ACPICA: Fix mutex errors when running _REG methods

Fixes a problem where mutex errors can occur when running a _REG
method that is in the same scope as a method-defined operation
region or an operation region under a module-level IF block.
This is rare, so the problem has not been seen before.
ACPICA BZ 826.

http://www.acpica.org/bugzilla/show_bug.cgi?id=826

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>

1 files changed, 20 insertions, 11 deletions

diff --git a/drivers/acpi/acpica/dswload.c b/drivers/acpi/acpica/dswload.c
index 9cc2289f872e..b40513dd6a6a 100644
--- a/drivers/acpi/acpica/dswload.c
+++ b/drivers/acpi/acpica/dswload.c
@@ -1052,9 +1052,22 @@ acpi_status acpi_ds_load2_end_op(struct acpi_walk_state *walk_state)
                         }
 
                         /*
-                         * If we are executing a method, initialize the region
+                         * The op_region is not fully parsed at this time. The only valid
+                         * argument is the space_id. (We must save the address of the
+                         * AML of the address and length operands)
+                         *
+                         * If we have a valid region, initialize it. The namespace is
+                         * unlocked at this point.
+                         *
+                         * Need to unlock interpreter if it is locked (if we are running
+                         * a control method), in order to allow _REG methods to be run
+                         * during acpi_ev_initialize_region.
                          */
                         if (walk_state->method_node) {
+                                /*
+                                 * Executing a method: initialize the region and unlock
+                                 * the interpreter
+                                 */
                                 status =
                                     acpi_ex_create_region(op->named.data,
                                                           op->named.length,
@@ -1063,21 +1076,17 @@ acpi_status acpi_ds_load2_end_op(struct acpi_walk_state *walk_state)
                                 if (ACPI_FAILURE(status)) {
                                         return (status);
                                 }
-                        }
 
-                        /*
-                         * The op_region is not fully parsed at this time. Only valid
-                         * argument is the space_id. (We must save the address of the
-                         * AML of the address and length operands)
-                         */
+                                acpi_ex_exit_interpreter();
+                        }
 
-                        /*
-                         * If we have a valid region, initialize it
-                         * Namespace is NOT locked at this point.
-                         */
                         status =
                             acpi_ev_initialize_region
                             (acpi_ns_get_attached_object(node), FALSE);
+                        if (walk_state->method_node) {
+                                acpi_ex_enter_interpreter();
+                        }
+
                         if (ACPI_FAILURE(status)) {
                                 /*
                                  *  If AE_NOT_EXIST is returned, it is not fatal