Re: [PATCH v1 1/2] pid: add pidfd_open()

[Aleksa Sarai <cyphar@xxxxxxxxxx>]

On 2019-05-16, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
> On 05/17, Aleksa Sarai wrote:
> > On 2019-05-16, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
> > > On 05/16, Christian Brauner wrote:
> > > > With the introduction of pidfds through CLONE_PIDFD it is possible to
> > > > created pidfds at process creation time.
> > >
> > > Now I am wondering why do we need CLONE_PIDFD, you can just do
> > >
> > > 	pid = fork();
> > > 	pidfd_open(pid);
> >
> > While the race window would be exceptionally short, there is the
> > possibility that the child will die
>
> Yes,
>
> > and their pid will be recycled
> > before you do pidfd_open().
>
> No.
>
> Unless the caller's sub-thread does wait() before pidfd_open(), of course.
> Or unless you do signal(SIGCHILD, SIG_IGN).

What about CLONE_PARENT?

-- 
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>

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