577740 - Crash [@ mozilla::ipc::RPCChannel::CxxStackFrame::CxxStackFrame]

Status: RESOLVED WORKSFORME

(Core :: IPC, defect)

Description

[Mark Finkle (:mfinkle) (use needinfo?)]

We see a lot of crashes in Fennec running on Maemo. See:

http://crash-stats.mozilla.com/report/list?range_value=2&range_unit=weeks&signature=mozilla%3A%3Aipc%3A%3ARPCChannel%3A%3ACxxStackFrame%3A%3ACxxStackFrame&version=Fennec%3A2.0a1pre

Comment 1

[Josh Matthews [:jdm]]

Oooh, this is a fun one.  Looks like something is invoking some JS on another thread which ends up calling nsIOService::SetOffline which invokes the various observers, so the ContentProcessParent tries to do IPDL stuff on the wrong thread.  We could either just do a thread check in ContentProcessParent and potentially dispatch a runnable, or we could make the observer object an proxy.  Decisions, decisions...

Comment 2

[Josh Matthews [:jdm]]

Attachment: Tentative patch

I don't believe I have any way of reproducing this crash, seeing as I don't have the hardware required.  If somebody could confirm/deny whether this patch does anything, I'd be mighty appreciative.

Comment 3

[Josh Matthews [:jdm]]

Attachment: Tentative patch

Now with actual patch attached.

Comment 4

[Josh Matthews [:jdm]]

Actually, looking at the crash stacks some more, I might be totally off base about my earlier guess.  If there's some way that somebody getting these crashes could reproduce them under GDB, I would be very interested in the results of
> fr 3
> p *this

Comment 5

[Josh Matthews [:jdm]]

Seeing as there have been no crashes with this stack since July 20th, I'm hopeful that this has gone away as a side-effect of some other landing.

Comment 6

[Doug Turner (:dougt)]

if NS_IPC_IOSERVICE_SET_OFFLINE_TOPIC is being dispatch on the wrong thread, that would be bad. :(

Either way, I don't think it is a bad thing to dispatch another event that actually does the call to SendSetOffline.

Comment 7

[Josh Matthews [:jdm]]

Haven't seen any of these crashes for a very long while; I'm going to mark this WFM.