[rtems commit] score: Fix and simplify thread wait locks

Sebastian Huber sebh at rtems.org
Wed Aug 3 11:57:54 UTC 2016


Module:    rtems
Branch:    master
Commit:    ff2e6c647d166fa54769f3c300855ef7f8020668
Changeset: http://git.rtems.org/rtems/commit/?id=ff2e6c647d166fa54769f3c300855ef7f8020668

Author:    Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:      Tue Aug  2 11:26:56 2016 +0200

score: Fix and simplify thread wait locks

There was a subtile race condition in _Thread_queue_Do_extract_locked().
It must first update the thread wait flags and then restore the default
thread wait state.  In the previous implementation this could lead under
rare timing conditions to an ineffective _Thread_Wait_tranquilize()
resulting to a corrupt system state.

Update #2556.

---

 cpukit/score/include/rtems/score/thread.h      |  11 ++
 cpukit/score/include/rtems/score/threadimpl.h  | 135 +++++++++++++------------
 cpukit/score/include/rtems/score/threadq.h     |  29 +-----
 cpukit/score/include/rtems/score/threadqimpl.h | 112 ++------------------
 cpukit/score/src/threadchangepriority.c        |   9 +-
 cpukit/score/src/threadinitialize.c            |   2 +-
 cpukit/score/src/threadqenqueue.c              |  44 ++++----
 cpukit/score/src/threadqops.c                  |  66 +++---------
 8 files changed, 139 insertions(+), 269 deletions(-)

diff --git a/cpukit/score/include/rtems/score/thread.h b/cpukit/score/include/rtems/score/thread.h
index d03f0c2..44080f3 100644
--- a/cpukit/score/include/rtems/score/thread.h
+++ b/cpukit/score/include/rtems/score/thread.h
@@ -326,6 +326,17 @@ typedef struct {
      * case the thread is enqueued on a thread queue.
      */
     Chain_Control Pending_requests;
+
+    /**
+     * @brief Tranquilizer gate used by _Thread_Wait_tranquilize().
+     *
+     * This gate is closed by _Thread_Wait_claim().  In case there are no
+     * pending requests during a _Thread_Wait_restore_default(), then this gate
+     * is opened immediately, otherwise it is placed on the pending request
+     * chain and opened by _Thread_Wait_remove_request_locked() as the last
+     * gate on the chain to signal overall request completion.
+     */
+    Thread_queue_Gate Tranquilizer;
   } Lock;
 
   /**
diff --git a/cpukit/score/include/rtems/score/threadimpl.h b/cpukit/score/include/rtems/score/threadimpl.h
index ea1c61f..965b2d1 100644
--- a/cpukit/score/include/rtems/score/threadimpl.h
+++ b/cpukit/score/include/rtems/score/threadimpl.h
@@ -1036,39 +1036,36 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_remove_request_locked(
   Thread_queue_Context *queue_context
 )
 {
-  _Chain_Extract_unprotected( &queue_context->Wait.Gate.Node );
-
-  if ( !_Chain_Is_empty( &the_thread->Wait.Lock.Pending_requests ) ) {
-    Thread_queue_Context *first;
+  Chain_Node *first;
 
-    first = THREAD_QUEUE_CONTEXT_OF_REQUEST(
-      _Chain_First( &the_thread->Wait.Lock.Pending_requests )
-    );
+  _Chain_Extract_unprotected( &queue_context->Wait.Gate.Node );
+  first = _Chain_First( &the_thread->Wait.Lock.Pending_requests );
 
-    _Thread_queue_Gate_open( &first->Wait.Gate );
+  if ( first != _Chain_Tail( &the_thread->Wait.Lock.Pending_requests ) ) {
+    _Thread_queue_Gate_open( (Thread_queue_Gate *) first );
   }
 }
 
 RTEMS_INLINE_ROUTINE void _Thread_Wait_acquire_queue_critical(
-  SMP_ticket_lock_Control *queue_lock,
-  Thread_queue_Context    *queue_context
+  Thread_queue_Queue   *queue,
+  Thread_queue_Context *queue_context
 )
 {
-  _SMP_ticket_lock_Acquire(
-    queue_lock,
+  _Thread_queue_Queue_acquire_critical(
+    queue,
     &_Thread_Executing->Potpourri_stats,
-    &queue_context->Lock_context.Lock_context.Stats_context
+    &queue_context->Lock_context
   );
 }
 
