[GTK] fast/css/relative-positioned-block-crash.html is intermittently crashing

[Zan Dobersek]

Here's the dashboard data:
http://test-results.appspot.com/dashboards/flakiness_dashboard.html#group=%40ToT%20-%20webkit.org&showAllRuns=true&tests=fast%2Fcss%2Frelative-positioned-block-crash.html

Here's the commit range in which the crash occurred for the first time:
http://trac.webkit.org/log/?verbose=on&rev=140440&stop_rev=140259

The crash log:
Crash log for DumpRenderTree (pid 21595):

...
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/home/slave/webkitgtk/gtk-linux-64-debug/build/WebKitBuild/Debug/Programs/DumpR'.
Program terminated with signal 11, Segmentation fault.
#0  0x00002ad34ffdea15 in WebCore::Position::Position (this=0x7fff71188070, anchorNode=..., anchorType=WebCore::Position::PositionIsBeforeAnchor) at ../../Source/WebCore/dom/Position.cpp:108
108	    ASSERT(!m_anchorNode || !m_anchorNode->isPseudoElement());

...

Thread 1 (Thread 0x2ad35e30e6c0 (LWP 21595)):
#0  0x00002ad34ffdea15 in WebCore::Position::Position (this=0x7fff71188070, anchorNode=..., anchorType=WebCore::Position::PositionIsBeforeAnchor) at ../../Source/WebCore/dom/Position.cpp:108
#1  0x00002ad34fbe9cea in WebCore::positionBeforeNode (anchorNode=0x1313a2d0) at ../../Source/WebCore/dom/Position.h:266
#2  0x00002ad3510868e6 in objectFocusedAndCaretOffsetUnignored (referenceObject=0x133921c0, offset=@0x7fff7118817c: -1) at ../../Source/WebCore/accessibility/atk/WebKitAccessibleWrapperAtk.cpp:1106
#3  0x00002ad3510870ae in WebCore::FrameSelection::notifyAccessibilityForSelectionChange (this=0x20a0a30) at ../../Source/WebCore/editing/gtk/FrameSelectionGtk.cpp:96
#4  0x00002ad350082588 in WebCore::FrameSelection::setSelection (this=0x20a0a30, newSelection=..., options=6, align=WebCore::FrameSelection::AlignCursorOnScrollIfNeeded, granularity=WebCore::CharacterGranularity) at ../../Source/WebCore/editing/FrameSelection.cpp:325
#5  0x00002ad3500894b2 in WebCore::FrameSelection::selectAll (this=0x20a0a30) at ../../Source/WebCore/editing/FrameSelection.cpp:1631
#6  0x00002ad350069755 in WebCore::executeSelectAll (frame=0x20a0400) at ../../Source/WebCore/editing/EditorCommand.cpp:1006
#7  0x00002ad35006b18a in WebCore::Editor::Command::execute (this=0x7fff71188500, parameter="(null)", triggeringEvent=0x0) at ../../Source/WebCore/editing/EditorCommand.cpp:1704
#8  0x00002ad34ff0e02c in WebCore::Document::execCommand (this=0x131d4190, commandName="selectall", userInterface=false, value="(null)") at ../../Source/WebCore/dom/Document.cpp:4157
#9  0x00002ad3509fad28 in WebCore::jsDocumentPrototypeFunctionExecCommand (exec=0x2ad3a42200e8) at DerivedSources/WebCore/JSDocument.cpp:2603
#10 0x00002ad35e5380e5 in ?? ()
#11 0x00007fff711886b0 in ?? ()
#12 0x00002ad34ef14418 in llint_op_call () from /home/slave/webkitgtk/gtk-linux-64-debug/build/WebKitBuild/Debug/.libs/libjavascriptcoregtk-3.0.so.0
#13 0x00002ad3a4220060 in ?? ()
#14 0x00000000020c0230 in ?? ()
#15 0x00007fff71188670 in ?? ()
#16 0x00002ad34eeb8ce7 in JSC::JSStack::installTrapsAfterFrame (this=0x0, frame=0x0) at ../../Source/JavaScriptCore/interpreter/JSStackInlines.h:213
#17 0x00002ad34eeb7a54 in JSC::JITCode::execute (this=0x2ad3a46209c0, stack=0x20c0230, callFrame=0x2ad3a4220060, globalData=0x2726cd0) at ../../Source/JavaScriptCore/jit/JITCode.h:135
#18 0x00002ad34eeb5211 in JSC::Interpreter::executeCall (this=0x20c0220, callFrame=0x2ad3a48ae388, function=0x2ad3a486edc0, callType=JSC::CallTypeJS, callData=..., thisValue=..., args=...) at ../../Source/JavaScriptCore/interpreter/Interpreter.cpp:1055
