CVE-2024-42245

CVE Details

Release Date:	2024-08-07
Impact:	Moderate	What is this?

Description

In the Linux kernel, the following vulnerability has been resolved:\nRevert 'sched/fair: Make sure to try to detach at least one movable task'\nThis reverts commit b0defa7ae03ecf91b8bfd10ede430cff12fcbd06.\nb0defa7ae03ec changed the load balancing logic to ignore env.max_loop if\nall tasks examined to that point were pinned. The goal of the patch was\nto make it more likely to be able to detach a task buried in a long list\nof pinned tasks. However, this has the unfortunate side effect of\ncreating an O(n) iteration in detach_tasks(), as we now must fully\niterate every task on a cpu if all or most are pinned. Since this load\nbalance code is done with rq lock held, and often in softirq context, it\nis very easy to trigger hard lockups. We observed such hard lockups with\na user who affined O(10k) threads to a single cpu.\nWhen I discussed this with Vincent he initially suggested that we keep\nthe limit on the number of tasks to detach, but increase the number of\ntasks we can search. However, after some back and forth on the mailing\nlist, he recommended we instead revert the original patch, as it seems\nlikely no one was actually getting hit by the original issue.

See more information about CVE-2024-42245 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	5.5
Vector String:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Version:	3.1
Attack Vector:	Local
Attack Complexity:	Low
Privileges Required:	Low
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	None
Integrity Impact:	None
Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 9 (kernel)	ELSA-2024-9315	2024-11-14