--- a/js/src/builtin/ParallelArray.js
+++ b/js/src/builtin/ParallelArray.js
@@ -948,17 +948,17 @@ function ParallelArrayScatter(targets, d
 
     return NewParallelArray(ParallelArrayView, [length], buffer, 0);
   }
 
   function checkTarget(i, t) {
       if ((t | 0) !== t)
         ThrowError(JSMSG_PAR_ARRAY_SCATTER_BAD_TARGET, i);
 
-      if (t >= length)
+      if (t < 0 || t >= length)
         ThrowError(JSMSG_PAR_ARRAY_SCATTER_BOUNDS);
   }
 }
 
 /**
  * The familiar filter() operation applied across the outermost
  * dimension.
  */

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/parallelarray/bug853576.js
@@ -0,0 +1,8 @@
+// |jit-test| error: Error;
+
+var len = 2;
+function add1(x) { return x+1; }
+var p = new ParallelArray(len, add1);
+var idx = [0,0].concat(build(len-4, add1)).concat([len-3,len-3]);
+var revidx = idx.reverse();
+var r = p.scatter(revidx, 0, function (x,y) { return x+y; }, len-2, {});