On 04/14, Christian Brauner wrote: > > @@ -2260,6 +2363,10 @@ long _do_fork(unsigned long clone_flags, > } > > put_pid(pid); > + > + if (clone_flags & CLONE_PIDFD) > + nr = pidfd; > + Well, this doesn't look nice ... CLONE_PARENT_SETTID doesn't look very usefule, so what if we add if ((clone_flags & (CLONE_PIDFD|CLONE_PARENT_SETTID)) == (CLONE_PIDFD|CLONE_PARENT_SETTID)) return ERR_PTR(-EINVAL); at the start of copy_process() ? Then it can do if (clone_flags & CLONE_PIDFD) { retval = pidfd_create(pid, &pidfdf); if (retval < 0) goto bad_fork_free_pid; retval = put_user(retval, parent_tidptr) if (retval < 0) goto bad_fork_free_pid; } Oleg.