For example fast/multicol/pagination-v-vertical-lr.html is crashing on the bot. Skipping it makes another one crash. I tested a debug build locally and then others failed with assert.
Backtrace of assertion hit. Created by manually running tests (WebKitTestRunner LayoutTests/fast/multicol/pagination-*.html) and digging in the core dump. The assertion happened when rendering pagination-v-horizontal-bt.html. Program terminated with signal 11, Segmentation fault. #0 0x00007f7c06458675 in WebCore::RenderLayerCompositor::computeCompositingRequirements (this=0x8495a0, layer=0x86e518, overlapMap=0x7fffc43354d0, compositingState=..., layersChanged=@0x7fffc433555f) at /home/balazs/master_clean/Source/WebCore/rendering/RenderLayerCompositor.cpp:758 758 ASSERT(willBeComposited == needsToBeComposited(layer)); (gdb) bt 20 #0 0x00007f7c06458675 in WebCore::RenderLayerCompositor::computeCompositingRequirements (this=0x8495a0, layer=0x86e518, overlapMap=0x7fffc43354d0, compositingState=..., layersChanged=@0x7fffc433555f) at /home/balazs/master_clean/Source/WebCore/rendering/RenderLayerCompositor.cpp:758 #1 0x00007f7c064568dc in WebCore::RenderLayerCompositor::updateCompositingLayers (this=0x8495a0, updateType= WebCore::CompositingUpdateAfterLayoutOrStyleChange, updateRoot=0x86e518) at /home/balazs/master_clean/Source/WebCore/rendering/RenderLayerCompositor.cpp:306 #2 0x00007f7c0621ee61 in WebCore::FrameView::updateCompositingLayers (this=0x809260) at /home/balazs/master_clean/Source/WebCore/page/FrameView.cpp:662 #3 0x00007f7c0622070c in WebCore::FrameView::layout (this=0x809260, allowSubtree=true) at /home/balazs/master_clean/Source/WebCore/page/FrameView.cpp:1145 #4 0x00007f7c05daf188 in WebCore::Document::implicitClose (this=0x6e5730) at /home/balazs/master_clean/Source/WebCore/dom/Document.cpp:2261 #5 0x00007f7c0615e67d in WebCore::FrameLoader::checkCallImplicitClose (this=0x695930) at /home/balazs/master_clean/Source/WebCore/loader/FrameLoader.cpp:797 #6 0x00007f7c0615e431 in WebCore::FrameLoader::checkCompleted (this=0x695930) at /home/balazs/master_clean/Source/WebCore/loader/FrameLoader.cpp:745 #7 0x00007f7c0615e17d in WebCore::FrameLoader::finishedParsing (this=0x695930) at /home/balazs/master_clean/Source/WebCore/loader/FrameLoader.cpp:679 #8 0x00007f7c05db800c in WebCore::Document::finishedParsing (this=0x6e5730) at /home/balazs/master_clean/Source/WebCore/dom/Document.cpp:4296 #9 0x00007f7c060348cc in WebCore::HTMLTreeBuilder::finished (this=0x6bd6e0) at /home/balazs/master_clean/Source/WebCore/html/parser/HTMLTreeBuilder.cpp:2829 #10 0x00007f7c06008c60 in WebCore::HTMLDocumentParser::end (this=0x6c0460) at /home/balazs/master_clean/Source/WebCore/html/parser/HTMLDocumentParser.cpp:381 #11 0x00007f7c06008d5d in WebCore::HTMLDocumentParser::attemptToRunDeferredScriptsAndEnd (this=0x6c0460) at /home/balazs/master_clean/Source/WebCore/html/parser/HTMLDocumentParser.cpp:390 #12 0x00007f7c06007d34 in WebCore::HTMLDocumentParser::prepareToStopParsing (this=0x6c0460) at /home/balazs/master_clean/Source/WebCore/html/parser/HTMLDocumentParser.cpp:153 #13 0x00007f7c06008da2 in WebCore::HTMLDocumentParser::attemptToEnd (this=0x6c0460) at /home/balazs/master_clean/Source/WebCore/html/parser/HTMLDocumentParser.cpp:402 #14 0x00007f7c06008e5b in WebCore::HTMLDocumentParser::finish (this=0x6c0460) at /home/balazs/master_clean/Source/WebCore/html/parser/HTMLDocumentParser.cpp:429 #15 0x00007f7c061579dd in WebCore::DocumentWriter::endIfNotLoadingMainResource (this=0x6bdc80) at /home/balazs/master_clean/Source/WebCore/loader/DocumentWriter.cpp:233 #16 0x00007f7c061578f3 in WebCore::DocumentWriter::end (this=0x6bdc80) at /home/balazs/master_clean/Source/WebCore/loader/DocumentWriter.cpp:212 #17 0x00007f7c0614b729 in WebCore::DocumentLoader::finishedLoading (this=0x6bdb60) at /home/balazs/master_clean/Source/WebCore/loader/DocumentLoader.cpp:284 #18 0x00007f7c06165647 in WebCore::FrameLoader::finishedLoading (this=0x695930) at /home/balazs/master_clean/Source/WebCore/loader/FrameLoader.cpp:2074 #19 0x00007f7c061816f9 in WebCore::MainResourceLoader::didFinishLoading (this=0x6c28c0, finishTime=0)
