lkml.org 
[lkml]   [2016]   [May]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH] acpi: cppc: Prevent cpc_desc_ptr points to the invalid data
On 25 May 2016 at 15:09, Hoan Tran <hotran@apm.com> wrote:
> When CPPC fails to request PCC channel, the CPC data is freed
> and cpc_desc_ptr points to the invalid data. This change prevents
> this issue by moving cpc_desc_ptr assignment after PCC channel
> request.
>
> Signed-off-by: Hoan Tran <hotran@apm.com>
> ---
> drivers/acpi/cppc_acpi.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index 8adac69..85fd8f7 100644
> --- a/drivers/acpi/cppc_acpi.c
> +++ b/drivers/acpi/cppc_acpi.c
> @@ -595,9 +595,6 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
> /* Store CPU Logical ID */
> cpc_ptr->cpu_id = pr->id;
>
> - /* Plug it into this CPUs CPC descriptor. */
> - per_cpu(cpc_desc_ptr, pr->id) = cpc_ptr;
> -
> /* Parse PSD data for this CPU */
> ret = acpi_get_psd(cpc_ptr, handle);
> if (ret)
> @@ -610,6 +607,9 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
> goto out_free;
> }
>
> + /* Plug PSD data into this CPUs CPC descriptor. */
> + per_cpu(cpc_desc_ptr, pr->id) = cpc_ptr;
> +

Are you seeing a real problem without this change? I'm missing where
this pointer is dereferenced if the PCC channel request fails.

Thanks,
Ashwin.

\
 
 \ /
  Last update: 2016-05-27 18:41    [W:0.069 / U:0.160 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site