sched/core: Make core-sched flips wait for in-flight selections
Summary
| CVE | CVE-2026-89520 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-11 20:19:34 UTC |
| Updated | 2026-10-03 11:17:42 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: sched/core: Make core-sched flips wait for in-flight selections Core scheduling's pick_next_task() operates on all sibling rqs under one acquisition of the shared core-wide lock. A ->pick_task() that releases the rq lock leaves every sibling __lock momentarily free, letting __sched_core_flip(false) complete mid-selection and rebind rq_lockp() under it. The selection resumes on the split locks, touching sibling state it no longer protects, and __schedule() finally releases a lock that was never taken while leaking the one that was. Count in-flight core-wide selections in the leader's rq->core_pick_in_flight and make __sched_core_flip() wait for the count to drain. The count only changes under the shared lock, which the flip holds while sampling, so no other ordering is needed. The wait can repeat while selections overlap, but the flip backs off between samples and flips are rare cookie-lifetime events. sched_core_cpu_deactivate() moves the count to the new leader - a stale copy left behind would bias it forever if that CPU later returns as its own leader. |
Risk And Classification
Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.001730000 probability, percentile 0.061140000 (date 2026-10-03)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | Secondary | 7.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 7.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 539f65125d20aacab54d02d77f10a839f45b09dc 3e2511bffa93a639774a99e392181e21d28677e2 git | Not specified |
| CNA | Linux | Linux | affected 539f65125d20aacab54d02d77f10a839f45b09dc 9d69422ddaa13526c2223444e237d948d6e44728 git | Not specified |
| CNA | Linux | Linux | affected 539f65125d20aacab54d02d77f10a839f45b09dc 23eda24f325a6e6d686d30ec75f2e9d6745e2015 git | Not specified |
| CNA | Linux | Linux | affected 539f65125d20aacab54d02d77f10a839f45b09dc f3629c63a4af3e491381780bc6c123cb498c4c40 git | Not specified |
| CNA | Linux | Linux | affected 5.14 | Not specified |
| CNA | Linux | Linux | unaffected 5.14 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.112 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.51 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2.4 7.2.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.3-rc1 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/9d69422ddaa13526c2223444e237d948d6e44728 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/3e2511bffa93a639774a99e392181e21d28677e2 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/f3629c63a4af3e491381780bc6c123cb498c4c40 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/23eda24f325a6e6d686d30ec75f2e9d6745e2015 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.