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.