 RTEMS_INLINE_ROUTINE void _Thread_Wait_release_queue_critical(
-  SMP_ticket_lock_Control *queue_lock,
-  Thread_queue_Context    *queue_context
+  Thread_queue_Queue   *queue,
+  Thread_queue_Context *queue_context
 )
 {
-  _SMP_ticket_lock_Release(
-    queue_lock,
-    &queue_context->Lock_context.Lock_context.Stats_context
+  _Thread_queue_Queue_release_critical(
+    queue,
+    &queue_context->Lock_context
   );
 }
 #endif
@@ -1098,22 +1095,27 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_acquire_critical(
 
   queue = the_thread->Wait.queue;
   queue_context->Wait.queue = queue;
-  queue_context->Wait.operations = the_thread->Wait.operations;
 
   if ( queue != NULL ) {
-    queue_context->Wait.queue_lock = &queue->Lock;
-    _Chain_Initialize_node( &queue_context->Wait.Gate.Node );
-    _Chain_Append_unprotected(
+    _Thread_queue_Gate_add(
       &the_thread->Wait.Lock.Pending_requests,
-      &queue_context->Wait.Gate.Node
+      &queue_context->Wait.Gate
     );
     _Thread_Wait_release_default_critical(
       the_thread,
       &queue_context->Lock_context
     );
-    _Thread_Wait_acquire_queue_critical( &queue->Lock, queue_context );
-  } else {
-    queue_context->Wait.queue_lock = NULL;
+    _Thread_Wait_acquire_queue_critical( queue, queue_context );
+
+    if ( queue_context->Wait.queue == NULL ) {
+      _Thread_Wait_release_queue_critical( queue, queue_context );
+      _Thread_Wait_acquire_default_critical(
+        the_thread,
+        &queue_context->Lock_context
+      );
+      _Thread_Wait_remove_request_locked( the_thread, queue_context );
+      _Assert( the_thread->Wait.queue == NULL );
+    }
   }
 #else
   (void) the_thread;
@@ -1154,12 +1156,12 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_release_critical(
 )
 {
 #if defined(RTEMS_SMP)
-  SMP_ticket_lock_Control *queue_lock;
+  Thread_queue_Queue *queue;
 
-  queue_lock = queue_context->Wait.queue_lock;
+  queue = queue_context->Wait.queue;
 
-  if ( queue_lock != NULL ) {
-    _Thread_Wait_release_queue_critical( queue_lock, queue_context );
+  if ( queue != NULL ) {
+    _Thread_Wait_release_queue_critical( queue, queue_context );
     _Thread_Wait_acquire_default_critical(
       the_thread,
       &queue_context->Lock_context
@@ -1218,6 +1220,13 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_claim(
   _Thread_Wait_acquire_default_critical( the_thread, &lock_context );
 
   _Assert( the_thread->Wait.queue == NULL );
+
+#if defined(RTEMS_SMP)
+  _Chain_Initialize_empty( &the_thread->Wait.Lock.Pending_requests );
+  _Chain_Initialize_node( &the_thread->Wait.Lock.Tranquilizer.Node );
+  _Thread_queue_Gate_close( &the_thread->Wait.Lock.Tranquilizer );
+#endif
+
   the_thread->Wait.queue = queue;
   the_thread->Wait.operations = operations;
 
@@ -1273,22 +1282,27 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_restore_default(
   Chain_Node       *node;
   const Chain_Node *tail;
 
-  _Thread_Wait_acquire_default_critical(
-    the_thread,
-    &lock_context
-  );
+  _Thread_Wait_acquire_default_critical( the_thread, &lock_context );
 
   node = _Chain_First( &the_thread->Wait.Lock.Pending_requests );
   tail = _Chain_Immutable_tail( &the_thread->Wait.Lock.Pending_requests );
 
-  while ( node != tail ) {
-    Thread_queue_Context *queue_context;
+  if ( node != tail ) {
+    do {
+      Thread_queue_Context *queue_context;
 
-    queue_context = THREAD_QUEUE_CONTEXT_OF_REQUEST( node );
-    queue_context->Wait.queue = NULL;
-    queue_context->Wait.operations = &_Thread_queue_Operations_stale_queue;
+      queue_context = THREAD_QUEUE_CONTEXT_OF_REQUEST( node );
+      queue_context->Wait.queue = NULL;
 
