ACPICA: Fix AcpiWalkNamespace race condition with table unload

[safe/jmp/linux-2.6] / drivers / acpi / acpica / tbinstal.c

diff --git a/drivers/acpi/acpica/tbinstal.c b/drivers/acpi/acpica/tbinstal.c
index c379930..f865d5a 100644 (file)
--- a/drivers/acpi/acpica/tbinstal.c
+++ b/drivers/acpi/acpica/tbinstal.c
@@ -434,27 +434,56 @@ void acpi_tb_terminate(void)
  *
  * PARAMETERS:  table_index         - Table index
  *
- * RETURN:      None
+ * RETURN:      Status
  *
  * DESCRIPTION: Delete all namespace objects created when this table was loaded.
  *
  ******************************************************************************/
 
-void acpi_tb_delete_namespace_by_owner(u32 table_index)
+acpi_status acpi_tb_delete_namespace_by_owner(u32 table_index)
 {
        acpi_owner_id owner_id;
+       acpi_status status;
+
+       ACPI_FUNCTION_TRACE(tb_delete_namespace_by_owner);
+
+       status = acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
+       if (ACPI_FAILURE(status)) {
+               return_ACPI_STATUS(status);
+       }
+
+       if (table_index >= acpi_gbl_root_table_list.count) {
+
+               /* The table index does not exist */
 
-       (void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
-       if (table_index < acpi_gbl_root_table_list.count) {
-               owner_id =
-                   acpi_gbl_root_table_list.tables[table_index].owner_id;
-       } else {
                (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
-               return;
+               return_ACPI_STATUS(AE_NOT_EXIST);
        }
 
+       /* Get the owner ID for this table, used to delete namespace nodes */
+
+       owner_id = acpi_gbl_root_table_list.tables[table_index].owner_id;
        (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
+
+       /*
+        * Need to acquire the namespace writer lock to prevent interference
+        * with any concurrent namespace walks. The interpreter must be
+        * released during the deletion since the acquisition of the deletion
+        * lock may block, and also since the execution of a namespace walk
+        * must be allowed to use the interpreter.
+        */
+       acpi_ut_release_mutex(ACPI_MTX_INTERPRETER);
+       status = acpi_ut_acquire_write_lock(&acpi_gbl_namespace_rw_lock);
+
        acpi_ns_delete_namespace_by_owner(owner_id);
+       if (ACPI_FAILURE(status)) {
+               return_ACPI_STATUS(status);
+       }
+
+       acpi_ut_release_write_lock(&acpi_gbl_namespace_rw_lock);
+
+       status = acpi_ut_acquire_mutex(ACPI_MTX_INTERPRETER);
+       return_ACPI_STATUS(status);
 }
 
 /*******************************************************************************