model: add todo synchronization comment

diff --git a/model.cc b/model.cc
index e23e9ec0a990b38e962b249f4d32c666f9885689..8267377faa791a2cfbc85f9027949c7338186635 100644 (file)
--- a/model.cc
+++ b/model.cc
@@ -576,6 +576,16 @@ void ModelChecker::process_relseq_fixup(ModelAction *curr, work_queue_t *work_qu
        ASSERT(release->same_thread(rf));
 
        if (write == NULL) {
+               /**
+                * @todo Forcing a synchronization requires that we set
+                * modification order constraints. For instance, we can't allow
+                * a fixup sequence in which two separate read-acquire
+                * operations read from the same sequence, where the first one
+                * synchronizes and the other doesn't. Essentially, we can't
+                * allow any writes to insert themselves between 'release' and
+                * 'rf'
+                */
+
                /* Must synchronize */
                if (!acquire->synchronize_with(release)) {
                        set_bad_synchronization();