60303 - xpconnect must bracket calls to natives with JS_{Suspend,Resume}Request

Status: VERIFIED FIXED

(Core :: XPConnect, defect, P3)

Description

[John Bandhauer]

see: "Additional Comments From [e-mail]  2000-11-15 23:04" in bug 54743

XPConnect risks JS deadlock by calling from JS into potentially blocking native
code without suspending the Request.

I'll attach a proposed fix.

Comment 1

[John Bandhauer]

Attachment: proposed fix

Comment 2

[John Bandhauer]

Oops... fixed the comment:

<    // JS Requests. Calling JS_SuspendRequest with a non-zero requestDepth
>    // JS Requests. Calling JS_SuspendRequest with a zero requestDepth

Comment 3

[Brendan Eich [:brendan]]

sr=[e-mail]; mccabe, can you r=?  I'm optimizing an sr before an r
cuz the patch is straightforward.

jband, do you think JS_SuspendRequest should defend against being called not in
a request?

/be

Comment 4

[John Bandhauer]

It could help find api usage errors if JS_EndRequest asserted cx->requestDepth
!= 0 before decrementing it. I don't think non-debug checks are good here - if
the calls aren't balanced then no help form the api will really help. 

Comment 5

[Brendan Eich [:brendan]]

Ok, I'll add that JS_EndRequest assertion to my patch in bug 54743.

/be

Comment 6

[Mike McCabe]

r=mccabe.

One place has a comment to the effect that the DOM breaks the rules.  Does it
make sense to fix this?  (Would it be costly?)

Comment 7

[John Bandhauer]

fixes checked in.

The DOM will stop breaking the request rules when it is converted to use xpconnect! 

Comment 8

[Phil Schwartau]

Marking Verified -