Hi Tianyu,
Found another issue at the second glance.
In case of x2apic, "if (apic_id < 0)" should be replaced
by "if (apic_id == -1)" for safety.
Best Regards!
Gerry
On 2014/4/30 13:08, Jiang Liu wrote:
> Hi Tianyu,
> With the suggested fix, we still need to protect
> acpi_processor_hotadd_init() when pr->apic_id is -1,
> otherwise it may cause invalid memory access.
>
> Best Regards!
> Gerry
>
> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index c29c2c3ec0ad..e17befc54c34 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -170,6 +170,9 @@ static int acpi_processor_hotadd_init(struct
> acpi_processor *pr)
> acpi_status status;
> int ret;
>
> + if (pr->apic_id < 0)
> + return -ENODEV;
> +
> status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
> if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT))
> return -ENODEV;
>
>
> On 2014/4/30 11:10, Lan Tianyu wrote:
>> According commit d640113fe(ACPI: processor: fix acpi_get_cpuid for UP
>> processor), Bios may not provide _MAT or MADT tables and acpi_get_apicid()
>> always returns -1. For these cases, original code will pass apic_id with
>> vaule of -1 to acpi_map_cpuid() and it will check the acpi_id. If acpi_id
>> is equal to zero, ignores apic_id and return zero for CPU0.
>>
>> Commit b981513(ACPI / scan: bail out early if failed to parse APIC
>> ID for CPU) changed the behavior. Return ENODEV when find apic_id is
>> less than zero after calling acpi_get_apicid(). This causes acpi-cpufreq
>> driver fails to be loaded on some machines. This patch is to fix it.
>>
>> Reference:https://bugzilla.kernel.org/show_bug.cgi?id=73781
>> Cc: sta...@vger.kernel.org v3.14
>> Reported-and-tested-by: KATO Hiroshi <ka...@mikage.ne.jp>
>> Reported-and-tested-by: Stuart Foster <smf.li...@ntlworld.com>
>> Signed-off-by: Lan Tianyu <tianyu....@intel.com>
>> ---
>> drivers/acpi/acpi_processor.c | 4 +---
>> 1 file changed, 1 insertion(+), 3 deletions(-)
>>
>> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
>> index c29c2c3..d55b603 100644
>> --- a/drivers/acpi/acpi_processor.c
>> +++ b/drivers/acpi/acpi_processor.c
>> @@ -260,10 +260,8 @@ static int acpi_processor_get_info(struct acpi_device
>> *device)
>> }
>>
>> apic_id = acpi_get_apicid(pr->handle, device_declaration, pr->acpi_id);
>> - if (apic_id < 0) {
>> + if (apic_id < 0)
>> acpi_handle_debug(pr->handle, "failed to get CPU APIC ID.\n");
>> - return -ENODEV;
>> - }
>> pr->apic_id = apic_id;
>>
>> cpu_index = acpi_map_cpuid(pr->apic_id, pr->acpi_id);
>>
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