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

From: Aleksa Sarai
Date: Thu May 16 2019 - 10:58:33 EST


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 and their pid will be recycled
before you do pidfd_open(). CLONE_PIDFD removes the race completely.

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

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