CVE-2026-93150

What the bug is

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/20260626181923.133658-1-longman%40redhat.com [2] https://sashiko.dev/#/patchset/20260630033344.352702-1-longman%40redhat.com

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

kernel/cgroup/cpuset-internal.h
kernel/cgroup/cpuset.c

What this is

CONTROL GROUP - CPUSETMAINTAINERS section matched on kernel/cgroup/cpuset-internal.h · cgroups@vger.kernel.org · Maintained

Check it on the machine

grep -wE 'CONFIG_CGROUPS|CONFIG_CPUSETS' /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

Show whether Debian builds this, per release

Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.

• bookwormy
• trixieYnot built on armel/rpi
• forky, sid, bookworm · linux-6.12y

y

built into the kernel image on every flavour - only a patch removes it

Y

built in where it is built at all; some flavours do not build it

Build switches

CONFIG_CGROUPS, CONFIG_CPUSETS

Reads as

all on means the file is compiled; any one off means it is not.

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2026-09-17 (31 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.20%, higher than 9.2% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

kernel/cgroup

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
6.5	6.12.110	e422b32e6a57
6.5	6.18.52	e5965ae3f7c9
6.5	7.2.6	78d9daf5e13a
6.5	7.3	95220e1f18f6
5.10.193	0	0
5.15.129	0	0
6.1.50	0	0
6.4.13	0	0

Debian advisories