The Fix
pip install celery==5.2.0rc2
Based on closed celery/celery issue #6945 · PR/commit linked
Production note: This usually shows up under retries/timeouts. Treat it as a side-effect risk until you can verify behavior with a canary + real traffic.
@@ -97,6 +97,11 @@ longer version:
$ ps auxww | awk '/celery worker/ {print $2}' | xargs kill -9
+.. versionchanged:: 5.2
+ On Linux systems, Celery now supports sending :sig:`KILL` signal to all child processes
+ after worker termination. This is done via `PR_SET_PDEATHSIG` option of ``prctl(2)``.
Option A — Upgrade to fixed release\npip install celery==5.2.0rc2\nWhen NOT to use: Do not use if it changes public behavior or if the failure cannot be reproduced.\n\n
Why This Fix Works in Production
- Trigger: - [x] I have included all related issues and possible duplicate issues in this issue
- Mechanism: Documents that child processes are automatically killed after worker exits, addressing issue #6945.
- Why the fix works: Documents that child processes are automatically killed after worker exits, addressing issue #6945. (first fixed release: 5.2.0rc2).
- If left unfixed, the same config can fail only in production (env differences), causing startup failures or partial feature outages.
Why This Breaks in Prod
- Production symptom (often without a traceback): - [x] I have included all related issues and possible duplicate issues in this issue
Proof / Evidence
- GitHub issue: #6945
- Fix PR: https://github.com/celery/celery/pull/6946
- First fixed release: 5.2.0rc2
- Reproduced locally: No (not executed)
- Last verified: 2026-02-09
- Confidence: 0.95
- Did this fix it?: Yes (upstream fix exists)
- Own content ratio: 0.63
Discussion
High-signal excerpts from the issue thread (symptoms, repros, edge-cases).
“Hey @matusvalo :wave:, Thank you for opening an issue”
“i should have suggest the document change in the PR which i forgot!”
“Yeah I will try to update the docs ASAP. It's not big deal just few sentences needs to be added/updated. I have added this bug…”
Failure Signature (Search String)
- - [x] I have included all related issues and possible duplicate issues in this issue
- i should have suggest the document change in the PR which i forgot!
Copy-friendly signature
Failure Signature
-----------------
- [x] I have included all related issues and possible duplicate issues in this issue
i should have suggest the document change in the PR which i forgot!
Error Message
Signature-only (no traceback captured)
Error Message
-------------
- [x] I have included all related issues and possible duplicate issues in this issue
i should have suggest the document change in the PR which i forgot!
What Broke
Workers did not kill child processes upon termination, leading to resource leaks.
Fix Options (Details)
Option A — Upgrade to fixed release Safe default (recommended)
pip install celery==5.2.0rc2
Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.
Fix reference: https://github.com/celery/celery/pull/6946
First fixed release: 5.2.0rc2
Last verified: 2026-02-09. Validate in your environment.
When NOT to Use This Fix
- Do not use if it changes public behavior or if the failure cannot be reproduced.
Did This Fix Work in Your Case?
Quick signal helps us prioritize which fixes to verify and improve.
Prevention
- Capture the exact failing error string in logs and tests so you can reproduce via a minimal script.
- Pin production dependencies and upgrade only with a reproducible test that hits the failing path.
Version Compatibility Table
| Version | Status |
|---|---|
| 5.2.0rc2 | Fixed |
Related Issues
No related fixes found.
Sources
We don’t republish the full GitHub discussion text. Use the links above for context.