Bug 66351 – Crash in Structure::visitChildren running iAd.js regression test suite under memory pressure

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Michael Saboff]

From <rdar://problem/9931094>

Received a crash running iAds tests.  The traceback is: 

0   JavaScriptCore                	0x34d76dee JSC::Structure::visitChildren(JSC::MarkStack&) + 450
1   JavaScriptCore                	0x34d7544c JSC::MarkStack::visitChildren(JSC::JSCell*) + 584
2   JavaScriptCore                	0x34d75104 JSC::MarkStack::drain() + 296
3   JavaScriptCore                	0x34d74aae JSC::Heap::markRoots() + 130
4   JavaScriptCore                	0x34d749d2 JSC::Heap::reset(JSC::Heap::SweepToggle) + 14
5   JavaScriptCore                	0x34d37602 JSC::Heap::reportExtraMemoryCostSlowCase(unsigned long) + 34
6   WebCore                       	0x3784df32 WebCore::HTMLCanvasElement::createImageBuffer() const + 402
7   WebCore                       	0x3784dd88 WebCore::HTMLCanvasElement::drawingContext() const + 12
8   WebCore                       	0x3784dc40 WebCore::CanvasRenderingContext2D::CanvasRenderingContext2D(WebCore::HTMLCanvasElement*, bool, bool) + 128
9   WebCore                       	0x3784db04 WebCore::HTMLCanvasElement::getContext(WTF::String const&, WebCore::CanvasContextAttributes*) + 76
10  WebCore                       	0x3784da24 WebCore::JSHTMLCanvasElement::getContext(JSC::ExecState*) + 1264
11  WebCore                       	0x3784d522 WebCore::jsHTMLCanvasElementPrototypeFunctionGetContext(JSC::ExecState*) + 90
12  ???                           	0x20f24278 0 + 552747640
13  JavaScriptCore                	0x34d73596 JSC::call(JSC::ExecState*, JSC::JSValue, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) + 46
14  JavaScriptCore                	0x34ddb0b6 JSC::PropertySlot::functionGetter(JSC::ExecState*) const + 130
15  JavaScriptCore                	0x34d38c7c JSC::JSValue::get(JSC::ExecState*, JSC::Identifier const&, JSC::PropertySlot&) const + 700
16  JavaScriptCore                	0x34d3cf5e JITStubThunked_op_get_by_id + 70
17  JavaScriptCore                	0x34d3cf0a cti_op_get_by_id + 2
18  JavaScriptCore                	0x34d73596 JSC::call(JSC::ExecState*, JSC::JSValue, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) + 46
19  JavaScriptCore                	0x34d0a702 JSC::JSObject::put(JSC::ExecState*, JSC::Identifier const&, JSC::JSValue, JSC::PutPropertySlot&) + 682
20  JavaScriptCore                	0x34d3dfd4 JITStubThunked_op_put_by_id + 108
21  JavaScriptCore                	0x34d3df5a cti_op_put_by_id + 2
22  JavaScriptCore                	0x34d73596 JSC::call(JSC::ExecState*, JSC::JSValue, JSC::CallType, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&) + 46
23  WebCore                       	0x377ae2e8 WebCore::JSEventListener::handleEvent(WebCore::ScriptExecutionContext*, WebCore::Event*) + 580
24  WebCore                       	0x377ae070 WebCore::EventTarget::fireEventListeners(WebCore::Event*, WebCore::EventTargetData*, WTF::Vector&) + 272
25  WebCore                       	0x376b5c14 WebCore::EventTarget::fireEventListeners(WebCore::Event*) + 136
26  WebCore                       	0x376bc18a WebCore::Node::handleLocalEvents(WebCore::Event*) + 54
27  WebCore                       	0x376bb9da WebCore::EventDispatcher::dispatchEvent(WTF::PassRefPtr) + 542
28  WebCore                       	0x376bb78c WebCore::EventDispatchMediator::dispatchEvent(WebCore::EventDispatcher*) const + 24
29  WebCore                       	0x376bb760 WebCore::EventDispatcher::dispatchEvent(WebCore::Node*, WebCore::EventDispatchMediator const&) + 92
30  WebCore                       	0x376bb6b8 WebCore::Node::dispatchEvent(WTF::PassRefPtr) + 28
31  WebCore                       	0x377fdcb6 WebCore::AnimationControllerPrivate::fireEventsAndUpdateStyle() + 162
32  WebCore                       	0x376a4240 WebCore::ThreadTimers::sharedTimerFiredInternal() + 92
33  WebCore                       	0x376a41b2 __ZN7WebCoreL10timerFiredEP16__CFRunLoopTimerPv + 58
34  CoreFoundation                	0x335fca60 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 8
35  CoreFoundation                	0x335fc6c6 __CFRunLoopDoTimer + 358
36  CoreFoundation                	0x335fb29c __CFRunLoopRun + 1200
37  CoreFoundation                	0x3357e4ee CFRunLoopRunSpecific + 294
38  CoreFoundation                	0x3357e3b6 CFRunLoopRunInMode + 98
39  WebCore                       	0x376f6f60 __ZL12RunWebThreadPv + 396
40  libsystem_c.dylib             	0x35d4b95e _pthread_start + 314
41  libsystem_c.dylib             	0x35d4e600 thread_start + 0

Getting the crash at the end of ContainerNode::insertBefore before it calls dispatchSubtreeModifiedEvent to notify all children of the change.  The node doesn't appear to be corrupt at the beginning of insertBefore processing.  This code does have a comment that nodes can be GC out from under it.  Trying to refine where the code in getting trashed….

I believe that the problem is in a JIT generated put by id that is generated in JIT::privateCompilePutByIdTransition().  I am instrumenting and branching to backup code to further debug.

It looks like, on ARM only, our JITStubCall mechanism tramples r0 before invoking optimized put_by_id for new properties

[Michael Saboff]

Created attachment 104128 [details]
Proposed patch

[WebKit Review Bot]

Attachment 104128 [details] did not pass style-queue:

Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'Source/JavaScriptCore/ChangeLog', u'Source..." exit_code: 1

Source/JavaScriptCore/jit/JITPropertyAccess32_64.cpp:473:  Should have only a single space after a punctuation in a comment.  [whitespace/comments] [5]
Total errors found: 1 in 2 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Gavin Barraclough]

Comment on attachment 104128 [details]
Proposed patch

Hey michael, looks great, should fix the style bot's issue.

[Michael Saboff]

Committed r93189: <http://trac.webkit.org/changeset/93189>

[Alexey Proskuryakov]

Can a regression test be made for this? Or are we running iAd.js as part of our regression tests already?