Re: [Devel] [PATCH] Allow signalling container-init

[Daniel Pittman <daniel-zvVxMF7wGoXk1uMJSBkQmQ@public.gmane.org>]

sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org writes:

> Should we include this in the patchset ?

[...]

> Only the global-init process must be special - any other
> container-init process must be killable to prevent run-away processes
> in the system.

One problem I hit while using OpenVZ is that some init processes --
notable upstart used by Ubuntu -- depend on the special signal processing
extended to init by the kernel.

The problem here was that a signal the kernel would otherwise have
blocked was sent to upstart, the default handler was invoked and init
was terminated.

> TODO:	Ideally we should allow killing the container-init only from
> 	ancestor containers and prevent it being killed from that or
> 	descendant containers.  But that is a more complex change and
> 	will be addressed by a follow-on patch. For now allow the
> 	container-init to be terminated by any process with sufficient
> 	privileges.

This will break, as far as I can see, by allowing the container root to
send signals to init that it doesn't expect.

Regards,
        Daniel
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