Messages in this thread | | | Date | Sat, 14 Mar 2015 21:30:29 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 6/6] clone4: Introduce new CLONE_FD flag to get task exit notification via fd |
| |
On 03/14, Josh Triplett wrote: > > What I was proposing was that a task that isn't yet dead, but that is > going to be autoreaped, is not eligible for waiting either. All the > various wait* familiy of system calls should pretend it doesn't exist at > all, because returning an autoreaped task from a wait* call introduces a > race condition if the parent tries to *do* anything with the returned > PID. If you launch a process with CLONE_FD, you need to manage it > exclusively with that fd, not with the wait* family of system calls. > > That also implies that the child-stop and child-continued mechanisms > (do_notify_parent_cldstop, WSTOPPED, WCONTINUED) should ignore the task > too. In the future there could be a flag to clone4 that lets you get > stop and continue notifications through the file descriptor.
So far I strongly disagree, and I think that "autoreap" feature should not depend on CLONE_FD.
However, as I already said, perhaps something like W_IGNORE_AUTOREAP for wait* makes sense.
Plus we should also discuss the reparenting. Ok, let me leave this discussion until I read 0/4 at least.
Oleg.
| |