#19 0x00002ad34ef99bf1 in JSC::call (exec=0x2ad3a48ae388, functionObject=..., callType=JSC::CallTypeJS, callData=..., thisValue=..., args=...) at ../../Source/JavaScriptCore/runtime/CallData.cpp:40
#20 0x00002ad34fc41f89 in WebCore::JSMainThreadExecState::call (exec=0x2ad3a48ae388, functionObject=..., callType=JSC::CallTypeJS, callData=..., thisValue=..., args=...) at ../../Source/WebCore/bindings/js/JSMainThreadExecState.h:56
#21 0x00002ad34fc70c73 in WebCore::JSEventListener::handleEvent (this=0x11f09010, scriptExecutionContext=0x131d4230, event=0x120f8bf0) at ../../Source/WebCore/bindings/js/JSEventListener.cpp:130
#22 0x00002ad34ff9bf90 in WebCore::EventTarget::fireEventListeners (this=0xd65a860, event=0x120f8bf0, d=0xd65a950, entry=WTF::Vector of length 1, capacity 1 = {...}) at ../../Source/WebCore/dom/EventTarget.cpp:256
#23 0x00002ad34ff9bc1b in WebCore::EventTarget::fireEventListeners (this=0xd65a860, event=0x120f8bf0) at ../../Source/WebCore/dom/EventTarget.cpp:203
#24 0x00002ad3504e31ae in WebCore::DOMWindow::dispatchEvent (this=0xd65a860, prpEvent=..., prpTarget=...) at ../../Source/WebCore/page/DOMWindow.cpp:1695
#25 0x00002ad3504e2f34 in WebCore::DOMWindow::dispatchLoadEvent (this=0xd65a860) at ../../Source/WebCore/page/DOMWindow.cpp:1669
#26 0x00002ad34ff0c487 in WebCore::Document::dispatchWindowLoadEvent (this=0x131d4190) at ../../Source/WebCore/dom/Document.cpp:3642
#27 0x00002ad34ff078d1 in WebCore::Document::implicitClose (this=0x131d4190) at ../../Source/WebCore/dom/Document.cpp:2399
#28 0x00002ad3504320cb in WebCore::FrameLoader::checkCallImplicitClose (this=0x20a0480) at ../../Source/WebCore/loader/FrameLoader.cpp:835
#29 0x00002ad350431e49 in WebCore::FrameLoader::checkCompleted (this=0x20a0480) at ../../Source/WebCore/loader/FrameLoader.cpp:778
#30 0x00002ad350431b9d in WebCore::FrameLoader::finishedParsing (this=0x20a0480) at ../../Source/WebCore/loader/FrameLoader.cpp:711
#31 0x00002ad34ff0f021 in WebCore::Document::finishedParsing (this=0x131d4190) at ../../Source/WebCore/dom/Document.cpp:4401
#32 0x00002ad3502075cf in WebCore::HTMLConstructionSite::finishedParsing (this=0x132542a0) at ../../Source/WebCore/html/parser/HTMLConstructionSite.cpp:337
#33 0x00002ad35023c822 in WebCore::HTMLTreeBuilder::finished (this=0x13254280) at ../../Source/WebCore/html/parser/HTMLTreeBuilder.cpp:2882
#34 0x00002ad35020e622 in WebCore::HTMLDocumentParser::end (this=0x1326e090) at ../../Source/WebCore/html/parser/HTMLDocumentParser.cpp:550
#35 0x00002ad35020e729 in WebCore::HTMLDocumentParser::attemptToRunDeferredScriptsAndEnd (this=0x1326e090) at ../../Source/WebCore/html/parser/HTMLDocumentParser.cpp:559
#36 0x00002ad35020d605 in WebCore::HTMLDocumentParser::prepareToStopParsing (this=0x1326e090) at ../../Source/WebCore/html/parser/HTMLDocumentParser.cpp:182
#37 0x00002ad35020e76e in WebCore::HTMLDocumentParser::attemptToEnd (this=0x1326e090) at ../../Source/WebCore/html/parser/HTMLDocumentParser.cpp:571
#38 0x00002ad35020e827 in WebCore::HTMLDocumentParser::finish (this=0x1326e090) at ../../Source/WebCore/html/parser/HTMLDocumentParser.cpp:609
#39 0x00002ad35042a265 in WebCore::DocumentWriter::end (this=0x1328a538) at ../../Source/WebCore/loader/DocumentWriter.cpp:244
#40 0x00002ad3504190d0 in WebCore::DocumentLoader::finishedLoading (this=0x1328a490) at ../../Source/WebCore/loader/DocumentLoader.cpp:295
#41 0x00002ad35046d61a in WebCore::MainResourceLoader::didFinishLoading (this=0x13290fb0, finishTime=0) at ../../Source/WebCore/loader/MainResourceLoader.cpp:543
#42 0x00002ad35046d795 in WebCore::MainResourceLoader::notifyFinished (this=0x13290fb0, resource=0x12fab4f0) at ../../Source/WebCore/loader/MainResourceLoader.cpp:553
