This seems wrong. invalidateWhitespaceOnlyTextSiblingsAfterAttachIfNeeded() does a textSibling.setNeedsStyleRecalc(); in the middle of style recalc, which schedules the style recalc timer, even through we're in the middle of style recalc. Seen with fast/backgrounds/size/contain-and-cover-zoomed.html * frame #1: 0x0000000104d02e3a WebCore`WebCore::Document::scheduleStyleRecalc(this=0x0000000116043580) + 218 at Document.cpp:1693 frame #2: 0x0000000105d1e49d WebCore`WebCore::Node::updateAncestorsForStyleRecalc(this=0x0000000117ff2fa0) + 349 at Node.cpp:671 frame #3: 0x0000000105d16aaa WebCore`WebCore::Node::setNeedsStyleRecalc(this=0x0000000117ff2fa0, changeType=FullStyleChange) + 170 at Node.cpp:685 frame #4: 0x00000001064b87cd WebCore`WebCore::Style::invalidateWhitespaceOnlyTextSiblingsAfterAttachIfNeeded(current=0x0000000117fb0130) + 253 at StyleResolveTree.cpp:371 frame #5: 0x00000001064b678c WebCore`WebCore::Style::resolveLocal(current=0x0000000117fb0130, inheritedStyle=0x0000000117f5b000, renderTreePosition=0x00007fff5fbfe168, inheritedChange=Force) + 396 at StyleResolveTree.cpp:757 frame #6: 0x00000001064b428d WebCore`WebCore::Style::resolveTree(current=0x0000000117fb0130, inheritedStyle=0x0000000117f5b000, renderTreePosition=0x00007fff5fbfe168, change=Force) + 301 at StyleResolveTree.cpp:918 frame #7: 0x00000001064b44eb WebCore`WebCore::Style::resolveTree(current=0x0000000117ff04e0, inheritedStyle=0x0000000117f64f00, renderTreePosition=0x00007fff5fbfe1f8, change=Force) + 907 at StyleResolveTree.cpp:955 frame #8: 0x00000001064b44eb WebCore`WebCore::Style::resolveTree(current=0x0000000117ff0410, inheritedStyle=0x0000000117f64e40, renderTreePosition=0x00007fff5fbfe280, change=Force) + 907 at StyleResolveTree.cpp:955 frame #9: 0x00000001064b415a WebCore`WebCore::Style::resolveTree(document=0x0000000116043580, change=Force) + 410 at StyleResolveTree.cpp:994 frame #10: 0x0000000104d0323d WebCore`WebCore::Document::recalcStyle(this=0x0000000116043580, change=Force) + 637 at Document.cpp:1781 frame #11: 0x0000000105052f5f WebCore`WebCore::Frame::setPageAndTextZoomFactors(this=0x00000001177f2000, pageZoomFactor=1, textZoomFactor=0.578703642) + 543 at Frame.cpp:981
Also seen with fast/css3-text/css3-text-decoration/text-decoration-scaled.html