--- x/kernel/futex/core.c
+++ y/kernel/futex/core.c
@@ -1659,8 +1659,10 @@ again:
 			 * Will set mm->futex_phash_new on failure;
 			 * futex_private_hash_get() will try again.
 			 */
-			if (!__futex_pivot_hash(mm, new) && custom)
+			if (!__futex_pivot_hash(mm, new) && custom) {
+				futex_private_hash_put(new);
 				goto again;
+			}
 		}
 	}
 	return 0;