Re: [PATCH] pidfd: add ioctl to retrieve pid info

From: Oleg Nesterov
Date: Fri Oct 04 2024 - 16:08:44 EST


I wasn't CC'ed, so I didn't see the patch, but looking at Christian's
reply ...

On 10/04, Luca Boccassi wrote:
> On Fri, 4 Oct 2024 at 10:29, Christian Brauner <brauner@xxxxxxxxxx> wrote:
> >
> > On Wed, Oct 02, 2024 at 03:24:33PM GMT, luca.boccassi@xxxxxxxxx wrote:
> > > + info.pid = pid_nr_ns(pid, task_active_pid_ns(task));
> >
> > I think this is wrong what this should return is the pid of the process
> > as seen from the caller's pid namespace.

Agreed,

> Thanks for the review, I applied the rest of the comments in v2 (I
> think at least), but for this one I can't tell, how should I do it?

I guess Christian meant you should simply use

info.pid = task_pid_vnr(task);

task_pid_vnr(task) returns the task's pid in the caller's namespace.

Oleg.