diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index 9754c370fc2..cacd8fe7a9b 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -290,9 +290,11 @@ BackgroundWorkerStateChange(void)
 			 * bgw_notify_pid completes before the store to in_use.
 			 */
 			notify_pid = slot->worker.bgw_notify_pid;
-			pg_memory_barrier();
 			slot->pid = 0;
+
+			pg_memory_barrier();
 			slot->in_use = false;
+
 			if (notify_pid != 0)
 				kill(notify_pid, SIGUSR1);
 
@@ -378,6 +380,8 @@ BackgroundWorkerStateChange(void)
  * points to it.  This convention allows deletion of workers during
  * searches of the worker list, and saves having to search the list again.
  *
+ * Caller is responsible for notifying bgw_notify_pid, if appropriate.
+ *
  * This function must be invoked only in the postmaster.
  */
 void
@@ -390,6 +394,13 @@ ForgetBackgroundWorker(slist_mutable_iter *cur)
 
 	Assert(rw->rw_shmem_slot < max_worker_processes);
 	slot = &BackgroundWorkerData->slot[rw->rw_shmem_slot];
+	Assert(slot->in_use);
+
+	/*
+	 * This memory barrier might not be completely necessary, but let's be
+	 * sure.
+	 */
+	pg_memory_barrier();
 	slot->in_use = false;
 
 	ereport(DEBUG1,