Re: [PATCH v2 2/2] pidfd: change pidfd_send_signal() to respect PIDFD_THREAD

[Christian Brauner]

On Wed, Feb 21, 2024 at 01:55:26PM +0100, Oleg Nesterov wrote:
> On 02/21, Christian Brauner wrote:
> >
> > On Tue, Feb 20, 2024 at 05:22:02PM +0100, Oleg Nesterov wrote:
> > >
> > > > > > +       /* Currently unused. */
> > > > > > +       if (info)
> > > > > > +               return -EINVAL;
> > > > >
> > > > > Well, to me this looks like the unnecessary restriction... And why?
> > > >
> > > > Because right now we aren't sure that it's used
> > >
> > > Yes, but...
> > >
> > > > and we aren't sure what use-cases are there.
> > >
> > > the same use-cases as for rt_sigqueueinfo() ?
> >
> > Specifically for pidfd_send_signal() I mean. To me it seems very
> > unlikely that anyone would be opening a pidfd to itself
> 
> Ah, with this, I do agree. And that is why (I think) we can remove
> the "task_pid(current) != pid" check in the "info != NULL" branch.

Ok, so let's try that. :)