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: stable@xxxxxxxxxxxxxxx v3.14
> Reported-and-tested-by: KATO Hiroshi <katoh@xxxxxxxxxxxx>
> Reported-and-tested-by: Stuart Foster <smf.linux@xxxxxxxxxxxx>
> Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
> ---
> 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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