CVE-2023-52942: cgroup/cpuset: Fix wrong check in update_parent_subparts_cpumask()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-03-27 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: cgroup/cpuset: Fix wrong check in update_parent_subparts_cpumask() It was found that the check to see if a partition could use up all the cpus from the parent cpuset in update_parent_subparts_cpumask() was incorrect. As a result, it is possible to leave parent with no effective cpu left even if there are tasks in the parent cpuset. This can lead to system panic as reported in [1]. Fix this probem by updating the check to fail the enabling the partition if parent's effective_cpus is a subset of the child's cpus_allowed. Also record the error code when an error happens in update_prstate() and add a test case where parent partition and child have the same cpu list and parent has task. Enabling partition in the child will fail in this case. [1] https://www.spinics.net/lists/cgroups/msg36254.html

Affected products

Linux kernel: from 6.1 before 6.1.11; 6.2-rc1, 6.2-rc2, 6.2-rc3, 6.2-rc4, 6.2-rc5, 6.2-rc6 — fixed in 6.1.11

How to fix

Upgrade to a fixed version: Linux kernel 6.1.11. Check the vendor advisory for mitigations.

References

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