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From: Roland McGrath <roland@redhat.com>
To: Oleg Nesterov <oleg@redhat.com>
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Cc: Andrew Morton <akpm@linux-foundation.org>,
       Christoph Hellwig <hch@infradead.org>, Ingo Molnar <mingo@elte.hu>,
       Pavel Emelyanov <xemul@openvz.org>,
       Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] ptrace: do_notify_parent_cldstop: fix the wrong
	->nsproxy usage
In-Reply-To: Oleg Nesterov's message of  Thursday, 28 May 2009 01:12:48 +0200 <20090527231248.GB10032@redhat.com>
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X-Windows: you'll envy the dead.
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Date: Wed, 27 May 2009 16:26:17 -0700 (PDT)
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> No, task_pid_vnr(current) in ptrace_notify() is not right. If the tracer
> does PTRACE_GETSIGINFO it gets the wrong .si_pid.

I don't follow.  PTRACE_GETSIGINFO gets the tracee's siginfo_t data--modulo
32/64 conversions it's the data structure the tracee process sees on its
stack when running a handler.  It's not like a signal sent into the
tracer's queue (like SIGCHLD in do_notify_*), where the kernel doing
translation to the tracer's context makes sense.  It's more like some
memory you read from the tracee.


Thanks,
Roland