diff --git a/CHANGES.txt b/CHANGES.txt
index c785f84f66a5..aaad3e77f63c 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -16,6 +16,8 @@ Merged from 3.0:
    for a table that's in system_schema.tables (CASSANDRA-13180)
 Merged from 2.2:
   * Use only one file pointer when creating commitlog segments (CASSANDRA-12539)
+Merged from 2.1:
+ * Coalescing strategy can enter infinite loop (CASSANDRA-13159)
 
 3.10
  * Fix secondary index queries regression (CASSANDRA-13013)
diff --git a/src/java/org/apache/cassandra/utils/CoalescingStrategies.java b/src/java/org/apache/cassandra/utils/CoalescingStrategies.java
index 0aa980fc7196..1a3c13d6490b 100644
--- a/src/java/org/apache/cassandra/utils/CoalescingStrategies.java
+++ b/src/java/org/apache/cassandra/utils/CoalescingStrategies.java
@@ -100,7 +100,7 @@ private static boolean maybeSleep(int messages, long averageGap, long maxCoalesc
     {
         // only sleep if we can expect to double the number of messages we're sending in the time interval
         long sleep = messages * averageGap;
-        if (sleep > maxCoalesceWindow)
+        if (sleep <= 0 || sleep > maxCoalesceWindow)
             return false;
 
         // assume we receive as many messages as we expect; apply the same logic to the future batch: