874592 - nsFrameMessageManager::NewProcessMessageManager constructs child process managers with no parent

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Jim Blandy :jimb]

An nsFrameMessageManager representing a child process (MM_CHROME | MM_PROCESSMANAGER) ought to have the process message manager (@mozilla.org/parentprocessmessagemanager;1) as its parent, but nsFrameMessageManager::NewProcessMessageManager sometimes constructs them with a null parent, so that messages from children don't propagate up to the parent.

To reproduce, add an assertion like this to nsFrameMessageManager::NewProcessMessageManager:

   nsFrameMessageManager* mm;
   if (aProcess) {
+    NS_ABORT_IF_FALSE(nsFrameMessageManager::sParentProcessManager,
+                      "parent process manager not created");
     mm = new nsFrameMessageManager(aProcess,
                                    nsFrameMessageManager::sParentProcessManager,

and then run: ./mach xpcshell-test netwerk/test/unit_ipc

The problem is that nsFrameMessageManager::NewProcessMessageManager tries to ensure that sParentProcessManager has been created, but doesn't actually store a pointer it anywhere that holds a reference to it long enough to keep it alive when we create the message manager for the particular child. nsFrameMessageManager::~nsFrameMessageManager recognizes that it's destroying the root, and clears sParentProcessManager, leaving it null by the time NewProcessMessageManager calls 'new nsFrameMessageManager'.

Comment 1

[Olli Pettay [:smaug][[e-mail]]]

Make if (!nsFrameMessageManager::sParentProcessManager) { to create
parent process mm using GetInterface?

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

Attachment: untested

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

Attachment: patch

Comment 4

[Jim Blandy :jimb]

Wow, fast work!

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

https://tbpl.mozilla.org/?tree=Try&rev=795837519810

Comment 6

[Olli Pettay [:smaug][[e-mail]]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/4a15bb4360f9

Comment 7

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/4a15bb4360f9