From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> commit 40d8abf364bcab23bc715a9221a3c8623956257b upstream. If the NumEntries field in the _CPC return package is less than 2, do not attempt to access the "Revision" element of that package, because it may not be present then. Fixes: 337aadff8e45 ("ACPI: Introduce CPU performance controls using CPPC") BugLink: https://lore.kernel.org/lkml/20220322143534.GC32582@xsang-OptiPlex-9020/ Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Reviewed-by: Huang Rui <ray.huang@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/acpi/cppc_acpi.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -681,6 +681,11 @@ int acpi_cppc_processor_probe(struct acp cpc_obj = &out_obj->package.elements[0]; if (cpc_obj->type == ACPI_TYPE_INTEGER) { num_ent = cpc_obj->integer.value; + if (num_ent <= 1) { + pr_debug("Unexpected _CPC NumEntries value (%d) for CPU:%d\n", + num_ent, pr->id); + goto out_free; + } } else { pr_debug("Unexpected entry type(%d) for NumEntries\n", cpc_obj->type); Patches currently in stable-queue which might be from rafael.j.wysocki@xxxxxxxxx are queue-4.9/pm-core-keep-irq-flags-in-device_pm_check_callbacks.patch queue-4.9/acpi-cppc-avoid-out-of-bounds-access-when-parsing-_cpc-data.patch queue-4.9/pm-suspend-fix-return-value-of-__setup-handler.patch queue-4.9/clocksource-acpi_pm-fix-return-value-of-__setup-hand.patch queue-4.9/acpi-apei-limit-printable-size-of-bert-table-data.patch queue-4.9/pm-hibernate-fix-__setup-handler-error-handling.patch queue-4.9/thermal-int340x-increase-bitmap-size.patch queue-4.9/acpica-avoid-walking-the-acpi-namespace-if-it-is-not.patch