Callback function might do an operation which creates a new transaction, which will result in a deadlock.

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#### Description Problem in detail described in ticket.

Summary is that the lock used to iterate expired transactions is also needed when creating a new transaction. If the callback function (directly or indirectly) do something that creates a new transaction, it will result in a deadlock.

In my case, this was the ims_charging module where a start charging request times out. The callback does t_continue() where the routing logic then rejects the call. This will create a stop request to the charging server, and it will block.

You can view, comment on, or merge this pull request online at:

https://github.com/kamailio/kamailio/pull/3643

-- Commit Summary --

* cdp: Avoid deadlock for callback on diameter timeout

-- File Changes --

M src/modules/cdp/transaction.c (35)

-- Patch Links --

https://github.com/kamailio/kamailio/pull/3643.patch https://github.com/kamailio/kamailio/pull/3643.diff