sched_ext: Keep kick_sync waiting on the rq's own CPU
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Fixed
No CVSS vector from any source. Fix status from CNA.
Summary
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Keep kick_sync waiting on the rq's own CPU kick_sync_wait_bal_cb() assumes it runs on the rq's CPU from the __schedule() tail: the snapshots it compares against live in that CPU's percpu area and the busy-wait runs with the rq lock dropped and IRQs enabled. However, dispatch can now drop the rq lock while the callback sits queued, and rq lock takers in that window (the sched class change paths, the scx task iterator) flush pending balance callbacks on release, running the callback on a foreign CPU. Such a run compares against unrelated snapshots and can deadlock when the executing CPU is itself a wait target. Bail on a foreign CPU and leave the wait state alone. The wait only observes progress that the resched kicks already guarantee and the rq's next wait picks up the stale cpus_to_sync bits.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 7.2.4, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 7 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
Timeline
- 2026-10-02 Threatist record created from CVE-2026-93220
- 2026-10-03 Alias added: GHSA-mp4r-853f-vhwr
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-06 Affected versions changed · Red Hat
- 2026-11-06 CVSS score added · Red Hat
References
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Sources
- CVE-2026-93220 · CVE Program
- CVE-2026-93220 · NVD
- FIRST EPSS
- GHSA-mp4r-853f-vhwr · GitHub Advisory Database · CC BY 4.0
- CVE-2026-93220 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences