Index: head/sys/x86/x86/busdma_bounce.c
===================================================================
--- head/sys/x86/x86/busdma_bounce.c
+++ head/sys/x86/x86/busdma_bounce.c
@@ -969,7 +969,7 @@
 	bus_size_t datacount1, datacount2;
 
 	if (map == NULL || (bpage = STAILQ_FIRST(&map->bpages)) == NULL)
-		return;
+		goto out;
 
 	/*
 	 * Handle data bouncing.  We might also want to add support for
@@ -1059,6 +1059,8 @@
 		}
 		dmat->bounce_zone->total_bounced++;
 	}
+out:
+	atomic_thread_fence_rel();
 }
 
 static void