Merge tag 'pidfd.v5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

Pull pidfd fix from Christian Brauner:
"This fixes a problem reported by lockdep when installing a pidfd via
fd_install() with siglock and the tasklisk write lock held in
copy_process() when calling clone()/clone3() with CLONE_PIDFD.

Originally a pidfd was created prior to holding any of these locks but
this required a call to ksys_close(). So quite some time ago in
6fd2fe494b17 ("copy_process(): don't use ksys_close() on cleanups") we
switched to a get_unused_fd_flags() + fd_install() model.

As part of that we moved fd_install() as late as possible. This was
done for two main reasons. First, because we needed to ensure that we
call fd_install() past the point of no return as once that's called
the fd is live in the task's file table. Second, because we tried to
ensure that the fd is visible in /proc/<pid>/fd/<pidfd> right when the
task is visible.

This fix moves the fd_install() to an even later point which means
that a task will be visible in proc while the pidfd isn't yet under
/proc/<pid>/fd/<pidfd>.

While this is a user visible change it's very unlikely that this will
have any impact. Nobody should be relying on that and if they do we
need to come up with something better but again, it's doubtful this is
relevant"

* tag 'pidfd.v5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
copy_process(): Move fd_install() out of sighand->siglock critical section