Work queues: Logic that sets the queued indication and the logic that does the actual queuing must be atomic

libc/wqueue/work_queue.c

@@ -107,16 +107,16 @@ static int work_qqueue(FAR struct usr_wqueue_s *wqueue,
 {
   DEBUGASSERT(work != NULL);
 
-  /* First, initialize the work structure */
-
-  work->worker = worker;           /* Work callback */
-  work->arg    = arg;              /* Callback argument */
-  work->delay  = delay;            /* Delay until work performed */
-
   /* Get exclusive access to the work queue */
 
   while (work_lock() < 0);
 
+  /* Initialize the work structure */
+
+  work->worker = worker;           /* Work callback. non-NULL means queued */
+  work->arg    = arg;              /* Callback argument */
+  work->delay  = delay;            /* Delay until work performed */
+
   /* Now, time-tag that entry and put it in the work queue. */
 
   work->qtime  = clock_systimer(); /* Time work queued */