diff --git a/sim.c b/sim.c
index f2a6b50..4cdb155 100644
--- a/sim.c
+++ b/sim.c
@@ -833,7 +833,7 @@ BEGIN_DUAL_PHASE_0(track)
     I32 ival[1];
     ival[0] = (I32)read_val_x;
     STORE(ival);
-    for (Isz i = 0; i < read_val_x; ++i) {
+    for (Isz i = 0; i < len; ++i) {
       LOCK(0, i + 1);
     }
   }