[PATCH 17/75] ACPI / memhotplug: Fix a stale pointer in error path

[Kamal Mostafa]

3.8.13.6 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Toshi Kani <toshi.kani at hp.com>

commit d19f503e22316a84c39bc19445e0e4fdd49b3532 upstream.

device->driver_data needs to be cleared when releasing its data,
mem_device, in an error path of acpi_memory_device_add().

The function evaluates the _CRS of memory device objects, and fails
when it gets an unexpected resource or cannot allocate memory.  A
kernel crash or data corruption may occur when the kernel accesses
the stale pointer.

Signed-off-by: Toshi Kani <toshi.kani at hp.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki at jp.fujitsu.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/acpi/acpi_memhotplug.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index b679bf8..6d11ec6 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -406,6 +406,7 @@ static int acpi_memory_device_add(struct acpi_device *device)
 	/* Get the range from the _CRS */
 	result = acpi_memory_get_device_resources(mem_device);
 	if (result) {
+		device->driver_data = NULL;
 		kfree(mem_device);
 		return result;
 	}
-- 
1.8.1.2