Re: [PATCH v2 0/5] pid: add pidfd_open()

[Christian Brauner]

On Sat, Mar 30, 2019 at 09:34:02AM -0700, Daniel Colascione wrote:
> On Sat, Mar 30, 2019 at 9:24 AM Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Sat, Mar 30, 2019 at 9:19 AM Christian Brauner <christian@xxxxxxxxxx> wrote:
> > >
> > > From pure API perspective that's all I care about: independence of procfs.
> > > Once we have pidfd_open() we can cleanly signal threads etc.
> >
> > But "independence from procfs" means that you damn well don't then do
> > "oh, now I have a pidfd, I want to turn it into a /proc fd and then
> > munge around there".
> >
> > So I'm literally saying that it had better really *be* independent
> > from /proc. It is the standalone version, but it's most definitely
> > also the version that doesn't then give you secret access to /proc.
> 
> Just to be clear, I'm not proposing granting secret access to procfs,
> and as far as I can see, nobody else is either. We've been talking
> about making it easier to avoid races when you happen to want a pidfd
> and a procfs fd that point to the same process, not granting access
> that you didn't have before. If you'd rather not connect procfs and
> pidfds, we can take this functionality off the table.

This is dead! Nothing like this will make it through this tree. I have
no intention of endangering pidfd_send_signal().

Christian