On Friday, August 24, 2018 4:51:26 AM CEST Dou Liyang wrote:
> ACPI driver should make sure all the processor IDs in their ACPI Namespace
> are unique. the driver performs a depth-first walk of the namespace tree
> and calls the acpi_processor_ids_walk() to check the duplicate IDs.
>
> But, the acpi_processor_ids_walk() mistakes the return value. If a
> processor is checked, it returns true which causes the walk break
> immediately, and other processors will never be checked.
>
> Repace the value with AE_OK which is the standard acpi_status value.
> And don't abort the namespace walk even on error.
>
> Fixes 8c8cb30f49b8 ("acpi/processor: Implement DEVICE operator for processor enumeration")
> Signed-off-by: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>
> ---
> Changelog:
> v2 --> v3:
> - Fix a compiler error reported by LKP
> v1 --> v2:
> - Fix the check against duplicate IDs suggested by Rafael.
>
> Now，the duplicate IDs only be found in Ivb42 machine, and we have added this check at
> linux-4.9. But, we introduced a bug in linux-4.12 by commit 8c8cb30f49b8.
>
> For resolving the bug, firstly, I removed the check[1]. because Linux will compare
> the coming ID with present processors when it hot-added a physical CPU and will avoid
> using duplicate IDs.
>
> But, seems we should consider all the possible processors. So, with this patch, All
> the processors with the same IDs will never be hot-plugged.
>
> [1] https://lkml.org/lkml/2018/5/28/213
> ---
> drivers/acpi/acpi_processor.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index 449d86d39965..fc447410ae4d 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -643,7 +643,7 @@ static acpi_status __init acpi_processor_ids_walk(acpi_handle handle,
>
> status = acpi_get_type(handle, &acpi_type);
> if (ACPI_FAILURE(status))
> - return false;
> + return status;
>
> switch (acpi_type) {
> case ACPI_TYPE_PROCESSOR:
> @@ -663,11 +663,12 @@ static acpi_status __init acpi_processor_ids_walk(acpi_handle handle,
> }
>
> processor_validated_ids_update(uid);
> - return true;
> + return AE_OK;
>
> err:
> + /* Exit on error, but don't abort the namespace walk */
> acpi_handle_info(handle, "Invalid processor object\n");
> - return false;
> + return AE_OK;
>
> }
>
>
Applied, thanks!
