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.
Vendor | Product | Version | CPE |
---|---|---|---|
linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"kernel/cpu.c"
],
"versions": [
{
"version": "1da177e4c3f4",
"lessThan": "3410b7023547",
"status": "affected",
"versionType": "git"
},
{
"version": "1da177e4c3f4",
"lessThan": "335a47ed71e3",
"status": "affected",
"versionType": "git"
},
{
"version": "1da177e4c3f4",
"lessThan": "3073f6df783d",
"status": "affected",
"versionType": "git"
},
{
"version": "1da177e4c3f4",
"lessThan": "38685e2a0476",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"kernel/cpu.c"
],
"versions": [
{
"version": "6.1.64",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.5.13",
"lessThanOrEqual": "6.5.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.6.3",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.7",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]