Bobby Holley (:bholley) Assignee
	Description • 11 years ago

Currently, we explicitly cut the edge from nsInProcessTabChildGlobal (inheriting from nsFrameScriptExecutor) during DelayedDisconnect(). This is problematic for AutoEntryScript, because it means that a strong stack reference to an nsIGlobalObject doesn't keep the JS global alive. So GetGlobalJSObject() can return non-null in AutoEntryScript(), but null in ~AutoEntryScript(), causing us to crash.

I talked about it with smaug, and we think that we can probably just move this work to Unlink. I'm going to try that.

	Bobby Holley (:bholley) Assignee
	Comment 1 • 11 years ago

https://tbpl.mozilla.org/?tree=Try&rev=9834a0a30188

	Bobby Holley (:bholley) Assignee
	Comment 2 • 11 years ago

This is already cycle-collected, so no extra work needs to happen.

	Bobby Holley (:bholley) Assignee
	Comment 3 • 11 years ago

AFAICT, nobody ever calls PreserveWrapper. Presumably, the CC machinery should
take care of us here.

	Olli Pettay [:smaug][bugs@pettay.fi]
	Comment 5 • 11 years ago

So you're still ok GetGlobalJSObject() returning null in some cases, just no change to the
return value between AutoEntryScript ctor and dtor?

	Olli Pettay [:smaug][bugs@pettay.fi]
	Comment 6 • 11 years ago

Comment on attachment 8409108 [details] [diff] [review]
Part 2 - Stop calling ReleaseWrapper in DelayedDisconnect(). v1

This patch as such wouldn't get r+, but with the next one this is ok.

	Bobby Holley (:bholley) Assignee
	Comment 7 • 11 years ago

(In reply to Olli Pettay [:smaug] from comment #5)
> So you're still ok GetGlobalJSObject() returning null in some cases, just no
> change to the
> return value between AutoEntryScript ctor and dtor?

I think so. My sense is that, if we've been unlinked, we're not likely to be holding onto a script or function living in it. We'll notice the crashes if we do.

remote:   https://hg.mozilla.org/integration/mozilla-inbound/rev/e5b5eed30c6e
remote:   https://hg.mozilla.org/integration/mozilla-inbound/rev/d8c4225f799f
remote:   https://hg.mozilla.org/integration/mozilla-inbound/rev/1af6111edd49

	Phil Ringnalda (:philor)
	Comment 8 • 11 years ago

https://hg.mozilla.org/mozilla-central/rev/e5b5eed30c6e
https://hg.mozilla.org/mozilla-central/rev/d8c4225f799f
https://hg.mozilla.org/mozilla-central/rev/1af6111edd49