Bug 2532339 (CVE-2026-89519) - CVE-2026-89519 kernel: sched_ext: Replace SCX_RQ_BAL_KEEP with a dispatch verdict return
Summary: CVE-2026-89519 kernel: sched_ext: Replace SCX_RQ_BAL_KEEP with a dispatch ver...
Keywords:
Status: NEW
Alias: CVE-2026-89519
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-11 22:27 UTC by OSIDB Bzimport
Modified: 2026-09-16 04:28 UTC (History)
17 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-09-11 22:27:46 UTC
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
    as well (Andrea).


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