#43 0x00002ad3503f54b0 in WebCore::CachedResource::checkNotify (this=0x12fab4f0) at ../../Source/WebCore/loader/cache/CachedResource.cpp:336
#44 0x00002ad3503f550a in WebCore::CachedResource::data (this=0x12fab4f0, allDataReceived=true) at ../../Source/WebCore/loader/cache/CachedResource.cpp:345
#45 0x00002ad3503f2b58 in WebCore::CachedRawResource::data (this=0x12fab4f0, data=..., allDataReceived=true) at ../../Source/WebCore/loader/cache/CachedRawResource.cpp:72
#46 0x00002ad350484f66 in WebCore::SubresourceLoader::didFinishLoading (this=0x130eb1f0, finishTime=0) at ../../Source/WebCore/loader/SubresourceLoader.cpp:278
#47 0x00002ad35047a869 in WebCore::ResourceLoader::didFinishLoading (this=0x130eb1f0, finishTime=0) at ../../Source/WebCore/loader/ResourceLoader.cpp:457
#48 0x00002ad350e909ab in WebCore::readCallback (asyncResult=0xd882590, data=0x1316bd60) at ../../Source/WebCore/platform/network/soup/ResourceHandleSoup.cpp:1367
#49 0x00002ad354ac8e5f in async_ready_callback_wrapper () from /home/slave/webkitgtk/gtk-linux-64-debug/build/WebKitBuild/Dependencies/Root/lib64/libgio-2.0.so.0
#50 0x00002ad354ae37ea in g_simple_async_result_complete () from /home/slave/webkitgtk/gtk-linux-64-debug/build/WebKitBuild/Dependencies/Root/lib64/libgio-2.0.so.0
#51 0x00002ad354ae39b2 in complete_in_idle_cb_for_thread () from /home/slave/webkitgtk/gtk-linux-64-debug/build/WebKitBuild/Dependencies/Root/lib64/libgio-2.0.so.0
#52 0x00002ad354caafd1 in g_idle_dispatch () from /home/slave/webkitgtk/gtk-linux-64-debug/build/WebKitBuild/Dependencies/Root/lib64/libglib-2.0.so.0
#53 0x00002ad354ca8903 in g_main_dispatch () from /home/slave/webkitgtk/gtk-linux-64-debug/build/WebKitBuild/Dependencies/Root/lib64/libglib-2.0.so.0
#54 0x00002ad354ca94b3 in g_main_context_dispatch () from /home/slave/webkitgtk/gtk-linux-64-debug/build/WebKitBuild/Dependencies/Root/lib64/libglib-2.0.so.0
#55 0x00002ad354ca96a3 in g_main_context_iterate () from /home/slave/webkitgtk/gtk-linux-64-debug/build/WebKitBuild/Dependencies/Root/lib64/libglib-2.0.so.0
#56 0x00002ad354ca9ad3 in g_main_loop_run () from /home/slave/webkitgtk/gtk-linux-64-debug/build/WebKitBuild/Dependencies/Root/lib64/libglib-2.0.so.0
#57 0x00002ad353e9be22 in gtk_main () from /home/slave/webkitgtk/gtk-linux-64-debug/build/WebKitBuild/Dependencies/Root/lib64/libgtk-3.so.0
#58 0x000000000049b862 in runTest (inputLine=...) at ../../Tools/DumpRenderTree/gtk/DumpRenderTree.cpp:770
#59 0x000000000049af18 in runTestingServerLoop () at ../../Tools/DumpRenderTree/gtk/DumpRenderTree.cpp:553
#60 0x000000000049e246 in main (argc=2, argv=0x7fff71189fa8) at ../../Tools/DumpRenderTree/gtk/DumpRenderTree.cpp:1512

[Joanmarie Diggs]

This appears to be the same intermittent crash as fast/css-generated-content/block-and-box-hit-testing.html.

(both of which I have yet to make crash, but I'm still trying)

[Joanmarie Diggs]

Seems the winner is the addition of assertions as part of the fix for bug 104462.

In terms of real-world use cases and AT users, so far I've only been able to reproduce this issue if I click with the mouse on an empty area in a render block. Going with the unignored parent's node seems like a reasonable thing to do  (and pass along to ATs) under these circumstances.

[Joanmarie Diggs]

Created attachment 185881 [details]
Patch

[WebKit Review Bot]

Comment on attachment 185881 [details]
Patch

Clearing flags on attachment: 185881

Committed r141503: <http://trac.webkit.org/changeset/141503>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.