Re: [RFC] [PATCH 00/19] Non disruptive application core dump infrastructureusing task_work_add()

[Janani Venkataraman1]

From:	Tejun Heo <tj@xxxxxxxxxx>
To:	Pavel Emelyanov <xemul@xxxxxxxxxxxxx>,
Cc:	Janani Venkataraman1/India/IBM@IBMIN,
            linux-kernel@xxxxxxxxxxxxxxx, amwang@xxxxxxxxxx,
            rdunlap@xxxxxxxxxxxx, andi@xxxxxxxxxxxxxx,
            aravinda@xxxxxxxxxxxxxxxxxx, hch@xxxxxx, mhiramat@xxxxxxxxxx,
            jeremy.fitzhardinge@xxxxxxxxxx, suzuki@xxxxxxxxxxxxxxxxxx,
            kosaki.motohiro@xxxxxxxxxxxxxx, adobriyan@xxxxxxxxx,
            tarundsk@xxxxxxxxxxxxxxxxxx, vapier@xxxxxxxxxx,
            roland@xxxxxxxxxxxxx, ananth@xxxxxxxxxxxxxxxxxx,
            gorcunov@xxxxxxxxxx, avagin@xxxxxxxxxx, oleg@xxxxxxxxxx,
            eparis@xxxxxxxxxx, d.hatayama@xxxxxxxxxxxxxx,
            james.hogan@xxxxxxxxxx, akpm@xxxxxxxxxxxxxxxxxxxx,
            torvalds@xxxxxxxxxxxxxxxxxxxx
Date:	10/08/2013 12:26 AM
Subject:	Re: [RFC] [PATCH 00/19] Non disruptive application core dump
            infrastructure using task_work_add()
Sent by:	Tejun Heo <htejun@xxxxxxxxx>



Hello,

On Fri, Oct 04, 2013 at 02:38:43PM +0400, Pavel Emelyanov wrote:
> > * It is not upstream yet.
>
> It is, starting from criu-v0.7 + linux-3.11
>
> > * There are concerns about the security of the dump.
>
> Can you elaborate on this? Is it fixable in CRIU at all?
>
> > * It involves a lot of changes and this approach provides a UNIX style
> >   interface.
>
> Can you also shed more light on this -- what changes do you mean?

Yeah, I'd like to hear more too.  It doesn't make much sense to me to
add something completely new if it can be served mostly by the
existing infrastructure.  Also, what do you mean by "disruption"?  You
mentioned signal but PTRACE_SEIZE is completely transparent
w.r.t. signals. If you mean without stopping the target process's
execution, what are you trying to use the dumping for and how much
gain are we talking about?  Also, isn't it kinda mandatory to stop the
process to get a consistent dump?  What am I missing here?

By disruption we do mean not using signals. PTRACE_SEIZE doesn't use
signals,
but the concern is, a seize can't be done on oneself and we are looking at
also
a self dump.

Thanks.
Janani

Thanks.

--
tejun



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