---
id: CVE-2026-98864
title: 'sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task

  ebf1ccff79c4 ("sched_ext: Fix ops.dequeue() semantics") moved the final
  ops_state store in scx_disp…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d <
    43457bf6550044c40bd6d3fcdf9ea66f5a55d139
  - >-
    Linux >= ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d <
    7de9a6fb44eae4f05e68c805d58b9c618815adfa
  - Linux 7.1
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:51:25.532Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98864'
references:
  - url: 'https://git.kernel.org/stable/c/43457bf6550044c40bd6d3fcdf9ea66f5a55d139'
  - url: 'https://git.kernel.org/stable/c/7de9a6fb44eae4f05e68c805d58b9c618815adfa'
tags:
  - cve.org
ingestedAt: '2026-10-18T16:47:32.459Z'
---

## Overview

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

sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task

ebf1ccff79c4 ("sched_ext: Fix ops.dequeue() semantics") moved the final
ops_state store in scx_dispatch_enqueue() after the DSQ unlock so that the
custody update and ops.dequeue() precede it. A task can thus be found on a
DSQ while still SCX_OPSS_DISPATCHING.

The dequeue and core-sched pick paths wait for the state to clear in
ops_dequeue() but the reenqueue paths don't. A reenqueue in that window runs
ops.enqueue() and sets SCX_OPSS_QUEUED before the dispatch has completed.
The dispatcher's final store then overwrites it with SCX_OPSS_NONE and
finish_dispatch() drops every later dispatch of the task.

Wait for SCX_OPSS_DISPATCHING to clear before dequeueing a task for
reenqueue, the same way ops_dequeue() does.

## Affected

- `Linux >= ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d < 43457bf6550044c40bd6d3fcdf9ea66f5a55d139`
- `Linux >= ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d < 7de9a6fb44eae4f05e68c805d58b9c618815adfa`
- `Linux 7.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.