diff --git a/src/common/utils/AtomicSharedPtrTable.h b/src/common/utils/AtomicSharedPtrTable.h
index 43be477..66e4195 100644
--- a/src/common/utils/AtomicSharedPtrTable.h
+++ b/src/common/utils/AtomicSharedPtrTable.h
@@ -32,10 +32,11 @@ struct AvailSlots {
 
     std::lock_guard lock(mutex);
     if (idx == nextAvail - 1) {
-      while (free.find(--nextAvail) != free.end()) {
-        // move back next avail as much as possible
-        ;
-      }
+        nextAvail--;
+        while (free.find(nextAvail - 1) != free.end()) {
+            // move back next avail as much as possible
+            free.erase(--nextAvail);
+        }
     } else {
       free.insert(idx);
     }