# CVE-2023-54246: rcuscale: Move rcu_scale_writer() schedule_timeout_uninterruptible() to _idle()

> A local attacker with high privileges can trigger a hung task warning and potential system instability by setting a specific kernel module parameter.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-54246, DEBIAN-CVE-2023-54246, GHSA-qqm3-hrh7-jh6j, UBUNTU-CVE-2023-54246

## What is CVE-2023-54246?

CVE-2023-54246 is a denial of service vulnerability in Linux, published on 30 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

rcuscale: Move rcu_scale_writer() schedule_timeout_uninterruptible() to _idle()

The rcuscale.holdoff module parameter can be used to delay the start
of rcu_scale_writer() kthread.  However, the hung-task timeout will
trigger when the timeout specified by rcuscale.holdoff is greater than
hung_task_timeout_secs:

runqemu kvm nographic slirp qemuparams="-smp 4 -m 2048M"
bootparams="rcuscale.shutdown=0 rcuscale.holdoff=300"

[  247.071753] INFO: task rcu_scale_write:59 blocked for more than 122 seconds.
[  247.072529]       Not tainted 6.4.0-rc1-00134-gb9ed6de8d4ff #7
[  247.073400] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  247.074331] task:rcu_scale_write state:D stack:30144 pid:59    ppid:2      flags:0x00004000
[  247.075346] Call Trace:
[  247.075660]  <TASK>
[  247.075965]  __schedule+0x635/0x1280
[  247.076448]  ? __pfx___schedule+0x10/0x10
[  247.076967]  ? schedule_timeout+0x2dc/0x4d0
[  247.077471]  ? __pfx_lock_release+0x10/0x10
[  247.078018]  ? enqueue_timer+0xe2/0x220
[  247.078522]  schedule+0x84/0x120
[  247.078957]  schedule_timeout+0x2e1/0x4d0
[  247.079447]  ? __pfx_schedule_timeout+0x10/0x10
[  247.080032]  ? __pfx_rcu_scale_writer+0x10/0x10
[  247.080591]  ? __pfx_process_timeout+0x10/0x10
[  247.081163]  ? __pfx_sched_set_fifo_low+0x10/0x10
[  247.081760]  ? __pfx_rcu_scale_writer+0x10/0x10
[  247.082287]  rcu_scale_writer+0x6b1/0x7f0
[  247.082773]  ? mark_held_locks+0x29/0xa0
[  247.083252]  ? __pfx_rcu_scale_writer+0x10/0x10
[  247.083865]  ? __pfx_rcu_scale_writer+0x10/0x10
[  247.084412]  kthread+0x179/0x1c0
[  247.084759]  ? __pfx_kthread+0x10/0x10
[  247.085098]  ret_from_fork+0x2c/0x50
[  247.085433]  </TASK>

This commit therefore replaces schedule_timeout_uninterruptible() with
schedule_timeout_idle().

## Which versions are affected by CVE-2023-54246?


## How do I fix CVE-2023-54246?

Apply the vendor's patch.

## Is CVE-2023-54246 being exploited?

There is no known exploitation of CVE-2023-54246 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-54246 and fix it if it is affected.

What it is: CVE-2023-54246 is a denial of service vulnerability in Linux, published on 30 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-54246 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-54246/ (Markdown: https://insights.sbomify.com/CVE-2023-54246/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-54246
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-54246
- OSV: https://osv.dev/vulnerability/CVE-2023-54246

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-54246/
Summaries are generated and may contain mistakes; the official description above is the record.