[PATCH 12/30] score: Protect thread scheduler state changes

[Sebastian Huber]

Update #2556.
---
 cpukit/score/include/rtems/score/schedulerimpl.h   | 31 +++++++++---
 .../score/include/rtems/score/schedulersmpimpl.h   | 57 +++++++++++++---------
 2 files changed, 58 insertions(+), 30 deletions(-)

diff --git a/cpukit/score/include/rtems/score/schedulerimpl.h b/cpukit/score/include/rtems/score/schedulerimpl.h
index 3108641..7c74765 100644
--- a/cpukit/score/include/rtems/score/schedulerimpl.h
+++ b/cpukit/score/include/rtems/score/schedulerimpl.h
@@ -21,6 +21,7 @@
 #define _RTEMS_SCORE_SCHEDULERIMPL_H
 
 #include <rtems/score/scheduler.h>
+#include <rtems/score/assert.h>
 #include <rtems/score/cpusetimpl.h>
 #include <rtems/score/priorityimpl.h>
 #include <rtems/score/smpimpl.h>
@@ -867,6 +868,11 @@ RTEMS_INLINE_ROUTINE void _Scheduler_Thread_change_state(
     _Scheduler_Thread_state_valid_state_changes
       [ the_thread->Scheduler.state ][ new_state ]
   );
+  _Assert(
+    _ISR_lock_Is_owner( &the_thread->Scheduler.Lock )
+      || the_thread->Scheduler.state == THREAD_SCHEDULER_BLOCKED
+      || !_System_state_Is_up( _System_state_Get() )
+  );
 
   the_thread->Scheduler.state = new_state;
 }
@@ -983,18 +989,23 @@ _Scheduler_Try_to_schedule_node(
   Scheduler_Get_idle_thread  get_idle_thread
 )
 {
-  Scheduler_Try_to_schedule_action action;
-  Thread_Control *owner;
-  Thread_Control *user;
+  ISR_lock_Context                  lock_context;
+  Scheduler_Try_to_schedule_action  action;
+  Thread_Control                   *owner;
+  Thread_Control                   *user;
 
   action = SCHEDULER_TRY_TO_SCHEDULE_DO_SCHEDULE;
+  user = _Scheduler_Node_get_user( node );
+
+  _Thread_Scheduler_acquire_critical( user, &lock_context );
 
   if ( node->help_state == SCHEDULER_HELP_YOURSELF ) {
+    _Scheduler_Thread_change_state( user, THREAD_SCHEDULER_SCHEDULED );
+    _Thread_Scheduler_release_critical( user, &lock_context );
     return action;
   }
 
   owner = _Scheduler_Node_get_owner( node );
-  user = _Scheduler_Node_get_user( node );
 
   if ( node->help_state == SCHEDULER_HELP_ACTIVE_RIVAL) {
     if ( user->Scheduler.state == THREAD_SCHEDULER_READY ) {
@@ -1026,6 +1037,11 @@ _Scheduler_Try_to_schedule_node(
     }
   }
 
+  if ( action == SCHEDULER_TRY_TO_SCHEDULE_DO_SCHEDULE ) {
+    _Scheduler_Thread_change_state( user, THREAD_SCHEDULER_SCHEDULED );
+  }
+
+  _Thread_Scheduler_release_critical( user, &lock_context );
   return action;
 }
 
@@ -1097,10 +1113,13 @@ RTEMS_INLINE_ROUTINE bool _Scheduler_Block_node(
   Scheduler_Get_idle_thread  get_idle_thread
 )
 {
-  Thread_Control *old_user;
-  Thread_Control *new_user;
+  ISR_lock_Context  lock_context;
+  Thread_Control   *old_user;
+  Thread_Control   *new_user;
 
