---
id: CVE-2026-80611
title: 'ACPI: processor_idle: Mark LPI enter functions as __cpuidle'
summary: |-
  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 follo…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= a36a7fecfe6071732075ad5aa31196adce13181b <
    c17fe25dcb55ab94f6aa2930b7504ea666d5fcc2
  - >-
    Linux >= a36a7fecfe6071732075ad5aa31196adce13181b <
    10f675902a5fc88ccfe34bb8aa37de50806b03b1
  - >-
    Linux >= a36a7fecfe6071732075ad5aa31196adce13181b <
    5b6165d7ec38477e8cfa41bfa464959957953822
  - >-
    Linux >= a36a7fecfe6071732075ad5aa31196adce13181b <
    8bbe4dd7964552f74c271c3a8d95a4331a8ab5f9
  - >-
    Linux >= a36a7fecfe6071732075ad5aa31196adce13181b <
    956ca5d72c76504824c8eb601879da9476973e15
  - Linux 4.8
published: '2026-08-28'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T12:46:33.836Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80611'
references:
  - url: 'https://git.kernel.org/stable/c/c17fe25dcb55ab94f6aa2930b7504ea666d5fcc2'
  - url: 'https://git.kernel.org/stable/c/10f675902a5fc88ccfe34bb8aa37de50806b03b1'
  - url: 'https://git.kernel.org/stable/c/5b6165d7ec38477e8cfa41bfa464959957953822'
  - url: 'https://git.kernel.org/stable/c/8bbe4dd7964552f74c271c3a8d95a4331a8ab5f9'
  - url: 'https://git.kernel.org/stable/c/956ca5d72c76504824c8eb601879da9476973e15'
tags:
  - cve.org
epss: 0.00209
epssPercentile: 0.10416
ingestedAt: '2026-10-21T12:48:53.571Z'
---

## Overview

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.

## Affected

- `Linux >= a36a7fecfe6071732075ad5aa31196adce13181b < c17fe25dcb55ab94f6aa2930b7504ea666d5fcc2`
- `Linux >= a36a7fecfe6071732075ad5aa31196adce13181b < 10f675902a5fc88ccfe34bb8aa37de50806b03b1`
- `Linux >= a36a7fecfe6071732075ad5aa31196adce13181b < 5b6165d7ec38477e8cfa41bfa464959957953822`
- `Linux >= a36a7fecfe6071732075ad5aa31196adce13181b < 8bbe4dd7964552f74c271c3a8d95a4331a8ab5f9`
- `Linux >= a36a7fecfe6071732075ad5aa31196adce13181b < 956ca5d72c76504824c8eb601879da9476973e15`
- `Linux 4.8`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.