Re: [PATCH] ACPI / APEI: Fix parsing HEST that includes Deferred Machine Check subtable

[Borislav Petkov]

On Mon, Nov 12, 2018 at 07:00:55PM +0000, Ghannam, Yazen wrote:
> From: Yazen Ghannam <yazen.ghannam@xxxxxxx>
> 
> ACPI 6.2 includes a new definition for a Deferred Machine Check "DMC"
> subtable.
> 
> The definition of this subtable was included in following commit:
> 
> c042933df2b1 ("ACPICA: Add support for new HEST subtable")
> 
> However, the HEST parsing function was not updated to include this new
> subtable. Therefore, Linux will fail to parse the HEST on systems that
> include a DMC entry.
> 
> Add the length check for the new DMC subtable so that HEST parsing
> doesn't fail on systems that include it.
> 
> Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
> ---
>  drivers/acpi/apei/hest.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/acpi/apei/hest.c b/drivers/acpi/apei/hest.c
> index b1e9f81ebeea..0935a0ef37e5 100644
> --- a/drivers/acpi/apei/hest.c
> +++ b/drivers/acpi/apei/hest.c
> @@ -53,6 +53,7 @@ static const int hest_esrc_len_tab[ACPI_HEST_TYPE_RESERVED] = {
>  	[ACPI_HEST_TYPE_AER_BRIDGE] = sizeof(struct acpi_hest_aer_bridge),
>  	[ACPI_HEST_TYPE_GENERIC_ERROR] = sizeof(struct acpi_hest_generic),
>  	[ACPI_HEST_TYPE_GENERIC_ERROR_V2] = sizeof(struct acpi_hest_generic_v2),
> +	[ACPI_HEST_TYPE_IA32_DEFERRED_CHECK] = -1,
>  };
>  
>  static int hest_esrc_len(struct acpi_hest_header *hest_hdr)
> @@ -75,6 +76,11 @@ static int hest_esrc_len(struct acpi_hest_header *hest_hdr)
>  		mc = (struct acpi_hest_ia_machine_check *)hest_hdr;
>  		len = sizeof(*mc) + mc->num_hardware_banks *
>  			sizeof(struct acpi_hest_ia_error_bank);
> +	} else if (hest_type == ACPI_HEST_TYPE_IA32_DEFERRED_CHECK) {
> +		struct acpi_hest_ia_deferred_check *mc;
> +		mc = (struct acpi_hest_ia_deferred_check *)hest_hdr;
> +		len = sizeof(*mc) + mc->num_hardware_banks *
> +			sizeof(struct acpi_hest_ia_error_bank);
>  	}
>  	BUG_ON(len == -1);
>  
> -- 

Reviewed-by: Borislav Petkov <bp@xxxxxxx>

-- 
Regards/Gruss,
    Boris.

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