Bug 197576 – Use WeakPtr for JSLazyEventListener::m_originalNode for safety

• Component: WebCore Misc.
• Status: RESOLVED FIXED

[Chris Dumez]

Use WeakPtr for JSLazyEventListener::m_originalNode for safety.

[Chris Dumez]

<rdar://problem/24314027>

[Chris Dumez]

Created attachment 368981 [details]
Patch

[Chris Dumez]

Comment on attachment 368981 [details]
Patch

Clearing flags on attachment: 368981

Committed r244926: <https://trac.webkit.org/changeset/244926>

[Chris Dumez]

All reviewed patches have been landed.  Closing bug.

[Alexey Proskuryakov]

Comment on attachment 368981 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=368981&action=review

> Source/WebCore/ChangeLog:3
> +        Use WeakPtr for JSLazyEventListener::m_originalNode for safety

Is this the correct behavior though? Seems like the node needs to be kept alive, and reference cycle needs to be broken in some other way. 

I think that it warrants a FIXME and assertion at least.

[Chris Dumez]

(In reply to Alexey Proskuryakov from comment #5)
> Comment on attachment 368981 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=368981&action=review
> 
> > Source/WebCore/ChangeLog:3
> > +        Use WeakPtr for JSLazyEventListener::m_originalNode for safety
> 
> Is this the correct behavior though? Seems like the node needs to be kept
> alive, and reference cycle needs to be broken in some other way. 

No, I do not think we want to keep the original node alive. When we crash (rdar://problem/24314027), the lazy event listener is for a Window object. Lazy event listener for a Window are supposed to have a m_originalNode that is nullptr. So either a lazy event listener was somehow transferred from an element/document to a Window or something else is going on.

> 
> I think that it warrants a FIXME and assertion at least.

I am planning on adding assertions to help find the underlying cause of <rdar://problem/24314027>. I'll add the FIXME with the assertions.