184548 - XPCOM glue leaves behind exit routine after DLL is unloaded

Status: RESOLVED FIXED

(Core :: XPCOM, defect)

Description

[Adam Lock]

If nsMemory::Alloc is called from a DLL using XPCOM glue (e.g. the ActiveX
plugin DLL) it causes an XPCOM exit routine to be registered via
NS_RegisterXPCOMExitRoutine. In the case of the Activex plugin, the DLL is
unloaded when the page is torn down but it leaves the exit routine behind...
When mozilla.exe exits, NS_ShutdownXPCOM calls the dud exit routine and crashes.

The ActiveX plugin uses both nsString classes and nsMemory directly which can
trigger this behaviour. Controls which don't fire events with long names or call
IWebBrowser::Navigate might be escape this problem.

Comment 1

[Doug Turner (:dougt)]

unloading of xpcom components is not supported.  However, this is a pretty easy
fix you are asking for.

Comment 2

[Doug Turner (:dougt)]

Attachment: patch v.1

This should work as long as XPCOMGlueStartup is called prior to *any* usage of
nsMemory and XPCOMGlueShutdown is called prior to your library being unloaded.

Note that nsMemory is implictly called by our string implementations.  (you
could be using nsEmbedString if you are using glue).

Comment 3

[Doug Turner (:dougt)]

Attachment: patch v.1

more context.  the patch is ugly cause I am removing some ifdef DEBUG_dougt
stuff.

Comment 4

[Adam Lock]

Comment on attachment 108804 [details] [diff] [review]
patch v.1

r=adamlock Thanks Doug, this fixes the problem.

Comment 5

[Adam Lock]

Comment on attachment 108804 [details] [diff] [review]
patch v.1

applying for sr/a. I understand if its too late for 1.3a but if there's still a
chance...

Comment 6

[Darin Fisher]

Comment on attachment 108804 [details] [diff] [review]
patch v.1

sr=darin

looks fine to me.

Comment 7

[Asa Dotzler [:asa]]

Comment on attachment 108804 [details] [diff] [review]
patch v.1

a=asa for checkin to 1.3a

Comment 8

[Doug Turner (:dougt)]

Fixed checked into trunk.

Checking in nsMemory.cpp;
/cvsroot/mozilla/xpcom/glue/nsMemory.cpp,v  <--  nsMemory.cpp
new revision: 1.5; previous revision: 1.4
done
Checking in standalone/nsXPCOMGlue.cpp;
/cvsroot/mozilla/xpcom/glue/standalone/nsXPCOMGlue.cpp,v  <--  nsXPCOMGlue.cpp
new revision: 1.8; previous revision: 1.7
done