Date: Tue, 20 Jan 2009 19:05:00 -0800
From: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: oleg@redhat.com, ebiederm@xmission.com, roland@redhat.com,
       bastian@waldi.eu.org, daniel@hozac.com, xemul@openvz.org,
       containers@lists.osdl.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/7][v7] Container-init signal semantics
Message-ID: <20090121030500.GA32138@us.ibm.com>
References: <20090117202638.GA11825@us.ibm.com> <20090119110906.58ccbcbd.kamezawa.hiroyu@jp.fujitsu.com>
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KAMEZAWA Hiroyuki [kamezawa.hiroyu@jp.fujitsu.com] wrote:
| On Sat, 17 Jan 2009 12:26:38 -0800
| Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> wrote:
| 
| > 
| > Container-init must behave like global-init to processes within the
| > container and hence it must be immune to unhandled fatal signals from
| > within the container (i.e SIG_DFL signals that terminate the process).
| > 
| > But the same container-init must behave like a normal process to 
| > processes in ancestor namespaces and so if it receives the same fatal
| > signal from a process in ancestor namespace, the signal must be
| > processed.
| > 
| > Implementing these semantics requires that send_signal() determine pid
| > namespace of the sender but since signals can originate from workqueues/
| > interrupt-handlers, determining pid namespace of sender may not always
| > be possible or safe.
| > 
| 
| Is this feature is for blocking signals from children to name-space
| creator(owner) ?  And automatically used when namespace/cgroup is created ?
| IOW, Container-init is Namespace-Cgroup-init ? 

I am not sure what "Namespace-cgroup-init refers" to.

But, yes, this patchset applies to the first process in a pid namespace
i.e the child of clone(NEWPID) call.

| 
| I'm glad if you add some documentation updates about how-it-works to patch set.

Yes,  when the patchset is accepted, I am planning to add some notes to
/sbin/init man page. 

Thanks,

Sukadev
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