CVE - CVE-2024-42245

CVE-ID
CVE-2024-42245	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
In the Linux kernel, the following vulnerability has been resolved: Revert "sched/fair: Make sure to try to detach at least one movable task" This reverts commit b0defa7ae03ecf91b8bfd10ede430cff12fcbd06. b0defa7ae03ec changed the load balancing logic to ignore env.max_loop if all tasks examined to that point were pinned. The goal of the patch was to make it more likely to be able to detach a task buried in a long list of pinned tasks. However, this has the unfortunate side effect of creating an O(n) iteration in detach_tasks(), as we now must fully iterate every task on a cpu if all or most are pinned. Since this load balance code is done with rq lock held, and often in softirq context, it is very easy to trigger hard lockups. We observed such hard lockups with a user who affined O(10k) threads to a single cpu. When I discussed this with Vincent he initially suggested that we keep the limit on the number of tasks to detach, but increase the number of tasks we can search. However, after some back and forth on the mailing list, he recommended we instead revert the original patch, as it seems likely no one was actually getting hit by the original issue.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/0fa6dcbfa2e2b97c1e6febbea561badf0931a38b URL:https://git.kernel.org/stable/c/0fa6dcbfa2e2b97c1e6febbea561badf0931a38b MISC:https://git.kernel.org/stable/c/1e116c18e32b035a2d1bd460800072c8bf96bc44 URL:https://git.kernel.org/stable/c/1e116c18e32b035a2d1bd460800072c8bf96bc44 MISC:https://git.kernel.org/stable/c/2feab2492deb2f14f9675dd6388e9e2bf669c27a URL:https://git.kernel.org/stable/c/2feab2492deb2f14f9675dd6388e9e2bf669c27a MISC:https://git.kernel.org/stable/c/d467194018dd536fe6c65a2fd3aedfcdb1424903 URL:https://git.kernel.org/stable/c/d467194018dd536fe6c65a2fd3aedfcdb1424903
Assigning CNA
kernel.org
Date Record Created
20240730	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20240730)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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