sched_ext: Don't warn on core-sched forced idle in put_prev_task_scx()
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
- Partial Red Hat: 1 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Don't warn on core-sched forced idle in put_prev_task_scx() put_prev_task_scx() warns when a runnable task drops to a lower sched_class without SCX_OPS_ENQ_LAST, on the assumption that balance_one() would have kept it running. Core scheduling breaks that: a forced-idle SMT sibling reschedules through the core_pick fast path in pick_next_task(), which skips pick_task_scx() and thus balance_one(), so a runnable task can drop to idle with ENQ_LAST unset. Gate the warning on sched_cpu_cookie_match(): a cookie mismatch means core scheduling forced the idle, while a match (or core scheduling off) still catches a genuine missing-ENQ_LAST drop.
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 6.12.114, 6.18.42, 7.1.6, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux for NVIDIA 26 | Affected | No fix planned: Out of support scope |
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-2026-68421
- 2026-10-03 Alias added: GHSA-wg3q-w98j-244c
- 2026-10-21 Fix available: Linux/[email protected], Linux/Linux@6267ebee9f2f3e26f4968bf6dc29d350620fa320 · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-30 Affected versions changed · Red Hat
References
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Sources
- CVE-2026-68421 · CVE Program
- CVE-2026-68421 · NVD
- FIRST EPSS
- GHSA-wg3q-w98j-244c · GitHub Advisory Database · CC BY 4.0
- CVE-2026-68421 · Red Hat security data · CC BY 4.0
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