On Sun, Aug 16, 2020 at 11:15 AM Eric Dumazet [off-list ref] wrote:

1) You also ignored what would happen at accept() time.

Please test your patches with ASAN.

Ouch, I will look into it - thanks for pointing that out & 3/

2) Also, why is that description specific to sockets ?

fcntl on struct file was deemed too intrusive - as far as fds are
concerned, regular files and pipes have names and local processes to
match against anyway
we're left with mostly remote targets - one example was to preserve
target host names after resolution (alas, I don't think there's a
clean flow to hook that transparently)