diff --git a/include/kernel.h b/include/kernel.h
index ee86c719b02..eb41e566f74 100644
--- a/include/kernel.h
+++ b/include/kernel.h
@@ -2708,9 +2708,11 @@ __syscall s32_t k_stack_alloc_init(struct k_stack *stack,
  * if the buffer wasn't dynamically allocated.
  *
  * @param stack Address of the stack.
+ * @retval 0 on success
+ * @retval -EAGAIN when object is still in use
  * @req K-STACK-001
  */
-void k_stack_cleanup(struct k_stack *stack);
+int k_stack_cleanup(struct k_stack *stack);
 
 /**
  * @brief Push an element onto a stack.
@@ -2722,10 +2724,11 @@ void k_stack_cleanup(struct k_stack *stack);
  * @param stack Address of the stack.
  * @param data Value to push onto the stack.
  *
- * @return N/A
+ * @retval 0 on success
+ * @retval -ENOMEM if stack is full
  * @req K-STACK-001
  */
-__syscall void k_stack_push(struct k_stack *stack, stack_data_t data);
+__syscall int k_stack_push(struct k_stack *stack, stack_data_t data);
 
 /**
  * @brief Pop an element from a stack.
diff --git a/kernel/stack.c b/kernel/stack.c
index 4a4cb4ee93c..fc737a56338 100644
--- a/kernel/stack.c
+++ b/kernel/stack.c
@@ -15,7 +15,7 @@
 #include <linker/sections.h>
 #include <ksched.h>
 #include <wait_q.h>
-#include <sys/__assert.h>
+#include <sys/check.h>
 #include <init.h>
 #include <syscall_handler.h>
 #include <kernel_internal.h>
@@ -81,23 +81,28 @@ static inline s32_t z_vrfy_k_stack_alloc_init(struct k_stack *stack,
 #include <syscalls/k_stack_alloc_init_mrsh.c>
 #endif
 
-void k_stack_cleanup(struct k_stack *stack)
+int k_stack_cleanup(struct k_stack *stack)
 {
-	__ASSERT_NO_MSG(z_waitq_head(&stack->wait_q) == NULL);
+	CHECKIF(z_waitq_head(&stack->wait_q) != NULL) {
+		return -EAGAIN;
+	}
 
 	if ((stack->flags & K_STACK_FLAG_ALLOC) != (u8_t)0) {
 		k_free(stack->base);
 		stack->base = NULL;
 		stack->flags &= ~K_STACK_FLAG_ALLOC;
 	}
+	return 0;
 }
 
-void z_impl_k_stack_push(struct k_stack *stack, stack_data_t data)
+int z_impl_k_stack_push(struct k_stack *stack, stack_data_t data)
 {
 	struct k_thread *first_pending_thread;
 	k_spinlock_key_t key;
 
-	__ASSERT(stack->next != stack->top, "stack is full");
+	CHECKIF(stack->next == stack->top) {
+		return -ENOMEM;
+	}
 
 	key = k_spin_lock(&stack->lock);
 
@@ -109,22 +114,21 @@ void z_impl_k_stack_push(struct k_stack *stack, stack_data_t data)
 		z_thread_return_value_set_with_data(first_pending_thread,
 						   0, (void *)data);
 		z_reschedule(&stack->lock, key);
-		return;
 	} else {
 		*(stack->next) = data;
 		stack->next++;
 		k_spin_unlock(&stack->lock, key);
 	}
 
+	return 0;
 }
 
 #ifdef CONFIG_USERSPACE
-static inline void z_vrfy_k_stack_push(struct k_stack *stack, stack_data_t data)
+static inline int z_vrfy_k_stack_push(struct k_stack *stack, stack_data_t data)
 {
 	Z_OOPS(Z_SYSCALL_OBJ(stack, K_OBJ_STACK));
-	Z_OOPS(Z_SYSCALL_VERIFY_MSG(stack->next != stack->top,
-				    "stack is full"));
-	z_impl_k_stack_push(stack, data);
+
+	return z_impl_k_stack_push(stack, data);
 }
 #include <syscalls/k_stack_push_mrsh.c>
 #endif