ACPI / scan: not cache _SUN value in struct acpi_device_pnp
The _SUN device indentification object is not guaranteed to return
the same value every time it is executed, so we should not cache its
return value, but rather execute it every time as needed. If it is
cached, an incorrect stale value may be used in some situations.
This issue was exposed by commit 202317a573b2 (ACPI / scan: Add
acpi_device objects for all device nodes in the namespace). Fix it
by avoiding to cache the return value of _SUN.
Fixes: 202317a573b2 (ACPI / scan: Add acpi_device objects for all device nodes in the namespace)
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: 3.14+ <stable@vger.kernel.org> # 3.14+
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 9a92989..3bf7764 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -667,8 +667,14 @@
acpi_device_sun_show(struct device *dev, struct device_attribute *attr,
char *buf) {
struct acpi_device *acpi_dev = to_acpi_device(dev);
+ acpi_status status;
+ unsigned long long sun;
- return sprintf(buf, "%lu\n", acpi_dev->pnp.sun);
+ status = acpi_evaluate_integer(acpi_dev->handle, "_SUN", NULL, &sun);
+ if (ACPI_FAILURE(status))
+ return -ENODEV;
+
+ return sprintf(buf, "%llu\n", sun);
}
static DEVICE_ATTR(sun, 0444, acpi_device_sun_show, NULL);
@@ -690,7 +696,6 @@
{
struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
acpi_status status;
- unsigned long long sun;
int result = 0;
/*
@@ -731,14 +736,10 @@
if (dev->pnp.unique_id)
result = device_create_file(&dev->dev, &dev_attr_uid);
- status = acpi_evaluate_integer(dev->handle, "_SUN", NULL, &sun);
- if (ACPI_SUCCESS(status)) {
- dev->pnp.sun = (unsigned long)sun;
+ if (acpi_has_method(dev->handle, "_SUN")) {
result = device_create_file(&dev->dev, &dev_attr_sun);
if (result)
goto end;
- } else {
- dev->pnp.sun = (unsigned long)-1;
}
if (acpi_has_method(dev->handle, "_STA")) {