On Thu, Jul 25, 2019 at 12:35:44PM +0200, Oleg Nesterov wrote: > On 07/24, Christian Brauner wrote: > > > > If CLONE_WAIT_PID is set the newly created process will not be > > considered by process wait requests that wait generically on children > > such as: > > I have to admit this feature looks a bit exotic to me... It might look like it from the kernels perspective but from the feedback on this when presenting on this userspace has real usecases for this. > > > --- a/kernel/exit.c > > +++ b/kernel/exit.c > > @@ -1019,6 +1019,9 @@ eligible_child(struct wait_opts *wo, bool ptrace, struct task_struct *p) > > if (!eligible_pid(wo, p)) > > return 0; > > > > + if ((p->flags & PF_WAIT_PID) && (wo->wo_type != PIDTYPE_PID)) > > + return 0; > > Even if ptrace == T ? > > This doesn't look right. Say, strace should work even if its tracee (or > one of the tracees) has PF_WAIT_PID. As in if (!ptrace && (p->flags & PF_WAIT_PID) && (wo->wo_type != PIDTYPE_PID)) return 0; Sure, we can allow that. Christian
