Re: [PATCH] ptrace: take into account saved_sigmask in PTRACE_{GET,SET}SIGMASK

[Oleg Nesterov]

On 11/19, Andrei Vagin wrote:
>
>  	case PTRACE_SETSIGMASK: {
>  		sigset_t new_set;
> @@ -962,6 +971,8 @@ int ptrace_request(struct task_struct *child, long request,
>  		child->blocked = new_set;
>  		spin_unlock_irq(&child->sighand->siglock);
>
> +		clear_tsk_restore_sigmask(child);
> +

I am not sure I understand this change...

I forgot everything I knew about criu, but iiuc PTRACE_SETSIGMASK is used
at "restore" time, doesn't this mean that TIF_RESTORE_SIGMASK/restore_sigmask
can not be set?

IOW, could you please explain how PTRACE_SETSIGMASK should be used, and why
it doesn't do something like

	if (test_tsk_restore_sigmask(child))
		child->saved_sigmask = new_set;
	else
		child->blocked = new_set;

which looks symmetrical to PTRACE_GETSIGMASK?

Oleg.