In the Linux kernel, the following vulnerability has been resolved:
sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed
With cgroup v2, the cpuset's cpus_allowed mask can be empty indicating that the cpuset will just use the effective CPUs of its parent. So cpuset_can_attach() can call task_can_attach() with an empty mask. This can lead to cpumask_any_and() returns nr_cpu_ids causing the call to dl_bw_of() to crash due to percpu value access of an out of bound CPU value. For example:
[80468.182258] BUG: unable to handle page fault for address: ffffffff8b6648b0 : [80468.191019] RIP: 0010:dl_cpu_busy+0x30/0x2b0 : [80468.207946] Call Trace: [80468.208947] cpuset_can_attach+0xa0/0x140 [80468.209953] cgroup_migrate_execute+0x8c/0x490 [80468.210931] cgroup_update_dfl_csses+0x254/0x270 [80468.211898] cgroup_subtree_control_write+0x322/0x400 [80468.212854] kernfs_fop_write_iter+0x11c/0x1b0 [80468.213777] new_sync_write+0x11f/0x1b0 [80468.214689] vfs_write+0x1eb/0x280 [80468.215592] ksys_write+0x5f/0xe0 [80468.216463] do_syscall_64+0x5c/0x80 [80468.224287] entry_SYSCALL_64_after_hwframe+0x44/0xae
Fix that by using effective_cpus instead. For cgroup v1, effective_cpus is the same as cpus_allowed. For v2, effective_cpus is the real cpumask to be used by tasks within the cpuset anyway.
Also update task_can_attach()'s 2nd argument name to cs_effective_cpus to reflect the change. In addition, a check is added to task_can_attach() to guard against the possibility that cpumask_any_and() may return a value >= nr_cpu_ids.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade kernel-tools-develUpgrade perfUpgrade kernel-livepatch-4.14.355-280.652Upgrade kernel-toolsUpgrade kernelUpgrade kernel-debuginfo-common-aarch64Upgrade python-perf-debuginfoUpgrade kernel-tools-debuginfoUpgrade perf-debuginfoUpgrade bpftool-debuginfoUpgrade python-perfUpgrade kernel-develUpgrade kernel-headersUpgrade kernel-livepatch-5.15.69-37.134Upgrade kernel-livepatch-5.10.144-127.601Upgrade kernel-debuginfoUpgrade bpftoolUpgrade kernel-debuginfo-common-x86_64 | Jul 9, 2025 | Jun 18, 2025 |
| Debian | — | Upgrade linux | Jun 20, 2025 | Jun 20, 2025 |
| Dell Powerstore Dsa2025429 | — | Upgrade Dell PowerStoreOS to the latest version | Dec 3, 2025 | Dec 2, 2025 |
| Dell Powerstore Dsa2026039 | — | Upgrade Dell PowerStoreOS to the latest version | Jan 13, 2026 | Jan 6, 2026 |
| Huawei Euleros 2_0_sp10 | — | Upgrade kernelUpgrade kernel-tools-libsUpgrade kernel-abi-stablelistsUpgrade python3-perfUpgrade kernel-tools | Sep 15, 2025 | Sep 9, 2025 |
| Huawei Euleros 2_0_sp13 | — | Upgrade kernel-toolsUpgrade kernel-abi-stablelistsUpgrade kernel-tools-libsUpgrade kernelUpgrade python3-perfUpgrade bpftool | Nov 21, 2025 | Sep 9, 2025 |
| Redhat_linux | — | No solution exists | Jul 9, 2025 | Jun 18, 2025 |
| Ubuntu | — | Upgrade linuxUpgrade linux-aws-5.15Upgrade linux-awsUpgrade linux-lowlatency-hwe-5.15Upgrade linux-gkeUpgrade linux-gcpUpgrade linux-raspiUpgrade linux-azureUpgrade linux-oracle-5.15Upgrade linux-riscv-5.15Upgrade linux-hwe-5.15Upgrade linux-gcp-5.15Upgrade linux-intel-iotg-5.15Upgrade linux-lowlatencyUpgrade linux-azure-5.15Upgrade linux-realtimeUpgrade linux-kvmUpgrade linux-gkeopUpgrade linux-azure-fdeUpgrade linux-ibmUpgrade linux-intel-iotgUpgrade linux-nvidiaUpgrade linux-oracle | Jun 26, 2025 | Jun 18, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | May 27, 2026 | Jun 18, 2025 |
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