CVE-2026-74593

Technical 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 sid

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