diff --git a/lightcrafts/src/main/java/com/lightcrafts/jai/utils/LCTileScheduler.java b/lightcrafts/src/main/java/com/lightcrafts/jai/utils/LCTileScheduler.java
index 583238af..e2258302 100644
--- a/lightcrafts/src/main/java/com/lightcrafts/jai/utils/LCTileScheduler.java
+++ b/lightcrafts/src/main/java/com/lightcrafts/jai/utils/LCTileScheduler.java
@@ -743,7 +743,7 @@ public Raster scheduleTile(OpImage owner,
         } else {
             // Check the cache: a null value indicates computation is
             // still in progress.
-            if(cache[0] == null) {
+            while (cache[0] == null) {
                 // Wait for the computation to complete.
                 try {
                     cache.wait(); // XXX Should there be a timeout?