diff --git a/src/btstack_run_loop.c b/src/btstack_run_loop.c
index c3b737f55..b9fdb5f06 100644
--- a/src/btstack_run_loop.c
+++ b/src/btstack_run_loop.c
@@ -94,6 +94,7 @@ void btstack_run_loop_disable_data_source_callbacks(btstack_data_source_t *ds, u
 void btstack_run_loop_add_data_source(btstack_data_source_t *ds){
     btstack_assert(the_run_loop != NULL);
     btstack_assert(the_run_loop->enable_data_source_callbacks != NULL);
+    btstack_assert(ds->process != NULL);
     the_run_loop->add_data_source(ds);
 }
 
@@ -102,7 +103,8 @@ void btstack_run_loop_add_data_source(btstack_data_source_t *ds){
  */
 int btstack_run_loop_remove_data_source(btstack_data_source_t *ds){
     btstack_assert(the_run_loop != NULL);
-    btstack_assert(the_run_loop->enable_data_source_callbacks != NULL);
+    btstack_assert(the_run_loop->disable_data_source_callbacks != NULL);
+    btstack_assert(ds->process != NULL);
     return the_run_loop->remove_data_source(ds);
 }
 
@@ -130,6 +132,7 @@ void * btstack_run_loop_get_timer_context(btstack_timer_source_t *ts){
  */
 void btstack_run_loop_add_timer(btstack_timer_source_t *ts){
     btstack_assert(the_run_loop != NULL);
+    btstack_assert(ts->process != NULL);
     the_run_loop->add_timer(ts);
 }