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.
CVSS
No CVSS.
References
Configurations
No configuration.
History
No history.
Information
Published : 2026-08-22 16:16
Updated : 2026-08-23 13:16
NVD link : CVE-2026-74593
Mitre link : CVE-2026-74593
CVE.ORG link : CVE-2026-74593
JSON object : View
Products Affected
No product.
CWE
No CWE.
