In the Linux kernel, the following vulnerability has been resolved:
cpu/hotplug: Don't offline the last non-isolated CPU
If a system has isolated CPUs via the "isolcpus=" command line parameter, then an attempt to offline the last housekeeping CPU will result in a WARN_ON() when rebuilding the scheduler domains and a subsequent panic due to and unhandled empty CPU mas in partition_sched_domains_locked().
cpuset_hotplug_workfn() rebuild_sched_domains_locked() ndoms = generate_sched_domains(&doms, &attr); cpumask_and(doms[0], top_cpuset.effective_cpus, housekeeping_cpumask(HK_FLAG_DOMAIN));
Thus results in an empty CPU mask which triggers the warning and then the subsequent crash:
WARNING: CPU: 4 PID: 80 at kernel/sched/topology.c:2366 build_sched_domains+0x120c/0x1408 Call trace: build_sched_domains+0x120c/0x1408 partition_sched_domains_locked+0x234/0x880 rebuild_sched_domains_locked+0x37c/0x798 rebuild_sched_domains+0x30/0x58 cpuset_hotplug_workfn+0x2a8/0x930
Unable to handle kernel paging request at virtual address fffe80027ab37080 partition_sched_domains_locked+0x318/0x880 rebuild_sched_domains_locked+0x37c/0x798
Aside of the resulting crash, it does not make any sense to offline the last last housekeeping CPU.
Prevent this by masking out the non-housekeeping CPUs when selecting a target CPU for initiating the CPU unplug operation via the work queue.
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon_linux_2023 | — | Upgrade kernel-develUpgrade perfUpgrade python3-perf-debuginfoUpgrade kernel-toolsUpgrade kernel-debuginfo-common-aarch64Upgrade bpftoolUpgrade bpftool-debuginfoUpgrade perf-debuginfoUpgrade kernel-libbpfUpgrade kernel-libbpf-develUpgrade kernelUpgrade kernel-libbpf-staticUpgrade kernel-modules-extraUpgrade kernel-tools-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-debuginfoUpgrade kernel-tools-develUpgrade kernel-headersUpgrade python3-perfUpgrade kernel-livepatch-6.1.66-91.160 | Feb 17, 2025 | May 21, 2024 |
| Debian | — | Upgrade linux | Jul 30, 2024 | May 21, 2024 |
| Huawei Euleros 2_0_sp10 | — | Upgrade python3-perfUpgrade kernelUpgrade kernel-tools-libsUpgrade kernel-abi-stablelistsUpgrade kernel-tools | Oct 8, 2024 | May 21, 2024 |
| Huawei Euleros 2_0_sp11 | — | Upgrade kernel-tools-libsUpgrade bpftoolUpgrade kernel-toolsUpgrade kernel-abi-stablelistsUpgrade kernelUpgrade python3-perf | Oct 8, 2024 | May 21, 2024 |
| Huawei Euleros 2_0_sp12 | — | Upgrade bpftoolUpgrade kernel-tools-libsUpgrade python3-perfUpgrade kernelUpgrade kernel-abi-stablelistsUpgrade kernel-tools | Oct 9, 2024 | May 21, 2024 |
| Redhat_linux | — | No solution existsUpgrade kernelUpgrade kernel-rt | Dec 5, 2024 | May 21, 2024 |
| Ubuntu | — | Upgrade linux-nvidia-6.5 | Nov 19, 2024 | May 21, 2024 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Oct 13, 2025 | May 21, 2024 |
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