Vulnerability in Kernel: blk-cgroup_bio_start() should use irq-safe operations on blkg->iostat_cpu

Kernel Updated 02 Oct 2025

Summary

14/11/2021

Disclosed on

N/A

Severity

No i

Fix available

Unrated

Severity

Not published

CVSS Score

GSD-2021-1002175: blk-cgroup: blk_cgroup_bio_start() should use irq-safe operations on blkg->iostat_cpu. Affects Kernel versions >= 2d146aa3aa842d7f5065802556b4f9a2c6e8ef12, < 5370b0f49078203acf3c064b634a09707167a864. No fix is published. How to fix ↓

Free scan

Check if this vulnerability affects your application

Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.

Check my app free

No signup required · Results in about 60 seconds

Upload your dependency manifest or SBOM

Drag & drop your file here or Browse

Java Javascript PHP Python Go Rust Ruby Dart C/C++ Elixir CycloneDX SPDX

Upload a supported dependency manifest or SBOM. No installation or source-code access required.

See supported files and SBOM formats

SBOM sbom.json · bom.json · bom.xml · *.spdx.json · *.cdx.json · *.cdx.xml

Java pom.xml · gradle.lockfile · buildscript-gradle.lockfile

Javascript package-lock.json · yarn.lock · pnpm-lock.yaml

PHP composer.lock

Python poetry.lock · requirements.txt · Pipfile.lock

Go go.mod

Rust Cargo.lock

Ruby Gemfile.lock

Dart pubspec.lock

C/C++ conan.lock

Elixir mix.lock

Enter your work email to receive your report link.

Verify your email to view the full report and start 30 days of continuous monitoring. No credit card required.

Background

The Kernel is a critical component of the Linux operating system that provides core functionality and interfaces with hardware devices. It manages system resources, including memory, processes, and input/output operations. The blk-cgroup module within the Kernel is responsible for managing block I/O operations and enforcing resource limits for block devices. This vulnerability affects the blk-cgroup_bio_start() function, which is used to start I/O operations for a block device within a control group (cgroup).

Vulnerability Detail

The blk-cgroup_bio_start() function in the Kernel's blk-cgroup module does not use irq-safe operations on the blkg->iostat_cpu variable. This can lead to race conditions and potential data corruption when multiple CPUs concurrently access the same blkg structure. An attacker with local access to the system could exploit this vulnerability to cause denial-of-service conditions or potentially execute arbitrary code with elevated privileges. The vulnerability was introduced in Kernel version v5.13 and has been fixed in version v5.15.

How To Fix

No fixed version is published for this vulnerability.

Tip — Not sure whether your app is affected? Vulert can check the versions your app actually runs. Scan free →

Workaround

As a temporary workaround, users can disable the blk-cgroup module by removing it from the Kernel configuration and rebuilding the Kernel without this module. However, this may impact the functionality of certain block I/O control group features.

Conclusion

The vulnerability in the Kernel's blk-cgroup module can lead to race conditions and potential data corruption. It is recommended to update the Linux Kernel to version v5.15 or later to mitigate this vulnerability. Users can also temporarily disable the blk-cgroup module as a workaround, but this may impact certain block I/O control group features. For further support on vulnerability remediation, please contact DevNack.com.

See every vulnerability recorded for Kernel →