Make RenderObject::isTransparent tolerate NULL style
Moving http://code.google.com/p/chromium/issues/detail?id=41555 into WebKit bug tracker as most probably it's a problem on WebKit side, not Chromium proper. After WebKit roll 57510 -> 57582 (http://codereview.chromium.org/1540037/show) almost all fast/ruby tests started to fail. Here is sample stack trace (obtained with gdb): #0 WebCore::RenderObject::isTransparent (this=0xaa28724) at third_party/WebKit/WebCore/rendering/RenderObject.h:662 #1 0x0886cba8 in WebCore::RenderBoxModelObject::requiresLayer (this=0xaa28724) at third_party/WebKit/WebCore/rendering/RenderBoxModelObject.h:62 #2 0x0889670b in WebCore::RenderBoxModelObject::styleDidChange (this=0xaa28724, diff=WebCore::StyleDifferenceEqual, oldStyle=0xaa287a8) at third_party/WebKit/WebCore/rendering/RenderBoxModelObject.cpp:276 #3 0x0888dc92 in WebCore::RenderBox::styleDidChange (this=0xaa28724, diff=WebCore::StyleDifferenceEqual, oldStyle=0xaa287a8) at third_party/WebKit/WebCore/rendering/RenderBox.cpp:165 #4 0x0886294a in WebCore::RenderBlock::styleDidChange (this=0xaa28724, diff=WebCore::StyleDifferenceEqual, oldStyle=0xaa287a8) at third_party/WebKit/WebCore/rendering/RenderBlock.cpp:231 #5 0x088e0277 in WebCore::RenderObject::setStyle (this=0xaa28724, style=@0xbfa77394) at third_party/WebKit/WebCore/rendering/RenderObject.cpp:1530 #6 0x088ebcfb in WebCore::RenderRubyRun::staticCreateRubyRun (parentRuby=0xaa2864c) at third_party/WebKit/WebCore/rendering/RenderRubyRun.cpp:222 #7 0x088eb2a5 in WebCore::RenderRubyAsInline::addChild (this=0xaa2864c, child=0xaa286d4, beforeChild=0x0) at third_party/WebKit/WebCore/rendering/RenderRuby.cpp:104 #8 0x085ad199 in WebCore::Node::createRendererIfNeeded (this=0xaa0bf68) at third_party/WebKit/WebCore/dom/Node.cpp:1393 #9 0x085de2a5 in WebCore::Text::attach (this=0xaa0bf68) at third_party/WebKit/WebCore/dom/Text.cpp:272 #10 0x08b13938 in WebCore::HTMLParser::insertNode (this=0xa842e38, n=0xaa0bf68, flat=false) at third_party/WebKit/WebCore/html/HTMLParser.cpp:399 #11 0x08b18b9f in WebCore::HTMLParser::insertNodeAfterLimitBlockDepth (this=0xa842e38, n=0xaa0bf68, flat=false) at third_party/WebKit/WebCore/html/HTMLParser.cpp:227 #12 0x08b15eb8 in WebCore::HTMLParser::parseToken (this=0xa842e38, t=0xa8460fc) at third_party/WebKit/WebCore/html/HTMLParser.cpp:268 #13 0x0868e9b1 in WebCore::HTMLTokenizer::processToken (this=0xa8460e0) at third_party/WebKit/WebCore/html/HTMLTokenizer.cpp:1941 #14 0x0869582c in WebCore::HTMLTokenizer::write (this=0xa8460e0, str=@0xbfa77628, appendData=true) at third_party/WebKit/WebCore/html/HTMLTokenizer.cpp:1760 #15 0x0870caf7 in WebCore::FrameLoader::write (this=0xa82e090, str=0x0, len=0, flush=true) at third_party/WebKit/WebCore/loader/FrameLoader.cpp:949 #16 0x0870cca3 in WebCore::FrameLoader::endIfNotLoadingMainResource (this=0xa82e090) at third_party/WebKit/WebCore/loader/FrameLoader.cpp:984 #17 0x0870cce1 in WebCore::FrameLoader::end (this=0xa82e090) at third_party/WebKit/WebCore/loader/FrameLoader.cpp:970 #18 0x086feda6 in WebCore::DocumentLoader::finishedLoading (this=0xa9d2400) at