"value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncpu/hotplug: Don't offline the last non-isolated CPU\n\nIf a system has isolated CPUs via the \"isolcpus=\" command line parameter,\nthen an attempt to offline the last housekeeping CPU will result in a\nWARN_ON() when rebuilding the scheduler domains and a subsequent panic due\nto and unhandled empty CPU mas in partition_sched_domains_locked().\n\ncpuset_hotplug_workfn()\n rebuild_sched_domains_locked()\n ndoms = generate_sched_domains(&doms, &attr);\n cpumask_and(doms[0], top_cpuset.effective_cpus, housekeeping_cpumask(HK_FLAG_DOMAIN));\n\nThus results in an empty CPU mask which triggers the warning and then the\nsubsequent crash:\n\nWARNING: CPU: 4 PID: 80 at kernel/sched/topology.c:2366 build_sched_domains+0x120c/0x1408\nCall trace:\n build_sched_domains+0x120c/0x1408\n partition_sched_domains_locked+0x234/0x880\n rebuild_sched_domains_locked+0x37c/0x798\n rebuild_sched_domains+0x30/0x58\n cpuset_hotplug_workfn+0x2a8/0x930\n\nUnable to handle kernel paging request at virtual address fffe80027ab37080\n partition_sched_domains_locked+0x318/0x880\n rebuild_sched_domains_locked+0x37c/0x798\n\nAside of the resulting crash, it does not make any sense to offline the last\nlast housekeeping CPU.\n\nPrevent this by masking out the non-housekeeping CPUs when selecting a\ntarget CPU for initiating the CPU unplug operation via the work queue."