diff --git a/src/maat_api.c b/src/maat_api.c
index 4c35c0a..c0304bc 100644
--- a/src/maat_api.c
+++ b/src/maat_api.c
@@ -428,13 +428,23 @@ int maat_get_table_id(struct maat *maat_inst, const char *table_name)
     return table_id;
 }
 
-static inline void maat_runtime_ref_inc(struct maat_runtime *maat_rt, int thread_id)
+static inline void maat_runtime_ref_inc(struct maat_runtime *maat_rt,
+                                        int thread_id)
 {
+    if (NULL == maat_rt) {
+        return;
+    }
+
 	alignment_int64_array_add(maat_rt->ref_cnt, thread_id, 1);
 }
 
-static inline void maat_runtime_ref_dec(struct maat_runtime *maat_rt, int thread_id)
+static inline void maat_runtime_ref_dec(struct maat_runtime *maat_rt,
+                                        int thread_id)
 {
+    if (NULL == maat_rt) {
+        return;
+    }
+
 	alignment_int64_array_add(maat_rt->ref_cnt, thread_id, -1);
 }
 
diff --git a/src/maat_bool_plugin.c b/src/maat_bool_plugin.c
index e4574b9..4478591 100644
--- a/src/maat_bool_plugin.c
+++ b/src/maat_bool_plugin.c
@@ -551,10 +551,13 @@ int bool_plugin_runtime_get_ex_data(void *bool_plugin_runtime, unsigned long lon
         return 0;
     }
 
-    struct bool_expr_match results[n_ex_data];
+    if (NULL == bool_plugin_rt->matcher) {
+        return 0;
+    }
 
+    struct bool_expr_match results[n_ex_data];
     n_item = ull_dedup(item_ids, n_item);
-    assert(bool_plugin_rt->matcher != NULL);
+    
 	int n_result = bool_matcher_match(bool_plugin_rt->matcher, item_ids, n_item, results, n_ex_data);
 	for (int i = 0; i < n_result; i++) {
 		ex_data_array[i] = ex_data_runtime_get_ex_data_by_container(bool_plugin_rt->ex_data_rt,
diff --git a/src/maat_expr.c b/src/maat_expr.c
index b80587d..e5a7c8f 100644
--- a/src/maat_expr.c
+++ b/src/maat_expr.c
@@ -960,9 +960,12 @@ int expr_runtime_scan(struct expr_runtime *expr_rt, int thread_id,
         return 0;
     }
 
+    if (NULL == expr_rt->hs) {
+        return 0;
+    }
+
     size_t n_hit_item = 0;
     struct hs_scan_result hit_results[MAX_SCANNER_HIT_ITEM_NUM];
-    
     int ret = adapter_hs_scan(expr_rt->hs, thread_id, data, data_len, 
                               hit_results, MAX_SCANNER_HIT_ITEM_NUM, 
                               &n_hit_item);
diff --git a/src/maat_flag.c b/src/maat_flag.c
index 0c03ef1..e645d0a 100644
--- a/src/maat_flag.c
+++ b/src/maat_flag.c
@@ -547,8 +547,11 @@ int flag_runtime_scan(struct flag_runtime *flag_rt, int thread_id,
         return 0;
     }
 
+    if (NULL == flag_rt->matcher) {
+        return 0;
+    }
+
     struct flag_result hit_results[MAX_SCANNER_HIT_ITEM_NUM];
-    
     int n_hit_item = flag_matcher_match(flag_rt->matcher, flag, 
                                         hit_results, MAX_SCANNER_HIT_ITEM_NUM);
     if (n_hit_item <= 0) {
diff --git a/src/maat_fqdn_plugin.c b/src/maat_fqdn_plugin.c
index 265090e..560841e 100644
--- a/src/maat_fqdn_plugin.c
+++ b/src/maat_fqdn_plugin.c
@@ -558,9 +558,11 @@ int fqdn_plugin_runtime_get_ex_data(void *fqdn_plugin_runtime, const char *query
         return 0;
     }
 
-    struct FQDN_match results[n_ex_data];
+    if (NULL == fqdn_plugin_rt->engine) {
+        return 0;
+    }
 
-    assert(fqdn_plugin_rt->engine != NULL);
+    struct FQDN_match results[n_ex_data];
 	int n_result = FQDN_engine_search(fqdn_plugin_rt->engine, query_fqdn, strlen(query_fqdn),
                                       results, n_ex_data);
 	for (int i = 0; i < n_result; i++) {
diff --git a/src/maat_interval.c b/src/maat_interval.c
index 57e4f3c..c738ef4 100644
--- a/src/maat_interval.c
+++ b/src/maat_interval.c
@@ -548,8 +548,11 @@ int interval_runtime_scan(struct interval_runtime *interval_rt, int thread_id,
         return 0;
     }
 