third_party/WebKit/WebCore/loader/DocumentLoader.cpp:268 #19 0x08711482 in WebCore::FrameLoader::finishedLoading (this=0xa82e090) at third_party/WebKit/WebCore/loader/FrameLoader.cpp:2824 #20 0x087209b7 in WebCore::MainResourceLoader::didFinishLoading (this=0xa9d3230) at third_party/WebKit/WebCore/loader/MainResourceLoader.cpp:424 #21 0x0872a194 in WebCore::ResourceLoader::didFinishLoading (this=0xa9d3230) at third_party/WebKit/WebCore/loader/ResourceLoader.cpp:443 #22 0x09248b93 in WebCore::ResourceHandleInternal::didFinishLoading (this=0xa9d7248) at third_party/WebKit/WebKit/chromium/src/ResourceHandle.cpp:180 #23 0x08ee745b in webkit_glue::WebURLLoaderImpl::Context::OnCompletedRequest (this=0xa9d6180, status=@0xa84948c, security_info=@0xa849494) at webkit/glue/weburlloader_impl.cc:552 #24 0x08f099da in NotifyCompletedRequest (this=0xa9d6200, status=@0xa84948c, security_info=@0xa849494) at webkit/tools/test_shell/simple_resource_loader_bridge.cc:199 #25 0x08f09eb0 in DispatchToMethod<<unnamed>::RequestProxy, void (<unnamed>::RequestProxy::*)(const URLRequestStatus&, const std::string&), URLRequestStatus, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > (obj=0xa9d6200, method=0x8f099a4 <NotifyCompletedRequest>, arg=@0xa84948c) at ./base/tuple.h:429 #26 0x08f09ee6 in Run (this=0xa849470) at ./base/task.h:296 #27 0x0812f016 in MessageLoop::RunTask (this=0xbfa78844, task=0xa849470) at base/message_loop.cc:328 #28 0x0812f6c7 in MessageLoop::DeferOrRunPendingTask (this=0xbfa78844, pending_task=@0xbfa779e4) at base/message_loop.cc:336 #29 0x0812f957 in MessageLoop::DoWork (this=0xbfa78844) at base/message_loop.cc:443 #30 0x0816ee0d in base::MessagePumpForUI::RunWithDispatcher (this=0xa7d6530, delegate=0xbfa78844, dispatcher=0x0) at base/message_pump_glib.cc:199 #31 0x0816f7bf in base::MessagePumpForUI::Run (this=0xa7d6530, delegate=0xbfa78844) at ./base/message_pump_glib.h:59 #32 0x081300b7 in MessageLoop::RunInternal (this=0xbfa78844) at base/message_loop.cc:204 #33 0x081300d1 in MessageLoop::RunHandler (this=0xbfa78844) at base/message_loop.cc:176 #34 0x08130175 in MessageLoop::Run (this=0xbfa78844) at base/message_loop.cc:154 #35 0x08049be2 in main (argc=Cannot access memory at address 0x0 Here, in isTransparent() style() returns NULL and we crash. Looking through committed revisions, I don't see what might have triggered that. I am not an expert in this area, but apparently the case of NULL style() should be handled here---at least RenderObject::setStyle naturally accepts the case when original style is NULL. Similarly hasMask() (another one in requiresLayer() check) checks style() before querying it. Thus, with my non-existent understanding of WebKit rendering process, I'd try to fix it checking if style() is NULL before querying opacity(). The bug is difficult to reproduce for me---at least on my box there seems to be troubles with hitting this path at all (probably something disables ruby support).
Created attachment 53533 [details] Patch
Comment on attachment 53533 [details] Patch I found one strange thing. Need some more time to investigate.
The reason seems to be spoiled build. Closing this bug.