Patch "ACPI: CPPC: Return error if _CPC is invalid on a CPU" has been added to the 4.4-stable tree

Patch "ACPI: CPPC: Return error if _CPC is invalid on a CPU" 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: Return error if _CPC is invalid on a CPU

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-return-error-if-_cpc-is-invalid-on-a-cpu.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 8343c40d3de32ebfe8f48b043964e4ba0e7701f7 Mon Sep 17 00:00:00 2001
From: Hoan Tran <hotran@apm.com>
Date: Fri, 17 Jun 2016 15:16:31 -0700
Subject: ACPI: CPPC: Return error if _CPC is invalid on a CPU

From: Hoan Tran <hotran@apm.com>

commit 8343c40d3de32ebfe8f48b043964e4ba0e7701f7 upstream.

Based on 8.4.7.1 section of ACPI 6.1 specification, if the platform
supports CPPC, the _CPC object must exist under all processor objects.
If cpc_desc_ptr pointer is invalid on any CPUs, acpi_get_psd_map()
should return error and CPPC cpufreq driver can not be registered.

Signed-off-by: Hoan Tran <hotran@apm.com>
Reviewed-by: Prashanth Prakash <pprakash@codeaurora.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 |   18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -216,8 +216,10 @@ int acpi_get_psd_map(struct cpudata **al
 			continue;
 
 		cpc_ptr = per_cpu(cpc_desc_ptr, i);
-		if (!cpc_ptr)
-			continue;
+		if (!cpc_ptr) {
+			retval = -EFAULT;
+			goto err_ret;
+		}
 
 		pdomain = &(cpc_ptr->domain_info);
 		cpumask_set_cpu(i, pr->shared_cpu_map);
@@ -239,8 +241,10 @@ int acpi_get_psd_map(struct cpudata **al
 				continue;
 
 			match_cpc_ptr = per_cpu(cpc_desc_ptr, j);
-			if (!match_cpc_ptr)
-				continue;
+			if (!match_cpc_ptr) {
+				retval = -EFAULT;
+				goto err_ret;
+			}
 
 			match_pdomain = &(match_cpc_ptr->domain_info);
 			if (match_pdomain->domain != pdomain->domain)
@@ -270,8 +274,10 @@ int acpi_get_psd_map(struct cpudata **al
 				continue;
 
 			match_cpc_ptr = per_cpu(cpc_desc_ptr, j);
-			if (!match_cpc_ptr)
-				continue;
+			if (!match_cpc_ptr) {
+				retval = -EFAULT;
+				goto err_ret;
+			}
 
 			match_pdomain = &(match_cpc_ptr->domain_info);
 			if (match_pdomain->domain != pdomain->domain)


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