diff --git a/src/pubsub.c b/src/pubsub.c
index a2c28ddcb..afe28f59b 100644
--- a/src/pubsub.c
+++ b/src/pubsub.c
@@ -350,6 +350,9 @@ void pubsubShardUnsubscribeAllChannelsInSlot(unsigned int slot) {
         }
         dictReleaseIterator(iter);
         kvstoreDictDelete(server.pubsubshard_channels, slot, channel);
+        /* After the dict becomes empty, the dict will be deleted.
+         * We break out without calling dictNext. */
+        if (!kvstoreDictSize(server.pubsubshard_channels, slot)) break;
     }
     dictReleaseIterator(di);
 }