+    if (NULL == interval_rt->matcher) {
+        return 0;
+    }
+
     struct interval_result hit_results[MAX_SCANNER_HIT_ITEM_NUM];
-    
     int n_hit_item = interval_matcher_match(interval_rt->matcher, integer, 
                                             hit_results, MAX_SCANNER_HIT_ITEM_NUM);
     if (n_hit_item <= 0) {
diff --git a/src/maat_ip.c b/src/maat_ip.c
index 62d4d2a..73e650d 100644
--- a/src/maat_ip.c
+++ b/src/maat_ip.c
@@ -714,12 +714,11 @@ int ip_runtime_scan(struct ip_runtime *ip_rt, int thread_id, int ip_type,
         return 0;
     }
     
-    struct scan_result ip_results[MAX_SCANNER_HIT_ITEM_NUM];
-
     /* if ip_addr = "0.0.0.0" means any ip */
     int any_ip_flag = 0;
-
     struct ip_data scan_data;
+    struct scan_result ip_results[MAX_SCANNER_HIT_ITEM_NUM];
+
     if (ip_type == IPv4) {
         scan_data.type = IPv4;
         scan_data.ipv4 = ntohl(*(uint32_t *)ip_addr);
@@ -746,6 +745,11 @@ int ip_runtime_scan(struct ip_runtime *ip_rt, int thread_id, int ip_type,
     if (1 == any_ip_flag) {
         struct interval_result port_results[MAX_SCANNER_HIT_ITEM_NUM];
         uint16_t host_port = ntohs(port);
+
+        if (NULL == ip_rt->intval_matcher) {
+            return 0;
+        }
+
         int n_hit_port_item = interval_matcher_match(ip_rt->intval_matcher, host_port, 
                                                      port_results, MAX_SCANNER_HIT_ITEM_NUM);
         if (n_hit_port_item <= 0) {
@@ -776,6 +780,10 @@ int ip_runtime_scan(struct ip_runtime *ip_rt, int thread_id, int ip_type,
             real_hit_item_cnt++;
         }
     } else {
+        if (NULL == ip_rt->ip_matcher) {
+            return 0;
+        }
+        
         int n_hit_ip_item = ip_matcher_match(ip_rt->ip_matcher, &scan_data,
                                              ip_results, MAX_SCANNER_HIT_ITEM_NUM);
         if (n_hit_ip_item <= 0) {
diff --git a/src/maat_ip_plugin.c b/src/maat_ip_plugin.c
index 321ebac..864ea35 100644
--- a/src/maat_ip_plugin.c
+++ b/src/maat_ip_plugin.c
@@ -597,6 +597,10 @@ int ip_plugin_runtime_get_ex_data(void *ip_plugin_runtime, const struct ip_addr
         return 0;
     }
 
+    if (NULL == ip_plugin_rt->ip_matcher) {
+        return 0;
+    }
+
     struct scan_result results[n_ex_data];
     struct ip_data ip_data = *(const struct ip_data *)ip_addr;
 	if (ip_data.type == IPv4) {
@@ -605,7 +609,6 @@ int ip_plugin_runtime_get_ex_data(void *ip_plugin_runtime, const struct ip_addr
 		ipv6_ntoh(ip_data.ipv6);
 	}
 
-    assert(ip_plugin_rt->ip_matcher != NULL);
 	int n_result = ip_matcher_match(ip_plugin_rt->ip_matcher, &ip_data, results, n_ex_data);
 	for (int i = 0; i < n_result; i++) {
 		ex_data_array[i] = ex_data_runtime_get_ex_data_by_container(ip_plugin_rt->ex_data_rt,
diff --git a/test/maat_framework_perf_gtest.cpp b/test/maat_framework_perf_gtest.cpp
index 34a2ebd..db92e5e 100644
--- a/test/maat_framework_perf_gtest.cpp
+++ b/test/maat_framework_perf_gtest.cpp
@@ -862,10 +862,6 @@ void* perf_fqdn_plugin_scan_thread(void *arg)
 		if (ret == 2) {
 			hit_times++;
 		}
-
-		for (j = 0; j < ret; j++) {
-			perf_fqdn_plugin_EX_free_cb(0, (void**)&(result[j]), 0, NULL);
-		}
 	}
 	clock_gettime(CLOCK_MONOTONIC, &end);
 
@@ -1093,10 +1089,6 @@ void* perf_bool_plugin_scan_thread(void *arg)
 		if (ret == 1) {
 			hit_times++;
 		}
-
-		for (j = 0; j < ret; j++) {
-			perf_bool_plugin_ex_free_cb(0, (void**)&(result[j]), 0, NULL);
-		}
 	}
 	clock_gettime(CLOCK_MONOTONIC, &end);
 
@@ -1286,10 +1278,6 @@ static void *ip_plugin_get_thread(void *arg)
 		if (ret > 0) {
 			hit_times++;
 		}
-
-		for (j = 0; j < ret; j++) {
-			perf_ip_plugin_EX_free_cb(table_id, (void**)&(results[j]), 0, NULL);
-		}
 	}
     clock_gettime(CLOCK_MONOTONIC, &end);