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Date: Tue, 23 Jul 2013 18:43:05 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: Mike Galbraith <bitbucket@online.de>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: ptrace(PTRACE_ATTACH)  [no intervering wait]
	ptrace(PTRACE_DETACH) may leave tracee stuck
Message-ID: <20130723164305.GA28460@redhat.com>
References: <1374573914.30532.68.camel@marge.simpson.net> <20130723155854.GA26211@redhat.com> <20130723163806.GA27905@redhat.com>
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Damn. Sorry for noise Mike,

On 07/23, Oleg Nesterov wrote:
>
> OTOH, in this particular case pldd.c doesn't really need PTRACE_DETACH,
> it can simply exit.

No it can't, I forgot that exit_ptrace() doesn't (and can't) clear
->exit_code. And this is another reason why PTRACE_DETACH needs the
stopped tracee.

Oleg.