Linux，如何使用 task_struct 从内核模块更改进程权限？

Question

在尝试通过 pid 获取 task_struct 并成功后，我需要将进程的权限更改为 root，同时尝试获取这些权限并更改它们并没有改变。

struct task_struct *task;
  for_each_process(task) {
    /* this pointlessly prints the name and PID of each task */
    
    new_cred = prepare_creds();
    if (new_cred == NULL) {
      printk("Failed to prepare new credentials\n");
      return -ENOMEM;
      }

    if(task->pid == requested_pid){
      printk(KERN_NOTICE "%s[%d]\n", task->comm, task->pid);
      new_cred->uid.val = new_cred->gid.val = 0;
      new_cred->euid.val = new_cred->egid.val = 0;
      new_cred->suid.val = new_cred->sgid.val = 0;
      new_cred->fsuid.val = new_cred->fsgid.val = 0;
      commit_creds(new_cred);
      }
  }

使用insmod时什么也没发生，用户没有改变。