Re: [RFC PATCH v4 06/17] vsock: check error queue to set EPOLLERR

[Stefano Garzarella]

On Tue, Jun 27, 2023 at 07:44:25AM +0300, Arseniy Krasnov wrote:
> On 26.06.2023 19:04, Stefano Garzarella wrote:
> > On Sat, Jun 03, 2023 at 11:49:28PM +0300, Arseniy Krasnov wrote:
> > > If socket's error queue is not empty, EPOLLERR must be set. Otherwise,
> > > reader of error queue won't detect data in it using EPOLLERR bit.
> > >
> > > Signed-off-by: Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx>
> > > ---
> > > net/vmw_vsock/af_vsock.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > This patch looks like it can go even without this series.
> >
> > Is it a fix? Should we add a fixes tag?
>
> Yes, it is fix and I can exclude it from this set to reduce number
> of patches, but there is no reproducer for this without MSG_ZEROCOPY
> support - at this moment this feature is the only user of error queue
> for AF_VSOCK.

Okay, so it's fine to keep it here, but please mention in the comment 
that without MSG_ZEROCOPY it can't be reproduced.

That way we know that we don't have to backport into the stable 
branches.

Thanks,
Stefano

> Thanks, Arseniy
>
> > Thanks,
> > Stefano
> >
> > > diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> > > index efb8a0937a13..45fd20c4ed50 100644
> > > --- a/net/vmw_vsock/af_vsock.c
> > > +++ b/net/vmw_vsock/af_vsock.c
> > > @@ -1030,7 +1030,7 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
> > >     poll_wait(file, sk_sleep(sk), wait);
> > >     mask = 0;
> > >
> > > -    if (sk->sk_err)
> > > +    if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
> > >         /* Signify that there has been an error on this socket. */
> > >         mask |= EPOLLERR;
> > >
> > > -- 
> > > 2.25.1