Crash log in release (unfortunately I'm not sure which test it belongs to) #0 0x00007f2ee9fdc893 in WebCore::WebGraphicsLayer::~WebGraphicsLayer() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #1 0x00007f2ee9fdcb99 in WebCore::WebGraphicsLayer::~WebGraphicsLayer() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #2 0x00007f2eea74741a in WebCore::RenderLayerBacking::destroyGraphicsLayers() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #3 0x00007f2eea74b319 in WebCore::RenderLayerBacking::~RenderLayerBacking() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #4 0x00007f2eea74b4d9 in WebCore::RenderLayerBacking::~RenderLayerBacking() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #5 0x00007f2eea73e494 in WebCore::RenderLayer::~RenderLayer() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #6 0x00007f2eea73e5e9 in WebCore::RenderLayer::~RenderLayer() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #7 0x00007f2eea73572f in WebCore::RenderLayer::destroy(WebCore::RenderArena*) () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #8 0x00007f2eea6fcc2c in WebCore::RenderBoxModelObject::destroyLayer() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #9 0x00007f2eea6cdba5 in WebCore::RenderBlock::willBeDestroyed() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #10 0x00007f2eea766acd in WebCore::RenderObject::destroy() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #11 0x00007f2eea2413e4 in WebCore::Document::detach() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #12 0x00007f2eea37f5e7 in WebCore::CachedFrame::destroy() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #13 0x00007f2eea38045f in WebCore::CachedPage::destroy() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #14 0x00007f2eea3861fb in WebCore::PageCache::releaseAutoreleasedPagesNow() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #15 0x00007f2ee9e8e554 in QWebSettings::clearMemoryCaches() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libQtWebKit.so.4 #16 0x00007f2e99196730 in WTR::LayoutTestController::platformInitialize() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libWTRInjectedBundle.so #17 0x00007f2e991939ab in WTR::LayoutTestController::LayoutTestController() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libWTRInjectedBundle.so #18 0x00007f2e99193a06 in WTR::LayoutTestController::create() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libWTRInjectedBundle.so #19 0x00007f2e99189512 in WTR::InjectedBundle::beginTesting() () from /home/balazs/master_clean/WebKitBuild/Release/lib/libWTRInjectedBundle.so
One more info: the rev I debugged is 102775.
*** Bug 73436 has been marked as a duplicate of this bug. ***
I skipped all of them to make buildbot happier a little bit - http://trac.webkit.org/changeset/103335
After some more investigation it seems like the assert and the crash are not the same issue. Filed https://bugs.webkit.org/show_bug.cgi?id=74999 for the assert.
Let's deal with the crash and the assert separately. *** This bug has been marked as a duplicate of bug 75000 ***