sched_ext: Take cgroup_lock() first in scx_cgroup_lock() (CVE-2026-74593) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-74593

sched_ext: Take cgroup_lock() first in scx_cgroup_lock()

Answer in brief

CVE-2026-74593 records a Unknown severity vulnerability in sched_ext: Take cgroup_lock() first in scx_cgroup_lock(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 22, 2026Updated Aug 22, 2026Source checked Aug 22, 2026First seen by HOL Aug 22, 2026Material review Aug 22, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=a5bd6ba30b3364354269b81ac55c2edca9a96d6d <a054c9ffa9b7a0dffb763837b91ac9d381ec6d10 \|\| >=a5bd6ba30b3364354269b81ac55c2edca9a96d6d <5f8b69642d18e1f3e11996707842ac530444e959	a054c9ffa9b7a0dffb763837b91ac9d381ec6d10, 5f8b69642d18e1f3e11996707842ac530444e959
Linux/Linuxgeneric	6.18	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to a054c9ffa9b7a0dffb763837b91ac9d381ec6d10 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 22, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Take cgroup_lock() first in scx_cgroup_lock() scx_cgroup_lock() write-locks scx_cgroup_ops_rwsem and then takes cgroup_lock(), which can deadlock through kernfs: scx enable/disable cgroup rmdir cpu.weight write ------------------ ------------ ---------------- cgroup_lock() percpu_down_write(rwsem) cgroup_lock() kernfs_get_active() percpu_down_read(rwsem) kernfs_drain() The enable path waits for the rmdir to release cgroup_mutex. The rmdir, deactivating the cpu controller's files, waits in kernfs_drain() for the write's active reference. The write, in scx_group_set_weight(), waits for the rwsem behind the pending writer. Take cgroup_lock() first. The set_* paths take no cgroup locks inside the read side, so a pending write-lock then only waits for read sections that always run to completion, and no dependency from the rwsem back to cgroup_mutex remains.

Quoted source text, attributed separately from HOL analysis.