<!--
IMPORTANT:
- for detailed contributing guidelines, read:
https://github.com/kamailio/kamailio/blob/master/.github/CONTRIBUTING.md
- pull requests must be done to master branch, unless they are backports
of fixes from master branch to a stable branch
- backports to stable branches must be done with 'git cherry-pick -x ...'
- code is contributed under BSD for core and main components (tm, sl, auth,
tls)
- code is contributed GPLv2 or a compatible license for the other components
- GPL code is contributed with OpenSSL licensing exception
-->
#### Pre-Submission Checklist
<!-- Go over all points below, and after creating the PR, tick all the
checkboxes that apply -->
<!-- All points should be verified, otherwise, read the CONTRIBUTING guidelines
from above-->
<!-- If you're unsure about any of these, don't hesitate to ask on sr-dev
mailing list -->
- [X] Commit message has the format required by CONTRIBUTING guide
- [X] Commits are split per component (core, individual modules, libs, utils,
...)
- [X] Each component has a single commit (if not, squash them into one commit)
- [ ] LLM/AI Coding Assistants were involved in creating the C code or other
included content
- [X] Code is formatted with `clang-format` using the config file
`.clang-format`
from source code folder
- [X] 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
- [X] 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:
<!-- Go over all points below, and after creating the PR, tick the checkboxes
that apply -->
- [ ] PR should be backported to stable branches
- [X] Tested changes locally
- [X] Related to issue #4807
#### Description
<!-- Describe your changes in detail -->
While read access to the global table is (somewhat) protected from concurrent
writes via double-buffering, the only thing that protects writes from other
concurrent writes ("add" and "remove" in particular) is rate limiting them via
`reload_delta`, which is fragile at best.
Races from concurrent writes would not lead to a crash, but can lead to lost
data due the existing copy/update/swap approach. Use a mutex to serialize
updates. (Doing updates/modifications directly on the global table in-place
without a full copy would be better, but would require much more work.)
The lock is not needed for read access. Concurrent read access is still a bit
racy, as readers could still end up using invalid/freed data when two or more
reloads happen in very short succession. A subsequent second commit will
address this.
You can view, comment on, or merge this pull request online at:
https://github.com/kamailio/kamailio/pull/4821
-- Commit Summary --
* dispatcher: serialize writes to global table
-- File Changes --
M src/modules/dispatcher/dispatch.c (46)
-- Patch Links --
https://github.com/kamailio/kamailio/pull/4821.patch
https://github.com/kamailio/kamailio/pull/4821.diff
--
Reply to this email directly or view it on GitHub:
https://github.com/kamailio/kamailio/pull/4821
You are receiving this because you are subscribed to this thread.
Message ID: <kamailio/kamailio/pull/[email protected]>
_______________________________________________
Kamailio - Development Mailing List -- [email protected]
To unsubscribe send an email to [email protected]
Important: keep the mailing list in the recipients, do not reply only to the
sender!
