Re: [PATCH 03/10] ptrace: implement PTRACE_SEIZE

From: Oleg Nesterov
Date: Mon May 23 2011 - 09:11:27 EST

On 05/19, Tejun Heo wrote:
> Hello,
> On Wed, May 18, 2011 at 11:55:39AM +0200, Tejun Heo wrote:
> > I've been thinking about Jan's suggestion to make ATTACH and DETACH
> > not require tracee to trap. We already have this for DETACH for cases
> > where the tracer is killed and it seems it wouldn't be too difficult
> > to make that happen for ATTACH either and for that to be truly useful
> > I suppose PTRACE_SETOPTIONS shouldn't require trapped state either.
> > Jan, would that be enough for the use cases you have on mind?
> I've been trying this and clean DETACH requires the tracee to be
> trapped (or not running). The arch detach hook, which BTW is not
> executed when the tracer is killed, modifies tracee state expecting it
> to be off-cpu.

Argh. Yes, ptrace_disable() is the problem, I didn't think about it :/


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