Description
In the Linux kernel, the following vulnerability has been resolved:

sched_ext: Fix the bypass dispatch claim for schedulers bypassed by an ancestor

scx_bypass() claims bypass dispatch when the scheduler's depth goes from
zero to one and releases it when the depth returns to zero, but propagates
only the depth to the descendants, not the claim. A descendant that starts
bypassing with its ancestor never claims, and one whose own bypass ends
under the ancestor's keeps its claim, as its depth does not return to zero.

A sub-scheduler enable whose bypass ends under a PM suspend thus leaks its
claim: the parent keeps hosting bypass dispatch and the sub-scheduler's next
bypass trips the WARN_ON_ONCE() on the claim. A sub-scheduler disable that
starts under a PM suspend has no claim, so once the resume lifts the root's
bypass its tasks sit on the parent's bypass DSQs with nobody consuming them.

Claim for every descendant whose depth goes from zero to one in the
propagation and release every scheduler in the subtree whose depth returned
to zero once the tasks have moved out of the bypass DSQs. A parent that is
bypassing itself when a descendant claims consumes only its own bypass DSQs,
empty until it leaves bypass and becomes the host.
Published: 2026-10-28
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Wed, 28 Oct 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-665

Wed, 28 Oct 2026 12:00:00 +0000

Type Values Removed Values Added
First Time appeared Linux linux
Vendors & Products Linux linux

Wed, 28 Oct 2026 10:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: sched_ext: Fix the bypass dispatch claim for schedulers bypassed by an ancestor scx_bypass() claims bypass dispatch when the scheduler's depth goes from zero to one and releases it when the depth returns to zero, but propagates only the depth to the descendants, not the claim. A descendant that starts bypassing with its ancestor never claims, and one whose own bypass ends under the ancestor's keeps its claim, as its depth does not return to zero. A sub-scheduler enable whose bypass ends under a PM suspend thus leaks its claim: the parent keeps hosting bypass dispatch and the sub-scheduler's next bypass trips the WARN_ON_ONCE() on the claim. A sub-scheduler disable that starts under a PM suspend has no claim, so once the resume lifts the root's bypass its tasks sit on the parent's bypass DSQs with nobody consuming them. Claim for every descendant whose depth goes from zero to one in the propagation and release every scheduler in the subtree whose depth returned to zero once the tasks have moved out of the bypass DSQs. A parent that is bypassing itself when a descendant claims consumes only its own bypass DSQs, empty until it leaves bypass and becomes the host.
Title sched_ext: Fix the bypass dispatch claim for schedulers bypassed by an ancestor
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-28T10:34:23.729Z

Reserved: 2026-09-25T10:25:14.391Z

Link: CVE-2026-99104

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-28T11:17:29.733

Modified: 2026-10-28T11:17:29.733

Link: CVE-2026-99104

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-28T12:00:22Z

Weaknesses