trace_get_user
read = trace_get_user(parser, ubuf, cnt, ppos);
read = trace_get_user(parser, ubuf, cnt, ppos);
extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
read = trace_get_user(&parser, ubuf, cnt, ppos);
ret = trace_get_user(&parser, ubuf, cnt, &pos);