CVE-2026-89519

/// Technical description

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

sched_ext: Replace SCX_RQ_BAL_KEEP with a dispatch verdict return

SCX_RQ_BAL_KEEP tells the pick to keep running the previous task, a leftover

from when balancing and picking were separate operations. An rq-level flag

only works while dispatches and picks pair up one to one, which core

scheduling breaks: selections interleave through dispatch's lock drops and a

pick can consume a stale flag, keeping a task that has since been dequeued.

Fixing core scheduling support requires the decision to travel with the

dispatch that made it. Make scx_dispatch_sched() and balance_one() return an

explicit verdict instead and drop the flag's plumbing from the tools autogen

enum headers.

Also factor the pick-side invocation, its follow-up queueing and the

post-dispatch checks out of do_pick_task_scx() into dispatch_pick(). No

functional changes intended.

v2: Drop the SCX_RQ_BAL_KEEP plumbing from the tools autogen enum headers

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References