ACPI / ACPICA: Avoid crashing if _PRW is defined for the root object
Some ACPI BIOSes define _PRW for the root object which causes
acpi_setup_gpe_for_wake() to crash when trying to dereference the
bogus device_node pointer. Avoid the crash by checking if
wake_device is not the root object before attempting to set up the
"implicit notify" mechanism for it.
The problem was introduced by commit bba63a296ffab20e08d9e8252d2f0d99
(ACPICA: Implicit notify support) that added the wake_device argument
to acpi_setup_gpe_for_wake().
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/drivers/acpi/acpica/evxfgpe.c b/drivers/acpi/acpica/evxfgpe.c
index e9562a7..3b20a34 100644
--- a/drivers/acpi/acpica/evxfgpe.c
+++ b/drivers/acpi/acpica/evxfgpe.c
@@ -212,37 +212,40 @@
return_ACPI_STATUS(AE_BAD_PARAMETER);
}
- /* Validate wake_device is of type Device */
-
- device_node = ACPI_CAST_PTR(struct acpi_namespace_node, wake_device);
- if (device_node->type != ACPI_TYPE_DEVICE) {
- return_ACPI_STATUS(AE_BAD_PARAMETER);
- }
-
flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
/* Ensure that we have a valid GPE number */
gpe_event_info = acpi_ev_get_gpe_event_info(gpe_device, gpe_number);
- if (gpe_event_info) {
- /*
- * If there is no method or handler for this GPE, then the
- * wake_device will be notified whenever this GPE fires (aka
- * "implicit notify") Note: The GPE is assumed to be
- * level-triggered (for windows compatibility).
- */
- if ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
- ACPI_GPE_DISPATCH_NONE) {
- gpe_event_info->flags =
- (ACPI_GPE_DISPATCH_NOTIFY |
- ACPI_GPE_LEVEL_TRIGGERED);
- gpe_event_info->dispatch.device_node = device_node;
- }
-
- gpe_event_info->flags |= ACPI_GPE_CAN_WAKE;
- status = AE_OK;
+ if (!gpe_event_info) {
+ goto unlock_and_exit;
}
+ /*
+ * If there is no method or handler for this GPE, then the
+ * wake_device will be notified whenever this GPE fires (aka
+ * "implicit notify") Note: The GPE is assumed to be
+ * level-triggered (for windows compatibility).
+ */
+ if (((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
+ ACPI_GPE_DISPATCH_NONE) && (wake_device != ACPI_ROOT_OBJECT)) {
+
+ /* Validate wake_device is of type Device */
+
+ device_node = ACPI_CAST_PTR(struct acpi_namespace_node,
+ wake_device);
+ if (device_node->type != ACPI_TYPE_DEVICE) {
+ goto unlock_and_exit;
+ }
+ gpe_event_info->flags = (ACPI_GPE_DISPATCH_NOTIFY |
+ ACPI_GPE_LEVEL_TRIGGERED);
+ gpe_event_info->dispatch.device_node = device_node;
+ }
+
+ gpe_event_info->flags |= ACPI_GPE_CAN_WAKE;
+ status = AE_OK;
+
+ unlock_and_exit:
acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
return_ACPI_STATUS(status);
}