[Asterisk-code-review] res xmpp: Prevent deadlock on module unload (asterisk[13])

[Sean Bright]

Sean Bright has posted comments on this change. ( https://gerrit.asterisk.org/5361 )

Change subject: res_xmpp: Prevent deadlock on module unload
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Patch Set 1:

> > > It would be better to fix the global obj to release the obj ref
 > > > outside of the global rwlock in astobj2.c.  There are a couple
 > > > other global obj functions that may do the same thing.
 > >
 > > The only thing that ao2_global_obj_release() does is grab the
 > lock,
 > > deref the object, and unlock. Short of just removing the lock, I
 > > don't know how I would "fix" it.
 > 
 > I was thinking you would simply need to defer unreffing the object
 > until after the lock was released to fix this deadlock problem.

OK, so I grab the write lock, copy the holder->obj pointer, NULL out the holder->obj pointer, unlock and then deref the saved pointer.

What happens when the destructors call ao2_global_obj_ref()?

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Gerrit-MessageType: comment
Gerrit-Change-Id: Idf40ae136b5070dba22cb576ea8414fbc9939385
Gerrit-PatchSet: 1
Gerrit-Project: asterisk
Gerrit-Branch: 13
Gerrit-Owner: Sean Bright <sean.bright at gmail.com>
Gerrit-Reviewer: Anonymous Coward #1000019
Gerrit-Reviewer: Richard Mudgett <rmudgett at digium.com>
Gerrit-Reviewer: Sean Bright <sean.bright at gmail.com>
Gerrit-HasComments: No