ACPI / memhotplug: Fix a stale pointer in error path

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@hp.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: 2.6.32+ <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index c711d11..999adb5 100644 (file)
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -323,6 +323,7 @@ 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;
        }