ACPICA: Report error if method creates 2 objects with the same name

Fixed a regression where an error was no
longer emitted if a control method attempts to create 2
objects of the same name. This previously and now returns
AE_ALREADY_EXISTS. When this exception occurs, it invokes
the mechanism that will dynamically serialize the control
method to possible prevent future errors. (BZ 440)

Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 17 insertions, 3 deletions

diff --git a/drivers/acpi/dispatcher/dswload.c b/drivers/acpi/dispatcher/dswload.c
index d60d0625b11c..565d4557d0e0 100644
--- a/drivers/acpi/dispatcher/dswload.c
+++ b/drivers/acpi/dispatcher/dswload.c
@@ -547,6 +547,7 @@ acpi_ds_load2_begin_op(struct acpi_walk_state *walk_state,
         acpi_status status;
         acpi_object_type object_type;
         char *buffer_ptr;
+        u32 flags;
 
         ACPI_FUNCTION_TRACE(ds_load2_begin_op);
 
@@ -752,12 +753,20 @@ acpi_ds_load2_begin_op(struct acpi_walk_state *walk_state,
                         break;
                 }
 
-                /* Add new entry into namespace */
+                flags = ACPI_NS_NO_UPSEARCH;
+                if (walk_state->pass_number == 3) {
+
+                        /* Execution mode, node cannot already exist */
+
+                        flags |= ACPI_NS_ERROR_IF_FOUND;
+                }
+
+                /* Add new entry or lookup existing entry */
 
                 status =
                     acpi_ns_lookup(walk_state->scope_info, buffer_ptr,
-                                   object_type, ACPI_IMODE_LOAD_PASS2,
-                                   ACPI_NS_NO_UPSEARCH, walk_state, &(node));
+                                   object_type, ACPI_IMODE_LOAD_PASS2, flags,
+                                   walk_state, &node);
                 break;
         }
 
diff --git a/drivers/acpi/parser/psparse.c b/drivers/acpi/parser/psparse.c
index a02aa62fe1e5..6e875cea17a9 100644
--- a/drivers/acpi/parser/psparse.c
+++ b/drivers/acpi/parser/psparse.c
@@ -540,6 +540,11 @@ acpi_status acpi_ps_parse_aml(struct acpi_walk_state *walk_state)
 
                         if ((status == AE_ALREADY_EXISTS) &&
                             (!walk_state->method_desc->method.mutex)) {
+                                ACPI_INFO((AE_INFO,
+                                           "Marking method %4.4s as Serialized",
+                                           walk_state->method_node->name.
+                                           ascii));
+
                                 /*
                                  * Method tried to create an object twice. The probable cause is
                                  * that the method cannot handle reentrancy.