diff --git a/runtime/src/bpf_map/map_common_def.hpp b/runtime/src/bpf_map/map_common_def.hpp
index 5fbce558..3948692a 100644
--- a/runtime/src/bpf_map/map_common_def.hpp
+++ b/runtime/src/bpf_map/map_common_def.hpp
@@ -5,6 +5,7 @@
  */
 #ifndef _MAP_COMMON_DEF_HPP
 #define _MAP_COMMON_DEF_HPP
+#include "linux/bpf.h"
 #include "spdlog/spdlog.h"
 #include <boost/container_hash/hash.hpp>
 #include <cinttypes>
@@ -68,6 +69,14 @@ struct bytes_vec_hasher {
 		return seed;
 	}
 };
+static inline bool check_update_flags(uint64_t flags)
+{
+	if (flags != BPF_ANY && flags != BPF_NOEXIST && flags != BPF_EXIST) {
+		errno = EINVAL;
+		return false;
+	}
+	return true;
+}
 } // namespace bpftime
 
 #endif
diff --git a/runtime/src/bpf_map/userspace/array_map.cpp b/runtime/src/bpf_map/userspace/array_map.cpp
index abfd4896..30143990 100644
--- a/runtime/src/bpf_map/userspace/array_map.cpp
+++ b/runtime/src/bpf_map/userspace/array_map.cpp
@@ -3,6 +3,8 @@
  * Copyright (c) 2022, eunomia-bpf org
  * All rights reserved.
  */
+#include "bpf_map/map_common_def.hpp"
+#include "linux/bpf.h"
 #include <bpf_map/userspace/array_map.hpp>
 #include <cerrno>
 
@@ -34,9 +36,16 @@ void *array_map_impl::elem_lookup(const void *key)
 long array_map_impl::elem_update(const void *key, const void *value,
 				 uint64_t flags)
 {
+	if (!check_update_flags(flags))
+		return -1;
 	auto key_val = *(uint32_t *)key;
+	if (key_val < _max_entries && flags == BPF_NOEXIST) {
+		errno = EEXIST;
+		return -1;
+	}
+
 	if (key_val >= _max_entries) {
-		errno = ENOENT;
+		errno = E2BIG;
 		return -1;
 	}
 	std::copy((uint8_t *)value, (uint8_t *)value + _value_size,
@@ -47,13 +56,16 @@ long array_map_impl::elem_update(const void *key, const void *value,
 long array_map_impl::elem_delete(const void *key)
 {
 	auto key_val = *(uint32_t *)key;
-	if (key_val >= _max_entries) {
-		errno = ENOENT;
-		return -1;
-	}
-	std::fill(&data[key_val * _value_size],
-		  &data[key_val * _value_size] + _value_size, 0);
-	return 0;
+	// kernel tests says element in an array map can't be deleted...
+	errno = EINVAL;
+	return -1;
+	// if (key_val >= _max_entries) {
+	// 	errno = ENOENT;
+	// 	return -1;
+	// }
+	// std::fill(&data[key_val * _value_size],
+	// 	  &data[key_val * _value_size] + _value_size, 0);
+	// return 0;
 }
 
 int array_map_impl::map_get_next_key(const void *key, void *next_key)
diff --git a/runtime/src/bpf_map/userspace/per_cpu_hash_map.cpp b/runtime/src/bpf_map/userspace/per_cpu_hash_map.cpp
index ade89d92..a08197b6 100644
--- a/runtime/src/bpf_map/userspace/per_cpu_hash_map.cpp
+++ b/runtime/src/bpf_map/userspace/per_cpu_hash_map.cpp
@@ -14,14 +14,6 @@
 #include <unistd.h>
 #include "platform_utils.hpp"
 
-static inline bool check_update_flags(uint64_t flags)
-{
-	if (flags != BPF_ANY && flags != BPF_NOEXIST && flags != BPF_EXIST) {
-		errno = EINVAL;
-		return false;
-	}
-	return true;
-}
 
 namespace bpftime
 {
diff --git a/runtime/unit-test/maps/kernel_unit_tests.cpp b/runtime/unit-test/maps/kernel_unit_tests.cpp
index 316524c5..9c010438 100644
--- a/runtime/unit-test/maps/kernel_unit_tests.cpp
+++ b/runtime/unit-test/maps/kernel_unit_tests.cpp
@@ -1,3 +1,4 @@
+#include "bpf_map/userspace/array_map.hpp"
 #include "bpf_map/userspace/per_cpu_hash_map.hpp"
 #include "catch2/catch_test_macros.hpp"
 #include "linux/bpf.h"
@@ -318,3 +319,59 @@ TEST_CASE("test_hashmap_walk (kernel)")
 
 	REQUIRE(i == max_entries);
 }
+
+TEST_CASE("test_arraymap (kernel)")
+{
+	shm_remove remover(SHM_NAME);
+	managed_shared_memory mem(boost::interprocess::create_only, SHM_NAME,
+				  20 << 20);
+	int key, next_key;
+	long long value;
+	auto value_size = sizeof(value);
+	array_map_impl map(mem, sizeof(value), 2);
+	const auto lookup_helper = [&](const void *key, void *value) -> long {
+		auto returned_value = map.elem_lookup(key);
+		if (!returned_value)
+			return -1;
+		memcpy(value, returned_value, sizeof(value_size));
+		return 0;
+	};
+
+	key = 1;
+	value = 1234;
+	/* Insert key=1 element. */
+	REQUIRE(map.elem_update(&key, &value, BPF_ANY) == 0);
+
+	value = 0;
+	REQUIRE((map.elem_update(&key, &value, BPF_NOEXIST) < 0 &&
+		 errno == EEXIST));
+
+	/* Check that key=1 can be found. */
+	REQUIRE((lookup_helper(&key, &value) == 0 && value == 1234));
+
+	key = 0;
+	/* Check that key=0 is also found and zero initialized. */
+	REQUIRE((lookup_helper(&key, &value) == 0 && value == 0));
+
+	/* key=0 and key=1 were inserted, check that key=2 cannot be inserted
+	 * due to max_entries limit.
+	 */
+	key = 2;
+	REQUIRE((map.elem_update(&key, &value, BPF_EXIST) < 0 &&
+		 errno == E2BIG));
+
+	/* Check that key = 2 doesn't exist. */
+	REQUIRE((lookup_helper(&key, &value) < 0 && errno == ENOENT));
+
+	/* Iterate over two elements. */
+	REQUIRE((map.map_get_next_key(NULL, &next_key) == 0 && next_key == 0));
+	REQUIRE((map.map_get_next_key(&key, &next_key) == 0 && next_key == 0));
+	REQUIRE((map.map_get_next_key(&next_key, &next_key) == 0 &&
+		 next_key == 1));
+	REQUIRE((map.map_get_next_key(&next_key, &next_key) < 0 &&
+		 errno == ENOENT));
+
+	/* Delete shouldn't succeed. */
+	key = 1;
+	REQUIRE((map.elem_delete(&key) < 0 && errno == EINVAL));
+}