-    node = _Chain_Next( node );
+      node = _Chain_Next( node );
+    } while ( node != tail );
+
+    _Thread_queue_Gate_add(
+      &the_thread->Wait.Lock.Pending_requests,
+      &the_thread->Wait.Lock.Tranquilizer
+    );
+  } else {
+    _Thread_queue_Gate_open( &the_thread->Wait.Lock.Tranquilizer );
   }
 #endif
 
@@ -1296,15 +1310,12 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_restore_default(
   the_thread->Wait.operations = &_Thread_queue_Operations_default;
 
 #if defined(RTEMS_SMP)
-  _Thread_Wait_release_default_critical(
-    the_thread,
-    &lock_context
-  );
+  _Thread_Wait_release_default_critical( the_thread, &lock_context );
 #endif
 }
 
 /**
- * @brief Tranquilizes the thread after a wait a thread queue.
+ * @brief Tranquilizes the thread after a wait on a thread queue.
  *
  * After the violent blocking procedure this function makes the thread calm and
  * peaceful again so that it can carry out its normal work.
@@ -1314,6 +1325,11 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_restore_default(
  *
  * On other configurations, this function does nothing.
  *
+ * It must be called after a _Thread_Wait_claim() exactly once
+ *  - after the corresponding thread queue lock was released, and
+ *  - the default wait state is restored or some other processor is about to do
+ *    this.
+ *
  * @param[in] the_thread The thread.
  */
 RTEMS_INLINE_ROUTINE void _Thread_Wait_tranquilize(
@@ -1321,22 +1337,7 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_tranquilize(
 )
 {
 #if defined(RTEMS_SMP)
-  Thread_queue_Context queue_context;
-
-  _Thread_queue_Context_initialize( &queue_context );
-  _Thread_Wait_acquire_default( the_thread, &queue_context.Lock_context );
-
-  if ( !_Chain_Is_empty( &the_thread->Wait.Lock.Pending_requests ) ) {
-    _Thread_queue_Gate_add(
-      &the_thread->Wait.Lock.Pending_requests,
-      &queue_context.Wait.Gate
-    );
-    _Thread_Wait_release_default( the_thread, &queue_context.Lock_context );
-    _Thread_queue_Gate_wait( &queue_context.Wait.Gate );
-    _Thread_Wait_remove_request( the_thread, &queue_context );
-  } else {
-    _Thread_Wait_release_default( the_thread, &queue_context.Lock_context );
-  }
+  _Thread_queue_Gate_wait( &the_thread->Wait.Lock.Tranquilizer );
 #else
   (void) the_thread;
 #endif
@@ -1354,13 +1355,21 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_cancel(
   Thread_queue_Context *queue_context
 )
 {
-  _Thread_queue_Context_extract( queue_context, the_thread );
+  Thread_queue_Queue *queue;
+
+  queue = the_thread->Wait.queue;
 
 #if defined(RTEMS_SMP)
-  if ( queue_context->Wait.queue != NULL ) {
+  if ( queue != NULL ) {
+    _Assert( queue_context->Wait.queue == queue );
 #endif
+
+    ( *the_thread->Wait.operations->extract )( queue, the_thread );
     _Thread_Wait_restore_default( the_thread );
+
 #if defined(RTEMS_SMP)
+    _Assert( queue_context->Wait.queue == NULL );
+    queue_context->Wait.queue = queue;
   }
 #endif
 }
diff --git a/cpukit/score/include/rtems/score/threadq.h b/cpukit/score/include/rtems/score/threadq.h
index a39a031..3c689ac 100644
--- a/cpukit/score/include/rtems/score/threadq.h
+++ b/cpukit/score/include/rtems/score/threadq.h
@@ -164,27 +164,9 @@ typedef struct {
     Thread_queue_Gate Gate;
 
