title: Is it okay to pass strings from user memory to printk?
body: <p>I am new to kernel programming, and confused about how you should handle data in user memory. If I confirm that the return value of <code>strlen_user(user_str)</code> does not equal zero, is it okay to pass user_str to <code>printk</code> , or should I always copy <code>user_str</code> to kernel memory instead?</p>