenderBox*>& positionedBoxes)
{
<snip>
            RenderStyle* style = t->style(firstLine);
            if (style->hasTextCombine() && o->isCombineText())
style is NULL, causing a NULL ptr read accessv violation:

id:             chrome.dll!WebCore::RenderBlock::findNextLineBreak ReadAV@NULL (bb0085b7cdfcb99eb1362265d1fea9f0)
description:    Attempt to read from unallocated NULL pointer+0x1C in chrome.dll!WebCore::RenderBlock::findNextLineBreak
stack:          chrome.dll!WebCore::RenderBlock::findNextLineBreak
                chrome.dll!WebCore::RenderBlock::layoutInlineChildren
                chrome.dll!WebCore::RenderBlock::layoutBlock
                chrome.dll!WebCore::RenderBlock::layout
                chrome.dll!WebCore::RenderBlock::layoutBlockChild
                chrome.dll!WebCore::RenderBlock::layoutBlockChildren
                chrome.dll!WebCore::RenderBlock::layoutBlock
                chrome.dll!WebCore::RenderBlock::layout
                chrome.dll!WebCore::RenderBlock::layoutBlockChild
                chrome.dll!WebCore::RenderBlock::layoutBlockChildren
                chrome.dll!WebCore::RenderBlock::layoutBlock
                chrome.dll!WebCore::RenderBlock::layout
                chrome.dll!WebCore::RenderDetails::layout
                chrome.dll!WebCore::RenderBlock::layoutBlockChild
                chrome.dll!WebCore::RenderBlock::layoutBlockChildren
                chrome.dll!WebCore::RenderBlock::layoutBlock
                chrome.dll!WebCore::RenderBlock::layout
                chrome.dll!WebCore::RenderBlock::layoutBlockChild
                chrome.dll!WebCore::RenderBlock::layoutBlockChildren
                chrome.dll!WebCore::RenderBlock::layoutBlock
                chrome.dll!WebCore::RenderBlock::layout
                chrome.dll!WebCore::RenderBlock::layoutBlockChild
                chrome.dll!WebCore::RenderBlock::layoutBlockChildren
                chrome.dll!WebCore::RenderBlock::layoutBlock
                chrome.dll!WebCore::RenderBlock::layout
                chrome.dll!WebCore::RenderView::layout
                chrome.dll!WebCore::FrameView::layout
                chrome.dll!WebCore::FrameView::updateLayoutAndStyleIfNeededRecursive
                chrome.dll!RenderWidget::DoDeferredUpdate
                chrome.dll!RenderWidget::CallDoDeferredUpdate
                chrome.dll!MessageLoop::RunTask
                chrome.dll!MessageLoop::DoWork
                chrome.dll!base::MessagePumpDefault::Run
                chrome.dll!MessageLoop::RunInternal
                chrome.dll!MessageLoop::Run
                chrome.dll!RendererMain

[Emil A Eklund]

Created attachment 88052 [details]
Patch

[Levi Weintraub]

Comment on attachment 88052 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=88052&action=review

> Source/WebCore/rendering/RenderObject.cpp:2375
> +    return style ? style : m_style.get();

Yup, this was my fix too, but I'd set style to 0 on 2361 to start. We don't need to set it to reference m_style.get() twice.

[Levi Weintraub]

*** Bug 57751 has been marked as a duplicate of this bug. ***

Comment on attachment 88052 [details]
Patch

Whatever is causing this, which is most likely a bug in <details> needs to be fixed.

[Emil A Eklund]

Comment on attachment 88052 [details]
Patch

Good point, I'll see if I can track down the root cause.

[Berend-Jan Wever]

This appears to have been fixed by now.