From: Deepa Dinamani
> Sent: 24 May 2019 18:02
...
> Look at the code before 854a6ed56839a:
>
> /*
> * If we changed the signal mask, we need to restore the original one.
> * In case we've got a signal while waiting, we do not restore the
> * signal mask yet, and we allow do_signal() to deliver the signal on
> * the way back to userspace, before the signal mask is restored.
> */
> if (sigmask) {
> ####### This err has not been changed since ep_poll()
> ####### So if there is a signal before this point, but
> err = 0, then we goto else.
> if (err == -EINTR) {
> memcpy(¤t->saved_sigmask, &sigsaved,
> sizeof(sigsaved));
> set_restore_sigmask();
> } else
> ############ This is a problem if there is signal
> pending that is sigmask should block.
> ########### This is the whole reason we have
> current->saved_sigmask?
> set_current_blocked(&sigsaved);
> }
What happens if all that crap is just deleted (I presume from the
bottom of ep_wait()) ?
I'm guessing that on the way back to userspace signal handlers for
signals enabled in the process's current mask (the one specified
to epoll_pwait) get called.
Then the signal mask is loaded from current->saved_sigmask and
and enabled signal handlers are called again.
No special code there that depends on the syscall result, errno
of the syscall number.
That seems exactly correct!
David
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