ACPICA: Fix AcpiWalkNamespace race condition with table unload
Added a reader/writer locking mechanism to allow multiple
concurrent namespace walks (readers), but a dynamic table unload
will have exclusive access to the namespace. This fixes a problem
where a table unload could delete the portion of the namespace that
is currently being examined by a walk. Adds a new file, utlock.c
that implements the reader/writer lock mechanism. ACPICA BZ 749.
http://www.acpica.org/bugzilla/show_bug.cgi?id=749
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/acpica/exconfig.c b/drivers/acpi/acpica/exconfig.c
index 70b39c7..3deb20a 100644
--- a/drivers/acpi/acpica/exconfig.c
+++ b/drivers/acpi/acpica/exconfig.c
@@ -520,13 +520,14 @@
}
}
- /*
- * Delete the entire namespace under this table Node
- * (Offset contains the table_id)
- */
- acpi_tb_delete_namespace_by_owner(table_index);
- (void)acpi_tb_release_owner_id(table_index);
+ /* Delete the portion of the namespace owned by this table */
+ status = acpi_tb_delete_namespace_by_owner(table_index);
+ if (ACPI_FAILURE(status)) {
+ return_ACPI_STATUS(status);
+ }
+
+ (void)acpi_tb_release_owner_id(table_index);
acpi_tb_set_table_loaded_flag(table_index, FALSE);
/* Table unloaded, remove a reference to the ddb_handle object */