     /**
-     * @brief The thread queue lock in case the thread is blocked on a thread
-     * queue at thread wait lock acquire time.
-     */
-    SMP_ticket_lock_Control *queue_lock;
-
-    /**
-     * @brief The thread queue after thread wait lock acquire.
-     *
-     * In case the thread queue is NULL and the thread queue lock is non-NULL
-     * in this context, then we have a stale thread queue.  This happens in
-     * case the thread wait default is restored while we wait on the thread
-     * queue lock, e.g. during a mutex ownership transfer.
-     *
-     * @see _Thread_Wait_restore_default().
+     * @brief The thread queue in case the thread is blocked on a thread queue.
      */
     Thread_queue_Queue *queue;
-
-    /**
-     * @brief The thread queue operations after thread wait lock acquire.
-     */
-    const Thread_queue_Operations *operations;
   } Wait;
 #endif
 } Thread_queue_Context;
@@ -349,19 +331,16 @@ struct Thread_queue_Queue {
 /**
  * @brief Thread queue priority change operation.
  *
+ * @param[in] queue The actual thread queue.
  * @param[in] the_thread The thread.
  * @param[in] new_priority The new priority value.
- * @param[in] prepend_it In case this is true, then the thread is prepended to
- *   its priority group in its scheduler instance, otherwise it is appended.
- * @param[in] queue The actual thread queue.
  *
  * @see Thread_queue_Operations.
  */
 typedef void ( *Thread_queue_Priority_change_operation )(
+  Thread_queue_Queue *queue,
   Thread_Control     *the_thread,
-  Priority_Control    new_priority,
-  bool                prepend_it,
-  Thread_queue_Queue *queue
+  Priority_Control    new_priority
 );
 
 /**
diff --git a/cpukit/score/include/rtems/score/threadqimpl.h b/cpukit/score/include/rtems/score/threadqimpl.h
index f0ca614..75ef4dd 100644
--- a/cpukit/score/include/rtems/score/threadqimpl.h
+++ b/cpukit/score/include/rtems/score/threadqimpl.h
@@ -234,115 +234,19 @@ RTEMS_INLINE_ROUTINE void _Thread_queue_Context_set_MP_callout(
   } while ( 0 )
 #endif
 
-/**
- * @brief Gets the thread wait queue of the thread queue context.
- *
- * On SMP configurations, the value is stored in the thread queue context,
- * otherwise in the thread itself.
- *
- * @param queue_context The thread queue context.
- * @param the_thread The thread.
- */
-#if defined(RTEMS_SMP)
-#define _Thread_queue_Context_get_queue( queue_context, the_thread ) \
-  ( queue_context )->Wait.queue
-#else
-#define _Thread_queue_Context_get_queue( queue_context, the_thread ) \
-  ( the_thread )->Wait.queue
-#endif
-
-/**
- * @brief Gets the thread wait operations of the thread queue context.
- *
- * On SMP configurations, the value is stored in the thread queue context,
- * otherwise in the thread itself.
- *
- * @param queue_context The thread queue context.
- * @param the_thread The thread.
- */
-#if defined(RTEMS_SMP)
-#define _Thread_queue_Context_get_operations( queue_context, the_thread ) \
-  ( queue_context )->Wait.operations
-#else
-#define _Thread_queue_Context_get_operations( queue_context, the_thread ) \
-  ( the_thread )->Wait.operations
-#endif
-
-/**
- * @brief Thread priority change by means of the thread queue context.
- *
- * On SMP configurations, the used data is stored in the thread queue context,
- * otherwise in the thread itself.
- *
- * @param queue_context The thread queue context.
- * @param the_thread The thread.
- * @param new_priority The new thread priority.
- * @param prepend_it Prepend it to its priority group or not.
- */
-#if defined(RTEMS_SMP)
-#define _Thread_queue_Context_priority_change( \
-    queue_context, \
-    the_thread, \
-    new_priority, \
-    prepend_it \
-  ) \
-    ( *( queue_context )->Wait.operations->priority_change )( \
-      the_thread, \
-      new_priority, \
-      prepend_it, \
-      ( queue_context )->Wait.queue \
-    )
-#else
-#define _Thread_queue_Context_priority_change( \
-    queue_context, \
-    the_thread, \
-    new_priority, \
-    prepend_it \
-  ) \
-    ( *( the_thread )->Wait.operations->priority_change )( \
-      the_thread, \
-      new_priority, \
-      prepend_it, \
-      ( the_thread )->Wait.queue \
-    )
-#endif
-
-/**
- * @brief Thread queue extract by means of the thread queue context.
- *
- * On SMP configurations, the used data is stored in the thread queue context,
- * otherwise in the thread itself.
- *
- * @param queue_context The thread queue context.
- * @param the_thread The thread.
- */
 #if defined(RTEMS_SMP)
-#define _Thread_queue_Context_extract( \
-    queue_context, \
-    the_thread \
-  ) \
-    ( *( queue_context )->Wait.operations->extract )( \
-      ( queue_context )->Wait.queue, \
-      the_thread \
-    )
-#else
-#define _Thread_queue_Context_extract( \
-    queue_context, \
-    the_thread \
-  ) \
-    ( *( the_thread )->Wait.operations->extract )( \
-      ( the_thread )->Wait.queue, \
-      the_thread \
-    )
-#endif
+RTEMS_INLINE_ROUTINE void _Thread_queue_Gate_close(
+  Thread_queue_Gate *gate
+)
+{
+  _Atomic_Store_uint( &gate->go_ahead, 0, ATOMIC_ORDER_RELAXED );
+}
 
