1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/acpi/executer/exmutex.c b/drivers/acpi/executer/exmutex.c
index b8d035c00b61..7c70938eef89 100644
--- a/drivers/acpi/executer/exmutex.c
+++ b/drivers/acpi/executer/exmutex.c
@@ -85,6 +85,7 @@ void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc)
         } else {
                 thread->acquired_mutex_list = obj_desc->mutex.next;
         }
+        return;
 }
 
 /*******************************************************************************
@@ -298,6 +299,17 @@ acpi_status acpi_ex_release_mutex_object(union acpi_operand_object *obj_desc)
                 return (AE_NOT_ACQUIRED);
         }
 
+        /* No obj_desc->Mutex.owner_thread for Global Lock */
+
+        /*
+         * Mutex to be released must be at the head of acquired list to prevent
+         * deadlock. (The head of the list is the last mutex acquired.)
+         */
+        if (obj_desc->mutex.owner_thread &&
+            (obj_desc != obj_desc->mutex.owner_thread->acquired_mutex_list)) {
+                return (AE_AML_MUTEX_ORDER);
+        }
+
         /* Match multiple Acquires with multiple Releases */
 
         obj_desc->mutex.acquisition_depth--;
@@ -403,6 +415,9 @@ acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
         }
 
         status = acpi_ex_release_mutex_object(obj_desc);
+        if (ACPI_FAILURE(status)) {
+                return_ACPI_STATUS(status);
+        }
 
         if (obj_desc->mutex.acquisition_depth == 0) {
 
@@ -411,6 +426,7 @@ acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
                 walk_state->thread->current_sync_level =
                     obj_desc->mutex.original_sync_level;
         }
+
         return_ACPI_STATUS(status);
 }