Bug 57751 – chrome.dll!WebCore::RenderBlock::findNextLineBreak ReadAV@NULL (bb0085b7cdfcb99eb1362265d1fea9f0)

• Component: CSS
• Status: RESOLVED DUPLICATE

[Berend-Jan Wever]

Created attachment 88050 [details]
Repro

Chromium: http://code.google.com/p/chromium/issues/detail?id=78309
Repro:
<style>
  :first-line{-webkit-mask-position-y:top}
</style>
<details>

\source\webcore\rendering\renderblocklinelayout.cpp:
RenderBlock::findNextLineBreak:
<snip>
            RenderStyle* style = t->style(firstLine);
            if (style->hasTextCombine() && o->isCombineText())
                toRenderCombineText(o)->combineText();
<snip>
The problem is that "style" can be NULL and the code does not handle this.

id:             chrome.dll!WebCore::RenderBlock::findNextLineBreak ReadAV@NULL (bb0085b7cdfcb99eb1362265d1fea9f0)
description:    Attempt to read from unallocated NULL pointer+0x1C in chrome.dll!WebCore::RenderBlock::findNextLineBreak
application:    Chromium 12.0.716.0
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::Document::implicitClose
                chrome.dll!WebCore::FrameLoader::checkCompleted
                chrome.dll!WebCore::FrameLoader::finishedParsing
                chrome.dll!WebCore::Document::finishedParsing
                chrome.dll!WebCore::HTMLDocumentParser::prepareToStopParsing
                chrome.dll!WebCore::DocumentWriter::endIfNotLoadingMainResource
                chrome.dll!WebCore::FrameLoader::finishedLoading
                chrome.dll!WebCore::MainResourceLoader::didFinishLoading
                chrome.dll!WebCore::ResourceLoader::didFinishLoading
                chrome.dll!WebCore::ResourceHandleInternal::didFinishLoading
                chrome.dll!webkit_glue::WebURLLoaderImpl::Context::OnCompletedRequest
                chrome.dll!ResourceDispatcher::OnRequestComplete
                chrome.dll!IPC::MessageWithTuple<...>::Dispatch<...>
                chrome.dll!ResourceDispatcher::DispatchMessageW
                chrome.dll!ResourceDispatcher::OnMessageReceived
                chrome.dll!ChildThread::OnMessageReceived
                ...

[Levi Weintraub]

I'll take this easy fix.

[Levi Weintraub]

*** This bug has been marked as a duplicate of bug 57487 ***

[Berend-Jan Wever]

I specifically looked for duplicates, as this looked very familiar, but didn't find any. And now if I search again, it does find it... very odd. Sorry for the noize - maybe I made a typo in my search...