13724 - AutoProxification causes deadlock

Status: RESOLVED FIXED

(Core :: XPCOM, defect, P3)

Description

[Doug Turner (:dougt)]

Here's my current example (simplified for brevity):

interface nsIImapMessageSink : nsISupports
{
       void SetupMsgWriteStream(in nsIFileSpec aFileSpec, in boolean
appendDummyEnvelope);
}

Now from thread A which happens to be an imap connection thread, I call
setupMsgWriteStream

                nsCOMPtr<nsIFileSpec> fileSpec;
                PRBool addDummyEnvelope = PR_TRUE;
                rv = msgurl->GetMessageFile(getter_AddRefs(fileSpec));
                if (NS_FAILED(rv)) return rv;
               m_imapMessageSink->SetupMsgWriteStream(fileSpec,
addDummyEnvelope);

Now, thread A is blocked until the message sink call to setupMsgWriteStream is
proxied and completed on thread B (which
is the UI thread). Thread B makes a call like the following:

SetupMsgWriteStream(nsIFileSpec * aFileSpec, PRBool addDummyEnvelope)
{
   *blah*
    aFileSpec->GetFileSpec(&fileSpec);
  *blah*
}

The call to GetFileSpec turns into a auto-proxy call back to thread A. But
events aren't getting pumped on thread A because
it is blocked waiting for B to return. Hence the dead lock.

Comment 1

[Doug Turner (:dougt)]

I have disabled this.  Re-address after beta

Comment 2

[Doug Turner (:dougt)]

I have a nested event loop know which prevents deadlock.  All I have to do is
remove the #ifdef's which I previously added.  I am going to mark this as
fixed, but leave the #ifdefs in until I fix 16773 and coclasses are invented.