-#if defined(RTEMS_SMP)
 RTEMS_INLINE_ROUTINE void _Thread_queue_Gate_add(
   Chain_Control     *chain,
   Thread_queue_Gate *gate
 )
 {
-  _Atomic_Store_uint( &gate->go_ahead, 0, ATOMIC_ORDER_RELAXED );
   _Chain_Append_unprotected( chain, &gate->Node );
 }
 
@@ -1087,10 +991,6 @@ extern const Thread_queue_Operations _Thread_queue_Operations_priority;
 
 extern const Thread_queue_Operations _Thread_queue_Operations_priority_inherit;
 
-#if defined(RTEMS_SMP)
-extern const Thread_queue_Operations _Thread_queue_Operations_stale_queue;
-#endif
-
 /**@}*/
 
 #ifdef __cplusplus
diff --git a/cpukit/score/src/threadchangepriority.c b/cpukit/score/src/threadchangepriority.c
index c569530..97e7950 100644
--- a/cpukit/score/src/threadchangepriority.c
+++ b/cpukit/score/src/threadchangepriority.c
@@ -46,11 +46,12 @@ static Thread_Control *_Thread_Apply_priority_locked(
    *  we are not REALLY changing priority.
    */
   if ( ( *filter )( the_thread, &new_priority, arg ) ) {
-    _Thread_queue_Context_priority_change(
-      queue_context,
+    _Scheduler_Thread_set_priority( the_thread, new_priority, prepend_it );
+
+    ( *the_thread->Wait.operations->priority_change )(
+      the_thread->Wait.queue,
       the_thread,
-      new_priority,
-      prepend_it
+      new_priority
     );
   } else {
     the_thread = NULL;
diff --git a/cpukit/score/src/threadinitialize.c b/cpukit/score/src/threadinitialize.c
index 209be9e..b5fef59 100644
--- a/cpukit/score/src/threadinitialize.c
+++ b/cpukit/score/src/threadinitialize.c
@@ -186,7 +186,7 @@ bool _Thread_Initialize(
     &the_thread->Wait.Lock.Default,
     "Thread Wait Default Lock"
   );
-  _Chain_Initialize_empty( &the_thread->Wait.Lock.Pending_requests );
+  _Thread_queue_Gate_open( &the_thread->Wait.Lock.Tranquilizer );
   _SMP_lock_Stats_initialize( &the_thread->Potpourri_stats, "Thread Potpourri" );
 #endif
 
diff --git a/cpukit/score/src/threadqenqueue.c b/cpukit/score/src/threadqenqueue.c
index a9b2c35..9ac57d0 100644
--- a/cpukit/score/src/threadqenqueue.c
+++ b/cpukit/score/src/threadqenqueue.c
@@ -176,7 +176,7 @@ static void _Thread_queue_Path_release( Thread_queue_Path *path )
 
     link = RTEMS_CONTAINER_OF( node, Thread_queue_Link, Path_node );
 
-    if ( link->Queue_context.Wait.queue_lock != NULL ) {
+    if ( link->Queue_context.Wait.queue != NULL ) {
       _Thread_queue_Link_remove( link );
     }
 
@@ -213,8 +213,6 @@ static bool _Thread_queue_Path_acquire(
    */
 
   _Chain_Initialize_empty( &path->Links );
-  _Chain_Initialize_node( &path->Start.Path_node );
-  _Thread_queue_Context_initialize( &path->Start.Queue_context );
 
   owner = queue->owner;
 
@@ -226,6 +224,8 @@ static bool _Thread_queue_Path_acquire(
     return false;
   }
 
