[DRAFT] Backport semaphore fixes

include/nuttx/sched.h

@@ -605,11 +605,11 @@ struct tcb_s
 
 #ifdef CONFIG_PRIORITY_INHERITANCE
 #if CONFIG_SEM_NNESTPRIO > 0
-  uint8_t  nsem_held;               /* used to condition priority restore */
   uint8_t  npend_reprio;             /* Number of nested reprioritizations  */
   uint8_t  pend_reprios[CONFIG_SEM_NNESTPRIO];
 #endif
   uint8_t  base_priority;                /* "Normal" priority of the thread */
+  FAR struct semholder_s *holdsem;       /* List of held semaphores         */
 #endif
 
   uint8_t  task_state;                   /* Current state of the thread     */

include/nuttx/semaphore.h

@@ -36,6 +36,21 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Initializers */
+
+#ifdef CONFIG_PRIORITY_INHERITANCE
+# if CONFIG_SEM_PREALLOCHOLDERS > 0
+#  define NXSEM_INITIALIZER(c, f) \
+    {(c), (f), NULL}                    /* semcount, flags, hhead */
+# else
+#  define NXSEM_INITIALIZER(c, f) \
+    {(c), (f), {SEMHOLDER_INITIALIZER, SEMHOLDER_INITIALIZER}}  /* semcount, flags, holder[2] */
+# endif
+#else /* CONFIG_PRIORITY_INHERITANCE */
+#  define NXSEM_INITIALIZER(c, f) \
+    {(c)}                               /* semcount, flags */
+#endif /* CONFIG_PRIORITY_INHERITANCE */
+
 /* Most internal nxsem_* interfaces are not available in the user space in
  * PROTECTED and KERNEL builds.  In that context, the application semaphore
  * interfaces must be used.  The differences between the two sets of

include/semaphore.h

@@ -58,19 +58,38 @@
 
 #ifdef CONFIG_PRIORITY_INHERITANCE
 struct tcb_s; /* Forward reference */
+struct sem_s;
+
 struct semholder_s
 {
 #if CONFIG_SEM_PREALLOCHOLDERS > 0
-  struct semholder_s *flink;     /* Implements singly linked list */
+  FAR struct semholder_s *flink;  /* List of semaphore's holder            */
 #endif
-  FAR struct tcb_s *htcb;        /* Holder TCB */
-  int16_t counts;                /* Number of counts owned by this holder */
+  FAR struct semholder_s *tlink;  /* List of task held semaphores          */
+  FAR struct sem_s *sem;          /* Ths corresponding semaphore           */
+  FAR struct tcb_s *htcb;         /* Ths corresponding TCB                 */
+  int16_t counts;                 /* Number of counts owned by this holder */
 };
 
 #if CONFIG_SEM_PREALLOCHOLDERS > 0
-#  define SEMHOLDER_INITIALIZER {NULL, NULL, 0}
+#  define SEMHOLDER_INITIALIZER   {NULL, NULL, NULL, NULL, 0}
+#  define INITIALIZE_SEMHOLDER(h) \
+    do { \
+      (h)->flink  = NULL; \
+      (h)->tlink  = NULL; \
+      (h)->sem    = NULL; \
+      (h)->htcb   = NULL; \
+      (h)->counts = 0; \
+    } while (0)
 #else
-#  define SEMHOLDER_INITIALIZER {NULL, 0}
+#  define SEMHOLDER_INITIALIZER   {NULL, NULL, NULL, 0}
+#  define INITIALIZE_SEMHOLDER(h) \
+    do { \
+      (h)->tlink  = NULL; \
+      (h)->sem    = NULL; \
+      (h)->htcb   = NULL; \
+      (h)->counts = 0; \
+    } while (0)
 #endif
 #endif /* CONFIG_PRIORITY_INHERITANCE */
 

libs/libc/semaphore/sem_init.c

@@ -78,10 +78,8 @@ int nxsem_init(FAR sem_t *sem, int pshared, unsigned int value)
 #  if CONFIG_SEM_PREALLOCHOLDERS > 0
       sem->hhead            = NULL;
 #  else
-      sem->holder[0].htcb   = NULL;
-      sem->holder[0].counts = 0;
-      sem->holder[1].htcb   = NULL;
-      sem->holder[1].counts = 0;
+      INITIALIZE_SEMHOLDER(&sem->holder[0]);
+      INITIALIZE_SEMHOLDER(&sem->holder[1]);
 #  endif
 #endif
       return OK;