28  * stack frame (if possible).
31  *	NOT_STACK: not at all on the stack
32  *	GOOD_FRAME: fully within a valid stack frame
33  *	GOOD_STACK: within the current stack (when can't frame-check exactly)
34  *	BAD_STACK: error condition (invalid stack position or bad stack frame)
38 	const void * const stack = task_stack_page(current);  in check_stack_object()  local
39 	const void * const stackend = stack + THREAD_SIZE;  in check_stack_object()
42 	/* Object is not on the stack at all. */  in check_stack_object()
43 	if (obj + len <= stack || stackend <= obj)  in check_stack_object()
47 	 * Reject: object partially overlaps the stack (passing the  in check_stack_object()
48 	 * check above means at least one end is within the stack,  in check_stack_object()
49 	 * so if this check fails, the other end is outside the stack).  in check_stack_object()
51 	if (obj < stack || stackend < obj + len)  in check_stack_object()
55 	ret = arch_within_stack_frames(stack, stackend, obj, len);  in check_stack_object()
59 	/* Finally, check stack depth if possible. */  in check_stack_object()
77  * __check_object_size() function. Normal stack buffer usage should never
208  * - fully contained by stack (or stack frame, when available)
224 	/* Check for bad stack object. */  in __check_object_size()
227 		/* Object is not touching the current process stack. */  in __check_object_size()
234 		 * process stack (when frame checking not available).  in __check_object_size()
238 		usercopy_abort("process stack", NULL, to_user,  in __check_object_size()