Re: [PATCH 2/6] kernel: add task_sigpending() helper

Oleg Nesterov
2020-10-08T13:24:52Z

On 10/05, Jens Axboe wrote:
>
> @@ -4447,7 +4447,7 @@ SYSCALL_DEFINE0(pause)
> __set_current_state(TASK_INTERRUPTIBLE);
> schedule();
> }
> - return -ERESTARTNOHAND;
> + return task_sigpending(current) ? -ERESTARTNOHAND : -ERESTARTSYS;
> }
>
> #endif
> @@ -4462,7 +4462,7 @@ static int sigsuspend(sigset_t *set)
> schedule();
> }
> set_restore_sigmask();
> - return -ERESTARTNOHAND;
> + return task_sigpending(current) ? -ERESTARTNOHAND : -ERESTARTSYS;
> }

Both changes are equally wrong. Why do you think sigsuspend() should ever
return -ERESTARTSYS ?

If get_signal() deques a signal, handle_signal() will restart this syscall
if ERESTARTSYS, this is wrong.

Oleg.