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Subject: Re: [PATCH 4/8] coredump_wait: don't call complete_vfork_done()
From: Matt Fleming <matt.fleming@linux.intel.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Roland McGrath <roland@hack.frob.com>, Tejun Heo <tj@kernel.org>,
        Denys Vlasenko <dvlasenk@redhat.com>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        linux-kernel@vger.kernel.org
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Date: Fri, 29 Jul 2011 16:26:15 +0100
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On Fri, 2011-07-29 at 16:25 +0200, Oleg Nesterov wrote:
>
> Please note that if ->vfork_done != NULL, then ->real_parent shares
> ->mm with us, by definition of CLONE_VFORK.
> 
> In this case, with or without this patch, the parent was already
> killed by zap_threads(). It can never do wait() or something else.
> 
> However. before 3/8, it was necessary to wakeup the TASK_UNINTERRUPTIBLE
> parent, otherwise we deadlock. Once again, it can't do anything,
> it will die immediately because of fatal_signal_pending().

D'oh, yes. I see now, thanks!