Re: [PATCH 1/1] pid_ns: move pid_ns_release_proc() fromproc_flush_task() to zap_pid_ns_processes()

From: Oleg Nesterov
Date: Thu Jun 24 2010 - 09:01:31 EST


On 06/23, Sukadev Bhattiprolu wrote:
>
> Oleg Nesterov [oleg@xxxxxxxxxx] wrote:
> | This is mostly cleanup and optimization, but also fixes the bug.
> |
> | proc_flush_task() checks upid->nr == 1 to detect the case when
> | a sub-namespace exits. However, this doesn't work in case when
> | a multithreaded init execs and calls release_task(old_leader),
> | the old leader has the same pid 1.
> |
> | Move pid_ns_release_proc() to zap_pid_ns_processes(), it is called
> | when we know for sure that init is exiting.
>
> Hmm, I almost agreed, but have a question :-)
>
> Yes, we know that the container-init is exiting. But if its parent (in
> the parent ns) waits on it and calls release_task(), won't we call
> proc_flush_task_mnt() on this container-init ? This would happen after
> dropping the mnt in zap_pid_ns_processes() no ?

Indeed. Thanks!

Somehow I forgot that init itself has not passed proc_flush_task().

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/