CVE-2026-93150

/// Technical description

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

cgroup/cpuset: Make nr_deadline_tasks an atomic_t

The nr_deadline_tasks variable in the cpuset structure was introduced by

commit 6c24849f5515 ("sched/cpuset: Keep track of SCHED_DEADLINE task

in cpusets"). It is reported by sashiko [1] that nr_deadline_tasks

can currently be modified by inc_dl_tasks_cs() under rq->lock and

by cpuset_attach() under cpuset_mutex. So if both updates happen

simultaneously, the nr_deadline_tasks variable can be corrupted leading

to incorrect operations down the road.

Fix that by changing its type to atomic_t so that nr_deadline_tasks

are always atomically updated. This fix patch is a low hanging fruit.

It can handle some of the races between a concurrent sched_setscheduler()

and cpuset_can_attach()/cpuset_attach() calls, but not all of them like

the other issue raised by sashiko [2]. This will be handled hopefully

in a future follow up patch.

[1] https://sashiko.dev/#/patchset/20260626

/// 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