diff --git a/src/libos/Cargo.toml b/src/libos/Cargo.toml
index 3dbbca11..9e4a22b1 100644
--- a/src/libos/Cargo.toml
+++ b/src/libos/Cargo.toml
@@ -41,7 +41,7 @@ modular-bitfield = "0.11.2"
 sgx_tstd = { path = "../../deps/rust-sgx-sdk/sgx_tstd" }
 
 [features]
-default = ["integrity_only_opt", "sgx_file_cache", "sgx1_exception_sim"]
+default = ["integrity_only_opt", "sgx_file_cache", "sgx1_exception_sim", "kernel_heap_monitor"]
 syscall_timing = []     # Timing for each syscall. But it has cost from more ocall.
 integrity_only_opt = [] # Clear bss only. It should be disabled if checking memory reads.
 sgx_file_cache = []     # Cache SgxFile objects. Invalidation is unimplemented.