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.
Metrics
No CVSS score has been published yet.
Affected software
Source: the vendor's advisory (CNA). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux | >= a5bd6ba30b3364354269b81ac55c2edca9a96d6d, < 2ca6b43edf83f8fc368cc3094ee5f3b1e8e0b0f0; >= a5bd6ba30b3364354269b81ac55c2edca9a96d6d, < a054c9ffa9b7a0dffb763837b91ac9d381ec6d10; >= a5bd6ba30b3364354269b81ac55c2edca9a96d6d, < 5f8b69642d18e1f3e11996707842ac530444e959 |
| Linux | Linux | 6.18 |
References
Timeline
- Published
- Aug 22, 2026
- Last modified
- Oct 14, 2026
- NVD status
- Received