Merge pull request #2892 from davidmoten/range-race

Fix Observable.range race condition

Author: akarnokd

src/main/java/rx/internal/operators/OnSubscribeRange.java

@@ -55,12 +55,11 @@ private RangeProducer(Subscriber<? super Integer> o, int start, int end) {
 
         @Override
         public void request(long n) {
-            if (REQUESTED_UPDATER.get(this) == Long.MAX_VALUE) {
+            if (requested == Long.MAX_VALUE) {
                 // already started with fast-path
                 return;
             }
-            if (n == Long.MAX_VALUE) {
-                REQUESTED_UPDATER.set(this, n);
+            if (n == Long.MAX_VALUE && REQUESTED_UPDATER.compareAndSet(this, 0, Long.MAX_VALUE)) {
                 // fast-path without backpressure
                 for (long i = index; i <= end; i++) {
                     if (o.isUnsubscribed()) {