[PATCH 4.4 025/113] ACPI / CPPC: Prevent cpc_desc_ptr points to the invalid data

Greg Kroah-Hartman
2016-09-05T16:50:32Z

From: Hoan Tran <hotran@apm.com>

commit 2324d15447a9db168b1f85e3feac635b1ff8edb8 upstream.

When CPPC fails to request a PCC channel, the CPC data is freed
and cpc_desc_ptr points to the invalid data.

Avoid this issue by moving the cpc_desc_ptr assignment after the PCC
channel request.

Signed-off-by: Hoan Tran <hotran@apm.com>
Acked-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/acpi/cppc_acpi.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -508,9 +508,6 @@ int acpi_cppc_processor_probe(struct acp
/* 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)
@@ -523,6 +520,9 @@ int acpi_cppc_processor_probe(struct acp
goto out_free;
}

+ /* Plug PSD data into this CPUs CPC descriptor. */
+ per_cpu(cpc_desc_ptr, pr->id) = cpc_ptr;
+
/* Everything looks okay */
pr_debug("Parsed CPC struct for CPU: %d\n", pr->id);