+  _Thread_Scheduler_acquire_critical( thread, &lock_context );
   _Scheduler_Thread_change_state( thread, THREAD_SCHEDULER_BLOCKED );
+  _Thread_Scheduler_release_critical( thread, &lock_context );
 
   if ( node->help_state == SCHEDULER_HELP_YOURSELF ) {
     _Assert( thread == _Scheduler_Node_get_user( node ) );
diff --git a/cpukit/score/include/rtems/score/schedulersmpimpl.h b/cpukit/score/include/rtems/score/schedulersmpimpl.h
index eced51b..e5423ff 100644
--- a/cpukit/score/include/rtems/score/schedulersmpimpl.h
+++ b/cpukit/score/include/rtems/score/schedulersmpimpl.h
@@ -526,22 +526,44 @@ static inline void _Scheduler_SMP_Allocate_processor_exact(
 static inline void _Scheduler_SMP_Allocate_processor(
   Scheduler_Context                *context,
   Scheduler_Node                   *scheduled,
-  Scheduler_Node                   *victim,
+  Thread_Control                   *victim_thread,
   Scheduler_SMP_Allocate_processor  allocate_processor
 )
 {
   Thread_Control *scheduled_thread = _Scheduler_Node_get_user( scheduled );
-  Thread_Control *victim_thread = _Scheduler_Node_get_user( victim );
 
   _Scheduler_SMP_Node_change_state( scheduled, SCHEDULER_SMP_NODE_SCHEDULED );
-  _Scheduler_Thread_change_state(
-    scheduled_thread,
-    THREAD_SCHEDULER_SCHEDULED
-  );
 
   ( *allocate_processor )( context, scheduled_thread, victim_thread );
 }
 
+static inline Thread_Control *_Scheduler_SMP_Preempt(
+  Scheduler_Context                *context,
+  Scheduler_Node                   *scheduled,
+  Scheduler_Node                   *victim,
+  Scheduler_SMP_Allocate_processor  allocate_processor
+)
+{
+  Thread_Control   *victim_thread;
+  ISR_lock_Context  lock_context;
+
+  victim_thread = _Scheduler_Node_get_user( victim );
+  _Scheduler_SMP_Node_change_state( victim, SCHEDULER_SMP_NODE_READY );
+
+  _Thread_Scheduler_acquire_critical( victim_thread, &lock_context );
+  _Scheduler_Thread_change_state( victim_thread, THREAD_SCHEDULER_READY );
+  _Thread_Scheduler_release_critical( victim_thread, &lock_context );
+
+  _Scheduler_SMP_Allocate_processor(
+    context,
+    scheduled,
+    victim_thread,
+    allocate_processor
+  );
+
+  return victim_thread;
+}
+
 static inline Scheduler_Node *_Scheduler_SMP_Get_lowest_scheduled(
   Scheduler_Context *context,
   Scheduler_Node    *filter,
@@ -581,20 +603,10 @@ static inline Thread_Control *_Scheduler_SMP_Enqueue_to_scheduled(
   );
 
   if ( action == SCHEDULER_TRY_TO_SCHEDULE_DO_SCHEDULE ) {
-    Thread_Control *lowest_scheduled_user =
-      _Scheduler_Node_get_user( lowest_scheduled );
+    Thread_Control *lowest_scheduled_user;
     Thread_Control *idle;
 
-    _Scheduler_SMP_Node_change_state(
-      lowest_scheduled,
-      SCHEDULER_SMP_NODE_READY
-    );
-    _Scheduler_Thread_change_state(
-      lowest_scheduled_user,
-      THREAD_SCHEDULER_READY
-    );
-
-    _Scheduler_SMP_Allocate_processor(
+    lowest_scheduled_user = _Scheduler_SMP_Preempt(
       context,
       node,
       lowest_scheduled,
@@ -748,13 +760,10 @@ static inline Thread_Control *_Scheduler_SMP_Enqueue_scheduled_ordered(
     );
 
     if ( action == SCHEDULER_TRY_TO_SCHEDULE_DO_SCHEDULE ) {
-      Thread_Control *user = _Scheduler_Node_get_user( node );
+      Thread_Control *user;
       Thread_Control *idle;
 
-      _Scheduler_SMP_Node_change_state( node, SCHEDULER_SMP_NODE_READY );
-      _Scheduler_Thread_change_state( user, THREAD_SCHEDULER_READY );
-
-      _Scheduler_SMP_Allocate_processor(
+      user = _Scheduler_SMP_Preempt(
         context,
         highest_ready,
         node,
@@ -836,7 +845,7 @@ static inline void _Scheduler_SMP_Schedule_highest_ready(
       _Scheduler_SMP_Allocate_processor(
         context,
         highest_ready,
-        victim,
+        _Scheduler_Node_get_user( victim ),
         allocate_processor
       );
 
-- 
1.8.4.5