Re: unshare() pid ns

[Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>]

Serge E. Hallyn wrote:
> Quoting Pavel Emelyanov (xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org):
>> sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org wrote:
>>> Pavel,
>>> unshare() of pid ns seems to fail with -EINVAL in 2.6.23-rc3-mm1.
>>> I thought we supported it in the earlier patchsets.  I guess
>>> I missed that in the review of recent patchsets.
>> I disabled unsharing of pid namespaces because it's almost
>> impossible. Look - you have to reattach all the pids to the
>> task with saving its ids as seen in previous namespaces.
> 
> We agree, but thought you for some perverse reason preferred unshare to
> clone for pidns :)

I did that in my first version of patches, but then realized
that such problem (the need in reattaching pids) makes the
unsharing ugly.

BTW, unsharing of a pid namespace is a valid operation, so I
think I will enable it in the nearest future. I have some
thought on how to make such a reattach ;)

> Thanks for clarifying.
> 
> -serge
>