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

Pre-Submission Checklist

Commit message has the format required by CONTRIBUTING guide
Commits are split per component (core, individual modules, libs, utils, ...)
Each component has a single commit (if not, squash them into one commit)
No commits to README files for modules (changes must be done to docbook files
in doc/ subfolder, the README file is autogenerated)

Type Of Change

Small bug fix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds new functionality)
Breaking change (fix or feature that would change existing functionality)

Checklist:

PR should be backported to stable branches
Tested changes locally
Related to issue #3641

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

0f6aecd cdp: Avoid deadlock for callback on diameter timeout

File Changes

(1 file)

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

Patch Links:

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