On Sat, Mar 30, 2019 at 09:34:02AM -0700, Daniel Colascione wrote:

On Sat, Mar 30, 2019 at 9:24 AM Linus Torvalds
[off-list ref] wrote:

quoted

On Sat, Mar 30, 2019 at 9:19 AM Christian Brauner [off-list ref] wrote:

quoted

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