Deepa Dinamani <deepa.kernel@xxxxxxxxx> wrote:
> So here is my analysis:
<snip everything I agree with>
> So the 854a6ed56839a40f6 seems to be better than the original code in
> that it detects the signal.
OTOH, does matter to anybody that a signal is detected slightly
sooner than it would've been, otherwise?
> But, the problem is that it doesn't
> communicate it to the userspace.
Yup, that's a big problem :)
> So a patch like below solves the problem. This is incomplete. I'll
> verify and send you a proper fix you can test soon. This is just for
> the sake of discussion:
>
> diff --git a/fs/eventpoll.c b/fs/eventpoll.c
> index 4a0e98d87fcc..63a387329c3d 100644
> --- a/fs/eventpoll.c
> +++ b/fs/eventpoll.c
> @@ -2317,7 +2317,7 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct
> epoll_event __user *, events,
> int, maxevents, int, timeout, const sigset_t __user *, sigmask,
> size_t, sigsetsize)
> {
> - int error;
> + int error, signal_detected;
> sigset_t ksigmask, sigsaved;
>
> /*
> @@ -2330,7 +2330,10 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct
> epoll_event __user *, events,
>
> error = do_epoll_wait(epfd, events, maxevents, timeout);
>
> - restore_user_sigmask(sigmask, &sigsaved);
> + signal_detected = restore_user_sigmask(sigmask, &sigsaved);
> +
> + if (signal_detected && !error)
> + return -EITNR;
>
> return error;
Looks like a reasonable API.
> @@ -2862,7 +2862,7 @@ void restore_user_sigmask(const void __user
> *usigmask, sigset_t *sigsaved)
> if (signal_pending(current)) {
> current->saved_sigmask = *sigsaved;
> set_restore_sigmask();
> - return;
> + return 0;
Shouldn't that "return 1" if a signal is pending?
