CVE-2024-42245: Revert "sched/fair: Make sure to try to detach at least one movable task"
First published: Wed Aug 07 2024(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Linux kernel | >=6.1<6.1.100 | |
| Linux Linux kernel | >=6.2<6.6.41 | |
| Linux Linux kernel | >=6.7<6.9.10 | |
| debian/linux | 5.10.223-1 5.10.226-1 6.1.115-1 6.1.112-1 6.11.7-1 6.11.9-1 |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
- https://git.kernel.org/stable/c/0fa6dcbfa2e2b97c1e6febbea561badf0931a38b
- https://git.kernel.org/stable/c/1e116c18e32b035a2d1bd460800072c8bf96bc44
- https://git.kernel.org/stable/c/2feab2492deb2f14f9675dd6388e9e2bf669c27a
- https://git.kernel.org/stable/c/d467194018dd536fe6c65a2fd3aedfcdb1424903
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-42245
- https://nvd.nist.gov/vuln/detail/CVE-2024-42245
- https://launchpad.net/bugs/cve/CVE-2024-42245
- https://security-tracker.debian.org/tracker/CVE-2024-42245
- https://ubuntu.com/security/CVE-2024-42245
- https://git.kernel.org/linus/2feab2492deb2f14f9675dd6388e9e2bf669c27a
- agent/references
- agent/author
- agent/type
- agent/description
- collector/nvd-api
- source/NVD
- agent/software-canonical-lookup
- agent/remedy
- agent/weakness
- agent/severity
- agent/softwarecombine
- collector/mitre-cve
- source/MITRE
- agent/title
- agent/last-modified-date
- agent/event
- agent/first-publish-date
- agent/tags
- collector/usn-cve
- source/Ubuntu
- collector/nvd-cve
- collector/security-tracker-debian
- source/Debian
- vendor/linux
- canonical/linux linux kernel
- version/linux linux kernel/6.1
- version/linux linux kernel/6.2
- version/linux linux kernel/6.7
- package-manager/debian