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Date: Fri, 20 Mar 2015 20:09:14 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Thiago Macieira <thiago.macieira@intel.com>
Cc: Josh Triplett <josh@joshtriplett.org>, Al Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
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Subject: Re: [PATCH v2 5/7] clone4: Add a CLONE_AUTOREAP flag to
	automatically reap the child process
Message-ID: <20150320190914.GA28357@redhat.com>
References: <cover.1426376419.git.josh@joshtriplett.org> <20150315233439.GA31890@thin> <20150320181404.GA26343@redhat.com> <1766646.jusoNDOCPE@tjmaciei-mobl4>
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On 03/20, Thiago Macieira wrote:
>
> On Friday 20 March 2015 19:14:04 Oleg Nesterov wrote:
> > Also. I forgot that the kernel always resets ->exit_signal to SIGCHLD on
> > exec or reparenting. Reparenting is probably fine. But what about exec?
> > Should it keep ->exit_signal == 0 if "autoreap" ? I think it should not, to
> > avoid the strange special case.
>
> Not delivering any signal was the objective of this patch series, so yes
> exit_signal == 0 should survive an exec and even re-exec.

OK, but then perhaps we should never send SIGCHLD (on exit) if "autoreap",
to make the logic simple.

And copy_process() should probably do

	if ((clone_flags & CSIGNAL) && (clone_flags && CLONE_AUTOREAP))
		return -EINVAL;

so that we still can change this behaviour later.

Oleg.