+  _Chain_Initialize_node( &path->Start.Path_node );
+  _Thread_queue_Context_initialize( &path->Start.Queue_context );
   link = &path->Start;
 
   do {
@@ -239,34 +239,36 @@ static bool _Thread_queue_Path_acquire(
 
     target = owner->Wait.queue;
     link->Queue_context.Wait.queue = target;
-    link->Queue_context.Wait.operations = owner->Wait.operations;
 
     if ( target != NULL ) {
       if ( _Thread_queue_Link_add( link, queue, target ) ) {
-        link->Queue_context.Wait.queue_lock = &target->Lock;
-        _Chain_Append_unprotected(
+        _Thread_queue_Gate_add(
           &owner->Wait.Lock.Pending_requests,
-          &link->Queue_context.Wait.Gate.Node
+          &link->Queue_context.Wait.Gate
         );
         _Thread_Wait_release_default_critical(
           owner,
           &link->Queue_context.Lock_context
         );
-        _Thread_Wait_acquire_queue_critical(
-          &target->Lock,
-          &link->Queue_context
-        );
+        _Thread_Wait_acquire_queue_critical( target, &link->Queue_context );
 
         if ( link->Queue_context.Wait.queue == NULL ) {
+          _Thread_queue_Link_remove( link );
+          _Thread_Wait_release_queue_critical( target, &link->Queue_context );
+          _Thread_Wait_acquire_default_critical(
+            owner,
+            &link->Queue_context.Lock_context
+          );
+          _Thread_Wait_remove_request_locked( owner, &link->Queue_context );
+          _Assert( owner->Wait.queue == NULL );
           return true;
         }
       } else {
-        link->Queue_context.Wait.queue_lock = NULL;
+        link->Queue_context.Wait.queue = NULL;
         _Thread_queue_Path_release( path );
         return false;
       }
     } else {
-      link->Queue_context.Wait.queue_lock = NULL;
       return true;
     }
 
@@ -330,6 +332,7 @@ void _Thread_queue_Enqueue_critical(
   if ( !_Thread_queue_Path_acquire( the_thread, queue, &path ) ) {
     _Thread_Wait_restore_default( the_thread );
     _Thread_queue_Queue_release( queue, &queue_context->Lock_context );
+    _Thread_Wait_tranquilize( the_thread );
     ( *queue_context->deadlock_callout )( the_thread );
     return;
   }
@@ -504,14 +507,15 @@ void _Thread_queue_Extract_critical(
 
 void _Thread_queue_Extract( Thread_Control *the_thread )
 {
-  Thread_queue_Context queue_context;
+  Thread_queue_Context  queue_context;
+  Thread_queue_Queue   *queue;
 
   _Thread_queue_Context_initialize( &queue_context );
   _Thread_Wait_acquire( the_thread, &queue_context );
 
-  if (
-    _Thread_queue_Context_get_queue( &queue_context, the_thread ) != NULL
-  ) {
+  queue = the_thread->Wait.queue;
+
+  if ( queue != NULL ) {
     bool unblock;
 
     _Thread_Wait_remove_request( the_thread, &queue_context );
@@ -520,14 +524,14 @@ void _Thread_queue_Extract( Thread_Control *the_thread )
       _Thread_queue_MP_callout_do_nothing
     );
     unblock = _Thread_queue_Extract_locked(
-      _Thread_queue_Context_get_queue( &queue_context, the_thread ),
-      _Thread_queue_Context_get_operations( &queue_context, the_thread ),
+      queue,
+      the_thread->Wait.operations,
       the_thread,
       &queue_context.Lock_context
     );
     _Thread_queue_Unblock_critical(
       unblock,
-      _Thread_queue_Context_get_queue( &queue_context, the_thread ),
+      queue,
       the_thread,
       &queue_context.Lock_context
     );
diff --git a/cpukit/score/src/threadqops.c b/cpukit/score/src/threadqops.c
index 8059446..d6e42fd 100644
--- a/cpukit/score/src/threadqops.c
+++ b/cpukit/score/src/threadqops.c
@@ -22,50 +22,25 @@
 #include <rtems/score/rbtreeimpl.h>
 #include <rtems/score/schedulerimpl.h>
 
