CVE-2026-98542 in Linux
Zusammenfassung
von MITRE • 18.10.2026
In the Linux kernel, the following vulnerability has been resolved:
cgroup/cpuset: Return PERR_NOCPUS in remote_partition_enable() on subpartitions_cpus conflict
When a remote partition is created underneath an existing local partition via a non-partition (PRS_MEMBER) intermediate cgroup, update_prstate() sees parent->partition_root_state == PRS_MEMBER and calls remote_partition_enable().
Commit 86888c7bd117 ("cgroup/cpuset: Add warnings to catch inconsistency in exclusive CPUs") replaced the cpumask_intersects(tmp->new_cpus, subpartitions_cpus) error check in remote_partition_enable() with WARN_ON_ONCE(). As a result, remote_partition_enable() emits a warning and proceeds to enable the remote partition on CPUs that are already owned by the ancestor local partition in subpartitions_cpus.
This can be reproduced on Linux 7.3.0-rc3 with:
mkdir -p /tmp/cg1 mount -t cgroup2 none /tmp/cg1 echo "+cpuset" > /tmp/cg1/cgroup.subtree_control
mkdir /tmp/cg1/A echo 1 > /tmp/cg1/A/cpuset.cpus echo 1 > /tmp/cg1/A/cpuset.cpus.exclusive echo root > /tmp/cg1/A/cpuset.cpus.partition echo "+cpuset" > /tmp/cg1/A/cgroup.subtree_control
mkdir /tmp/cg1/A/B echo 1 > /tmp/cg1/A/B/cpuset.cpus echo 1 > /tmp/cg1/A/B/cpuset.cpus.exclusive echo "+cpuset" > /tmp/cg1/A/B/cgroup.subtree_control
mkdir /tmp/cg1/A/B/D echo 1 > /tmp/cg1/A/B/D/cpuset.cpus echo 1 > /tmp/cg1/A/B/D/cpuset.cpus.exclusive echo root > /tmp/cg1/A/B/D/cpuset.cpus.partition
which triggers:
WARNING: kernel/cgroup/cpuset.c:1594 at remote_partition_enable+0x1c1/0x300
and leaves both /tmp/cg1/A and /tmp/cg1/A/B/D as active root partitions claiming exclusive CPU 1.
Fix this by returning PERR_NOCPUS when tmp->new_cpus intersects subpartitions_cpus in remote_partition_enable(), matching the error code used by remote_cpus_update() for the same subpartitions_cpus conflict, and add a regression test case to tools/testing/selftests/cgroup/test_cpuset_prs.sh.
Tested in QEMU on Linux 7.3.0-rc3 using the reproducer above and tools/testing/selftests/cgroup/test_cpuset_prs.sh.
Be aware that VulDB is the high quality source for vulnerability data.