# CVE-2026-80611: ACPI: processor_idle: Mark LPI enter functions as __cpuidle

> Enabling function tracing or Kprobes on Linux kernels can trigger RCU warnings during idle entry, potentially causing system instability or denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-98063, BELL-CVE-2026-80611, DEBIAN-CVE-2026-80611, GHSA-vvhc-p9vw-ph6p, UBUNTU-CVE-2026-80611

## What is CVE-2026-80611?

CVE-2026-80611 is a denial of service vulnerability in Linux, published on 28 Aug 2026. 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:

ACPI: processor_idle: Mark LPI enter functions as __cpuidle

When function tracing or Kprobes is enabled, entering an ACPI Low
Power Idle (LPI) state triggers the following RCU splat:

  RCU not on for: acpi_idle_lpi_enter+0x4/0xd8
  WARNING: CPU: 8 PID: 0 at include/linux/trace_recursion.h:162 function_trace_call+0x1e8/0x228

The acpi_idle_lpi_enter() function is invoked within the cpuidle
path after RCU has already been disabled for the current local CPU.
Consequently, ftrace's function_trace_call() expects RCU to be
actively watching before recording trace data, emitting a warning
if it is not.

Fix this by annotating acpi_idle_lpi_enter(), the generic __weak
stub, and the RISC-V implementation of acpi_processor_ffh_lpi_enter()
with __cpuidle. This moves these functions into the '.cpuidle.text'
section, implicitly disabling ftrace instrumentation (notrace) along
this sensitive path and preventing trace-induced RCU warnings during
idle entry.

## Which versions are affected by CVE-2026-80611?


## How do I fix CVE-2026-80611?

Apply the vendor's patch.

## Is CVE-2026-80611 being exploited?

There is no known exploitation of CVE-2026-80611 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80611 and fix it if it is affected.

What it is: CVE-2026-80611 is a denial of service vulnerability in Linux, published on 28 Aug 2026. 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-2026-80611 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-2026-80611/ (Markdown: https://insights.sbomify.com/CVE-2026-80611/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80611
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80611
- OSV: https://osv.dev/vulnerability/CVE-2026-80611

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80611/
Summaries are generated and may contain mistakes; the official description above is the record.