-static void _Thread_queue_Default_priority_change(
+static void _Thread_queue_Do_nothing_priority_change(
+  Thread_queue_Queue *queue,
   Thread_Control     *the_thread,
-  Priority_Control    new_priority,
-  bool                prepend_it,
-  Thread_queue_Queue *queue
+  Priority_Control    new_priority
 )
 {
   (void) queue;
-
-  _Scheduler_Thread_set_priority( the_thread, new_priority, prepend_it );
+  (void) the_thread;
+  (void) new_priority;
 }
 
 static void _Thread_queue_Do_nothing_extract(
   Thread_queue_Queue *queue,
-  Thread_Control    *the_thread
-)
-{
-  /* Do nothing */
-}
-
-#if defined(RTEMS_SMP)
-static void _Thread_queue_Stale_queue_priority_change(
-  Thread_Control     *the_thread,
-  Priority_Control    new_priority,
-  bool                prepend_it,
-  Thread_queue_Queue *queue
+  Thread_Control     *the_thread
 )
 {
-  ISR_lock_Context lock_context;
-
   (void) queue;
-
-  /*
-   * This operation is used to change the priority in case we have a thread
-   * queue context with a stale thread queue.  We own the thread queue lock of
-   * the former thread queue.  In addition, we need the thread wait default
-   * lock, see _Thread_Wait_restore_default().
-   */
-
-  _Thread_Wait_acquire_default_critical( the_thread, &lock_context );
-  _Scheduler_Thread_set_priority( the_thread, new_priority, prepend_it );
-  _Thread_Wait_release_default_critical( the_thread, &lock_context );
+  (void) the_thread;
 }
-#endif
 
 static Thread_queue_Heads *_Thread_queue_Queue_enqueue(
   Thread_queue_Queue *queue,
@@ -216,10 +191,9 @@ static bool _Thread_queue_Priority_less(
 }
 
 static void _Thread_queue_Priority_priority_change(
+  Thread_queue_Queue *queue,
   Thread_Control     *the_thread,
-  Priority_Control    new_priority,
-  bool                prepend_it,
-  Thread_queue_Queue *queue
+  Priority_Control    new_priority
 )
 {
   Thread_queue_Heads          *heads = queue->heads;
@@ -227,8 +201,6 @@ static void _Thread_queue_Priority_priority_change(
 
   _Assert( heads != NULL );
 
-  _Scheduler_Thread_set_priority( the_thread, new_priority, prepend_it );
-
   priority_queue = _Thread_queue_Priority_queue( heads, the_thread );
 
   _RBTree_Extract(
@@ -389,11 +361,12 @@ static void _Thread_queue_Priority_inherit_enqueue(
     owner->priority_restore_hint = true;
     _Atomic_Fence( ATOMIC_ORDER_ACQ_REL );
 
-    _Thread_queue_Context_priority_change(
-      &path->Start.Queue_context,
+    _Scheduler_Thread_set_priority( owner, priority, false );
+
+    ( *owner->Wait.operations->priority_change )(
+      owner->Wait.queue,
       owner,
-      priority,
-      false
+      priority
     );
   } else {
     path->update_priority = NULL;
@@ -424,7 +397,7 @@ void _Thread_queue_Boost_priority(
 #endif
 
 const Thread_queue_Operations _Thread_queue_Operations_default = {
-  .priority_change = _Thread_queue_Default_priority_change,
+  .priority_change = _Thread_queue_Do_nothing_priority_change,
   .extract = _Thread_queue_Do_nothing_extract
   /*
    * The default operations are only used in _Thread_Change_priority() and
@@ -434,7 +407,7 @@ const Thread_queue_Operations _Thread_queue_Operations_default = {
 };
 
 const Thread_queue_Operations _Thread_queue_Operations_FIFO = {
-  .priority_change = _Thread_queue_Default_priority_change,
+  .priority_change = _Thread_queue_Do_nothing_priority_change,
   .enqueue = _Thread_queue_FIFO_enqueue,
   .extract = _Thread_queue_FIFO_extract,
   .first = _Thread_queue_FIFO_first
@@ -453,10 +426,3 @@ const Thread_queue_Operations _Thread_queue_Operations_priority_inherit = {
   .extract = _Thread_queue_Priority_extract,
   .first = _Thread_queue_Priority_first
 };
-
-#if defined(RTEMS_SMP)
-const Thread_queue_Operations _Thread_queue_Operations_stale_queue = {
-  .priority_change = _Thread_queue_Stale_queue_priority_change,
-  .extract = _Thread_queue_Do_nothing_extract
-};
-#endif




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