---
id: CVE-2026-98219
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sched_ext: Close the pre-enable ops error claim window

  scx_alloc_and_add_sched() publishes ops->priv before
  scx_root_enable_workfn() switches the state to SCX_ENABLING…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sched_ext: Close the pre-enable ops error claim window

  scx_alloc_and_add_sched() publishes ops->priv before
  scx_root_enable_workfn() switches the state to SCX_ENABLING…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 105dcd005be2ac1d5541921db8feb1d0f98d59d5 <
    959c66dc4a915be306c35691095c787c61dc7df9
  - >-
    Linux >= 105dcd005be2ac1d5541921db8feb1d0f98d59d5 <
    c7a1c6e8004ab12a9c9bfdcb603f60f9bf4a3cee
  - Linux 7.1
published: '2026-10-06'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T09:18:08.730'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98219'
references:
  - url: 'https://git.kernel.org/stable/c/959c66dc4a915be306c35691095c787c61dc7df9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c7a1c6e8004ab12a9c9bfdcb603f60f9bf4a3cee'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-06T08:50:17.439Z'
---

## Overview

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

sched_ext: Close the pre-enable ops error claim window

scx_alloc_and_add_sched() publishes ops->priv before
scx_root_enable_workfn() switches the state to SCX_ENABLING. An error
claimed via scx_bpf_error_bstr() from an associated BPF program in that
window is consumed by scx_disable_workfn(), which takes the pre-enable
shortcut in scx_root_disable(). The shortcut returns without any teardown
and restores SCX_DISABLED with an unconditional scx_set_enable_state() xchg
racing the enable workfn's own transition. The enable then completes with
the claim consumed: the scheduler stays up but can never be disabled again,
and bpf_scx_unreg() frees it while still in use, resulting in a
use-after-free. Both WARN_ON_ONCE()s fire back to back:

  WARNING: kernel/sched/ext/ext.c:7522 at
  scx_root_enable_workfn+0xeec/0x1be0, CPU#3: scx_enable_help/276

  WARNING: kernel/sched/ext/ext.c:6398 at scx_root_disable+0xb50/0xdb8,
  CPU#0: sched_ext_helpe/664

scx_root_enable_workfn() switches to SCX_ENABLING before the scheduler
allocation, so ops->priv is never visible while SCX_DISABLED. The allocation
failure path restores SCX_DISABLED.

## Remediation

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