Patch "ACPI / CPPC: Prevent cpc_desc_ptr points to the invalid data" has been added to the 4.4-stable tree

Patch "ACPI / CPPC: Prevent cpc_desc_ptr points to the invalid data" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ACPI / CPPC: Prevent cpc_desc_ptr points to the invalid data

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     acpi-cppc-prevent-cpc_desc_ptr-points-to-the-invalid-data.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 2324d15447a9db168b1f85e3feac635b1ff8edb8 Mon Sep 17 00:00:00 2001
From: Hoan Tran <hotran@apm.com>
Date: Wed, 25 May 2016 12:09:23 -0700
Subject: ACPI / CPPC: Prevent cpc_desc_ptr points to the invalid data

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);
 


Patches currently in stable-queue which might be from hotran@apm.com are

queue-4.4/acpi-cppc-return-error-if-_cpc-is-invalid-on-a-cpu.patch
queue-4.4/acpi-cppc-prevent-cpc_desc_ptr-points-to-the-invalid-data.patch